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Ethnoagroforestry practices and their relationship with soil fertility were studied in the semiarid Tehuacan Valley. Such practices involve management of manure, vegetation patches, wild and cultivated plants, soil, and water. This study aimed to: i) describe agroforestry management practices that influence soil fertility in maize multicultural system (milpa)-cacti forest (chichipera) AFS; ii) analyze the status of soil fertility in cultivated areas of these AFS; and iii) analyze the influence of agroforestry practices on soil nutrimental parameters of cultivated areas. In depth interviews were conducted, along with participatory tours with peasants and soil sampling in the agroforestry plots. Ethnoagroforestry practices favor adequate levels of macronutrients and organic matter in the milpa-chichipera AFS, despite Fe, Cu, and Zn deficiencies. The supply of organic matter is fundamental because it preserves soil fertility and moisture in all the plots studied. Smallholders (43%) use manure, but in irregular and insufficient way. Only 27% of interviewed people leave the land fallow for 1-2 after periods of 2-4 years of use, which does not allow the soil to reestablish fertility. Smallholders practice wild vegetation management, enabling 90% of plots to reach a high level of vegetation cover (>25%), furthermore 33% of agroforestry plots depend exclusively on this management to reestablish soil fertility. Labor force, economic conditions and plots characteristics influence agroforestry management. The amount of manure and the interaction between the agroforestry practices (vegetation cover, type of agroforestry practices, amount of manure, and fallow years) are related to the presence of N, K, Cu and B in the soil. To maintain and improve soil fertility in the milpa-chichipera AFS is important to consider local practices, biophysical conditions, and socio-economic factors. [ABSTRACT FROM AUTHOR]

Background and aims: Elevated CO (C) and temperature (T) can not only affect crop physiology and growth but also soil nutrient availability, which could in turn influence crop response to C and T. However, such indirect impacts of C and T on crop productivity are often unexplored, potentially underestimating the impact of C and T at a system level. Methods: To explore the possible role of soil nutrient availability in mediating crop responses to C and T, we examined the effects of C and T on cotton productivity and soil nutrient availability in two soils. Results: Early vegetative growth response was dominated by the interaction between C and T; T accelerated vegetative growth while C enhanced photosynthesis and vegetative growth at ambient temperature. When soil nitrogen availability became low during the reproductive phase, altered soil nitrogen availability at C and T and differences in soil characteristics influenced resource allocation and yield response, resulting in a doubling of cotton yield at T but only a marginal increase at C. Conclusions: Changes in soil nutrient availability induced by C and T during crop development can enhance or limit yield responses to C and T. Thus, soil responses should also be considered when developing adaptation strategy for climate change. [ABSTRACT FROM AUTHOR]

A guava based intercropping systems comprising of nine intercrops such as mango ginger, turmeric, tomato, cowpea, frenchbean, ragi, niger, upland paddy and control (without intercrop) was conducted to study the influence of various intercropping systems on plant and soil health of guava orchard. The results revealed that guava + cowpea system showed significant improvement in bulk density, electrical conductivity, water holding capacity, organic carbon content and pH of orchard soil. The guava + cowpea system also recorded significantly maximum available nitrogen and potassium content in the soil, whereas the maximum available phosphorus content were obtained in guava + mango ginger system. The nitrogen, phosphorus, and potassium (N, P and K) content of guava leaf were found to be maximum under the guava + cowpea system. The fruit yield of guava was recorded highest in guava +cowpea intercropping system. However, the total soluble solids (TSS) and acidity of fruits were not affected by the intercropping systems. [ABSTRACT FROM AUTHOR]

A multi-element mineral conditioner (MMC) is a kind of slightly alkaline soil conditioner prepared by calcining a mixture of calcium or magnesium-based desulfurized flue gas residue, potassium feldspar, gypsum, dolomite, and limestone powder, rich in available K, Ca, Mg, Si, and other micronutrients. To evaluate the effect of MMC on the concentration of essential cations in red soil and in the crops grown thereon, a 4-month field experiment was conducted. By applying the MMC, the acidity of the red soil caused by weathering and chronic acid rain in Southern China can be neutralized, and the essential cations severely lacking in red soil and crops can be adequately replenished. Due to the addition of essential cations to red soil, the 1:1 type clay mineral gradually transformed into 2:1 type clay mineral. The grain yield was increased and the quality of rice was improved. The concentrations of Pb, Cd, Hg, and As in rice grains grown in the treated soil was significantly decreased. These results demonstrate that use of MMC can ameliorate soil and improve its fertility, reduce the reliance of crops on chemical fertilizers, raise the rice yield and improve the quality of red soil. [ABSTRACT FROM AUTHOR]

There is a growing interest in precision viticulture with the development of global positioning system and geographical information system technologies. Limited information is available on spatial variation of bud behavior and its possible association with soil properties. The objective of this study was to investigate spatial variability of bud burst percentage and its association with soil properties based on 2-year experiments at a vineyard of arid northwest China. Geostatistical approach was used to describe the spatial variation in bud burst percentage within the vineyard. Partial least square regressions (PLSRs) of bud burst percentage with soil properties were used to evaluate the contribution of soil properties to overall spatial variability in bud burst percentage for the high, medium and low bud burst percentage groups. Within the vineyard, the coefficient of variation (CV) of bud burst percentage was 20% and 15% for 2012 and 2013 respectively. Bud burst percentage within the vineyard showed moderate spatial variability, and the overall spatial pattern of bud burst percentage was similar between the two years. Soil properties alone explained 31% and 37% of the total spatial variation respectively for the low group of 2012 and 2013, and 16% and 24% for the high group of 2012 and 2013 respectively. For the low group, the fraction of variations explained by soil properties was found similar between the two years, while there was substantial difference for the high group. The findings are expected to lay a good foundation for developing remedy measures in the areas with low bud burst percentage, thus in turn improving the overall grape yield and quality. [ABSTRACT FROM AUTHOR]

The article highlights strategies to prevent the invasion of common ragweed Ambrosia (A.) artemisiifolia, as well as control and eradicate the plant. Topics discussed include risk assessment to determine whether A. artemisiifolia could establish in the country, countries where common ragweed is not widely distributed, and direct measures against the plant and the adaptation of the crop rotation system to reduce common ragweed occurrence.

