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Soil is a natural body of mineral and organic material differentiated into horizons, which differ among themselves as well as from underlying materials in their morphology, physical make-up, chemical composition and biological characteristics. In Pune city due to industrialization and other anthropogenic activity the soil from its eastern part has been polluted. The The sewage water in the Mula - Mutha River flows through the Manjari village and hence it is felt necessary to carry out the soil analysis to understand the pollution levels of the soils in the adjoining area. Since plants depend on the soils for their nutrients, water and minerals supply, the soil type is a major factor in determining what types of plants will grow in a any area. In the present study the analyses of soil samples collected from the sugarcane field of Manjari, Hadapsar, and Phursungi located in the SE part of the Pune city which is influenced by the solid waste disposal as well as industrial effluents. In the first place soils samples from 12 representative locations were collected for their analysis. Physical parameters like pH, Electrical conductivity (EC), organic carbon (%) and chemical parameters like phosphorus, potassium, copper, iron, manganese, zinc and boron were anlyzed. From this study it has been revealed that there is excessive dose of phosphorous and potassium into the soil because most farmers are using excessive chemical fertilizers. Similarly Cu, Fe, Mn and Zn concentration has also been seen higher than the normal range and due to poorer drainage conditions of this area making soil alkaline. Thus it is concluded that variable concentrations of various parameters and irregular distributions of micronutrients may be attributed due to the added fertilizers during the crop formation. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed to evaluate variations in the seed bank within a 3-year temporal series in order to answer the following questions: 1) Does the seed bank''s species richness and seed density differ among climatic seasons and between years? 2) Are there differences in the richness and density of seed banks between the litter and mineral soil? 3) Can the seed bank''s species richness and seed density be explained by characteristics such as the previous year''s precipitation and soil depth (litter or mineral soil)? The samples were collected from litter and mineral soil (0–5 cm), in 210 sub-plots, during the dry and rainy seasons of each year (August 2005 through February 2008). Overall, 79 species were recorded. On average, 1 168, 304 and 302 seeds.m−2 were recorded in the seed bank during years I, II and III, respectively. This study showed that the Caatinga''s seed bank is rich in herbaceous species, yet species'' density and richness are low in the litter. Furthermore, about 43% of the variation in species richness and density was explained by soil depth (litter and mineral soil) and previous years'' rainfall. [Copyright &y& Elsevier]

This study investigated Hg uptake from soil into garden crops to help assess the significance of human consumption of crops as a potential route of exposure to Hg. Locations for both a floodplain and a control garden were identified within the Augusta Forestry Center near Crimora, VA, USA, which is about 16 river-km downstream from the city of Waynesboro, along the South River. The floodplain garden had measured soil Hg concentrations ranging from 4.2 to 78 mg Hg kg−1dry weight basis in the surface to 15-cm deep layer. A total of 139 samples from the floodplain garden from 17 different crops were analyzed for Hg. All crop samples (except for nine) had less than 0.1 μg Hg g−1wet weight basis (ww). Many samples were less than the method detection limit (MDL) of 0.003 μg Hg g−1ww. Based on the measured Hg concentrations and several conservative assumptions (e.g., Hg assumed present when less than MDL; 100% consumption from the geographical area in which study was conducted; and 100% bioavailable Hg as methyl Hg), consumption of crops with these Hg levels is not expected to be a significant route of Hg exposure. [ABSTRACT FROM AUTHOR]

Audience segmentation is a useful tool for designing effective campaigns. Further, the efficiency promised in diffusion science rests to some degree on the existence of adopter categories that can be identified and used to strategically disseminate prevention innovations. This study investigates the potential to identify adopter categories in potential recipients (n = 127) of an innovation to prevent food shortages in Mozambique. A 5-class model was found using latent class analysis, but it showed important differences from existing descriptions of adopter categories. Implications for theory and practice are discussed. [ABSTRACT FROM PUBLISHER]

Abstract: Pig slurry is commonly spread on crop fields as a means of managing this agricultural waste product. However, this practice has an impact on the environment, e.g. increasing soil copper (Cu) and zinc (Zn) concentrations. Many studies have assessed the fate of these elements, but some questions remain, especially with respect to tropical agrosystems which have yet to be studied in depth. The aim of this study was to determine the fate of Cu and Zn from pig slurry spreading while also focusing on describing the dynamics of these elements in a tropical system and accounting for the three compartments of the water–soil–plant system. We observed that all of the Zn accumulated within the 20–60cm soil layer. Although the uncertainty calculated for these results was high, these findings were confirmed by the absence of uptake by the plant cover and of leaching via water flows. This pattern for Zn in a tropical setting differed from findings generally reported in temperate areas. The Zn accumulation mechanism in tropical soil seems to be a reversible sorption phenomenon, suggesting the possibility of long-term Zn leaching. The Cu mass derived from pig slurry spreading was stored in the 0–20cm soil layer. This result obtained in a tropical environment was similar to that noted in temperate areas. This could be explained by Cu speciation in the pig slurry (insoluble copper sulfide), and was therefore relatively independent of the soil–climate system. [Copyright &y& Elsevier]

Soil salt-alkalinization is a widespread environmental stress that limits crop growth and agricultural productivity. The influence of soil alkalization caused by Na2CO3 on plants is more severe than that of soil salinization. Plants have evolved some unique mechanisms to cope with alkali stress; however, the plant alkaline-responsive signaling and molecular pathways are still unknown. In the present study, Na2CO3 responsive characteristics in leaves from 50-day-old seedlings of halophyte Puccinellia tenuiflora were investigated using physiological and proteomic approaches. Comparative proteomics revealed 43 differentially expressed proteins in P. tenuiflora leaves in response to Na2CO3 treatment for seven days. These proteins were mainly involved in photosynthesis, stress and defense, carbohydrate/energy metabolism, protein metabolism, signaling, membrane and transport. By integrating the changes of photosynthesis, ion contents, and stress-related enzyme activities, some unique Na2CO3 responsive mechanisms have been discovered in P. tenuiflora. This study provides new molecular information toward improving the alkali tolerance of cereals. [ABSTRACT FROM AUTHOR]

Growing concerns about the multifaceted harmful effects of conventional agriculture have led many farmers and consumers to seek alternative practices and systems, such as organic and biodynamic farming systems, that promote to improve the soil and product quality and will make agriculture more sustainable. In this research were determined in apple and wine grape crops for conventional, organic and biodynamic farming systems the following soil parameters: conductivity, pH, organic substance, soil mean weight diameter (MWD), organic C, total N, the percentage of mycorrhizal colonization rate and the number of earthworms in soil. It was also determined the qualitative characteristics of fruits in all these three farming systems and in case of apples are: fruit diameter, weight of fruit, color of skin and flesh firmness. While in the case of the wine grapes are: weight of 100 berries, peel weight of 50 berries, 100 pips weight, berries diameter and pH, acidity and sugars in the juice. The results indicated that, in the majority of all measurements the most positive effects were presented at the organic and biodynamic farming system versus conventional. Regarding the soil parameters, were found positive effects of biodynamic farming system on the following parameters: total N, organic C, mycorrhizal colonization rate , while for organic farming system were found positive effects on the following parameters: organic C and MWD. Between organic and biodynamic farming system, and for the fruit characteristics, more positive effects in the case of apples displays the biodynamic farming system whereas in the wine grapes the organic farming system. [ABSTRACT FROM AUTHOR]

