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International audience; Green roofs recover green spaces in urban areas and benefit the public, farmers, and wildlife by providing many environmental, ecological, and economic advantages. Green roofs reduce stormwater runoff, mitigate urban heat island effects, absorb dust and smog, sequester carbon dioxide, produce oxygen, create space for food production, and provide natural habitat for animals and plants. Here, we studied the environmental impact of green roofs in terms of runoff quality and greenhouse gas CO2 sequestration. We screened more than 650 scientific papers and we reviewed detailed findings from 52 publications. There are two major points: (1) Concerning pollution, the concentrations of minor pollutants, such as heavy metals, biochemical oxygen demand (BOD), total suspended solids (TSS), and turbidity, are small and thus do not pose an immediate threat to the environment. However, the concentrations of major pollutants, such as nitrogen of 0.49–9.01 mg/l and phosphorus of 0.04–25 mg/l, vary highly for different green roofs and can adversely affect runoff quality. Nutrient leaching may be controllable through proper mitigation measures including better design and system management which require further research. According to both laboratory experiments and field monitoring data, the main factors affecting runoff quality are precipitation properties, growth media composition and depth, plant species, and maintenance protocols. Research gaps exist in quantifying how these factors affect leachate pollutant load. Systematic studies are needed for improving green roof designs to reduce adverse impacts. (2) Concerning CO2 sequestration, studies reveal that green roofs directly sequester substantial amounts of carbon in plants and soils through photosynthesis. Green roofs reduce ambient CO2 concentrations in the vicinities. Green roofs also indirectly reduce CO2 releases from power plants and furnaces by reducing demand for heating and cooling, suggesting long-term economic and environmental benefits of green roofs.

International audience; Chemical control has highly expanded over the last 30 years in sub-Saharan Africa to reduce bio-aggressors on all crops. Pest management of fruits and vegetables by small farmers in sub-Saharan Africa have developed anarchically in a fuzzy regulation framework. Pesticide toxicity and excessive application are often criticized both by farmers and consumers. Here, we review pesticide management in sub-Saharan Africa over the past 30 years. We then propose options to improve and reduce pesticide application, in order to decrease environmental and human hazards. The major points are as follows: (1) global changes in sub-Saharan Africa such as urbanization modify farmer practices and crop losses. (2) Pesticides are more and more used by small farmers in an unsustainable way. (3) The risk of pesticide application for human health and environment is poorly known. (4) We propose options to reduce pesticide application based upon integrated pest management (IPM) and agroecology. Moreover, IPM increases farmer economy, thus decreasing poverty.

International audience; Coffee production is impacting the climate by emitting greenhouse gasses. Coffee production is also vulnerable to climate change. As a consequence, the coffee sector is interested in climate-friendly forms of coffee production, but there is no consensus of what exactly this implies. Therefore, we studied two aspects of the climate impact of coffee production: the standing carbon stocks in the production systems and the product carbon footprint, which measures the greenhouse gas emissions per unit weight of coffee produced. We collected data from 116 coffee farms in five Latin American countries, Mexico, Guatemala, Nicaragua, El Salvador, and Colombia, for four coffee production systems: (1) traditional polycultures, (2) commercial polycultures, (3) shaded monocultures, and (4) unshaded monocultures. We found that polycultures have a lower mean carbon footprint, of 6.2–7.3 kg CO2-equivalent kg−1 of parchment coffee, than monocultures, of 9.0–10.8 kg. We also found that traditional polycultures have much higher carbon stocks in the vegetation, of 42.5 Mg per ha, than unshaded monocultures, of 10.5 Mg. We designed a graphic system to classify production systems according to their climate friendliness. We identified several strategies to increase positive and reduce negative climate impacts of coffee production. Strategies include diversification of coffee farms with trees, the use of their wood to substitute for fossil fuel and energy-intensive building materials, the targeted use of fertilizer, and the use of dry or ecological processing methods for coffee instead of the traditional fully washed process.

International audience; In urban agriculture, plant growth is limited by the availability of light. Light emitting diodes (LED) could provide specific quality and quantity of light overcoming existing limitations for normal plant growth. However, there have been very few investigations on the applications of LED in incubators and plant growth chambers. The devices fabricated in this study, were lighted with 100 % red, 100 % blue, 70 % red plus 30 % blue, or 100 % white LED. We cultivated Mentha piperita, Mentha spicata and Mentha longifolia, lentil, basil, and four ornamentals to test the effect of various LED lights on plants productivity compared with field and greenhouse conditions. Our results show that 70/30 % red-blue LED light increased Mentha essential oil yield up to four times along with increases in plant photosynthesis and fresh weight compared with field condition. The red-blue LED incubator also led to a better growth of lentil and basil and to higher flower buds and less days to flowering for pot flowers versus greenhouse conditions. Our findings demonstrate that LED could improve economic characteristics of plant species by probably stimulating plant metabolism.

International audience; Chicken production is popular in Kampala City, Uganda. Indeed about 70 % of all poultry products consumed in Kampala are produced locally. However, the high cost of feed is a major limiting factor. As a consequence, chicken farmers are formulating and mixing their own feeds. However, these own-mixed feeds may not meet recommended nutrient levels. We therefore studied five classes of own-mixed chicken feeds: broiler starter, broiler finisher, chick mash, grower mash, and layer mash. Samples of the chicken feeds were collected from farmers in and around Kampala City. We analyzed crude protein, ether extract, crude fiber, total starch, ash, calcium, phosphorus, and gross energy contents of the feeds. The apparent metabolizable energy content was calculated. We compared data with dietary requirements recommended for chickens in the tropics. Results show that own-mixed rations contained 21.9–36.3 % less protein than minimum recommendations. Broiler rations contained 16.2–20 % less metabolizable energy than minimum recommendations, and their crude fiber content was 37.5–50 % higher than the maximum recommendation. Layer mash contained 66.7 % less calcium and 17.5 % less metabolizable energy than minimum recommendations. All the five classes of own-mixed chicken rations were very high in ash content, ranging from 17.0 to 21.2 %. We conclude that own-mixed chicken rations do not conform to the dietary recommendations. There is therefore a need to give chicken farmers training on feed formulation and mixing.

International audience; Major pests such as blast, sheath blight, bacterial blight, plant hoppers, leaf folder, and stem borers occur in rice paddy fields. These pests cause high damage to the grain and straw yield. The application of high N fertilizer loads increases the predisposition of rice crops to be infected by pests. Many agrochemicals used to control pests lead to pest adaptation and resistance, loss of soil fertility and organic carbon, soil erosion, decreasing biodiversity, and desertification. Chemical fertilizers and pesticides unduly applied also lead to major impact on environment and food safety. Here, we review nonchemicals control methods such as genomic diversity of rice host; cultural practices; physical measures; duck, fish, and bullfrog with rice commensalism; and biogas fermentative liquid and residue. We also discuss the current progress of nonchemical control methods in China.

International audience; Soil salinity and drought are major abiotic factors that limit crop growth and productivity worldwide. Indeed, soil salinity and drought disrupt the cellular ionic and osmotic balance. Although silicon (Si) is generally considered nonessential for plant growth and developments, Si uptake by plants can alleviate both biotic and abiotic stresses. Silicon application could therefore improve crop production under adverse climate and soil conditions. Several reports have reviewed the benefits of silicon application on crop growth, but the mechanisms of silicon action have not been systematically discussed. Here, we review recent advances on silicon uptake, transport, and accumulation in plants and how silicon alleviates salinity toxicity and drought stress. The major points are the following: (1) both passive and active silicon uptake may coexist in plants; (2) although silicon transporters have been identified in some plants, more silicon transporters remain to be identified, and the process of silicon transport needs further clarification; (3) the mechanisms for silicon-mediated tolerance of salinity and drought have been extensively investigated at both physiological and biochemical levels. The physiological aspects include increasing water uptake by roots, maintaining nutrient balance, decreasing water loss from leaves, and promoting photosynthetic rate. At the biochemical level, silicon may improve antioxidant defense abilities by increasing the activities of antioxidant enzymes and the contents of non enzymatic antioxidants; silicon may also contribute to osmotic adjustment and increase photosynthetic enzymatic activities; and (4) silicon can regulate the levels of endogenous plant hormones under stress conditions, whereas silicon involvement in signaling and regulation of gene expression related to increasing stress tolerance remains to be explored.

International audience; Slow-release fertilizers could improve the productivity of field crops and reduce environmental pollution. So far, no slow-release fertilizers are suited for maize cultivation in semiarid areas of China. Therefore, we tested attapulgite-coated fertilizers. Attapulgite-coated fertilizers were prepared by dividing chemical fertilizers into three parts according to the nutrient demand of maize in its three main growth stages and coating each part with a layer of attapulgite. This design is novel and unique, satisfying the demands of maize throughout the whole growing season with slow release of nutrients from the coated layers. A field experiment was conducted in 2010 and 2011, using three fertilizer rates, in kg/ha: 94.22 nitrogen (N) and 22.49 phosphorus (P), 139.09 N and 38.98 P, and 254.23 N and 50.98 P. Five types of fertilizers were compared: 20 and 30 % attapulgite-coated chemical fertilizer, 20 and 30 % attapulgite-mixed chemical fertilizer, and chemical fertilizer only. The results show that the soil mineral N and available P of attapulgite-coated fertilizer has a slow-release behavior that allows a better synchronization between nutrient availability and plant needs. Attapulgite-coated fertilizer increased the grain yield by 15.1–18.4 %. The use of attapulgite-coated fertilizers also improved partial factor productivity of N fertilizer by 10.0–26.7 % and P fertilizer by 11.0–26.7 %, compared with the control fertilized without coated formulates. Given their good performance, the attapulgite-coated fertilizers could be a promising alternative slow-release fertilizer for sustainable agriculture in semiarid areas.