Phosphorus (P) is a non-renewable resource, a major plant nutrient that is essential for modern agriculture. Currently, global food and feed production depends on P extracted from finite phosphate rock reserves mainly confined to a small number of countries. P limitation and its potential socio-economic impact may well exceed the potential effects of fossil fuel scarcity. The efficiency of P usage today barely reaches 20%, with the remaining 80% ending up in wastewater or in surface waters as runoff from fields. When recovered from wastewater, either chemically or biologically, P is often present in a form that does not meet specifications for agricultural use. As an alternative, the potential of microalgae to accumulate large quantities of P can be a way to direct this resource back to crop plants. Algae can acquire and store P through luxury uptake, and the P enriched algal biomass can be used as bio-fertilizer. Technology of large-scale algae cultivation has made tremendous progress in the last decades, stimulated by perspectives of obtaining third generation biofuels without requiring arable land or fresh water. These new cultivation technologies can be used for solar-driven recycling of P and other nutrients from wastewater into algae-based bio-fertilizers. In this paper, we review the specifics of P uptake from nutrient-rich waste streams, paying special attention to luxury uptake by microalgal cells and the potential application of P-enriched algal biomass to fertilize crop soils. [ABSTRACT FROM AUTHOR]

Extraction of vegetation information from remotely sensed images has remained a long-term challenge due to the influence of soil background. To reduce this effect, the slope and intercept of the soil line (SL) should be known to calculate SL-related vegetation indices (VIs). These VIs can be used to estimate the biophysical parameters of agricultural crops. However, it is a difficult task to retrieve the SL parameters under the vegetation canopy. A feasible method for retrieving these parameters involves extracting the bottom boundary line in two-dimensional spectral spaces (i.e., red and near-infrared bands). In this study, the slope and intercept of the SL was extracted from Landsat 8 OLI images of a test site in northeastern Germany. Different statistical methods, including the Red-NIRmin method, quantile regression method (using a floating tau with the smallest p-value), and a new approach proposed in this paper using a fixed quantile tau known as the diffuse non-interceptance (DIFN) value, were applied to retrieve the SL parameters. The DIFN value describes the amount of light visible below the canopy that reaches the soil surface. Therefore, this value can be used as a threshold for retrieving the bottom soil line. The simulated SLs were compared with actual ones extracted from ground truth data, as recorded by a handheld spectrometer, and were also compared with the SL retrieved from bare soil pixels of the Landsat 8 image collected after harvest. Subsequently, the SL parameters were used to separately estimate the dry biomasses of winter wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and canola (Brassica napus L.) at the local and field scales using different SL-related vegetation indices. The SL can be retrieved more accurately at the local scale compared with the field scale, and its simulation can be critical in the field due to significant differences from the actual SL. Moreover, the slope and intercept of the simulated SLs found using the floating and fixed quantile tau (slope ≈ 1.1 and intercept ≈ 0.05) show better agreement with the actual SL parameters (slope ≈ 1.2 and intercept ≈ 0.03) in the late growing stages (i.e., end of ripening and senescence stages) of crops. The slope and intercept of the soil line extracted from bare soil pixels of the Landsat 8 OLI data after harvest (slope = 1.3, intercept = 0.03, and R² = 0.94) are similar to those of the simulated SL. The correlation coefficient (R²) of the simulated SLs are greater than 0.97 during different growing stage and all of the SL parameters are statistically significant (p < 0.05) at the local scale. The results also imply the need for different vegetation indices to best retrieve the crop biomass depending on the growing stage, but relatively small differences in performances were observed in this study. [ABSTRACT FROM AUTHOR]

A direct soil DNA extraction method from soil samples (250 g) was applied for detection of the soilbome sugar-beet-infecting pathogen Rhizoctonia solani anastomosis group (AG) 2-2IIIB using a newly developed real-time polymerase chain reaction assay that showed specificity to AG2-2IIIB when tested against various R. solani AG. The assay showed a good relation between cycle threshold and amount of AG2-2IIIB sclerotia detected in three spiked field soils and was also able to detect the pathogen in naturally infested field soil samples. A field trial was conducted to quantify R. solani AG2-2IIIB soil inoculum potential (IP) before and after growing a susceptible and a resistant sugar beet variety as well as after subsequent growth of an expected nonhost winter rye. Plants of the susceptible sugar beet variety displayed a higher disease severity. A more than sixfold increase of the R. solani AG2-2IIIB soil IP was observed in contrast to the resistant variety that resulted in a constant IP. Growing winter rye significantly reduced soil IP to the initial level at sowing. Further research is required to better understand the interaction between disease occurrence and soil IP as well as the environmental influence on IP development. [ABSTRACT FROM AUTHOR]

This study investigated the fluoride present in tea plants ( Camellia sinensis (L.) O. Kuntze) and its relationship to soils, varieties, seasons and tea leaf maturity. The study also explored how different manufacturing processes affect the leaching of fluoride into tea beverages. The fluoride concentration in the tea leaves was significantly correlate to the concentration of water-soluble fluoride in the soil. Different tea varieties accumulated different levels of fluoride, with varieties, Anji baicha having the highest and Nongkang zao having the lowest fluoride concentration. In eight different varieties of tea plant harvested over three tea seasons, fluoride concentration were highest in the summer and lowest in the spring in china. The fluoride concentration in tea leaves was directly related to the maturity of the tea leaves at harvest. Importantly, the tea manufacturing process did not introduced fluoride contamination. The leaching of fluoride was 6.8% and 14.1% higher in black and white tea, respectively, than in fresh tea leaves. The manufacturing step most affecting the leaching of fluoride into tea beverage was withering used in white, black and oolong tea rather than rolling or fermentation. The exposure and associated health risks for fluoride concentration in infusions of 115 commercially available teas from Chinese tea markets was determined. The fluoride concentration ranged from 5.0 to 306.0 mg kg −1 , with an average of 81.7 mg kg −1 . The hazard quotient (HQ) of these teas indicated that there was no risk of fluorosis from drinking tea, based on statistical analysis by Monte Carlo simulation. [ABSTRACT FROM AUTHOR]

Livelihood status, smallholder farming, and climate change are directly interconnected in sub-Sahara Africa. Simulations predict that yields of main crops will decrease and will be negatively impacted due to climate change within the next 30–40 years. The results of a simulation and survey about land use management and demography reveal the competitiveness of drought adapted pearl millet varieties concerning yields and the potential impact on sustainable smallholder farming in a semiarid region of Kenya. We highlight the ability of adapted crops to improve livelihood through increased income generation and food security with the help of optimized farm management. [ABSTRACT FROM PUBLISHER]