Many concerns have been raised about urban sprawl and the subsequent disappearance of agricultural land. Regulations have been put in place to reduce urban sprawl and protect agricultural areas in many countries, but how much potentially crop suitable land really is endangered by urban areas on a global scale has not been addressed so far. In this study, we compare the extent of urban areas as produced by the Center for Sustainability and the Global Environment, Madison, WI, USA, with a map of potential crop suitable areas produced by us. We show that, of the postulated 0.5% of the Earth's surface currently covered by urban areas, Asia, Europe and North America take away the largest shares and that 1% of the globally available highly crop suitable areas are currently taken up by cities, with Japan and California being extreme examples of up to 15% of highly suitable areas covered with cities. [ABSTRACT FROM AUTHOR]

Densification of the shrub layer has been reported in many subarctic regions, raising questions about the implication for large herbivores and their resources. Shrubs can tolerate browsing and their level of tolerance could be affected by browsing and soils productivity, eventually modifying resource availability for the caribou. Our objective was to assess the compensatory growth potential of a subarctic shrub, Betula glandulosa Michx., in relation with caribou browsing and nutriment availability for the plants. We used a simulated browsing (0, 25 and 75% of available shoots) and nitrogenfertilisation (0 and 10 g m-2) experiment to test two main hypotheses linking tolerance to resource availability, the Compensatory Continuum Hypothesis and the Growth Rate Hypothesis as well as the predictions from the Limiting Resource Model. We seek to explicitly integrate the relative browsing pressure in our predictions since the amount of tissues removed could affect the capacity of long-lived plants to compensate. Birches fully compensated for moderate browsing with an overall leaf biomass similar to unbrowsed birches but undercompensated under heavy browsing pressure. The main mechanism explaining compensation appears to be the conversion of short shoots into long shoots. The leaf area increased under heavy browsing pressure but only led to undercompensation. Fertilisation for two consecutive years did not influence the response of birch, thus we conclude that our results support the LRM hypothesis of equal tolerance under both high and low nitrogen availability. Our results highlight that the potential for compensatory growth in dwarf birch is surpassed under heavy browsing pressure independently of the fertilisation regime. In the context of the worldwide decline in caribou herds, the reduction in browsing pressure could act synergistically with global climate change to promote the current shrub expansion reported in subarctic regions. [ABSTRACT FROM AUTHOR]

It has been debated how different farming systems influence the composition of soil bacterial communities, which are crucial for maintaining soil health. In this research, we applied high-throughput pyrosequencing of V1 to V3 regions of bacterial 16S rRNA genes to gain further insight into how organic and conventional farming systems and crop rotation influence bulk soil bacterial communities. A 2×2 factorial experiment consisted of two agriculture management systems (organic versus conventional) and two crop rotations (flax-oat-fababean-wheat versus flax-alfalfa-alfalfa-wheat) was conducted at the Glenlea Long-Term Crop Rotation and Management Station, which is Canada's oldest organicconventional management study field. Results revealed that there is a significant difference in the composition of bacterial genera between organic and conventional management systems but crop rotation was not a discriminator factor. Organic farming was associated with higher relative abundance of Proteobacteria, while Actinobacteria and Chloroflexi were more abundant in conventional farming. The dominant genera including Blastococcus, Microlunatus, Pseudonocardia, Solirubrobacter, Brevundimonas, Pseudomonas, and Stenotrophomonas exhibited significant variation between the organic and conventional farming systems. The relative abundance of bacterial communities at the phylum and class level was correlated to soil pH rather than other edaphic properties. In addition, it was found that Proteobacteria and Actinobacteria were more sensitive to pH variation. [ABSTRACT FROM AUTHOR]

Background: Zinc deficiency has been recognized as an important factor affecting both human health and crop production. Rice ( Oryza sativa) is relevant to both concerns, as it is susceptible to soil Zn deficiency and is a staple food for some of the Zn-deficient human population. Improving the processes by which Zn moves from the soil into the plant and eventually into the edible part of the grain has the potential to mitigate problems associated with Zn deficiency in crops and humans. This review article focuses on soil- and plant-related processes affecting Zn chemistry in rice-grown soils and Zn uptake and transport in a rice plant. Scope: This review covers advances in soil chemistry regarding the reasons for inconsistent Zn deficiency in rice soils and the limitations of soil test methods for predicting Zn response for rice. We then review advances in plant physiology related to root Zn uptake and internal Zn distribution mechanisms in rice and explore interactions between specific root processes and the soil chemistry of particular environments. We aim to provide an overview of the soil science research for plant scientists and vice versa, in order to promote and facilitate future interdisciplinary collaborations. Conclusions: Priority research areas to fill in knowledge gaps are: 1) improving our ability to predict Zn deficiency in rice soils, 2) understanding the relationship between Zn-deficiency tolerance mechanisms and grain Zn accumulation, 3) exploring the effectiveness of root Zn uptake mechanisms in contrasting soil environments. [ABSTRACT FROM AUTHOR]

Abstract: The increasing number of cases on soil contamination by heavy metals has affected crop yields, besides representing an imminent risk to food. Some of these contaminants, such as cadmium, are very similar to micronutrients and thus more easily absorbed by the plants. This study assessed the effect of increasing amounts of cadmium on the content and translocation of micro and macronutrients in tomato. Tomatoes were grown in Clark''s nutrient solution and subjected to increasing levels of Cd: 0, 0.025, 0.1, 0.5 and 1.0mgL−1. The plants contaminated by cadmium had a maximum reduction in the aerial part compared to the control of: 2.25gkg−1, 2.80gkg−1, 18.93mgkg−1 and 14.15mgkg−1 for K, Ca, Mn and Zn, respectively. In other parts of the tomato were reduced from 2.3gkg−1 K in fruits and 280.5mgkg−1 of Mn in the roots. In addition to changes in the levels of some nutrients, the restricted Cd translocation in 1.15percent P and 2.8percent Cu to shoots compared to control, but did not affect the translocation of K, Ca, Mg and Zn. [Copyright &y& Elsevier]

Although cotton plant mapping has been valuable in understanding growth and development, variation in fruit distribution among plants is a significant mapping challenge. Choosing a sample that is large enough to generate useful information, but small enough to minimize time and resources, can make plant mapping more accessible for evaluating cotton crop growth characteristics throughout the cotton belt. The purpose of this research was to identify the effects of sample size and main-stem node grouping on sample variability. Plants were sampled in 10-m sections from six cotton cultivars at five locations in Georgia in 2009 and one location in 2010. The relative errors associated with sample sizes of one to 50 plants, as well as the statistical power associated with each sample size, were computed. On average, 37 plants per cultivar among five cultivars were required to reach a statistical power of 0.90, with the required number based on the magnitude of difference between cultivars in the fraction of plants having a boll at a given fruiting site. Grouping of main-stem nodes and the use of moving weighted averages decreased the error on a node-by-node basis. The use of these methods resulted in the loss of some node-by-node information that might be of value in particular cases, but the number of plants required to generate the same statistical power and standard deviation was decreased from a mean of 37 to a mean of 19 plants. These techniques should allow the use of smaller plant samples and make plant mapping more accessible. [ABSTRACT FROM AUTHOR]