International audience; Rice–prawn farming in Asian countries is a sustainable practice using less fertilizers. Organic farming of rice and giant river prawns in rotational crops was tested in the waterlogged paddy fields of Kuttanad, Kerala as part of the Indian Organic Aquaculture Project. Rice was cultivated during November to February, followed by a crop of freshwater prawns in the same field from March to September. Here, we study the production of four certified farms growing organic rice and organic prawns compared with four conventional farms growing rice and prawns in rotational crops. We evaluate the economic viability by cost-return and partial budgeting analysis. Our results show that farming rice organically reduced yields by 23 %, from 5,690 kg/ha in conventional farming compared to 4,376 kg/ha in organic farming. However, the organic prawn crop yield of 396 kg/ha was 10 % higher than the yield of the conventional system, of 360 kg/ha, although the differences were not significant. Furthermore, total investment for organic rice was approximately 20 % greater than for the non-organic rice crop. Total investment for organic prawns was 17 % greater than for the non-organic prawn crop. Net revenue was 11 % lower for organic rice than for conventional rice. Organic prawns realized 117 % higher net revenue than conventional prawns. Although organic rice farming realized lower returns than conventional, its combination with organic prawn farming enhanced net revenue by 20 % over conventional rice/conventional prawn production.

International audience; Agroecology is a promising alternative to industrial agriculture, with the potential to avoid the negative social and ecological consequences of input-intensive production. Transitioning to agroecological production is, however, a complex project that requires diverse contributions from the outside of scientific institutions. Agroecologists therefore collaborate with traditional producers and agroecological movements. Permaculture is one such agroecological movement, with a broad international distribution and a unique approach to system design. Despite a high public profile, permaculture has remained relatively isolated from scientific research. Though the potential contribution of permaculture to agroecological transition is great, it is limited by this isolation from science, as well as from oversimplifying claims, and the lack of a clear definition. Here, we review scientific and popular permaculture literature. A systematic review discusses quantitative bibliometric data, including keyword analysis. A qualitative review identifies and assesses major themes, proposals, and claims. The manuscript follows a stratified definition of permaculture as design system, best practice framework, worldview, and movement. The major points of our analysis are as follows: (1) Principles and topics largely complement and even extend principles and topics found in the agroecological literature. (2) Distinctive approaches to perennial polyculture, water management, and the importance of agroecosystem configuration exceed what is documented in the scientific literature and thus suggest promising avenues of inquiry. (3) Discussions of practice consistently underplay the complexity, challenges, and risks that producers face in developing diversified and integrated production systems. (4) The movement is mobilizing diverse forms of social support for sustainability, in geographically diverse locations. (5) And scholarship in permaculture has always been a diverse marginal sector, but is growing.

International audience; Intensive irrigated rice-wheat crop systems have caused serious soil depletion and nitrogen loss in the Tai Lake region of China. A possible solution is the incorporation of legumes in rice because legumes are a source of nitrogen. There is actually little knowledge on the impact of legumes on rotation, soil fertility, and nitrogen loss. Therefore, we studied the effect of five rice-based rotations, including rice-wheat, rice-rape, rice-fallow, rice-bean, and rice-vetch, on soil nitrogen, rice yield, and runoff loss. A field experiment was conducted in the Tai Lake region from 2009 to 2012. Crop residues from rape, bean, and vetch were used to partially replace chemical fertilizer in rice. Results show that replacing 9.5–21.4 % of mineral nitrogen fertilizer by residues maintained rice yields of rice-rape, rice-bean, and rice-vetch rotations, compared to the rice-wheat reference. Moreover, using legumes as a winter crop in rice-bean and rice-vetch combinations increased rice grain yield over 5 %, and increased rice residue nitrogen content by 9.7–20.5 %. Nitrogen runoff decreased 30–60 % in rice-rape, rice-bean, and rice-vetch compared with rice-wheat. Soil mineral nitrogen and microbial biomass nitrogen content were also improved by application of leguminous residues.

International audience; Crop residues are essential fertilizer source of low-input farming systems in Sub-Saharan Africa. However, crop residues provide nutrients only if they decompose in the soil. Decomposition is assumed to be very low during the dry season due to the scarcity of water, but there are few quantitative knowledge on decomposition under such conditions. Therefore, we studied the decomposition of legume residues, haricot bean (Phaseolus vulgaris L.), and pigeon pea (Cajanus cajan L. (Millps) using litterbag experiments in two coffee and two crop land agroecosystems of southern Ethiopia. The residues were surface applied and subsoil buried under irrigated and non-irrigated conditions and were then retrieved after 30–180 days. We measured mass loss, decay rate constant (k), and C and N concentrations. Results demonstrate an unexpected high decomposition in seasonal dry soils, even when the litterbags were placed on the soil surface. Interestingly, 89 % of the initial N of pigeon pea and 85 % of haricot bean were released after 150 days, on the average. Thus microbial decomposition is unexpectedly high during the dry season. This finding has implications for the effect of plant residues on the supply of mineral N to crops growing during subsequent wet season.

International audience; Gray mold, caused by Botrytis cinerea, is a common threat for greenhouse production of tomatoes. Control of this disease can be difficult even with chemical treatments, and alternative methods are needed. Nitrogen (N) fertilization is known to modify the impact of pathogens on plants. However, there is scarce knowledge about the effect of fertilization on the efficacy of biocontrol. Here, we studied the effect of N fertilization on biocontrol agents Trichoderma atroviride and Microdochium dimerum that protect tomato against B. cinerea. Plants were grown for 2 months in a greenhouse with a soil-less drip irrigation system. Differential N fertilization (five concentrations of nitrate) was applied for the last 4 weeks prior to leaf pruning, biocontrol agent application, and B. cinerea inoculation. Results show that increasing N fertilization up to 10 mmol/L reduced disease by half for controls. High N fertilization also increased biocontrol, with a protection index rising from nearly 0 to up to 100 % depending on the biocontrol agent and the pressure of the pathogen. Indeed, high N fertilization delayed stem symptoms and slowed lesion expansion. To our knowledge, this is the first report of an effect of N fertilization on the efficacy of biocontrol against an airborne disease. Therefore, adapting N fertilization is a promising technique to protect greenhouse tomato.

International audience; Multifunctional agriculture is the core of sustainable agriculture because the suitable integration of multiple functions is a key for economically viable, environmentally safe, and socially equitable development in rural areas. Past investigations on multifunctional agriculture have mostly focused on the economy of multiple functions. There is scarce knowledge on structural relationships of multifunctional agriculture, notably in rural areas. To fill this gap, we used an analytical actor network to identify the structural relationships. Results show that the average income of farmers increased by 20 % in multifunctional agriculture networks. Results also show that the actor network reached a state of equilibrium. We also build a structural equation model using interviews and participatory observations. Here, we incorporated data from 366 tourists, constituting 87.5 % of those surveyed, and 52 local residents in Dalishu Village of Liaoning Province, China. Networking methods improved the efficiency of multifunctional agriculture by bridging ecology, tourism, society, and land use.

International audience; Animal urban agriculture has a vital role to feed the ever-growing population of African cities. However, there is a lack of knowledge on animal farming, animal feed and manure recycling in cities. Here, we mapped animal farms in Kampala City. We determined the number and type of animals kept. We identified animal feeds and the manure management practices. The results show that animal farms are predominantly located on the periphery of the city. Poultry are the dominant animal species in the city, followed by pigs, cattle, goats and sheep. The most common feedstuffs are fruit and vegetable peel and pasture. Sixty percent of the animal manure is discarded, whereas 32 % is recycled as fertiliser. Therefore, the fertiliser potential of manure is underutilised.

The glyphosate herbicide has been extensively used for long time periods in woody crops to control a broad range of weeds. The rapid determination of resistant weeds in different woody crops could maintain the efficacy of herbicides and could improve weed management using rotating strategies. Unfortunately Sumatran fleabane has developed a resistance to glyphosate. The mechanism of resistance of Sumatran fleabane is unknown so far. Therefore, here, we studied the resistance of a Sumatran fleabane biotype collected from a citrus orchard, under greenhouse and laboratory conditions. Our results show a resistance factor of 7.4. The resistant biotype absorbed and translocated lower amounts of 14C-glyphosate compared to the susceptible biotype. Moreover, at the molecular level, the target site sequence of the EPSPS2 gene showed a Pro-182-Thr substitution in the resistant biotype. As a consequence, this biotype uses mechanisms of reduced absorption-translocation and target site mutation to resist against glyphosate. This is the first study to report the reduced absorption and a mutation in the EPSPS2 gene in the resistance mechanism in the Conyza genus. © 2013 INRA and Springer-Verlag France., The Monsanto Company and Spain’s MICINN Project (AGL2010-16774) supported this research.