Precision agriculture accounts for within-field variability for targeted treatment rather than uniform treatment of an entire field. It is built on agricultural mechanization and state-of-the-art technologies of geographical information systems (GIS), global positioning systems (GPS) and remote sensing, and is used to monitor soil, crop growth, weed infestation, insects, diseases, and water status in farm fields to provide data and information to guide agricultural management practices. Precision agriculture began with mapping of crop fields at different scales to support agricultural planning and decision making. With the development of variable-rate technology, precision agriculture focuses more on tactical actions in controlling variable-rate seeding, fertilizer and pesticide application, and irrigation in real-time or within the crop season instead of mapping a field in one crop season to make decisions for the next crop season. With the development of aerial variable-rate systems, low-altitude airborne systems can provide high-resolution data for prescription variable-rate operations. Airborne systems for multispectral imaging using a number of imaging sensors (cameras) were developed. Unmanned aerial vehicles (UAVs) provide a unique platform for remote sensing of crop fields at slow speeds and low-altitudes, and they are efficient and more flexible than manned agricultural airplanes, which often cannot provide images at both low altitude and low speed for capture of high-quality images. UAVs are also more universal in their applicability than agricultural aircraft since the latter are used only in specific regions. This study presents the low-altitude remote sensing systems developed for detection of crop stress caused by multiple factors. UAVs, as a special platform, were discussed for crop sensing based on the researchers' studies. [ABSTRACT FROM AUTHOR]

Tillage and use of organic manure are important agronomic practices that sustain high crop and soil productivity. Hence, a three-year (2007 to 2009) study was conducted to evaluate the effect of site, tillage and poultry manure (PM) treatments on soil and plant nutrients composition, growth and yield of cocoyam (Xanthosoma sagittifolium). The study was a 2 × 5 × 5 factorial experiment with two sites (Owo - site 1 and Obasooto - site 2), five tillage methods; manual clearing (MC), manual ridging (MR), manual mounding (MM), ploughing plus harrowing (P+H) and ploughing plus harrowing twice (P+2H) and five levels of PM (0, 2.5, 5.0, 7.5, 10.0 t ha-1). Treatments were replicated thrice. Soil OM, N, P, K, Ca, Mg and leaf nutrients reduced with increase in tillage intensity, thus MC conserved soil nutrients the most, and increased nutrient uptake. Soil and plant nutrient concentration was lowest under the P+2H treatment. The MC, MR and MM treatments led to faster growth and higher tuber yield. As PM increased from 0 to 10.0 t ha-1 soil pH, OM, soil and plant N, P, K, Ca and Mg increased. The 7.5 t ha-1 PM gave the highest leaf K, Ca and Mg values. Owo site had significantly higher yield and growth parameters of cocoyam compared with Obasooto site. Yield and growth parameters of cocoyam increased with increase in PM level up to 7.5 t ha-1. Out of all tillage cum manure treatments, MC+7.5 t ha-1 PM gave the highest values of yield and growth parameters. [ABSTRACT FROM AUTHOR]

The paper's purpose is to present eco-pedological resources and the qualitative evaluation in order to facilitate the sustainable development of the presented land (land occupying the highest percentage). The research is oriented on the soils, the accent being on the qualitative evaluation so as to facilitate the sustainable development. The proposed objectives for the elaboration of this paper, were the following: -the characterization of the studied area form the point of view of the natural condition; the study of the environmental factor influence on soil formation and evolution; the study and determination of soil physical and chemical characteristics; as a result of these studies and research, the evaluation of the soil's productive capacity for a more correct and sustainable usage; the pedological research and studies diversification and specialization. As research materials we used: - land belonging to an administrative-territorial unit for the 6119 ha surface. The calculation of average productions per ha for each bonited plant is done based on a bonitary grade awarded as reported to the technologic level which can be insure at one point, and which establishes the productive capacity of each bonitary point. [ABSTRACT FROM AUTHOR]

In a greenhouse pot experiment, lettuce plants ( Lactuca sativa L.) were grown in a Hg-contaminated sandy soil with and without inoculation with arbuscular mycorrhizal fungi (AMF) (a commercial inoculum containing infective propagules of Rhizophagus irregularis and Funneliformis mosseae) amended with different rates of a humic acid (0, 1, and 2 g kg of soil), with the objective of verifying the synergistic effects of the two soil treatments on the Hg tolerance of lettuce plants. Our results indicated that the plant biomass was significantly increased by the combined effect of AMF and humic acid treatments. Addition of humic matter to soil boosted the AMF effect on improving the nutritional plant status, enhancing the pigment content in plant leaves, and inhibiting both Hg uptake and Hg translocation from the roots to the shoots. This was attributed not only to the Hg immobilization by stable complexes with HA and with extraradical mycorrhizal mycelium in soil and root surfaces but also to an improved mineral nutrition promoted by AMF. This work indicates that the combined use of AMF and humic acids may become a useful practice in Hg-contaminated soils to reduce Hg toxicity to crops. [ABSTRACT FROM AUTHOR]

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This study systematically analyzed the performance of multivariate hyperspectral vegetation indices of rice ( Oryza sativa L. ) in estimating the arsenic content in agricultural soils. Field canopy reflectance spectra was obtained in the jointing-booting growth stage of rice. Newly developed and published multivariate vegetation indices were initially calculated to estimate soil arsenic content. The well-performing vegetation indices were then selected using successive projections algorithm (SPA), and the SPA selected vegetation indices were adopted to calibrate a multiple linear regression model for estimating soil arsenic content. Results showed that a three-band vegetation index ( R 716 − R 568 )/( R 552 − R 568 ) performed best in the newly developed vegetation indices in estimating soil arsenic content. The photochemical reflectance index (PRI) and red edge position (REP) performed well in the published vegetation indices. Moreover, the linear combination of two vegetation indices (( R 716 − R 568 )/( R 552 − R 568 ) and REP) selected using SPA improved the estimation of soil arsenic content. These results indicated that the newly developed three-band vegetation index ( R 716 − R 568 )/( R 552 − R 568 ) might be recommended as an indicator for estimating soil arsenic content in the study area. PRI and REP could be used as universal vegetation indices for monitoring soil arsenic contamination. [ABSTRACT FROM AUTHOR]

In article the settlement scheme and mathematical model of five-mass system of the combined unit for processing of soil and crops of seeds are resulted. On the basis of numerical decisions of system of the differential equations laws of movement milling and wing unit shaft are received, graphic dependences of change of parametres of the combined unit for processing of soil and crops of seeds are defined and recommendations for choice rational values of parametres and modes of movement of working bodies are given. [ABSTRACT FROM AUTHOR]