The agricultural production systems leading to loss of soil organic carbon (SOC) might be contributing to release of CO into the atmosphere. Therefore, an attempt was made to assess the organic carbon stock in the soil profile and related soil properties under different cropping systems like rice-fallow, rice-groundnut, rice-potato, rice-rice, mango and guava orchard in the Deras command in Odisha province, India. Analyses on particle size distribution and pH revealed that soil was sandy loam to sandy clay loam and acidic in nature. The bulk density ranged from 1.54 to 1.79 Mg m depending on the soil depth and cropping system; it was lower in the soils of mango and guava orchards. Available water capacity of soils was significantly highest in the rice-rice system in almost every soil depths except in the 0-15-cm layer. The SOC stock was highest within 0-15-cm soil and gradually decreased with increase in depth in each land use systems. In 0-15 cm depth, highest SOC stock (16.80 Mg ha) was estimated in rice-fallow system and the lowest (11.81 Mg ha) in the soils of guava orchard. In 15-30 cm, it ranged from 8.74 in rice-rice system to 16.08 Mg ha in mango orchard. In the 30-45-cm soil depth, the SOC stock ranged from 6.41 in rice-potato to 15.71 Mg ha in rice-fallow system. The total SOC stock within the 0-60-cm soil profile ranged from 33.68 to 59.10 Mg ha among rice-based systems, highest being in soils under rice-fallow system and the lowest for rice-rice system. The mango and guava orchard soils had 68.53 and 54.71 Mg ha of SOC, respectively, in the 0-90-cm soil depth. The change of SOC stock due to continuous cropping was positive in every land use systems; however, the increase was the highest in rice-fallow system followed by mango orchard. [ABSTRACT FROM AUTHOR]

Efforts for increasing soil organic matter (SOM) content under agricultural systems have primarily focused on management practices that reduce exposure of SOM to decomposition via minimum tillage. We assess an alternative approach, termed "fall conservation deep tillage" (FCDT), to SOM stabilization through fall incorporation of crop residues into the soil profile together with N fertilizer. In an eastern Nebraska field under irrigated maize (Zea mays L), we measured total soil C and N stocks on an equal soil mass basis (0- to 30-cm depth) and the composition of four SOM fractions after 14 yr of previous no-till management and 1, 2, and 3 yr after conversion to FCDT. After 3 yr of FCDT, redistribution of soil C, N, and soil organic matter fractions occurred within the soil profile; however, total soil C and N stocks remained unchanged. An increase in the soil--crop residue contact surface through FCDT increased free light fraction by 170% in deeper strata in the soil profile. Change from no-till to FCDT led to initial reduction of C and N stocks as mobile and calcium bound humic acid fractions after 1 yr of tillage, suggesting enhanced decomposition and/ or condensation. By the second and third years of FCDT, stabilization of crop residues into these humified fractions was significant. The trends observed after 3 yr of FCDT at field-scale match prior plot-scale experiments from the same region and suggest that a positive balance of soil C and N accrual and loss may be achieved by enhancing the soil-residue contact surface in these soils. [ABSTRACT FROM AUTHOR]

The inclusion of winter annual cereal cover crops (WCC) in grain crop rotations is a common management practice promoted to protect soil resources and enhance water quality. However, the effects of long-term incorporation of WCC into no-till grain crop rotations on soil physical properties are not well established. We evaluated the long-term effects of WCC on soil physical properties after 13 yr of use at three locations in Maryland, USA. Continuous maize (Zea mays L.) was the summer grain crop. In the control treatment, maize was followed by winter fallow and in the WCC treatment, cereal rye (Secale cereal L.) was planted as a WCC in the off-season. We examined aggregate stability, total and labile organic matter, soil bulk density (BD), air permeability (AP), water infiltration rate (WIR), and hydraulic conductivity (HC), during the growing and off-season. Aggregate stability increased under the WCC treatment but there were no increases in total organic matter and labile organic matter. Only during the winter sampling season at the two Coastal Plain locations, soils under WCC displayed improved soil physical properties in comparison with the same soils under winter fallow. The heavier-textured soils at the Piedmont location exhibited no consistent differences attributable to WCC. [ABSTRACT FROM AUTHOR]

A characterization of the process of organic agriculture production of Calendula officinalis L. in the State of Santa Catarina is presented, evidencing particularities and discrepancies contrasting to the models already described in specialized literature, by field visits, participative observations and interviews with a medicinal plant producer. The main particularities identified were the health in the agricultural family, demonstrated by the practice of organic culture, besides pest control and the handling of production. The main evidenced problems or divergences were: soil characteristics; period of the marigold planting and its following stages, such as transplanting and flowering. Aspects of the crop were conflicting as for the period of the day indicated for the procedure, as well as the absence of information from the producer about the existence of other government incentives to the agricultural section. It is recommended to the rural extensions and/or competent institutions to seek for guiding the organic producers of marigold to promote adequate practices for the cultivation of this medicinal species. [ABSTRACT FROM AUTHOR]

Abstract: The usefulness of a digestate from an anaerobic codigestion process as a fertiliser product was evaluated in a field experiment using two horticultural crops (watermelon and cauliflower), during two successive growing seasons. The effects of the digestate were compared with those of a traditional organic amendment (cattle manure) and a conventional mineral fertiliser. Digestate addition to soil provided a source of available nutrients (nitrogen and phosphorus) in the short-term and had positive effects on soil biological properties such as microbial biomass and enzyme activities, compared to the non-amended soil. The digestate application to soil led to yields comparable to the mineral fertilisation for the summer watermelon crop. However, for the winter cauliflower crop, only plots treated with the mineral fertiliser had good production. Nitrogen from the digestate is rapidly and highly available for plant growth in the short-term but also can be easily lost, together with a slow rate of microbial processes due to low temperatures, could reduce the fertilising capacity of the digestate. This seemed to be the main limiting factor for the winter cauliflower crop, where digestate or cattle manure, used as basal dressing, were not enough to satisfy the crop demand for nitrogen during its whole growth cycle. [Copyright &y& Elsevier]

Abstract: The combined use of plants and associated microorganisms has great potential for remediating soil contaminated with organic compounds such as pesticides. The objective of this study was to determine whether the bacterial inoculation influences plant growth promotion and chlorpyrifos (CP) degradation and accumulation in different parts of the plant. Ryegrass was grown in soil spiked with CP and inoculated with a pesticide degrading bacterial strain Bacillus pumilus C2A1. Inoculation generally had a beneficial effect on CP degradation and plant biomass production, highest CP degradation (97%) was observed after 45days of inoculation. Furthermore, inoculated strain efficiently colonized in the rhizosphere of inoculated plant and enhanced CP and its primary metabolite 3,5,6-trichloro-2-pyridinol (TCP) degradation. There was significantly less CP accumulation in roots and shoots of inoculated plants as compared to uninoculated plants. The results show the effectiveness of inoculated exogenous bacteria to boost the remediation of CP contaminated sites and decrease levels of toxic pesticide residues in crop plants. [Copyright &y& Elsevier]