International audience; Agricultural intensification has increased crop productivity but decreased agroecosystem services. Agricultural intensification is occurring notably for horticultural crops such as lettuce. In conventional agriculture, lettuce protection is achieved mostly by preventive applications of pesticides with about eight treatments for a 60–90-day-long cycle in the Mediterranean region. However, new sustainable control strategies are needed due to pesticide impact on environment and human health, emerging pesticide resistance, and stricter policies on levels of pesticide residues in food. Here, we review knowledge and methods allowing to grow lettuce with less pesticides. Advances shown are based on pest ecology and pathogen control by the agroecosystem. The major points are as follows: (1) pest and pathogen community composition depends partly on climatic conditions. The identification of pests and pathogens that can threaten the crop is the first step to design innovative lettuce cropping systems less dependent on pesticides. (2) The numerous alternative techniques currently available should be combined to control lettuce pests and pathogens. The effects of alternative techniques on non-target organisms including non-target pests are poorly known so far. (3) Designing sustainable systems requires taking into account ecological interactions and suitability of different management techniques of low impact.

International audience; Rice (Oryza sativa L.) is the premier food crop in the world, being a major staple food for more than half of the world’s population. The potential for a further increase in grain yield will be limited in the future, and more food will need to be produced from the same available arable land. Italy has a long history of rice cultivation, but is now facing challenges to develop new strategies to maintain competitiveness of this sector in the global market. To prepare for the inevitable reduction of both rice prices and incentives from the European Community, and market protection, growers are evaluating the potential of hybrid rice cultivation to increase yields and maintain high quality standards for milling industries. Here we reviewed the characteristics of the Italian rice sector and the first experiences of hybrid cultivation in north Italy during 2012, using them to project the potential challenges and opportunities for both breeders and rice growers. If well managed this technology can represent a solution for sustainable rice production in Italy and in the other European rice growing countries. With hybrid vigor increased yield are obtained from reduced seed rate, lower nitrogen fertilizer, lower reliance on chemical treatments to control diseases, which helps compensate for the increased seed costs. Moreover, partially in contrast with current beliefs, it is shown that it may be possible to produce rice in rather rich countries obtaining a local production.

International audience; Most agronomy practices such as fertilization, irrigation, and soil treatment involve plant root interactions. However, the role of plant roots is rarely assessed during agricultural experiments due to the lack of suitable methods. Plant varieties with a larger root system use soil water and nutrients in dry environments more effectively than varieties with a smaller root system. Such large root varieties can be developed by breeding. Therefore, we evaluated the effects of selection for large or small root systems in 12 barley populations developed via the mutual crossing of four parents in the F3 generation as a response to selection in the preceding F2 generation. Root system size was analyzed by measuring electrical capacitance. Results show that our selection method was effective because the progeny of plants with larger root systems also had larger root systems. Conversely, the progeny of plants with smaller root systems also had smaller root systems. The average differences were +40 and −43 % in the parental segregating generation and +4 and −2 % in the progeny. The root system size impacted the grain yield, which showed a twofold greater response to selection. Indeed, plants with a root system increase of 3.9 % exhibited a yield increase of 8.1 %. Some varieties transmitted larger root systems to their progeny, and some transmitted smaller root systems. Thus, we show that the method used enabled the comparison of root system size in the same crop, in the same soil, and at the same time, which is particularly suitable for selecting root system size in practical breeding. We do not know any other suitable method for the repeated evaluation of intact plants and harvesting of seeds from the selected plants. Root system size has not yet been reported by other authors as a selection criterion in practical breeding, with the exception of root crops such as sugar beet and carrots.

International audience; Mankind is actually facing serious issues due to the overexploitation of fossil fuels, biomass, soils, nitrogen, and phosphorus. It is claimed that biochar addition to soil improves C sequestration to prevent CO2 from atmospheric cycling. Biochar addition should also increase soil fertility in a similar way as anthropogenic dark earths of Central Amazonia. Previous studies have shown that biochar stimulates plant growth and increase fertilizer efficiency, especially when biochar is combined with organic fertilizers such as compost. However, little is known about optimum addition amounts and mixture ratios of biochar and compost. Indeed most experiments to mimic Terra preta de Indio focused on biochar alone or biochar in combination with mineral fertilizers. Therefore, we studied optimum biochar and compost amounts and mixture ratios with respect to plant response and soil fertility. We tested the effect of total amount from 0 to 200 Mg/ha, and biochar proportion from 0 % to 50 % biochar, of 18 different compost mixtures on growth of oat (Avena sativa L.) and soil properties in a fully randomized greenhouse study with sandy and loamy soil substrates. We sampled soil substrates before and after plant growth and analyzed plant growth and yield, total organic carbon (TOC), total nitrogen (TN), mineralized nitrogen (Nmin), soil reaction (pH), and electrical conductivity (EC) applying standard procedures. Results show that biomass production was increased with rising biochar and compost amounts. Oat plant height and seed weight was improved only with rising biochar amounts, but not with compost amounts. This could be explained by increase of total organic C and total N but not by plant-available ammonium and nitrate. The positive influence of composted biochar on plant growth and soil properties suggests that composting is a good way to overcome biochar’s inherent nutrient deficiency, making it a suitable technique helping to refine farm-scale nutrient cycles.

International audience; This article reports a new experimental method to measure plant nitrophily. Knowledge of the nitrophily of plant species has many potential applications such as studying the long-term evolution of flora and designing nitrogen management strategies in cropping systems. Plant nitrophily is commonly measured by the Ellenberg N score based on the natural occurrence of species along soil nitrogen gradients. The Ellenberg N score is known for species from restricted geographical areas representing a small proportion of total plant species diversity. In addition, measuring Ellenberg N score is not convenient. We propose a new definition of plant nitrophily referring to plant leaf area response to nitrogen availability. We compared habitat-based and response-based values of nitrophily to design a simple method to estimate a plant nitrophily index (NI). Eleven monocotyledonous and dicotyledonous plant species were grown in a greenhouse experiment at two levels of soil nitrogen. Nine species were weeds covering the range of the Ellenberg N score. Two crop species with unknown nitrophily, wheat and oilseed rape, were studied to illustrate our method. Plant leaf area was measured at one date for each species × nitrogen treatment combination. A NI was calculated as the ratio of leaf area at high nitrogen to leaf area at low nitrogen. Our results show for weeds a high interspecific diversity of the NI, ranging from 1.0 to 4.2. The NI was strongly and positively correlated to Ellenberg N score, with R 2 of 0.73. The more nitrophilic a species according to habitat preferences, the more leaf area responded to increasing nitrogen supply. This is the first time that a quantitative relationship is found between Ellenberg N score and a growth variable measured non-destructively for both monocotyledonous and dicotyledonous species. Therefore, calculating the response of leaf area to nitrogen supply provides a new simple and non-destructive method that can be used for the assessment of a NI of any species. As an illustration of the method, a NI was estimated for new species. It was at 2.1 and 4.5 for wheat and oilseed rape, respectively, indicating that they were respectively moderately and highly nitrophilic. This method will help to assess the relative nitrophily of weeds vs. crops. Such knowledge could be used to design nitrogen management strategies promoting crop growth but not weed growth, thus reducing the use of herbicides.

International audience; By the year 2050, agriculture will have to provide the food and nutrition requirements of some 9 billion people. Moreover, to maintain that level of productivity indefinitely it must do so using environmentally sustainable production systems. This task will be profoundly complicated by the effects of climate change, increasing competition for water resources and loss of productive lands. Agricultural production methods will also need to recognize and accommodate ongoing rural to urban migration and address a host of economic, ecological and social concerns about the ‘high inputs/high outputs’ model of present-day industrial agriculture. At the same time, there is a need to confront the unacceptable levels of continuing food and nutrition insecurity, greatest in the emerging economy countries of Africa and Asia where poverty, rapid population growth and climate change present additional challenges and where agriculture is practiced primarily by small-scale farmers. Within this context, we here review science-based evidence arguing that diversification with greater use of highly valuable but presently under-valorised crops and species should be an essential element of any model for sustainable smallholder agriculture. The major points of these development opportunity crops are presented in four sections: agricultural farming systems, health and nutrition, environmental sustainability and prosperity of the populations. For each section, these crops and their associated indigenous knowledge are reported to bring benefits and services when integrated with food systems. In this paper, we conclude that not only a change in policy is needed to influence behaviours and practices but also strong leadership able to synergize the various initiatives and implement an action plan.