Cold waterlogged paddies typically have low to average yield due to their relatively low soil temperature, poorly developed plough layer, and lack of available nutrients. Despite the above, yield can be improved by targeted measures, such as supplementing with special organic materials. Past research has shown that biochar can play an important role in sequestering soil C, building soil fertility, and improving crop yield. However, the effects of biochar on crop yield and soil properties in cold waterlogged paddies have not been thoroughly investigated. We hypothesized that biochar improves soil fertility, and thus, increases rice grain yield in cold waterlogged paddies. A 2-year field experiment was conducted in 2011 and 2012 to investigate the effect of bamboo biochar (BB), rice straw biochar (RB), and rice straw (RS) on soil physical and chemical properties, grain yield, and yield components in a cold waterlogged paddy in Zhejiang Province, China. Results showed that both BB and RB significantly increased soil pH and soil organic carbon compared to control, whereas their effects on total N were either very small or non-significant. Application of RB significantly increased soil available P and K in both years, and the increases relative to control were greater in 2011 (by 33.9% and 99.1%, respectively) than in 2012 (by 15.3% and 28.6%, respectively). Moreover, RB application resulted in the greatest improvement in grain yield (8.5–10.7% greater than that from the control), and this may be attributed to increased nutrient availability (mainly P and K). Yield component analysis indicated that experimental treatments had the greatest effect on thousand-grain weight, followed by the number of productive tillers per plant and harvest index. Neither biochar nor RS significantly affected the total nutrient (N + P 2 O 5 + K 2 O) content of grains, although the K content of grains from BB and RB plots was significantly higher than in those from control plots in 2012. The total nutrient content of straw under RB treatment was significantly higher than that under control and RS treatments in 2012, mainly due to increased K content (by 12.0%) of straw. The total nutrient uptake by grain was significantly (13.6–16.4%) higher under RB treatment than under control treatment. This was primarily due to the relatively high K uptake by RB grains (15.9–22.6% greater than that by the controls). Similarly, the total nutrient uptake by straw from RB plots was significantly greater than that of straw from the control plot. Further studies on biochar in cold waterlogged paddies are essential in order to evaluate the long-term effects of biochar and its behavior in soils. [ABSTRACT FROM AUTHOR]

Plants rely primarily on rainfall infiltrating their root zones - a supply that is inherently variable, and fluctuations are predicted to increase on most of the Earth's surface. Yet, interrelationships between water availability and plant use on short timescales are difficult to quantify and remain poorly understood., To overcome previous methodological limitations, we coupled high-resolution in situ observations of stable isotopes in soil and transpiration water. We applied the approach along with Bayesian mixing modeling to track the fate of 2H-labeled rain pulses following drought through soil and plants of deciduous tree ecosystems., We resolve how rainwater infiltrates the root zones in a nonequilibrium process and show that tree species differ in their ability to quickly acquire the newly available source. Sessile oak ( Quercus petraea) adjusted root uptake to vertical water availability patterns under drought, but readjustment toward the rewetted topsoil was delayed. By contrast, European beech ( Fagus sylvatica) readily utilized water from all soil depths independent of water depletion, enabling faster uptake of rainwater., Our results demonstrate that species-specific plasticity and responses to water supply fluctuations on short timescales can now be identified and must be considered to predict vegetation functional dynamics and water cycling under current and future climatic conditions. [ABSTRACT FROM AUTHOR]

Anin situelectrokinetic (EK) system was designed and applied to highly saline greenhouse soil with a view to investigating the effects of the EK process on growing crops.In situEK tests in field scale were conducted on the salt accumulated lands in the greenhouse where cabbages and lettuces were being cultivated. A voltage gradient of 0.25–0.6 V cm−1was applied for 50 days in the cultivated lands. The changes in the process, viz. current, voltage, and soil temperatures, were monitored. After the EK process, the initial electrical conductivity (EC, 6.0 dS m−1) of the soil was reduced to about 1.7 dS m−1homogeneously below the recommended value (2.5 dS m−1). The growth rate of cabbages and lettuces under EK treatment was about twice higher than those in the untreated area. The present study revealed that the EK process encourages the growth of the crops considerably and also removes the salts in the soil efficiently during the growth of the crops. [ABSTRACT FROM AUTHOR]

Recently, the assumption that stands with fast growth will have minor losses to insect and disease attack has been challenged. Although tree growth and health are both critical for long-term forest productivity, standardized forest-health data are rarely collected in conjunction with tree-growth data. Using six Long-Term Soil Productivity (LTSP) installations in British Columbia, Canada, we explore the relationships between lodgepole pine ( Pinus contorta Douglas ex Loudon) growth and disease occurrence. Treatment plots and random groups of 100 trees that had larger trees generally had more disease. These findings suggest that we can no longer assume that fast-growing plantations will be free of disease, which has implications for predicting future timber supply. [ABSTRACT FROM AUTHOR]

Tillage practices affect physical properties of soil that are crucial for better crop production. The study was carried out to compare the efficiency of two different tillage implements and their effect on some soil physical properties. The tillage implements included cultivator and disc plow. The soil properties viz. soil moisture, bulk density and infiltration rate were determined before and after the tillage practices. However, the efficiency of tillage operation including operating speed, travel reduction and fuel consumption were taken during the tillage operation. The comparative analysis showed that the cultivator was better in reducing soil bulk density (12-18%) along with increasing the infiltration rate up to 61.5% and conserving soil moisture up to 95%. The disc plow, on the other hand, reduced the bulk density of soil more effectively with up to 21% efficiency and enhancing soil porosity (23%). However, disc plow was less efficient in increasing infiltration rate (38%) and conserving soil moisture (87-90%). Comparatively higher fuel consumption (23.3 L hr-1) was observed in operating disc plow with less operating speed (4.1 km hr-1) and higher travel reduction (27.5%). On the other hand, higher cultivator operating speed (4.76km hr-1) was observed with less travel reduction (21.8%) and fuel consumption (14.9 Lhr-1). The cultivator, being more economical and having good effects on soil properties, was the best option for tillage operations in the clay soils of cotton-wheat rotation system under semi-arid climate of Tandojam, Pakistan. [ABSTRACT FROM AUTHOR]

The author's response to the comments made on his study "Evidence of soil nutrient availability as the proximate constraint on growth of treeline trees in northwest Alaska" featured within the issue is presented. Topics include diurnal and seasonal ground temperature amplitudes, soil microclimate effects on stomatal conductance and photosynthesis, and genetic programming of trees.