The presence of residual organochlorine and organophosphorus pesticides was evaluated at different periods of sugarcane cultivation in agricultural soil and water samples from the town of Tlaltizapan, which is located in the state of Morelos in Mexico, to determine the presence and persistence of these compounds and their possible effects on the region. The compounds p,p′-DDE, p,p′-DDD (metabolites of p,p′-DDT), γ-HCH and heptachlor were found in more of 95% of the sampling zones in the three monitoring periods performed along 2 years. The highest concentration detected (129.6 μg/kg dry soil) was for α-HCH, but its frequency of detection was ∼5%. The low detection frequency of α-HCH and the high concentration values of γ-HCH indicate the repeated use of technical-grade HCH and Lindane (γ-HCH) in the region. Among the organophosphorus pesticides, ethyl parathion was the compound with the highest soil concentration, at ∼2000 μg/kgdry soil, during the initial monitoring. However, this compound was detected in the second monitoring with a concentration of ∼4 μg/kgdry soil, but it was not detected in the third, indicating that is was not accumulated in the environment. The heptachlor was the compound most commonly found in all water samples, within a range of 0.45–1.25 ng/L. The presence of this organochlorine compound in the water samples indicated a possible migration from the soil to water bodies due to soil erosion. The presence of organophosphorus compounds was not detected in the water samples, which could be attributed to the moderate persistence of these compounds and their consequent degradation before arriving at the water bodies. [ABSTRACT FROM AUTHOR]

On soils lacking in water-soluble sulphur, the sulphur fertilization of winter wheat, in general, increases the yields. There are not sufficient investigations about the influence of sulphur on the quality of yield. The objective of this work was to investigate the content and quality of protein in wheat grain depending on sulphur fertilization. The present study relies on field trials conducted on two different soils during 2004–2009. Sulphur was applied with NS-fertilizer Axan or Axan Super at the rate of S 10 or 13.6 kg ha−1 accompanied by a nitrogen background of N 100 kg ha−1. The rates of N- and NS-fertilizers were divided and applied at the beginning and at the end of tillering. At harvest, the grain samples from trial variants in four replications were taken, and the contents of crude protein, wet gluten, amino acids (lysine, threonine, cysteine, methionine) and gluten index in wheat grain were determined. Besides, the contents of amino acids were recalculated on their concentrations in protein. The protein and wet gluten contents in grain varied significantly depending on weather conditions of the trial years. On break-stony soil, sulphur increased the yield by 1.16 t ha−1 on average, i.e. by 21.7%. With increasing yields the protein and wet gluten concentrations in grain decreased. Under the influence of sulphur, the gluten index increased significantly – from 58 to 74, i.e. by 27.6%. In 2004 and 2005, sulphur increased the cysteine and methionine content in wheat grain. Although sulphur application in many cases decreased the protein and wet gluten contents in wheat grain, it improved the biological quality of protein because the concentrations of above-mentioned amino acids recalculated on their concentrations in protein increased significantly. The sulphur application in pseudopodzolic soil had a weaker effect on the grain quality than in break-stony soil. [ABSTRACT FROM AUTHOR]

While biofuel crops are widely studied and compared for their energy and carbon footprints, less is known about their effects on other soil properties, particularly hydrologic characteristics. Soils under three biofuel crops, corn (Zea mays), switchgrass (Panicum virgatum), and willow (Salix spp.), were analyzed seven years after establishment to assess the effects on soil bulk density (ρb), penetration resistance (PR), water-holding capacity, and infiltration characteristics. The PR was the highest under corn, along with the lowest associated water content, while PR was 50–60% lower under switchgrass. In accordance with PR data, surface (0–10 cm) bulk density also tended to be lower under switchgrass. Both water infiltration rates and cumulative infiltration amounts varied widely among and within the three crops. Because the Philip model did not fit the data, results were analyzed using the Kostiakov model instead. Switchgrass plots had an average cumulative infiltration of 69 cm over 3 hours with a constant infiltration rate of 0.28 cm min−1, compared with 37 cm and 0.11 cm min−1 for corn, and 26 cm and 0.06 cm min−1 for willow, respectively. Results suggest that significant changes in soil physical and hydrologic properties may require more time to develop. Soils under switchgrass may have lower surface bulk density, higher field water capacity, and a more rapid water infiltration rate than those under corn or willow. [ABSTRACT FROM AUTHOR]

Currently, efficient and cost-efficient methods are needed to manage fields in order to maximize economic return, minimize environmental impact, and improve soil and crop site-specific management. Management zones (MZs) of uniform production potential may offer a solution to the problems associated with grid soil sampling while still effectively describing variability in soil properties. In this study, a hillside field of 4 ha was selected as the study site and 111 soil samples were taken from the topsoil (0–20 cm), on an ∼20-m grid. Soil samples were analyzed for pH, organic matter, active soil organic matter, total nitrogen, alkalytic nitrogen, available phosphorous, available potassium and cation-exchange capacity. Their spatial variability was analyzed and spatial distribution maps were constructed using geostatistical techniques. Principal component analysis (PCA) and fuzzy c-means clustering algorithm were then performed to delineate MZs, and eigenvalues were used to select the principal components (PCs) for cluster analysis. Fuzzy performance index and normalized classification entropy were used to determine the optimum cluster number. The results revealed that the optimum number of MZs for this study area was three and analysis of variance indicated that the MZs were reasonable for the area. Based on the description of MZs, it was concluded that the area could be managed in a site-specific way. [ABSTRACT FROM AUTHOR]

A field study was carried out in the period 2000-2006 at the Experimental Station in Tomaszkowo belonging to the University of Warmia and Mazury in Olsztyn. Its aim was to compare weed infestation of a mixture of spring barley and field pea grown in a four crop rotation with different crop selection and sequence. Each year during tillering of spring barley and before the harvest of the mixture, weed species composition and density were evaluated, while additionally weed biomass was also estimated before the harvest. These results were used to determine species constancy, Simpson's dominance index, the Shannon-Wiener diversity and evenness indices as well as the community similarity index based on floristic richness, numbers and biomass of particular weed species. The cropping frequency and the position of the mixture in the crop rotation did not differentiate the species composition and total biomass of weed communities in the cereal-legume mixture crops. The crop rotation in which the mixture constituted 50% and was grown after itself had a reducing effect on weed numbers. Growing field pea in the 4-year crop rotation promoted weed infestation of the mixture and the dominance of weed communities. Capsella bursa-pastoris, Chenopodium album, Echinochloa crus-galli, Elymus repens, Polygonum convolvulus, and Sonchus arvensis were constant components of the agrophytocenoses. The weed communities were more similar in terms of their floristic composition than in terms of weed density and air-dry weight of weeds. [ABSTRACT FROM AUTHOR]

The present study was conducted to investigate the impact of textile dye on the early seedling stage of 3 crops: barley, maize, and wheat. Seeds were imbibed in different concentrations of textile dye for 12 h and were then grown in a controlled growth room for 8 days with a related dye solution. Some growth and polyphasic chlorophyll fluorescence parameters were measured and analysed to appraise the effect of textile dye on the 3 crops. Although different crop species showed differences in response to different concentrations, textile dye generally affected almost all radicle growth parameters more adversely than coleoptile growth parameters. While photosynthetic performance indexes of wheat increased significantly in all textile dye treatments, those same parameters in barley strongly decreased in all concentrations. While performance indexes of maize increased up to 250 ppm, indexes decreased with the highest dye concentration. Analysis of polyphasic chlorophyll fluorescence and growth parameters allowed for the separation of wheat, which exhibited a better performance than the other crops under textile dye treatment. The results point out that the impact of textile dye is dependent on its concentration and that it is crop-specific. In addition, textile dye may not be detrimental for these 3 crops. [ABSTRACT FROM AUTHOR]