International audience; Incorporation of spring-applied manure is known to reduce N volatilization losses and hence increase the N value of the manure. However, traditional incorporation methods are not compatible with reduced-tillage systems requiring minimum residue coverage of 30 %. Here, eight New York dairy farms participated in 2008 in a 2-year on-farm trial. This trial was designed to test the hypothesis that shallow mixing of soil involving aerator incorporation of spring-applied manure is as effective as chisel incorporation of manure in conserving manure N for corn (Zea mays, L) uptake while retaining more surface residue. The eight fields selected for this trial varied from first to third year corn after hay and had varying manure histories. All fields were subjected to a randomized complete block design with four replicates comparing surface application of manure, as control, shallow incorporation of manure with an aerator, and chisel incorporation of manure. Starter N applications were 39 kg N/ha or less, and manure application rates ranged from 51 to 112 kL/ha. Results show that shallow incorporation of manure significantly reduced soil disturbance and retained, on average, 30 % more surface residue cover than obtained with chisel incorporation. Chisel and aerator-based incorporation resulted in similar soil nitrate levels at 13 of 16 site years, suggesting similar levels of N conservation. Across all sites and years, incorporation increased silage yield by 0.9–1.5 Mg DM/ha, independent of incorporation method. Based on these results, we show that shallow mixing of soil and spring-applied manure is a suitable option for conserving N and maintaining greater surface residue coverage without compromising on yield or silage quality.

International audience; The growing demand for food poses major challenges to humankind. We have to safeguard both biodiversity and arable land for future agricultural food production, and we need to protect genetic diversity to safeguard ecosystem resilience. We must produce more food with less input, while deploying every effort to minimize risk. Agricultural sustainability is no longer optional but mandatory. There is still an on-going debate among researchers and in the media on the best strategy to keep pace with global population growth and increasing food demand. One strategy favors the use of genetically modified (GM) crops, while another strategy focuses on agricultural biodiversity. Here, we discuss two obstacles to sustainable agriculture solutions. The first obstacle is the claim that genetically modified crops are necessary if we are to secure food production within the next decades. This claim has no scientific support, but is rather a reflection of corporate interests. The second obstacle is the resultant shortage of research funds for agrobiodiversity solutions in comparison with funding for research in genetic modification of crops. Favoring biodiversity does not exclude any future biotechnological contributions, but favoring biotechnology threatens future biodiversity resources. An objective review of current knowledge places GM crops far down the list of potential solutions in the coming decades. We conclude that much of the research funding currently available for the development of GM crops would be much better spent in other research areas of plant science, e.g., nutrition, policy research, governance, and solutions close to local market conditions if the goal is to provide sufficient food for the world’s growing population in a sustainable way.

International audience; Irrigation has a critical role for crop production worldwide. In particular, irrigation is a major issue due to the growing food demand and climate change. Irrigation affects yields and the emission of greenhouse gases such as CO2 and N2O by soils. Here, we review the effect of irrigation on soil organic carbon and N2O emissions. We analysed 22 investigations in various regions of the world. Interactions between irrigation, soil and management factors are described. The main points are: (1) The influence of irrigation is strongly dependent on climate and initial soil organic carbon content. For instance, irrigation of cultivated desert soils led to an average increase of 90 % to over 500 % of soil organic carbon. (2) Irrigation of semiarid regions increases soil organic carbon by 11 % to 35 %. (3) No consistent effects of irrigation were observed in humid regions. In many cases, N2O emissions increase after precipitation or irrigation. (4) Comparison of N2O emissions from irrigated and non-irrigated fields shows that availability of reactive nitrogen compounds controls increased N2O emissions under irrigation, in most cases. Here, increases of about 50 % to 140 % in N2O emissions were reported.

International audience; Sewage sludge, a waste material commonly known as biosolids, has good potential as a valuable agricultural resource, providing that its nutrient imbalances could be overcome. Sewage sludge is rich in phosphorus but low in nitrogen and potassium. Technology exists to supplement sewage sludge with mineral fertilizers, such as urea and muriate of potash as sources of nitrogen and potassium, respectively, to produce an organo-mineral fertilizer with balanced crop nutrient requirements. Here, an experimental plot trial set up in 2008 was established at Broxton, Cheshire, UK, to compare crop yield response for typical crop varieties. Crops included wheat, oilseed rape, barley, beans and forage maize, treated with conventional fertilizer and organo-mineral fertilizer. The organo-mineral fertilizer is a nutrient-balanced sludge-based product produced by drying digested sewage sludge cake at 80 °C in a tumbling evaporator, which produces sludge granules of 3–6 mm in diameter. Analysis was carried out on soil NPK and crop yield. N use efficiency was measured to assess N uptake. Results show that there is no significant difference in crop yield between treatments over the three trial years, with the exception of one crop. This finding demonstrates that the new organo-fertilizer is as efficient as conventional fertilizers. Moreover, levels of heavy metal in soil did not exceed permissible levels. The novelty of this research lies in the fact that it is the first field scale trial of a modified sewage sludge product that has the potential to transform a hitherto waste product into a practical fertilizer product. We conclude that the organo-mineral fertilizer is a promising alternative product for sustainable agriculture.

International audience; The huge research efforts to develop integrated pest management (IPM) have failed to reduce pesticide use and to foster IPM adoption by farmers. Indeed, despite five decades since the concept of integrated control and threshold theory was developed, and four decades since IPM programs have been implemented in USA, Asia, Latin America, Australia, and India, the widespread use of complex IPM practices has not been adopted. This failure can be explained by IPM complexity, policy restrictions, and counteracting forces of the pesticide industry. This article is a study of drivers that rule the adoption or rejection of IPM by 150 farmers from the Indian state of Punjab. Cotton was cultivated under an insecticide resistance management-based IPM program. This program was implemented in Punjab from 2002 to 2007. A rating scale was developed to measure farmers’ perceived attitudes. An adoptability index was developed. Results show that farmers exhibited very different adoption attitudes. Specifically, farmers adopted widely practices that have no complexity, higher economic advantage, and observability. IPM practices with adoptability indices higher than 0.60 have been widely adopted. The predicted adoptability and effective actual adoption of IPM practices were well correlated with a correlation coefficient of 0.88. Technological attributes complexity and relative economic advantage induced a variation of 99 % in the adoptability. Overall the findings show that relative economic advantage, benefit visibility, compatibility with past experiences, and complexity are the most effective drivers in predicting adoption or rejection. Whereas, unexpectedly, socio-personal and economic factors used by most scientists are relatively insignificant. The new methodological frame can be applied to predict the adoption of agricultural innovations.

International audience; Agrobiodiversity can improve the sustainability of cropping systems in a context of low external inputs and unpredictable climate change. Agrobiodiversity strategies to grow wheat are breeding ad hoc cultivars for organic and low-input systems, wheat–legume intercrops and living mulches, cultivar mixtures, and the use of genetically heterogeneous populations. However, applying those strategies can fail due the lack of a well-focused framework. Therefore, we need a better integration between breeding and management and a clear focus on crop traits related to key agroecosystem services. Here, we review the use of agrobiodiversity in wheat production, focusing on breeding and management. We discuss five agroecosystem services: (1) weed reduction, (2) nitrogen use efficiency, (3) abiotic stress tolerance, (4) disease and pest reduction and (5) yield and yield stability. We categorise agrobiodiversity into functional identity, functional composition, and functional diversity, in order to link crop traits to agroecosystem services. Linking crop traits to agroecosystem services could in turn lead to concrete options for farmers and policy. We discuss the relations between crop identity and crop heterogeneity. We also discuss the partitioning of crop heterogeneity between functional composition and functional diversity.

International audience; Agronomists need methodologies to assess the sustainability of cropping systems. Few models such as MASC have been recently developed for evaluation. The effective use of those models is still a challenge, notably for low-input systems. Here a more specific model entitled MASC-OF was developed and applied to study stockless organic cropping systems. The MASC-OF model is original because it is based on agricultural advisers’ needs and expertises. Two groups of advisers supported by agronomic scientists were involved in a nine-step methodology to progress from preliminary meetings to data analysis. The methodology allowed advisers to design a model including their own views on what is a sustainable organic cropping system. Soil fertility and weed and pest control were integrated as a new branch in the original MASC model. We also developed evaluation criteria for each basic attribute, defining aggregation rules and weighting attributes. Tested case studies were based on 44 real cropping systems identified on 19 farms in the Midi-Pyrenees region of France and on 23 cropping system types developed by the advisers from the Centre, Ile-de-France, Pays de Loire, Poitou-Charentes and Rhône-Alpes regions of France. Our results show that a high score of economic sustainability is the most difficult to achieve. This finding is explained by low productivity of cereal crops and high variability of market prices for organic grain. Further, agronomic viability is also difficult to ensure, as a consequence of poor soil-fertility management practices. The ability to achieve social acceptability for the producer, including workload and health risk, is high. By contrast, acceptability for the society has a medium score due to reduced productivity and contribution to local employment. Environmental sustainability is the easiest dimension to achieve, despite nitrogen-loss risks in some situations and high water and energy consumption in irrigated systems. Overall our findings show that the potential for the development of more sustainable organic cropping systems in stockless farms is high.