The freeze–thaw process can lead to water enrichment in freezing layers of soil, and may have beneficial effects on vegetation restoration efforts in sandy land habitats. This study determined the characteristics of soil water migration in dunes and interdune areas during freeze–thaw process, and discussed its potential application to the restoration and recovery of sandy land plant communities. In this research, the mobile sand dunes and interdune lowlands were chosen as the study objects in Horqin Sandy Land, north China. We investigated the soil temperature and moisture content on depths of 20 cm, 50 cm, 100 cm and 150 cm during soil freeze–thaw period (from September 20, 2010 to April 9, 2011), and determined the migrated water during freezing–thawing processes on soil of sand dunes and interdune lowlands, and discussed its potential application on plant recovery processes. Results showed that the soil freeze–thaw process occurred mostly at a depth of 0–100 cm, and the longest period of soil that remained frozen is 104 days at a depth of 20 cm and the shortest period is 39 days at a depth of 100 cm in sand dunes. The number of freeze–thaw cycles was not different between sand dune and interdune area over winter. Most freeze–thaw cycles occurred in the thawing process, and mostly at a depth of 0–50 cm. The freeze–thaw cycles of interdune areas only occurred in the thawing process, but the freeze–thaw cycles of sand dunes occurred both in the process of freezing and thawing. More water of the interdune areas apparently migrated than did in the sand dunes. The range of soil water storage content at depths of 0 to 100 cm increased to 92.4 mm on interdune, and 10.8 mm on sand dunes during the freeze–thaw process. A negative correlation was found between soil temperature and moisture at depths of 100 cm and 150 cm, and while a positive correlation existed at depths of 20 cm and 50 cm. The freeze–thaw process can lead to water enrichment in freezing layer of soil on sand dunes and interdune. Soil texture affected the quantity of soil water migrating during the freeze/thaw process, and more water migrated in interdune areas than in sand dune habitat. [ABSTRACT FROM AUTHOR]

We used the APSIM model to explore the ability to simulate soil organic carbon (SOC) from three long term agricultural experiments (LTAE) over 24–44 years in eastern Australia (Hamilton Victoria, Wagga Wagga New South Wales and Warwick Queensland). The model was initialized for each location soil type using a 20-year spin-up period to reach stable SOC fractions. The model was not tuned to any of the data at each site. The cropping systems model simulated reasonably well the calculated changes in SOC over the 24–44-year period at the three different sites under various agronomic management practices. At Hamilton calculated SOC did not change significantly over 32 years and the APSIM-Agpasture model represented this satisfactorily. Root mean square error was 4.9 t C ha − 1 (0–30 cm) (5.2%) ranging from 1.5 to 10.9 t C ha − 1 (1.7 to 11.8%) over time. Similarly, over twenty-four years of continuous cropping at Wagga Wagga under a Wheat-Lupin crop rotation using APSIM-Wheat and APSIM-Lupin under stubble retention and zero tillage showed a largely neutral trend over time with RMSE of 3.4 t C ha − 1 (0–30 cm) (9.5%) ranging from 1.4 to 7.8 t C ha − 1 (4 to 21%) over time. The SOC was much lower at Wagga Wagga compared to that at Hamilton. Forty-four years of continuous cropping at the Queensland site resulted in significant declines in SOC irrespective of the farming practices applied. However, the rates of decline were different with the least decline achieved from high N application with stubble retention. The modelled changes, using APSIM-Wheat and APSIM-Barley, in SOC matched reasonably well the calculated behaviour with the greatest decline under zero N application with overall RMSE of 4.1 t C ha − 1 (0–30 cm) (4.5%) ranging from 1.4 to 8.7 t C ha − 1 (2 to 7%) over time. The biophysical simulation model exemplified by the APSIM model explained well the observed changes in SOC at the various locations without specifically fitting the model to the observed data, despite large variation in the calculated data. This indicates that the SOC model was robust over the moderate to long term period. As such the model is suitable to extrapolate a simulated response beyond these locations under various treatment combinations that should predict realistic SOC stocks within the expected mean error of less than 10% (3 to 6 t C ha − 1 0–30 cm). [ABSTRACT FROM AUTHOR]

The objective of this study was to propose a model for explaining rice responses to a wide range of N application rates in various growth attributes associated with the occurrence of chalky grains. We improved the sub-model for N uptake process of a previous rice model which was originally developed for explaining genotypic and environmental variations in the whole growth processes, considering the difference in the rate of N loss from the plant-soil system between indigenously supplied soil mineral N and fertilizer N. A total of 80 growth datasets of cultivar ‘Koshihikari’ grown at Shiga prefecture, Japan, in 2010 was utilized for the calibration and validation of the model. The rice growth model well explained the above-ground biomass growth (RMSD = 78.7 g m−2) and rough dry grain yield (RMSD = 83.2 g m−2) for the validation data-set, simultaneously. The simulated carbohydrate content available per single spikelet was negatively correlated with the observed percentage of the milky-white grain which includes white-cored grain (r = −.77,p < .001) for all the data-sets of calibration and validation. On the other hand, the observed percentage of the sum of white-back and white-base grains was closely correlated with the simulated plant N content available per single spikelet (r = −.59,p < .001). It was suggested that the present rice growth model would rationally explain the effects of N application on the occurrence of the chalky grains through the dynamic change of the carbohydrate content and plant N content available per single spikelet. [ABSTRACT FROM AUTHOR]

The Crop Environment Resource Synthesis (CERES) models have been developed and utilized for the last 30 years to simulate crop growth in response to climate, soil, genotypes and management across locations throughout the world. We reviewed 215 papers found in the literature that contained field observed data where the CERES models were tested. Over 30 simulated variables of the CERES models have been tested in 43 different countries under various experimental treatments. Across all testing conditions, the CERES models simulated grain yield with a root mean square error (RMSE) of less than 1400 kg/ha (~10% relative error, RE), 1200 kg/ha (~20% RE) and 800 kg/ha (~10% RE) for maize, wheat, and rice, respectively. Phenological development was simulated with less than 7 days difference from the observations in most studies. The CERES models simulated aboveground biomass, harvest index, evapotranspiration, and soil water reasonably well too. The simulations of grain number (up to 4340 root mean square error, RMSE), grain weight (up to 22% error), intercepted photosynthetically active radiation (IPAR, up to 0.41 MJ/plant), leaf area index (LAI, 31.9% error), soil temperature (over 10°C difference), and nitrogen (N) dynamics (up to 80% error) were less accurate. In fact the average error of CERES model simulations tends to be higher under marginal crop growing conditions such as extreme heat or cold, water and nutrient deficit conditions. [ABSTRACT FROM AUTHOR]