In connection with the conduction of field experiments to evaluate new complex herbicides for weed control in corn, wheat and winter rape, analyzes of some soil parameteres were carried out in order to trace their dynamics as a result of cultivation and application of herbicides. [ABSTRACT FROM AUTHOR]

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Forest restoration projects have become increasingly common around the world and planting trees is almost always a key component. Low seedling survival and growth may result in restoration failures and various mechanical site preparation techniques for treatment of soils and vegetation are important tools used to help counteract this. In this article, we synthesize the current state-of-knowledge concerning mechanical site preparation for improved tree establishment when carried out in different forest restoration situations, point out critical research gaps and provide some recommendations for future directions. Mechanical site preparation often results in improved seedling survival and growth. However, if not intensive methods with much soil disturbance are used, it is a rather ineffective tool for controlling competing vegetation. Methods such as scarification, mounding and subsoiling also lead to multiple interactions among soil physical and chemical properties that affect plant survival and growth, and it may be difficult to determine the actual cause-effect relationship of any positive seedling responses. Most research to date on mechanical site preparation and plantation performance has been conducted using a few conifer tree species. Seedling responses differ among tree species and alternative species are often used during restoration compared to production forestry indicating a need for additional research for improved understanding. Several management objectives such as soil protection and increased biodiversity are many times relevant during forest restoration, and mechanical site preparation methods should be implemented carefully because they can have large impacts on the environment. [ABSTRACT FROM AUTHOR]

The fungi Colletotrichum coccodes and Verticillium dahliae are two pathogens of potato which are prevalent in potato field soils and seed tubers. The objective of this study was to investigate the influence of seed lot infection by C. coccodes and V. dahliae on disease severity and yield using infested seed lots and fields with and without potato in their recent cropping histories. Greater incidence of C. coccodes in seed led to more root colonization in 2008 (both field types) but not in 2007 and did not influence tuber quantity or yield. Incidence of infection in seed lots by V. dahliae was not related to canopy necrosis, infection of progeny tubers, or yield. However, seed lots exhibited more V. dahliae aboveground vascular colonization, canopy necrosis, infested plant debris, and infected progeny tubers in 5-year potato rotation fields compared with long potato rotation fields. In general, foliar disease symptoms and yield reductions were not related to levels of either pathogen in seed lots. Symptoms of both diseases were more severe and yields were lower in fields with potato in their recent cropping histories, emphasizing the importance of soilborne inoculum in the development of black dot and Verticillium wilt of potato. [ABSTRACT FROM AUTHOR]

Plants need to acquire nitrogen (N) efficiently from the soil for growth. Nitrate is one of the major N sources for higher plants. Therefore, nitrate uptake and allocation are key factors in efficient N utilization. Membrane-bound transporters are required for nitrate uptake from the soil and for the inter- and intracellular movement of nitrate inside the plants. Four gene families, nitrate transporter 1/peptide transporter (NRT1/PTR), NRT2, chloride channel (CLC), and slow anion channel-associated 1 homolog 3 (SLAC1/SLAH), are involved in nitrate uptake, allocation, and storage in higher plants. Recent studies of these transporters or channels have provided new insights into the molecular mechanisms of nitrate uptake and allocation. Interestingly, several of these transporters also play versatile roles in nitrate sensing, plant development, pathogen defense, and/or stress response. [Copyright &y& Elsevier]

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Metamifop is a herbicide used for the control of annual grass weeds in rice. Agrochemicals leaching into aquatic environments are of concern due to their potential persistence. Thus, this study was undertaken to determine the terminal residue of metamifop in rice crop and soil. Field experiments with rice were conducted at Tamil Nadu Agricultural University, Coimbatore, India. Metamifop was applied during 2–3 and 5–6 leaf stages of the weeds at different doses, namely, 0, 75, 100, and 125 g active ingredient (ai) ha−1. Paddy grains, straw, and soil samples were collected at harvest and analyzed for metamifop by HPLC. Residues were high in the plots which had received 125 g ai ha−1 at 2–3 leaf and 5–6 leaf stage. Though the metamifop residues were below 10 µg kg−1 in all substrates, N-(2-fluorophenyl)-2-hydroxy-N-methylpropionamide, a metabolite of metamifop, was detected in the soil and grain ranged from 4 to 221 µg kg−1. Hence, it is important to study the metamifop residue and its metabolites in soil and its biomagnification potential in crops. [ABSTRACT FROM PUBLISHER]

Abstract: In the absence of significant mechanical disturbance such as under permanent no-till (NT), crop type should be a prominent factor controlling soil organic C (SOC) pools. Microbial cell residues have been shown to be influenced by plant species and are believed to contribute significantly to soil organic matter formation. We performed a study to investigate the co-accumulation of microbial cell wall residues (glucosamine, GlcN and muramic acid, MurN) and organic C (total and particle-size fractions) in the surface layer (0- to 5-cm depth) of an Oxisol after 7 yr under NT, as affected by different crop types. SOC content associated with pigeon pea [Cajanus cajan (L.) Millsp.] was 20% and 18% higher than that with corn (Zea mays L.) or sunflower (Helianthus annuus L.), respectively. The highest particulate organic C (POC) content in soil was also found under pigeon pea, which showed values 54, 46, and 48% higher than under corn, sunflower, and oilseed radish (Raphanus sativus L. var. oleiformis Pers.), respectively. Changes in POC explained most of the variation in SOC. The positive impact of pigeon pea on POC and SOC was attributed to rapid decomposition of its residues, due to their low C/N ratio, followed by selective preservation of lignin-rich particulate organic matter. The accrual of POC was closely associated with the accumulation of fungal and bacterial cell wall residues. This may be due to preferential feeding of fungi and bacteria on recently deposited plant-derived C sources present in the form of particulate organic matter. This observation is consistent with a recent model suggesting that microbial residues play a greater role in the formation of SOC than previously considered. We emphasize that this effect was mediated by the accumulation of POC and influenced by crop type. [Copyright &y& Elsevier]

Daisy is a soil-plant-atmosphere system model focusing on agro-ecosystems. It simulates water, heat, carbon, and nitrogen balances as well as crop production and pesticide fate in agro-ecosystems subjected to various management strategies. The basic scale of application is the field (management unit), which may be simulated in one or two dimensions. Daisy allows several different process descriptions for water flow, evapotranspiration, crop growth, and solute transport. Furthermore, it can operate in a distributed mode (several fields) and link up with distributed hydrological models. In this case, statistical and remote sensing data are relevant. Considerations concerning the objective of a given study and available data determine the choice of process descriptions. All applications require information concerning weather (at minimum, daily values of solar radiation, air temperature, and precipitation), soil (texture, organic matter, hydraulic parameters, etc.), location of groundwater, and vegetation cover. Applications that focus on nitrogen dynamics require a description of crop rotation, tillage, use of fertilizer and manure, irrigation, sowing, harvesting, and organic matter turnover in the soil In carbon and nitrogen balance simulations, the uncertainty associated with crop growth is particularly important because Daisy only considers water and nitrogen stress. Dry matter and nitrogen yield may require calibration. Uncertainty associated with initialization of the organic matter pools and the parameterization of organic fertilizers is considered to be of major importance. For pesticide transport calculations, descriptions of macroporosity and hydraulic conditions close to the surface are critical. Daisy has been validated in several international comparative validation studies. [ABSTRACT FROM AUTHOR]