International audience; This study shows an average yield increase of 415–1,338 kg ha−1 per unit increase of the Shannon diversity index for feed barley cultivar use. There is a global quest to increase food production sustainably. Therefore, judicious farmer choices such as selection of crop cultivars are increasingly important. Cultivar diversity is limited and, as a consequence, corresponding crop yields are highly impacted by local weather variations and global climate change. Actually, there is little knowledge on the relationships between yields of regional crops and cultivar diversity, that is evenness and richness in cultivar use. Here, we hypothesized that higher cultivar diversity is related to higher regional yield. We also assumed that the diversity-yield relationship depends on weather during the growing season. Our data were based on farm yield surveys of feed and malting barley, Hordeum vulgare L.; spring wheat, Triticum aestivum L.; and spring turnip rape, Brassica rapa L. ssp. oleifera, from 1998 to 2009, representing about 4,500–5,500 farms annually. We modeled the relationships between regional yields and Shannon diversity indices in high-yielding (south-west) and low-yielding (central-east) regions of Finland using linear mixed models. Our results show that an increase of Shannon diversity index increases yield of feed barley. Feed barley had also the greatest cultivar diversity. In contrast, an average yield decrease of 1,052 kg ha−1 per unit increase in Shannon index was found for spring rape in 2006 and 2008. Our findings show that cultivar diversification has potential to raise mean regional yield of feed barley. Increasing cultivar diversity thus offers a novel, sustainability-favoring means to promote higher yields.

International audience; The 7 billion global population is projected to grow by 70 million per annum, increasing by 30 % to 9.2 billion by 2050. This increased population density is projected to increase demand for food production by 70 % notably due to changes in dietary habits in developing countries towards high quality food, e.g. greater consumption of meat and milk products and to the increasing use of grains for livestock feed. The availability of additional agricultural land is limited. Any expansion will happen mostly at the expense of forests and the natural habitats containing wildlife, wild relatives of crops and natural enemies of crop pests. Furthermore, more agricultural land will be used to produce bio-based commodities such as biofuel or fibre instead of food. Thus, we need to grow food on even less land, with less water, using less energy, fertiliser and pesticide than we use today. Given these limitations, sustainable production at elevated levels is urgently needed. The reduction of current yield losses caused by pests is a major challenge to agricultural production. This review presents (1) worldwide crop losses due to pests, (2) estimates of pesticide-related productivity, and costs and benefits of pesticide use, (3) approaches to reduce yield losses by chemical, as well as biological and recombinant methods of pest control and (4) the challenges of the crop-protection industry. The general public has a critical function in determining the future role of pesticides in agriculture. However, as long as there is a demand for pesticide-based solutions to pest control problems and food security concerns, the externality problems associated with the human and environmental health effects of pesticides need also to be addressed.

International audience; Composts are potential substitutes of mineral fertilizers for sustainable agriculture. Composts are commonly applied to soil at high dose, e.g. from 20 to 30 t (dry matter) per ha and year, to compensate organic matter loss and nutrient depletion. Recently, amendment of soluble substances from urban compost at a much lower dose of 1.55 t per ha enhanced tomato productivity much more than the compost itself. Here, we studied the effect of soluble substances at 0–700 kg per ha on red pepper. We measured productivity, chlorophyll, and soil chemical composition. The most remarkable result is an observed maximum productivity for only 140 kg per ha of compost soluble substances. The increases amounted to 90 % for the precocious crop yield, to 66 % for the total crop production, and to 17 % for the per fruit weight. The discovery that the highest effects occur at such low treatment dose is very promising to enhance crop productivity in a sustainable way. No detectable change of soil chemical composition was observed.

Agricultural practices affect the physical and chemical characteristics of the soil, which in turn may influence soil microorganisms with consequences on soil biological functioning. However, there is little knowledge on the interactions between agricultural management, soil physicochemical properties, and soil microbial communities, notably in tropical ecosystems with few studies conducted in strongly weathered and acid soils. Here, we investigated the early effect of tillage and crop residues management on top soil physical, chemical, and microbial properties in an acid savannah grassland of northeastern Laos. We initiated a 3-year rotation of rice/corn/soybean under three no-till systems (NTs) distinguished by the cover crops associated prior to and with the main crops, and one conventional tillage-based system (CT). The effect of agricultural management was evaluated 2 years after land reclamation in reference to the surrounding natural pasture (PAS). Our results demonstrate that NTs improve soil physicochemical characteristics (aggregate stability, organic carbon, and cation exchange capacity) as well as microbial abundance (total biomass, bacterial and fungal densities). A significant discrimination of the genetic structure of soil bacterial community was also observed between NTs, CT, and PAS. Interestingly, bacterial abundance and diversity were differently influenced by soil environment changes: microbial density was affected by the quantity and diversity of crop residues, soil organic carbon, and exchangeable base contents, whereas soil bacterial genetic structure was mainly determined by exchangeable aluminum content, pH, cation exchange capacity, and C/N ratio. Altogether, our study represents one of the most complete environmental evaluations of agricultural practices in tropical agrosystems and leads to recommend no-till systems with high residue restitutions to improve the physical, chemical, and microbial properties of tropical acid soils and thus contribute to the sustainability of agriculture in these ecosystems.

International audience; Expansion of agricultural land use has increased emission of greenhouse gases, exacerbating climatic changes. Most agricultural soils have lost a large portion of their antecedent soil organic carbon storage, becoming a source of atmospheric carbon-dioxide. In addition, agricultural soils can also be a major source of nitrous oxide and methane. Adoption of conservation agricultural practices may mitigate some of the adverse impacts of landuse intensification. However, optimal implementation of these practices is not feasible under all physical and biotic conditions. Of a wide range of conservation practices, the most promising options include agroforestry systems and soil application of biochar, which can efficiently sequester large amounts of carbon over the long-run. In addition, these practices also increase agronomic productivity and support a range of ecosystem services. Payments to farmers and land managers for sequestrating carbon and improving ecosystem services is an important strategy for promoting the adoption of such practices, aimed at mitigating climate change while decreasing environmental footprint of agriculture and sustaining food security.

Soil quality is recognised as being a key parameter of sustainable agricultural management. Existing methods of life cycle impact assessment (LCIA) do not include any soil quality indicators other than soil organic matter content. This paper rectifies this omission by presenting Swiss Agricultural Life Cycle Assessment for Soil Quality (SALCA-SQ), a LCIA conform method, to assess effects of agricultural management practices on soil quality. SALCA-SQ characterises all major types of impacts of land management practices on the quality of arable soils by means of nine indicators covering soil physical, chemical and biological aspects: rooting depth of soil, macropore volume, aggregate stability, organic carbon content, heavy metal content, organic pollutants, earthworm biomass, microbial biomass and microbial activity. Since these indicators are not measured directly, the impacts of agricultural management activities are assessed via impact class modelling to determine the most probable changes in soil quality indicators as a result of on-farm agricultural practices. To illustrate the application and results of SALCA-SQ, treatment effects of a long-term field trial on soil quality were assessed and compared against measured field data. The data generated by SALCA-SQ revealed the important influence of fertiliser regime on soil quality. Field measurements generally confirmed SALCA-SQ assessments, but small differences between measured data in different treatments could not be predicted. Case studies on theoretical scenarios covering a broad spectrum of site conditions and management practices demonstrated the potential of SALCA-SQ to assess the effects of the major impact classes on the nine soil quality indicators, thus giving a refined picture of the potential effects of a farming system on soil quality. In principle, these results support the assumption that SALCA-SQ has the potential to assess effects of agricultural management practices on soil quality, but validity in a strict scientific sense remains to be substantiated. In addition, SALCA-SQ can be used by agricultural advisory services and farmers to analyse agricultural management effects on soil quality and move soil management in a more sustainable direction.

Threats of desertification have been projected for the Mediterranean basin under relatively minor warming and drying scenarios. This situation raises the need for mitigation strategies and adaptation of crop production. Crop vulnerability assessment is therefore needed. In Tunisia, olive culture is a major activity. In some cases, olive is the only crop able to grow in local conditions. However, olive production may be among the more vulnerable systems to climate change since perennial crops adapt slowly. No studies have been dedicated to vulnerability evaluation of olive production. Here, the vulnerability of Tunisian olive trees to drought was assessed under extremely low precipitation levels, of 50% of normal precipitation, from 1999 to 2002. The impact of drought was quantified using a severity scale with three levels. A map of the impact of drought on olive trees was constructed for all Tunisian olive groves. We found that the number of wilting olive trees in 2002 was 7.8 millions of about 60 millions trees. A correlation was observed between olive tree affection by drought and olive orchard age. Thus, under the same drought conditions, senescent orchards were less resistant to drought than young ones. Locally, data showed that compact soils and soils containing more than 1% gypsum were not suitable for olive growth under drought.

Innovations in the agri-food sector are needed to create a sustainable food supply. Sustainable food supply requires unexpectedly that densely populated regions remain food producers. A Dutch innovation program has aimed at showing the way forward through creating a number of practice and scientific projects. Generic lessons from the scientific projects in this program are likely to be of interest to agricultural innovation in other densely populated regions in the world. Based on the executed scientific projects, generic lessons across the whole innovation program are derived. We found that the agricultural sector requires evolutionary rather than revolutionary changes to reshaping institutions. Measuring sustainability is possible against benchmarks and requires stakeholder agreement on sustainability values. Results show the importance of multiple social views and multiple stakeholder involvement in agricultural innovation. Findings call for flexible goal rather than process-oriented management of innovation. Findings also emphasise the essential role of profit in anchoring sustainable development in business. The results agree with concepts of evolutionary innovation. We conclude that there is no single best solution to making the agri-food sector more sustainable densely populated areas, but that the combination of a range of solutions and approaches is likely to provide the best way forward.