Mangrove forests have a simple architecture. They shelter a few number of arboreal species that grow in a saline environment subject to tidal activity. The research objective was to evaluate possible interactions between physical-chemical soil attributes and plant-leaf nutrient concentrations of different mangrove species. Different mangrove species growing in the same soil, and the same mangrove species growing in two different soil classes were evaluated as to their leaf nutrient concentration patterns. The study was carried out in mangrove areas of the State of Paraná, southern Brazil, in two distinct soil classes: HISTOSOL THIOMORPHIC Salic sodic and GLEYSOL THIOMORPHIC Salic sodic; and three different species: Avicennia schaueriana, Laguncularia racemosa and Rhizophora mangle. Two subareas were delimited within each area from which soil and leaf samples were collected. Samplings from five individuals of each dominant mangrove species were taken from the soil (0-10 cm deep) under each tree crown projection. The data was submitted to statistical analysis using a set of simple and multivariate analysis in order to determine possible differences among mangrove species leaf nutrient concentrations, and whether these differences might be correlated with the soil attributes or not. The results exposed that the nutritional state of the mangrove species is different and independent form the soil attributes in which they grow. Few correlations were found among leaf nutrient concentrations and soil attributes, suggesting differential selective nutrient uptake among species. [ABSTRACT FROM AUTHOR]

A combination of linear and weighted goal programming for crop rotation planning has been used in developing a tool/model for solving several management goals simultaneously. The model was implicated for the case of organic farming in Slovenia. The results yielded reasonably accurate information regarding different economic parameters and nitrogen off-take from calculated crop rotation. The model was tested in four different scenarios with the influence of various goals' weighting the results. From the obtained results, it is obvious that a combination of weighted goal programming and linear programming gives rise to a better solution from an economic perspective (i.e. higher total income per crop rotation and lower costs per crop rotation). It also provides a better solution for diversified and economically feasible crops for inclusion in crop rotation compared with the situation when farmers use only a linear mathematical technique. An investigation of the results showed that the model does not prefer mono-crop production strategies, which represent crucial drawbacks for organic agriculture, such as soil depletion, diseases and pests outbreak and soil degradation. The developed model can help farmers to obtain answers regarding four main issues in crop rotation planning; i) cropping strategy, ii) potential hiring of extra resources, iii) quantity of harvested crops and iv) quantity of fertilizer being saved in the second year of planning. [ABSTRACT FROM AUTHOR]

Sayings of Ghagh and Bhaddri are very popular in our country. Through these sayings prediction of disasters like drought or flood can be made in advance. Predictions of such situations helps in adopting measures to face them in advance. Planning of such crops can be done which give more production in drought. Farming of such crops can avoid loss of capital and drought can also be mitigated. Only, it is needs to take advantage of this indigenous knowledge. [ABSTRACT FROM AUTHOR]

Despite the importance of mucilage for soil–plant relations, little is known about the effect of soil drying on mucilage exudation. We introduce a method to collect mucilage from maize growing in wet and dry soils. Mucilage was collected from brace roots. The amount of mucilage exuded did not change with soil water content and transpiration rate. Mucilage exuded in dry soils had a higher degree of hydrophobicity, suggesting that the wetting properties of mucilage change in response to soil drying. [ABSTRACT FROM AUTHOR]

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Substantial gaps have been reported between the average farmer’s maize yield and yield potential in China, especially the North China Plain (NCP). This maize yield gap as identified by previous studies indicates large opportunities for raising yield by improving agronomy. Agronomic factors are either transient or persistent. Transient factors, which explain yield differences depending on unpredictable weather conditions, can have significantly different optimums from one year to another. While those transient factors are difficult to improve without reliable forecasts, persistent factors influence yield more consistently and therefore represent the best near-term targets for shrinking yield gaps. In this study, multi-year satellite images are used to quantify field-scale maize yield variation in Quzhou County of NCP, and this variation is then analyzed to determine the role of soil type and persistent management factors in explaining yield gaps. Results indicate that (i) remote sensing can provide reasonably reliable estimates of maize yields in this region; (ii) soil type has a clear effect on maize yields, and one that interacts strongly with growing season rainfall amounts; and (iii) on average roughly 20% of yield differences that appear within any one year are related to factors that persist in other years. Overall, the study presents a generalizable methodology of assessing yield gap as well as the proportion arising from persistent factors using satellite data. Our results suggest that the majority of yield gap is dominated by transient factors, and shrinking this gap may require high quality forecasts to make informed optimal management decisions. [ABSTRACT FROM AUTHOR]

Conservation agriculture (CA) is based on minimum soil disturbance, permanent soil cover, and crop rotation; it is promoted as a sustainable alternative to systems involving conventional tillage. Adoption of CA changes weed dynamics and communities and therefore necessitates adjusting weed control methods. The objectives of this review are to summarize literature concerning CA principles and their interactive effects on weed life cycles and community composition, briefly review CA-appropriate cultural practices for additional weed control, and identify areas where further research is needed. No-till systems accumulate seeds near the soil surface where they are more likely to germinate but are also exposed to greater mortality risks through weather variability and predation. Assuming no seed input into the system, germinable seedbanks under no-till decrease more rapidly than under conventional tillage. Reducing tillage may shift weed communities from annual dicots to grassy annuals and perennials. Surface residues lower average soil temperatures and may delay emergence of both crops and weeds. Germination and growth of small-seeded annuals will suffer from restricted light availability, physical growth barriers and potential allelopathic effects from surface residue. Crop rotation affects weeds via allelopathy and altered timing of both crop management and resource demands. Rotations should incorporate crops sown in varied seasons (e.g., autumn and spring), annuals and perennials, different herbicides, and/or various crop families. Literature indicates implementing no-till without crop rotation can result in severe weed problems; greater rotational crop diversity results in easier weed management. Additional cultural practices for CA include: (i) selecting highly competitive varieties; (ii) altering planting dates; (iii) preventing weed seed recruitment; (iv) adjusting planting arrangement, densities, and fertilizer placement; and (v) microbial bio-controls. Further research is needed concerning: (i) the interactive effects of tillage and surface residue on weeds; (ii) the use of models and/or meta-analyses to predict weed responses, and to identify intervention points in CA; and (iii) the weed-suppressive potential of longer (4+ years) rotations. [ABSTRACT FROM AUTHOR]