Capillary barriers (CBs) occur at the interface between two soil layers having distinct differences in hydraulic characteristics. In preliminary work without growing crops, it was demonstrated that CBs implemented in sandy soils increased hydrostatic volumetric water content by 20-70%, depending on soil texture and depth of barrier insertion. We hypothesized that the introduction of an artificial CB at the lower root-zone boundary of horticultural crops can increase yields as a result of increased water content and uptake efficiency. The effects of introduced CBs on soil water content, plant growth, and yields of bell peppers ( Capsicum annum L), lettuce ( Lactuca sativa L), tomatoes ( Lycopersicon esculantum L.), and melons ( Cucumis melo L .) were studied in a desert environment in southern Israel. Inclusion of a CB increased soil water content by 60% and biomass and fruit yields by 25% for pepper, and increased matric head and biomass yield by 80 and 36%, respectively, for lettuce. Neither tomatoes nor melons reacted significantly to the presence of CBs, in spite of increased soil moisture. Daily soil matric head amplitude was reduced fivefold when lettuce was grown with a CB. Spatial variability was highly reduced when a CB was present. When peppers were grown with a CB, the standard deviations of water content and biomass yield were reduced by 40% relative to control. [ABSTRACT FROM AUTHOR]

In view of concerns raised about economic and ecological consequences of agricultural chemicals, organic amendments, such as vermiwash, have been considered appropriate strategies for crop improvement. However, research work evaluating the efficacy of foliar sprays of vermiwash in vegetable crops on acidic soils is quite limited. The present investigation, therefore, was carried out to evaluate the effect of different concentrations of vermiwash (VW) on okra (Abelmoschus esculentus L.) under field conditions on acidic soil. We also evaluated the response of Naga chilli (Capsicum assamicum) to foliar spray of 20% concentration of vermiwash. Results revealed that the application of VW significantly improved the vegetative and yield attributes of both the test crops. In okra, 20% VW exhibited the largest increase in marketable weight among all the treatments. The plants of Naga chilli receiving foliar spray of 20% VW registered a 27.47% increase in shoot height and a 11.93% increase in chlorophyll content (SPAD) as compared with control. In regards to yield attributes of the Naga chilli, foliar spray of 20% VW resulted in a 23.07 % increase (significant at P = 0.05) in number of seeds per fruit and a 43.47% increase (significant at P = 0.05) in average fruit weight in comparison with control. We suggest that foliar spray of 20% concentration of vermiwash could considerably improve the growth and yield of okra and Naga chilli on acidic soil. [ABSTRACT FROM AUTHOR]

Great uncertainties remain in the impact of cropping systems on soil organic carbon (SOC) stocks in paddy fields that hold a large potential for carbon (C) sequestration. In this study, a meta-analysis was performed to examine trends on SOC stocks in unfertilized and fertilized fields from three of the most common rice cropping systems in China. Results showed that rice cropping without any nutrient application (Control) significantly increased SOC stocks by 9% compared to the initial level in double rice cropping systems (DR), whereas no significant effects were observed in single rice cropping systems (SR) and rice-upland crop rotation systems (RU). Paddy soils sequestered C in all the three cropping systems under inorganic NPK fertilization, and the magnitude of the increase in SOC stocks was in the order DR > RU > SR. Soil C stocks increased with the increasing cropping duration. Continuous rice cropping for more than 20 years led to average SOC gains of 15% and 23% in the control and NPK treatments, respectively. Furthermore, it seems that C sequestration was still occurring in the longest fields from the included studies. Thus, no SOC saturation trend was found over the investigated cropping duration. However, the negative relationship between SOC changes and their initial C stocks suggests indirectly the possibility of SOC saturation in paddy fields. [ABSTRACT FROM AUTHOR]

Silica (Si) is of great concern to agronomists because it has a beneficial effect on plant resistance to various stresses, enabling yield optimization in economically important crop species. Yet biogenic silica (BSi) cycling in soils controls a large part of the Si export fluxes to rivers and oceans. Despite the importance of agricultural-harvest- related Si removal, previous studies have not addressed this topic thoroughly. By performing a detailed quantification of agricultural Si export in Western Europe's Scheldt River basin, we show that harvest not only disrupts BSi cycling but also introduces an agricultural Si pathway, with major export Si fluxes as compared with BSi production in climax forest communities and grasslands. Harvesting substantially changes terrestrial Si cycling because reconstitution of BSi to soils in litter fall is prevented. The agricultural Si loop clearly constitutes an important flow of BSi out of terrestrial ecosystems - one that is currently unrecognized in global biogeochemical Si cycling. [ABSTRACT FROM AUTHOR]

Abstract: Improvements in sensor technology in recent decades led to the creation of ground, air and space imaging systems, whose data can be used in archaeological studies. Greece is one of the lucky areas that are rich in archaeological heritage. The detection of prehistoric/historic undiscovered constructions on satellite images or aerial photos is a complex and complicated matter. These marks are not visible from the ground, they can, however, be traced on satellite or aerial images, because of the differences in tone and texture. These differences appear as crop, soil and shadow marks. Undoubtedly, the detection of buried structures requires a suitable spatial resolution image, taken under appropriate meteorological conditions and during the best period of the vegetation growing cycle. According to the pertinent literature, detecting covered memorials may be achieved either accidentally or, usually, after a systematic investigation based on historical narratives. The purpose of this study is to determine the factors that facilitate or hinder the detection of buried structures through high spatial resolution satellite imagery. In this study, pan sharpened images from the QuickBird-2 satellite were used, of a spatial resolution of 0.60-0.70m. This study concerns the detection of marks of the ancient Via Egnatia, from the ancient Amphipolis to Philippi (Eastern Macedonia, Greece). We studied different types of vegetation in the region and their phenological cycle. Taking into account the vegetation phenological cycle of the study area as well as the meteorological data, four pan sharpened QuickBird-2 images of a spatial resolution of 0.60–0.70m. were used, during four different seasons. By processing the four images, we can determine the one acquired during the most appropriate conditions for the detection of buried structures. The application of this methodology in the study area had positive results, and not only was the main purpose of this study – the detection of parts of the ancient Via Egnatia – achieved, but the locations of dozens of other buried archaeological remains were also determined. [Copyright &y& Elsevier]

Global biogeochemical cycles have been deeply modified by human activities in recent decades. But detailed studies analyzing the influence of current economic and social organizations on global biogeochemical cycles within a system perspective are still required. Country level offers a relevant scale for assessing nutrient management and identifying key driving forces and possible leaks in the nutrient cycle. Conceptual modeling helps to quantify nutrient flows within the country and we developed such an approach for France. France is a typical Western European country with intensive agriculture, trade and an affluent diet, all of which may increase internal and external P flows. Phosphorus (P) was taken as a case study because phosphate rock is a non-renewable resource which future availability is becoming increasingly bleak. A conceptual model of major P flows at the country scale was designed. France was divided into agriculture, industry, domestic, import and export sectors, and each of these sectors was further divided into compartments. A total of 25 internal and eight external P flows were identified and quantified on a yearly basis for a period of 16 years (from 1990 to 2006) in order to understand long-term P flows. All the P flows were quantified using the substance flow analysis principle. The results showed that the industrial sector remained the largest contributor to P flows in France, followed by the agriculture and domestic sectors. Soil P balance was positive. However, a positive P balance of 18 kg P ha-1 in 1990 was reduced to 4 kg P ha-1 in 2006, mainly due to the reduced application of inorganic P fertilizer. The overall country scale P balance was positive, whereas half of this additional P was lost to the environment mainly through the landfilling of municipal and industrial waste, disposal of treated wastewater from which P was partially removed, and P losses from agricultural soils though erosion and leaching. Consequences for global P resources and soil and water compartments are discussed. Some opportunities to more effectively close the P cycle in France by both improving the intensity of P recycling and decreasing losses are quantified. [ABSTRACT FROM AUTHOR]