Zinc (Zn) deficiency is a widely occurring constraint for rice production and for human nutrition. Scarcity of water is leading to a shift from flooded to aerobic rice production, which can have an impact on Zn deficiency in rice. Zinc bioavailability is a function of both soil and plant factors that can be altered by water management, particularly in relation to conditions in the rhizosphere. Biogeochemical modeling based on bulk soil conditions failed to predict the effect of water management on Zn bioavailability, but revealed that dissolved organic anions, pH, and redox conditions were major determinants. Rhizosphere sampling is needed to understand the difference in Zn mobilization and uptake between flooded and aerobic cultivation systems. Zinc bioavailability is not only affected by changes in the chemical properties of the soils, but also by biological processes such as mycorrhizal inoculation and root release of organic compounds into rhizosphere. Phytosiderophores and organic acids are two classes of Zn chelators secreted from roots that have been linked to the release of Zn from soil-bound forms and its subsequent uptake by plants. A shift to aerobic condition provides a favorable environment for activity of mycorrhizal fungi and enhanced mycorrhizal inoculation under aerobic conditions has been shown to increase plant Zn uptake. Aerobic rice genotypes with varying tolerance to Zn deficiency display a trade-off between mycorrhizal Zn responsiveness and root exudation of Zn chelator in the rhizosphere, which is probably due to a competition for carbon. Potential agronomic management practices in aerobic rice production systems are discussed, with an emphasis on their roles in improving bioavailability of Zn. Addition of Zn fertilizers by soil or foliar application have been shown to increase Zn concentration in cereal grains but the extent of the increase differs among crop species. The shift from flooded to aerobic condition can cause significant N transformations, which may consequently affect Zn mobilization and uptake. An appropriate N management strategy, including an effective combination of source, rate, application method, and timing, should consider the effects on soil pH. Application of P fertilizer should be done with careful consideration to the effect on Zn uptake. A reasonable cropping system (intercropping and crop rotation) could prevent Zn deficiency and offer an effective and sustainable pathway to Zn biofortification. Keeping these points in mind, this review describes our current knowledge of Zn bioavailability as affected by changes in soil–plant interactions caused by the transition from flooded to aerobic rice cultivation.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; Agricultural policymakers are addressing the sustainable development issue by designing new agricultural systems. Farmers are ultimately asked to make deep changes at field scale. Designing cropping systems has previously been done using prototyping methodologies. Prototyping methodologies use a five-step designing process at field scale and request multicriteria analysis of the resulting prototypes. However, sustainable dynamics implies considering changes at larger scales, farm and region, as well as creating feedback and facilitating participation of all the stakeholders involved in the process. Here we studied citrus production in Guadeloupe, French West Indies, where farmers must reduce pesticide loads despite unresolved weed control issues. We designed the DISCS method, which stands for "participatory redesign and assess innovative cropping systems", to improve classical prototyping methods by implementing a multi-scale, multi-stakeholder, participatory approach. Compared to classical prototyping methods, the DISCS method differs by implementing three progress loops, at experimental field, farm, and regional scales. Three categories of professional stakeholders are involved: farmers, researchers, and agricultural advisers, who are collectively in charge of designing and testing cropping system prototypes. In addition, local public stakeholders including representatives of state institutions are consulted. Progress is assessed using scale-specific sets of indicators. The DISCS method was applied to develop low-pesticide citrus cropping systems. Five weed control prototypes were jointly designed by citrus farmers and researchers, and two multicriteria assessment tools were built for use at the experimental station and on the farms. Results show that involved farmers transferred the new techniques to their own farms on their own initiative, thus spontaneously becoming pilot farmers. The DISCS method is therefore the result of a co-design process between farmers and researchers. The DISCS method creates an ongoing dynamic relationship between agricultural and public stakeholders to build a solution that can continuously be adjusted to stakeholders' expectations.

Globally, besides human medicine, an increasing amount of antibiotics as veterinary drugs and feed additives are used annually in many countries with the rapid development of the breeding industry (livestock breeding and aquaculture). As a result, mostly ingested antibiotic doses (30–90%) and their metabolites to humans and animals, as emerging persistent contaminants, were excreted together with urine and feces, and subsequently disseminated into environmental compartments in forms of urban wastewater, biosolids, and manures. More importantly, significant amount of antibiotics and their bioactive metabolites or degradation products were introduced in agro-ecosystems through fertilization and irrigation with antibiotics-polluted manures, biosolids, sewage sludge, sediments, and water. Subsequently, accumulation and transport of antibiotics in soil–crop systems, particularly soil–vegetable systems, e.g., protected vegetable and organic vegetable production systems, poses great risks on crops, soil ecosystem, and quality of groundwater- and plant-based products. The aim of this review is to explore the sources, fates (degradation, adsorption, runoff, leaching, and crop uptake), and ecological risks of antibiotics in agro-ecosystems and possible food security and public health impacts. Three topics were discussed: (1) the occurrence, fates, and ecological impacts of antibiotics in agro-ecosystems, a global agro-ecological issue; (2) the potential ecological risks and public health threat of antibiotic pollution in soil–vegetable system, especially protected vegetable and organic vegetable production systems; and (3) the strategies of reducing the introduction, accumulation, and ecological risks of antibiotics in agro-ecosystems. To summarize, environmental contamination of antibiotics has become increasingly serious worldwide, which poses great risks in agro-ecosystems. Notably, protected vegetable and organic vegetable production systems, as public health closely related agro-ecosystems, are susceptible to antibiotic contamination. Occurrence, fate, and ecotoxicity of antibiotics in agro-ecosystems, therefore, have become most urgent issues among antibiotic environmental problems. Nowadays, source control, including reducing use and lowering environmental release through pretreatments of urban wastes and manures is a feasible way to alleviate negative impacts of antibiotics in agro-ecosystems.

Humans are currently confronted by many global challenges. These include achieving food security for a rapidly expanding population, lowering the risk of climate change by reducing the net release of greenhouse gases into the atmosphere due to human activity, and meeting the increasing demand for energy in the face of dwindling reserves of fossil energy and uncertainties about future reliability of supply. Legumes deliver several important services to societies. They provide important sources of oil, fiber, and protein-rich food and feed while supplying nitrogen (N) to agro-ecosystems via their unique ability to fix atmospheric N2 in symbiosis with the soil bacteria rhizobia, increasing soil carbon content, and stimulating the productivity of the crops that follow. However, the role of legumes has rarely been considered in the context of their potential to contribute to the mitigation of climate change by reducing fossil fuel use or by providing feedstock for the emerging biobased economies where fossil sources of energy and industrial raw materials are replaced in part by sustainable and renewable biomass resources. The aim of this review was to collate the current knowledge regarding the capacity of legumes to (1) lower the emissions of the key greenhouse gases carbon dioxide (CO2) and nitrous oxide (N2O) compared to N-fertilized systems, (2) reduce the fossil energy used in the production of food and forage, (3) contribute to the sequestration of carbon (C) in soils, and (4) provide a viable source of biomass for the generation of biofuels and other materials in future biorefinery concepts. We estimated that globally between 350 and 500 Tg CO2 could be emitted as a result of the 33 to 46 Tg N that is biologically fixed by agricultural legumes each year. This compares to around 300 Tg CO2 released annually from the manufacture of 100 Tg fertilizer N. The main difference is that the CO2 respired from the nodulated roots of N2-fixing legumes originated from photosynthesis and will not represent a net contribution to atmospheric concentrations of CO2, whereas the CO2 generated during the synthesis of N fertilizer was derived from fossil fuels. Experimental measures of total N2O fluxes from legumes and N-fertilized systems were found to vary enormously (0.03–7.09 and 0.09–18.16 kg N2O–N ha−1, respectively). This reflected the data being collated from a diverse range of studies using different rates of N inputs, as well as the large number of climatic, soil, and management variables known to influence denitrification and the portion of the total N lost as N2O. Averages across 71 site-years of data, soils under legumes emitted a total of 1.29 kg N2O–N ha−1 during a growing season. This compared to a mean of 3.22 kg N2O–N ha−1 from 67 site-years of N-fertilized crops and pastures, and 1.20 kg N2O–N ha−1 from 33 site-years of data collected from unplanted soils or unfertilized non-legumes. It was concluded that there was little evidence that biological N2 fixation substantially contributed to total N2O emissions, and that losses of N2O from legume soil were generally lower than N-fertilized systems, especially when commercial rates of N fertilizer were applied. Elevated rates of N2O losses can occur following the termination of legume-based pastures, or where legumes had been green- or brown-manured and there was a rapid build-up of high concentrations of nitrate in soil. Legume crops and legume-based pastures use 35% to 60% less fossil energy than N-fertilized cereals or grasslands, and the inclusion of legumes in cropping sequences reduced the average annual energy usage over a rotation by 12% to 34%. The reduced energy use was primarily due to the removal of the need to apply N fertilizer and the subsequently lower N fertilizer requirements for crops grown following legumes. Life cycle energy balances of legume-based rotations were also assisted by a lower use of agrichemicals for crop protection as diversification of cropping sequences reduce the incidence of cereal pathogens and pests and assisted weed control, although it was noted that differences in fossil energy use between legumes and N-fertilized systems were greatly diminished if energy use was expressed per unit of biomass or grain produced. For a change in land use to result in a net increase C sequestration in soil, the inputs of C remaining in plant residues need to exceed the CO2 respired by soil microbes during the decomposition of plant residues or soil organic C, and the C lost through wind or water erosion. The net N-balance of the system was a key driver of changes in soil C stocks in many environments, and data collected from pasture, cropping, and agroforestry systems all indicated that legumes played a pivotal role in providing the additional organic N required to encourage the accumulation of soil C at rates greater than can be achieved by cereals or grasses even when they were supplied with N fertilizer. Legumes contain a range of compounds, which could be refined to produce raw industrial materials currently manufactured from petroleum-based sources, pharmaceuticals, surfactants, or food additives as valuable by-products if legume biomass was to be used to generate biodiesel, bioethanol, biojet A1 fuel, or biogas. The attraction of using leguminous material feedstock is that they do not need the inputs of N fertilizer that would otherwise be necessary to support the production of high grain yields or large amounts of plant biomass since it is the high fossil energy use in the synthesis, transport, and application of N fertilizers that often negates much of the net C benefits of many other bioenergy sources. The use of legume biomass for biorefineries needs careful thought as there will be significant trade-offs with the current role of legumes in contributing to the organic fertility of soils. Agricultural systems will require novel management and plant breeding solutions to provide the range of options that will be required to mitigate climate change. Given their array of ecosystem services and their ability to reduce greenhouse gas emissions, lower the use of fossil energy, accelerate rates of C sequestration in soil, and provide a valuable source of feedstock for biorefineries, legumes should be considered as important components in the development of future agroecosystems.