Overwintered cover crops mechanically terminated into mulch can be a weed management tool for reduced-tillage organic agriculture. However, the impacts of management options for cover cropping are not well understood, including cover crop variety, termination timing and termination method. In a field experiment, conducted in 2012 and 2013 in Western Washington, we examined three grains, four vetches and one barley–vetch mix terminated with two mechanical methods and at two different times. We determined the influence of cover crop variety and termination time on cover crop biomass production and tissue nitrogen (N), effectiveness of cover crop termination, soil nitrate–N and percent weed cover. We also determined the influence of termination method on percent weed cover. Cover crop biomass ranged between 3 and 9 Mg ha−1 and was not influenced by termination time; the greatest production was from three varieties of grain. Rye varieties were more effectively terminated with a roller–crimper than barley. Mean soil nitrate–N levels ranged from 1.9 to 18 mg kg−1 and were the greatest with vetches. Post-termination weed cover was greater in 2013 than in 2012 and the cover crop variety influenced weed cover at the Late termination time only. Neither plant N concentration in the cover crop mulch nor soil nitrate influenced weed cover. The results of this study indicate that cover crop biomass and termination timing are important factors influencing weed cover and termination effectiveness in cover crop mulch. [ABSTRACT FROM AUTHOR]

Interactions between plant and soil communities are known to play an integral role in shaping ecosystems. Plants influence the composition of soil communities and soil communities in turn influence plant performance. Such a plant-soil feedback may incur selection pressure on plants and the associating soil community. However, the evolutionary consequences of these above-belowground feedback interactions remain largely speculative. Here we assess whether plant-soil feedback effects differ between intraspecific plant populations and between generations within the same plant population. We used two populations of Trifolium pratense and assessed their performance when grown in association with their home versus away soil biota. Both populations were colonized by distinct microbial communities and performed better with their own home soil communities than with the soil community from the other intraspecific population, demonstrating intraspecific positive feedback effects of home soil. In one of the two populations, we found that plant performance and the root associated microbiota community differed between parental and progeny plants when inoculated with their own home soil. Differences in root associated community characteristics could explain more than 80% of the variation in performance among the progeny and parental plants. Our results highlight that intraspecific differences in both plant and associated soil communities shape plant-soil feedback effects, and consequently indicate that plant-soil feedback can influence the direction of selection between intraspecific plant populations. [ABSTRACT FROM AUTHOR]

Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species., We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR., All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment., We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands. [ABSTRACT FROM AUTHOR]

The exposure of inhabitants from 13 cities of The Upper Silesia Industrial Region to cadmium and lead has been estimated on the basis of heavy metals content in commonly consumed vegetables. The samples were collected from agricultural fields, allotments and home gardens in these cities. Cadmium and lead concentrations in samples of soil and vegetables – cabbage, carrots and potatoes were determined. High content of heavy metals in the arable layer of soil in Upper Silesia (max. 48.8 and 2470 mg kg −1 d.w. for Cd and Pb, respectively) explained high Cd and Pb concentrations in locally cultivated vegetables which are well above the permissible level. Three exposure scenarios with different concentrations of Pb and Cd in vegetables were taken into consideration. In the Scenario I where the content of heavy metals was equal to maximum permissible level, the value of hazard quotient (HQ) for Pb and Cd was 0.530 and 0.704, respectively. In the scenarios where were assumed consumption of contaminated vegetables from Upper Silesia the value of hazard quotient (HQ) for Pb and Cd was 0.755 and 1.337 for Scenario II and 1.806 and 4.542 for Scenario III. The study showed that consumption of vegetables cultivated in Upper Silesia Region on the agricultural fields, allotments and in home gardens may pose a significant health risk. [ABSTRACT FROM AUTHOR]

Response of maize growth traits to different preceding crops was estimated at 105, 120 and 135 kgN/ fed., during 2013 and 2014 summer seasons. Preceding crops significantly affected maize grain yield and its attributes, i.e. number of grains/ ear, 100-grain and ear grain weights in addition to harvest index. Maize gave maximum and minimum values of those traits after faba bean and sugar beet, producing lower estimates than those that contained faba bean. Grain weight/ ear and grain yield/ fed., in addition to harvest index, significantly responded to N application levels, where their highest values were obtained from 135 kgN/fed. Response of grain yield and harvest index to crop sequence × N level interaction effects were significant during the two seasons. Data indicated that S6 sequence produced the greatest values of grain yield and harvest index with 135 kgN/ fed, while, the reverse occurred with the result of S1 sequence × 105 kgN/ fed interaction. Interaction data, also, showed that S6 and S5 sequences, under 135 kgN/ fed were similar in their effects on both traits in the two seasons. Data indicated the importance of relay cropping as a way to save time for a third or fourth crop growing. Results of stepwise regression revealed that both 100- grain weight and number of grains/ ear explained about 96% of the variation in grain yield in both seasons, indicating the importance of these two traits in determining productivity of maize. Also, factors affecting these two traits, such as N fertilization, might have an effect on grain yield production. [ABSTRACT FROM AUTHOR]

The aim of the paper was to characterise and present cartographically water deficits of crop plants grown on different soils in Poland. The calculation of water deficits was carried out for 40 meteorological stations of the Institute of Meteorology and Water Management and the Institute of Technology and Life Sciences using meteorological data from the growing seasons 1970-2004 for most crops grown in Poland. Estimations were made for soils suitable for growing the selected crop plants. Water deficits were determined for a probability of exceedance of 20 and 50%. They served to create a relative database. Maps of water deficit were generated for each crop and for two probabilities. The estimated share of soil area suitable for growing the particular crops was calculated for water deficits greater than 40 mm. Water deficits of a given crop on soils suitable for growing at probabilities of their occurrence once in 5 years are also presented in the paper. [ABSTRACT FROM AUTHOR]

Macroalgae can be grown in industrial waste water to sequester metals and the resulting biomass used for biotechnological applications. We have previously cultivated the freshwater macroalga Oedogonium at a coal-fired power station to treat a metal-contaminated effluent from that facility. We then produced biochar from this biomass and determined the suitability of both the biomass and the biochar for soil amelioration. The dried biomass of Oedogonium cultivated in the waste water contained several elements for which there are terrestrial biosolids criteria (As, Cd, Cr, Cu, Pb, Ni, Se and Zn) and leached significant amounts of these elements into solution. Here, we demonstrate that these biomass leachates impair the germination and growth of radishes as a model crop. However, the biochar produced from this same biomass leaches negligible amounts of metal into solution and the leachates support high germination and growth of radishes. Biochar produced at 750 °C leaches the least metal and has the highest recalcitrant C content. When this biochar is added to a low-quality soil it improves the retention of nutrients (N, P, Ca, Mg, K and Mo) from fertilizer in the soil and the growth of radishes by 35–40%. Radishes grown in the soils amended with the biochar have equal or lower metal contents than radishes grown in soil without biochar, but much higher concentrations of essential trace elements (Mo) and macro nutrients (P, K, Ca and Mg). The cultivation of macroalgae is an effective waste water bioremediation technology that also produces biomass that can be used as a feedstock for conversion to biochar for soil amelioration. [ABSTRACT FROM AUTHOR]