Ammonia concentration and fluxes were measured above a growing triticale field for two months during May and June 2010 at the NitroEurope crop site in Grignon (Fr-Gri) near Paris, France. The measurement campaign started 15 days following a 40 kg N ha-1 application of an ammonium nitrate solution. A new mini-wedd (Wet Effluent Denuder) flow injection analyser with three channels (ROSAA, RObust and Sensitive Ammonia Analyser) was used to measure NH3 fluxes using the aerodynamic gradient method. The measured ammonia concentrations varied from 0.01 to 39 µg NH3 m-3 and were largely influenced by advection from the nearby farm. The ammonia fluxes ranged from -560 to 220 ng NH3 m-2 s-1 and averaged -29 ng NH3 m-2 s-1. During some periods the large deposition fluxes could only be explained by a very small surface resistance, which may be partly due to the high concentrations of certain acid gases (HNO3 and SO2) observed in this suburban area. Ammonia emissions were also observed. The canopy compensation point Γc was around 1.5 µg NH3 m-3 on average. The canopy emission potential Γc (Cc normalised for the temperature response of the Henry equilibrium) decreased over the course of the measurement campaign from Γc = 2200 to Γc = 450, the latter value being close to the median stomatal emission potential (Γs) and lower than the median ground emission potential (Γg) for managed ecosystems reported in the literature. The temporal dynamics of the measured NH3 flux compared well with the Surfatm-NH3 model using fitted parameters. The subjectivity of the model fitting is discussed based on a sensitivity analysis. [ABSTRACT FROM AUTHOR]

The lack of accurate detection of Gaeumannomyces graminis var. tritici inoculum in soil has hampered efforts to predict the risk of severe take-all for wheat growers. The current study used a molecular method to quantify soil G. graminis var. tritici concentrations in commercial wheat fields in New Zealand and to compare them with the proportion of crops surpassing the thresholds for visible and moderate to severe take-all over three growing seasons. The study evaluated a soil G. graminis var. tritici DNA-based take-all prediction system developed in Australia, with four take-all risk categories. These categories were found to be useful for predicting disease severity in second wheat but did not clearly separate risk between fields in medium- and high-risk categories. A sigmoidal relationship was identified between inoculum concentration and the proportion of fields exceeding the two disease thresholds. A logistic response curve was used to further examine this relationship and evaluate the boundaries between take-all risk categories. G. graminis var. tritici boundaries between medium- and high-risk categories were clustered near or within the upper plateau of the relationship. Alternative G. graminis var. tritici boundaries for a three-category system were identified that provided better separation of take-all risk between categories. This information could improve prediction of the risk of severe take-all. [ABSTRACT FROM AUTHOR]

The afforestation of abandoned farmland significantly influences soil organic carbon (OC). However, the dynamics between OC inputs after afforestation and the original OC are not well understood. To learn more about soil OC dynamics after afforestation of farmland, we measured the soil OC content in paired forest and farmland plots in Shaanxi Province, China. The forest plots had been established on farmland 18, 24, 48, 100, and 200 yr previously. The natural 13C abundance of soil organic matter was also analyzed to distinguish between crop- and forest-derived C in the afforested soils. We observed a nonlinear accumulation of total OC in the 0-80 cm depth of the mineral soil across time. Total soil OC accumulated more rapidly under forest stands aged 18 to 48 yr than under forest stands aged 100 or 200 yrs. The rate of OC accumulation was also greater in the 0-10 cm depth than in the 10-80 cm depth. Forest-derived OC in afforested soils also accumulated nonlinearly across time, with the greatest increase in the 0-20 cm depth. Forest-derived OC in afforest soils accounted for 52-86% of the total OC in the 0-10 cm depth, 36-61% of the total OC in the 10-20 cm depth, and 11-50% of the total OC in the 20-80 cm depth. Crop-derived OC concentrations in the 0-20 cm depth decreased slightly after afforestation, but there was no change in crop-derived OC concentrations in the 20-80 cm depth. The results of our study support the claim that afforestation of farmland can sequester atmospheric CO2 by increasing soil OC stocks. Changes in the OC stocks of mineral soils after afforestation appear to be influenced mainly by the input of forest-derived C rather than by the loss of original OC. [ABSTRACT FROM AUTHOR]

Continued use of the crop-livestock system in agricultural areas can promote changes in soil physical attributes, as well as affect the productivity of crops grown in rotation with pasture. The aim of this study was to evaluate the effects of methods of sowing and the interval between the withdrawal and desiccation of pasture on soil physical attributes, aboveground biomass of pasture and productivity of crops sown in succession. It was conducted an experiment in a rural property in Campos Novos, which uses the crop-livestok system, with the following treatments: two types of pasture seeding in autumn (direct seeding without and with subsequent soil harrowing), allocated in main plots, and four intervals of removing animals from the pasture before desiccation (removal of the animals at 28, 14 and 1 day before the desiccation and control, without grazing), allocated as subplots. It was determined the aboveground biomass of pasture, the soil physical attributes after desiccation of grassland and yield of soybeans and corn. The form of winter pasture seeding does not affect the soil physical attributes and crop productivity, while increasing the interval between the withdrawal and desiccation of winter pasture increases the production of the aboveground biomass of the pasture. [ABSTRACT FROM AUTHOR]

Abstract: The efficacy of no-till agriculture for increasing C in soils has been questioned in recent studies. This is a serious issue after many publications and reports during the last two decades have recommended no-till as a practice to mitigate greenhouse gas emissions through soil C sequestration. Our objective was to investigate the possibility that the lack of C increase in some no-till systems may be due to changes in crop productivity and subsequent C input to soils. A meta-analysis of 74 published studies was conducted to determine if crop production varies between no-till and full tillage management. The results were used to estimate the change in C input due to no-till adoption and the influence on soil organic C stocks at steady-state using the Century model. We found that crop productivity can be reduced with adoption of no-till, particularly in cooler and/or wetter climatic conditions. The influence varies, however, and crop productivity can even increase in some regions following adoption of no-till. In cases where crop production and C inputs decreased due to no-till, the potential reduction in soil organic C stocks was offset by a decrease in soil C decomposition rates, except in cases where C inputs declined by 15% or more. Challenges still remain for understanding the full impact of no-till adoption on soil organic C stocks, such as changes on C inputs in deeper subsurface horizons, the influence of variation in NT seeding methods on soil disturbance, and changes in SOM stabilization due to saturation limits in mineral soil fractions, which may further modify net C storage in soils. [Copyright &y& Elsevier]