International audience; Agriculture should now provide not only high yields but also sustainable development with a sound management of the diversity of ecosystems. Due to this increased complexity of objectives, models have recently become major tools that can integrate several parameters. Failure to apply models outside research is however a major issue. Here, to identify the precise grounds of this failure, we analyzed what models are intended for by scientists during their design. We performed a literature analysis on agronomic modelling practices. Specifically, we analyzed 518 scientific article abstracts reporting either new models or improved existing models. Articles were published in eight mainstream agronomy journals over a 10-year period. We also analyzed 25 full-text contents randomly selected from the initial dataset. In order to assess how models match the uses they are intended for, we first analyzed the design methodology used to build models. Second, we studied how authors defined the potential use of models by analyzing both the claimed objectives and references to model use and users. We then compared our findings on design methodology with our findings on intended use. Our results first show that the design methodology for modelling is presented as a segmented and standardized process. Each article refers to one or more of the following six steps to describe the design process for modelling: (1) description of the model structure, inputs, outputs and validity domain, (2) description of the data used to build the model, (3) model formalism, (4) calibration parameterisation, (5) validation, and (6) application. We found that information about the design process like iterations, errors, improvements is never emphasized in the abstracts, whereas this information is sometimes quoted in the full-text contents. This finding demonstrates that the design methodology for modelling is not addressed as a research topic. Second, we show that whereas 88.8% of authors claim in their abstracts that the major objective of their models is to improve understanding as opposed to support action, 19.5% of authors also quote a possible use of their models outside research. The initial objective of understanding is thus extended to use the models as tools for action. Overall, we conclude that the agricultural research community is not highly concerned by the effects of the design methodology on the suitability of the model structure and on potential applications. Moreover, although the six steps of the design process may be appropriate for designing models devoted to improve understanding, no specific methods are proposed to design models for action. We did not find evidence that the modellers connect the design of the model with its use by end-users. We suggest that this issue could be solved by developing participatory methodology design involving end-users in model design.

International audience; Farmers must yearly allocate fields to different crops and choose crop management options. Far from being obvious, these decisions are critical because they modify farm productivity and profitability in the short and long run. To support farmers and efficiently allocate scarce resources, decision support models are developed. Decision support models are mainly based on two concepts, the cropping plan and the crop rotation decisions. These decisions concern crop choice, crop spatial distribution within the farmland and crop temporal successions over years. Decisions are at the core of the farm management. Decisions have strong impacts on resource use efficiency and on environmental processes at both farm and landscape scales. We review here more than 120 references where cropping plan and crop rotation decision concepts were incorporated into models. Our aim is to review how these two concepts have been formalised and used in agronomic, economic and land-use studies. We found that cropping plan decisions selection and design have been done using many approaches based on different objectives and handled at very different scales. The main results show that (1) cropping plan design decisions have mainly been tackled as a static concept, i.e. as if they were a single decision made only once a year or once a rotation; (2) modelling the achievement of a suitable cropping plan is often based on a single monetary criterion optimization procedure instead of a multi-criteria assessment; and (3) when considered, uncertainty of information is defined as stochastic factors or probability of occurrence, but this probability is kept static whatever the knowledge of the dynamic evolution of various constraints. We argue that cropping plan and crop rotation decisions are on the contrary dynamic processes incorporated into a succession of other planned and adaptive decisions made at annual and long-term horizons. For supporting farmers in their decisions, new cropping plan decision models will require new modelling paradigm. A promising improvement could be reached by including explicitly the simulation of the farmers' decision-making processes, based on the simulation of the decision-making processes rather than on single normative approaches.

The optimization of nitrogen (N) fertilization is the object of intense research efforts around the world. Overfertilization is commonly used as a form of insurance against uncertain soil fertility level. However, this practice results in lower nitrogen use efficiency, high levels of residual N after harvest, and losses in the environment. Determining an N recommendation that would preserve actual crop requirements, profitability of the farm, and quality of the environment has been subjected to a number of research initiatives with a variable degree of success. On one hand, soil tests are capable of estimating the intensity of N release at any point in time, but rarely the capacity factor over a longer period. On the other hand, in the context of in-season N applications, crops are often considered good integrators of factors such as the presence of mineral N, climatic conditions, soil properties, and crop management. Strategies have been proposed with plant sensor-based diagnostic information for N recommendations, but the sensitivity of reflectance-based parameters alone do not provide complete satisfaction (delayed sensitivity, need of specific chlorophyll, biomass or cover fraction ranges, lack of specificity to the N stress). Fluorescence sensing methods have been used to monitor crop physiology for years, and they may offer solutions for N status diagnosis over reflectance-based methods. In this paper, we review three plant fluorescence components related to four sensing approaches—variable chlorophyll fluorescence, leaf chlorophyll content-related fluorescence emission ratio, blue-green fluorescence, and epidermal screening of chlorophyll fluorescence by phenolic compounds—from the perspective of their relevance to N fertilization management of agricultural crops. We examine the existence of N-induced changes in each case, together with applications and limitations of the approach. Among these approaches, the fluorescence emission ratio method is the most important and the most widely used to date. However, blue-green fluorescence and epidermal screening of chlorophyll fluorescence by phenolic compounds has also received a great deal of attention particularly with the recent commercial release of instruments which can measure in real time and in vivo both the leaf chlorophyll content and several phenolic compounds (anthocyanins, flavonoids, hydroxycinnamic acids). Overall, our conclusion is that fluorescence-based technologies allow for highly sensitive plant N status information, independently from soil interference, leaf area, or biomass status. They also allow for probing not only the chlorophyll status but also other physiological parameters known to react to N fertility conditions. These new parameters have the potential to provide new N status indicators that can be assessed remotely in a precision agriculture context.

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; International audience; Potato crop is the fourth main food crop in the world and it will certainly feed a big part of the global population in the next years. The economical outlets for this crop are great; however, numerous diseases either soil- or air-borne can cause huge losses in the production. Worldwide, about 40 soil-borne diseases affect potato and cause severe damages especially on tubers, the economically most important part of the plant. The occurrence and development of soil-borne diseases depend on very diverse factors affecting either the pathogen or the plant. Favorable conditions for potato diseases development are frequently the same as the conditions needed for potato growth: temperature between 10°C and 25°C, high humidity, medium pH, etc. Adapted cultural practices such as a rotation longer than 4 years, appropriate fertilization and water management, an adapted delay between haulm killing and harvest, and dry and cool conditions for tuber storage are good ways to control potato diseases. In most cases, potato pathogens develop specific survival forms, dissemination ways and host penetration methods. The genetic variability of the pathogens implies the use of adapted diagnostic and control methods. Decision support systems developed to predict yield losses allow choosing good control methods such as the use of healthy seeds, adapted pesticides, cultural practices, and biological control agents for each potato disease. The complexity of the interactions between a pathogen and its host, influenced by biotic and abiotic factors of the environment, make the control of the diseases often very difficult. However, deep knowledge of pathosystems allows setting up integrated pest management systems allowing the production of healthy and good quality potatoes.