Nearly one-half of New Zealand’s ruminant livestock graze on hill country pastures where spatial differences in soil conditions are highly variable and excretal deposition is influenced by pasture production, animal grazing and resting behaviour that impact the nitrous oxide (N 2 O) emission factor from excreta (EF 3 ). New Zealand currently uses country-specific EF 3 values for urine and dung of 0.01 and 0.0025, respectively, to estimate direct N 2 O emissions from excreta. These values have largely been developed from trials on flat pastoral land. The use of the same EF 3 for hill pasture with medium and steep slopes has been recognised as a possible source of overestimation of N 2 O emissions in New Zealand. The objectives of this study were to develop and describe an approach that takes into account the effects of slope in estimating hill country N 2 O emissions from the dung and urine of ruminant animals (sheep, beef cattle, and deer) across different slope classes, and then compare these estimates with current New Zealand inventory estimates. We use New Zealand as a case study to determine the direct N 2 O emissions between 1990 and 2012 from sheep, beef cattle and deer excreta using updated estimates of EF 3 for sloping land, the area of land in different slope classes by region and farm type, and a nutrient transfer model to allocate excretal-N to the different slope classes, and compare the changes between these hill pastures-specific and current inventory estimates. Our findings are significant – the proposed new methodology using New Zealand specific EFs calculated from a national series of hill country experiments resulted in 52% lower N 2 O estimates relative to using current inventory emission factors, for the period between 1990 and 2012 and reduces New Zealand’s total national agricultural N 2 O greenhouse inventory estimates by 16%. The improved methodology is transparent, and complete, and has improved accuracy of emission estimates. On this basis, the improved methodology of estimating N 2 O emission is recommended for adoption where hill land grasslands are grazed by sheep, beef cattle and deer. [ABSTRACT FROM AUTHOR]

Agricultural intensification continues to be a major threat to sustainable development in mountain regions of the world since it is largely associated with lower soil fertility, increased soil erosion, pollution and eutrophication of water bodies, reduced biodiversity, and livelihood challenges. Agroforestry, the purposeful cultivation of trees and crops in interacting combinations, has the potential to provide environmental benefits and to contribute to livelihood security, and is receiving increasing attention as a sustainable land management option. Whereas many studies highlight general positive environmental and socio-economic effects of agroforestry systems, effects of the transition to agroforestry practices have rarely been quantified and studied in detail, in particular in Nepal. This paper analyses alterations of soil properties after the adoption of agroforestry practices in a typical mid-hill region of Nepal. Three agrosystems were compared with a special focus on soil fertility: (i) a mature, fully developed agroforestry system (AF); (ii) the predominant conventional system (CS) characterized by mono-cropping; and (iii) a system that has been in transition to AF for two years (TS). The results show significant differences in soil pH, aluminium content, base saturation, electric conductivity, organic matter and nitrogen content, and cation exchange capacity between AF and CS soils, indicating a higher soil quality and more fertile soil conditions in the AF soils. The contrasting soil quality has to be largely attributed to the differing land management practices. After two years of transition, the TS soil data already show a convergence towards the AF values in several parameters. This study gives quantitative evidence that agroforestry systems have the potential to significantly enhance soil quality and long-term soil productivity, with positive effects appearing shortly after the conversion from conventional monocropping systems. [ABSTRACT FROM AUTHOR]

The ‘parklands’ that form the most widespread farming systems in the Sahelian zone of West Africa are farming systems in which annual crops are grown under scattered trees preserved from the natural vegetation by farmers following clearing the woodlands to make crop fields. Being mixed agricultural systems, the interactions between trees and crops have always been a key element determining the management options applied by farmers. This has also attracted the attention of scientists, with the first studies of this nature dating back to the 1960’s. A combination of field trials, observational studies and modeling has been deployed to understand soil–tree–crop interactions, including sharing of growth resources by the system components. Based on this understanding, management options have been discussed with farmers. The most common experimental designs used are transects from the base of tree trunk toward the open field, concentric zones around trees or sectors under trees where various experimental treatments are applied, depending on the objectives of the studies. Key findings disentangled the contributions of each component of the system to the island of high fertility around trees using isotopic techniques, tree effects on adjacent C 4 cultivated plants and alternative C 3 crops that tolerate tree shade. Tree management practices such as pruning have been tested to modify the crown architecture and the patterns of root distribution in order to improve light availability and resource use efficiency. Increases in land use intensity require more active management by farmers of tree regeneration. Despite scientific advances, there are still some methodological challenges in determining the “park effect”, the tradeoffs and synergies between and among goods and services, and how to boost the provisioning, supporting and regulating functions of such agroforestry systems. Providing such ecosystem service functions is critical in the quest for ensuring food security while achieving adaptation and mitigation goals in vulnerable environments like the drylands. [ABSTRACT FROM AUTHOR]

Soil compaction is a major threat to natural resources. However, little information is available on the impacts of soil compaction on arthropod diversity especially relative to different types of vegetation, land use and restoration activities. In response to this dearth of information, we studied soil compaction, as well as percentage soil moisture and mean leaf litter depth, associated with four vegetation types: natural vegetation (fynbos, the historic condition), agricultural land (vineyards), invasive alien trees, and vegetation cleared of invasive alien trees (recovering vegetation). Our study took place in the Cape Floristic Region, South Africa, a biodiversity hotspot, yet also an area of intense viticulture and heavy invasion by alien plants. We sampled soil surface-active arthropods using pitfall traps, and compared species richness and abundance in different vegetation types with various levels of soil compaction and other soil variables. Overall, vineyards had the highest soil compaction while natural fynbos and aliens had low and comparable compaction. For both arthropod species richness and abundance, the order of the four vegetation types was, from highest to lowest: natural fynbos, alien cleared sites, vineyards, and alien infested sites. Level of soil compaction negatively correlated with arthropod species richness but not with abundance. Neither soil moisture nor leaf litter depth on their own significantly affected arthropod species richness or abundance. While alien trees overall had a strong negative effect on both arthropod species richness and abundance, and much more so than vineyards, the situation is reversible, with removal of aliens being associated with rapid recovery of soil structure and of arthropod assemblages. This is an encouraging sign for restoration. [ABSTRACT FROM AUTHOR]