Novel technologies to reduce tillage in organic systems include a no-tillage roller/crimper for terminating cover crops prior to commercial crop planting. The objective of this experiment was to compare: (1) weed management and yield effects of organic tilled and no-tillage systems for corn (Zea mays L.), soybean [Glycine max (L.) Merr.] and irrigated tomato (Lycopersicon esculentum Mill.), using a roller/crimper and two cover crop combinations [hairy vetch/rye (Vicia villosa Roth/Secale cereale L.) and winter wheat/Austrian winter pea (Triticum vulgare L./Pisum sativum L. ssp. arvense (L.) Poir.)]; and (2) the economic performance of each system. Weed management ranged from fair to excellent in the organic no-tillage system for soybean and tomato crops, with the rye/hairy vetch mulch generally providing the most weed suppression. Corn suffered from low rainfall, competition from weeds and hairy vetch re-growth and, potentially, low soil nitrogen (N) from lack of supplemental fertilization and N immobilization during cover crop decomposition. No-tillage corn yields averaged 5618 and 634 kg ha−1 in 2006 and 2007, respectively, which was 42–92% lower than tilled corn. No-tillage soybeans in 2007 averaged 2793 kg ha−1 compared to 3170 kg ha−1 for tilled soybeans, although no-tillage yields were 48% of tilled yields in the dry year of 2006. Irrigated tomato yields averaged 40 t ha−1 in 2006 and 63 t ha−1 in 2007, with no statistical differences among tillage treatments. Economic analysis for the three crops revealed additional cover crop seed and management costs in the no-tillage system. Average organic corn returns to management were US$1028 and US$2466 ha−1 greater in the tilled system compared to the no-tillage system in 2006 and 2007, respectively, which resulted mainly from the dramatically lower no-tillage yields. No-tillage soybean returns to management were negative in 2006, averaging US$ −14 ha−1, compared to US$742 ha−1 for tilled soybeans. However, in 2007, no-tillage soybean returns averaged US$1096 ha−1. The 2007 no-tillage irrigated tomato returns to management averaged US$53,515 compared to US$55,515 in the tilled system. Overall, the organic no-tillage soybean and irrigated tomato system demonstrated some promise for reducing tillage in organic systems, but until economic benefits from soil carbon enhancement can be included for no-tillage systems, soil improvements probably cannot offset the economic losses in no-tillage systems. Irrigation could improve the performance of the no-tillage system in dry years, especially if grain crops are rotated with a high-value irrigated tomato crop. [ABSTRACT FROM AUTHOR]

Conservation agriculture's underlying principles—minimal soil disturbance, soil cover and crop rotation—are increasingly recognized as essential for sustainable agriculture. This article summarizes three contrasting cases of adapting conservation agriculture (CA) to smallholder conditions in the (sub)tropics: a) irrigated rice-wheat systems in South Asia; b) rainfed maize/wheat and irrigated wheat systems in Mexico; and c) rainfed maize in Southern Africa. In the South Asia case, farm surveys show rapid and widespread adoption of zero tillage wheat—primarily due to a substantial cost saving (15–16%). In the other cases, uptake so far has been limited—although long-term trials show continuously higher and more stable yields both for maize and wheat. Under marginal conditions CA can generate substantial yield increases—averaging some 50% over conventional smallholder maize yields of 1 ton per ha over 6 years in on-farm trails in Southern Africa. The diverse experiences attest to the wide adaptability of CA systems, which can generate clear economic and potentially enormous environmental benefits. The case studies and wider literature however also reiterate the substantial challenges in terms of targeting, adapting and adopting CA—particularly for smallholders in the (sub)tropics. CA systems are best developed in situ through a multi-stakeholder adaptive learning process to create viable CA-based options that are technically sound, economically attractive, and socially acceptable. [ABSTRACT FROM AUTHOR]

Abstract: Sensors for on-the-go collection of data on soil and crop have become essential for successful implementation of precision agriculture. This paper analyses the potentials and develops general procedures for on-the-go data acquisition of soil sensors. The methods and procedures used to manage data with respect to a farm management information system (FMIS) are described. The current data communication standard for tractors and machinery in agriculture is ISO 11783, which is rather well established and has gained market acceptance. However, there are a significant number of non-ISO 11783 compliant sensors in practice. Thus, two concepts are proposed. The first concept is on-the-go data collection based on ISO 11783, which mostly covers data on parameters related to tractor and machine performance, e.g. speed, draught, fuel consumption, etc. Process data from sensors with Control Area Network (CAN) interfaces is converted into ISO 11783 XML and then imported into relational database at FMIS using RelaXML tool. There is also the export function from database to task controller (TC) to provide task management, as described in ISO 11783:10. The second concept is on-the-go data collection with non-ISO 11783 sensors. This data is likely to be recorded in many formats, which require an import service. An import service is based on local or public sharing or semantic mapping outputting a common format for FMIS (e.g. AgroXML). Import is best performed as close to the generation of sensor data as possible to maximise the availability of metadata. A case study of sensor based variable rate fertilisation (VRF) has been undertaken focussing on German fertilisation rules. [Copyright &y& Elsevier]

Abstract: Assessing the environmental impacts of agricultural practices at the catchment scale increasingly involves the use of spatially distributed models that include cropping systems as input. Use of these models for diagnosis and evaluation requires large datasets at large spatial and temporal scales. The description of spatial dynamics of cropping systems at a fine resolution (i.e. field level) is particularly needed. As these data are scarce or not available, our objective was to propose a model that first reconstructs spatial dynamics of past cropping systems from available data, and second constructs alternative spatial cropping systems, corresponding to agricultural practice scenarios. Classification systems for farms and fertilisation practices were defined to classify farm-level organisation for crop-succession and crop management strategies, in particular nitrogen fertilisation. Winter cover crops and multiple strategies per crop at the farm level can be represented with this model. Cropping systems are modelled in three steps: we modelled crop cover succession in summer with Markov chains based on empirical data and in winter with rules based on expert agronomic knowledge; lastly a Knapsack-based algorithm was used to allocate a crop management system to fields with constraints on several crop management strategies per crop type. Results of a case study performed on the Frémeur catchment (western France) show that this model respects the main constraints for cropping system modelling to assess agricultural practices at the catchment scale. From a scenario discussed with stakeholders and regional authorities characterised by stable areas of summer crops, the decrease in bare soil area in winter and overall reduction in total nitrogen fertilisation for different types of crops and farms we demonstrate the model’s ability to simulate coherent cropping systems. Thus, if faced with a lack of data or knowledge about the local factors that drive changes in cropping systems, the model can construct the spatial dynamics of cropping systems, which can be used as input to distributed nitrate transfer models to assess agricultural practices at the catchment scale. [Copyright &y& Elsevier]

Field studies have indicated that plant-available P supply is the main determinant of the performance of arbuscular mycorrhiza (AM) of crops. Direct evidence is, however, weak. Our aim was to test the hypothesis that plant-available P is the main factor determining the benefit from AM to plant P uptake and growth in contrasting cropping systems. We compared a conventional system with full and half fertilisation rates and a low-input system with and without composting of residues. After 15 years, plant P response functions, with and without AM, were determined in a bioassay. At equal plant availability of P, the benefits from AM were similar to those at the P status in the field: The benefits were greater in the low-input system than in the conventional system, irrespective of the fertilisation rate but clearest with composting. This shows that differences between the systems in the benefit from AM to a particular crop genotype are not mainly due to differences in plant-available P. The results suggest also that differences in P pools, in growth-limiting factors such as N supply and in phytotoxicity to AMF hyphae play roles in determining the benefit. It is not likely that differences in AMF communities are important. [ABSTRACT FROM AUTHOR]