The close links of climate, soil conditions, and agricultural productivity have been used in Central Europe for taxation purposes since the eighteenth century. Since agroclimatic conditions are variable, their fluctuations in the past centuries can provide a valuable context for analyzing changes expected in the coming decades. Here, historical agroclimatic conditions and future projections were constructed for key agricultural regions in Central Europe. The agroclimatic zoning method used in this study incorporates (1) the sum of temperatures for days with a mean temperature above 10°C during the frost-free period, (2) the water deficit during the summer period from June to August, defined as the difference between precipitation and reference evapotranspiration, and (3) information regarding the suitability of soil and terrain for agriculture production based on twentieth century soil surveys. Changes in selected agroclimatological indices were also analyzed. To produce a weather series representing climate conditions between 1803 and 2008 over the study area, we used a stochastic weather generator trained on high-quality daily observations from 52 representative meteorological stations during the baseline period from 1961 to 1990. To estimate the extent of agroclimatic zones and the values of selected agroclimatic indices, the parameters of the weather generator were perturbed by the deviations of the temperature and precipitation means from the baseline using a long-term climate series from 1803 to 2008, from Brno. To generate a weather series representing the climate in 2050, we used an approach known as “pattern-scaling” in combination with outputs of three general circulation models. To our knowledge, this is the first study analyzing both continuous fluctuations in agroclimatic conditions over the past 200 years and expected shifts in the coming decades over Central Europe.

The ability of agriculture to adapt to environmental changes and to address main issues of food quality and environment protection is a fundamental factor in achieving sustainability. Low yield capacity of contemporary sustainable farming systems, however, is a major obstacle to future growth of sustainable agriculture. In addition, increasing pressure is placed for higher food supply due to the projected population increase. To overcome these barriers and stimulate the wide adoption of sustainable agriculture, ample supply of cultivars that satisfy the requirements for sustainability without compromising productivity is essential. Otherwise, the viability of sustainable agriculture is unsound. Moreover, plant breeding has to be a non-stop process supporting agriculture because of the ongoing climate changes. The studies of the effects of competition on crop yield and selection efficiency unravelled important findings for plant breeders. Firstly, the uppermost cultivar type is the mono-genotypic and particularly the highest evolutionary grade of ‘pure line’. Secondly, single plant selection is effective only when it is realized in the absence of competition for growth resources. Honeycomb methodology, by considering as a major principle the application of selection in the absence of competition, counteracts the disturbing effects of competition on selection effectiveness. Furthermore, the honeycomb experimental designs cope with the confounding implications of soil heterogeneity. These two findings help breeders to consider the individual plant as an evaluating and selection unit. As a consequence, the development of pure line cultivars that fully meet the needs of a sustainable agriculture is possible. Most importantly, honeycomb breeding exploits effectively not only favourable but marginal environments as well through the development of density-neutral cultivars. Marginal environments are exploited optimally when lower plant populations are used. It is of essence to realize that without the ability of exploiting successfully marginal environments which represent the majority of the production environments globally, sustainability in agriculture becomes problematic.

An increasing number of soils of poor quality with unbalanced metal concentrations are used worldwide for crop cultivation. Even though plants are able to develop strategies to cope with metal stress, either metal deficiency or excess, this unbalance affects the whole plant. Chloroplasts are key organelles for organic matter synthesis and biomass production. Under metal stress, chloroplasts suffer severe alterations of their ultrastructure, associated with profound molecular and metabolic damages. These alterations are accompanied by unbalanced metal distribution in plants, in particular in edible crop organs. Toxic metals get either accumulated or there is a deficiency of nutrients, resulting in a weak nutritional value. Nonetheless, there is more and more knowledge on the functioning and regulation of metal transporters in plants. Such knowledge will allow growing crops with well-balanced metal concentrations in edible parts even on metal unbalanced soils. This review shows that almost all vital functions of chloroplasts, such as photosynthesis, CO2 fixation, nitrogen and sulfur assimilation, and protein and nucleic acid metabolism, require metals. Therefore, the uptake of essential metals is necessary for the proper functioning of chloroplasts and, in turn, for crop productivity. We describe nutrient uptake mechanisms of plants and processes that influence essential and non-essential metal concentrations in different plant organs. We present an overview of metal transporters in chloroplasts. Several questions still need to be elucidated about the uptake and the trafficking of essential and non-essential metals into and within chloroplasts. Similarly to transporters present in other cellular compartments, the carriers are often not metal-specific. Therefore, essential and non-essential metals may compete for carriers. As a result, unbalanced soil metal concentrations can be reflected in the plants and in the chloroplasts. Metal deficiency or excess causes reduced growth and decreased productivity of crops. It can lead to human malnutrition. Several complex physiological processes can be responsible for the reduced biomass observed in plants with unbalanced metal concentration. In this review, we have focused on the structural and functional alterations of chloroplasts under metal deficiency or excess. Interestingly, besides specific differences, our data indicate several similarities in the response of chloroplasts to metal deficiency or excess. Indeed, oxidative stress and several ultrastructural alterations, e.g., increase in the number and size of plastoglobuli, disorganized grana and disturbed thylakoids, and swelling of the intrathylakoidal space, are observed in both cases. This indicates that changes in chloroplast ion homeostasis rather than the specific effect of a metal are responsible for decreased plant productivity. Therefore, sustainable agriculture has to take into consideration solutions that enable undisturbed metal and ion homeostasis in chloroplasts of crop plants grown even in soils with unbalanced metal concentrations.

International audience; Although there is increasing awareness of the importance of food legumes in human, animal and soil health, adoption of improved production technologies for food legume crops is not proceeding at the same pace as for cereal crops. Over the previous decade, the only food legumes to have shown significant production increases have been chickpea, lentil and faba bean in North America, chickpea in Australia, and faba bean in Europe. In smallholder farming in developing countries, production trends have mostly been static or have declined over the past decade despite the existence of technology that should permit higher and more stable yields. Ability to reverse negative trends is jeopardized by climate change as food legumes are mostly grown rainfed and are being exposed to increasingly variable and extreme weather. This review examines recent innovations in cultivation technology for the major food legumes-chickpea, lentil, dry pea, faba bean, lupin, common bean, mung bean, black gram, cowpea, and pigeonpea-and explores constraints to their adoption, particularly by resource-poor smallholder farmers. Conservation agriculture, involving minimum soil disturbance, maximum soil cover, and diverse rotations, has contributed to sustainable cropping system production in large-scale commercial farming systems in the Americas, Europe, Australia, and Turkey. Temperate food legumes have been incorporated into such systems. Adoption of conservation agriculture is only just beginning for smallholder farming in Asia and Africa, catalyzed by the development of low-cost implements suitable for minimum tillage. Water use efficiency improves with conservation agriculture as it allows for earlier planting, reduced soil evaporation, better weed management, and increased access to nutrients. Ecosystem-based approaches to plant nutrition are evolving which place more reliance on accessing organic and mineral reservoirs than in replenishing the immediately available pool with chemical fertilizers, leading to enhanced nutrient use efficiency of cropping systems. Ecosystem-based approaches are also being applied to management of weeds, diseases, and insect pests of food legumes, again with decreased reliance on synthetic chemicals. In achieving sustainable agricultural production systems, there is increasing realization of the need to move towards the tenets of organic agriculture, as exemplified in conservation agriculture and ecosystem-based approaches to plant nutrition and pest management. This does not necessarily imply a desire to qualify for organic product certification but more a realization of the need for sustainable agriculture. The movement towards conservation and organic agriculture encourages greater inclusion of food legumes, and legumes generally, in cropping systems. Unfortunately, however, technology transfer to resource-poor farming situations, where most food legumes are produced, remains a major bottleneck to meeting global demand. More participatory approaches to technology development, testing, and dissemination are required than hitherto practiced. It is suggested that this process could be enhanced by better focusing on major constraints within the value addition chain for food legumes.

Citrus is a crop of major economic importance in Spain, cultivated during the dry season when irrigation is essential to guarantee yields of high quality. As water resources are progressively more insufficient, more effective water management in agriculture is crucial. Deficit irrigation in many agricultural crops has frequently proved to be an efficient tool for improving water-use efficiency. We hypothesise that, despite the effectiveness of deficit irrigation, the most suitable strategy in citrus orchards remains to be defined for Mediterranean environment. In this study, for the period from 2006 to 2008, a 12-year-old orange orchard, Citrus sinensis L. Osb. cv. Navelina, grafted onto Carrizo citrange, C. sinensis L. Osb. × Poncirus trifoliata L. Osb., were subjected under two deficit-irrigation strategies defined as follows: (1) low-frequency deficit irrigation applied according to the plant–water status, and (2) sustained-deficit irrigation with a water-stress ratio of 0.6, defined as the ratio of actual water-limited supply in this treatment related to the water supply of the control treatment. The control treatment was irrigated at 100% of ETC for the entire irrigation season (ETC: crop evapotranspiration). Midday stem–water potential (Ψstem) and stomatal conductance (gS) were used to estimate the water status of the trees. The lowest Ψstem and gS values were registered in the deficit-irrigation treatments with a seasonal pattern consistent with the irrigation dynamics applied in each case. Ψstem and gS values significantly differed from those of the control trees. Although the integrated stress levels were similar in deficit-irrigation treatments, differences in yield and fruit quality were found, having a more positive response to low-frequency deficit irrigation with an increase of 25% in yield in comparison to the sustained-deficit irrigation treatment. Here, we thus demonstrate the significant differences in water productivity. Indeed, water productivity parameter not only depends on the amount of water, but also on the irrigation strategy applied, which promoted substantial water savings without significant impact on yield. The present study highlights that low-frequency deficit irrigation should be adopted as a most appropriate strategy for achieving sustainable water management and attains reasonable yields and improves quality in citrus orchards under Mediterranean semiarid climate.