Effects Of Agricultural Management Research Articles

Response of soil carbon dioxide emissions to no-tillage and moldboard plow systems on Andosols in a humid, subtropical climate, Japan

Characterization of soil carbon dioxide (CO2) emissions can help us to understand the effects of agricultural management on climate change and the ability of soil to sequester atmospheric carbon. However, there is a lack of studies on the effects of tillage and cover crops on soil CO2 emissions on Andosols in the humid, subtropical climate. The present study aimed to quantify soil CO2 emissions and identify the factors accounting for CO2 emissions among no-tillage (NT) and moldboard plow (MP) systems under different cover crop treatments at an experimental site established in 2002 in Kanto, Japan. A split-plot field experiment was conducted from May 2017 to November 2018 comprising two tillage systems (NT and MP) and three cover crops: fallow, hairy vetch (HV), and rye (RY). Higher soil CO2 daily emissions at 80% of the measurements and significantly greater CO2 seasonal and annual emissions were observed in the NT system as compared to the MP system. The relationship between CO2 daily flux and soil temperature was well-described by exponential functions (p < 0.001). Soil volumetric water content (θv) was significantly positively associated with soil CO2 daily emissions when soil temperature ranged from 10 °C to 20 °C (p < 0.05) and 20 °C to 30 °C (p < 0.01), and the response of soil CO2 flux to soil temperature and θv was well-described by a multiplicative model (RMSE: 1.2920, R2: 0.7777). Although there was no difference in soil temperature between NT and MP, significantly higher soil θv was found in NT than in MP. In addition, significant exponential correlations were observed between soil organic carbon (SOC) stocks and annual CO2 emissions in four different soil layers (0–2.5 cm, 0–7.5 cm, 0–15 cm, and 0–30 cm). The HV and RY cover crops had a positive effect on SOC stocks. NT increased SOC stocks significantly compared to MP at 0–2.5 cm (p < 0.001) and 0–7.5 cm (p < 0.05) depth while no significant SOC stock difference at 0–15 cm and 0–30 cm depth between NT and MP were observed. These results suggest that surface SOC enrichment and higher soil θv result in higher soil CO2 emissions in 15-year NT systems on Andosols in the humid, subtropical climate of Kanto, Japan. The carbon sources and their proportions of soil CO2 emissions require further clarification to properly assess the benefits of NT in soil carbon sequestration.

Investigating the Effects of Agricultural Water Management in a Mediterranean Coastal Aquifer under Current and Projected Climate Conditions

Coastal delta plains are areas with high agricultural potential for the Mediterranean region because of their high soil fertility, but they also constitute fragile systems in terms of water resources management because of the interaction of underlying aquifers with the sea. Such a case is the Pinios River delta plain located in central Greece, which also constitutes a significant ecosystem. Soil and Water Assessment Tool (SWAT) and SEAWAT models were combined in order to simulate the impact of current water resources management practices in main groundwater budget components and groundwater salinization of the shallow aquifer developed in the area. Moreover, potential climate change impact was investigated using climate data from Regional Climate Model for two projected periods (2021–2050 and 2071–2100) and two sea level rise scenarios (increase by 0.5 and 1 m). Modeling results are providing significant insight: although the contribution of the river to groundwater inflows is significant, direct groundwater recharge from precipitation was found to be higher, while capillary rise constitutes a major part of groundwater outflows from the aquifer. Moreover, during the simulation period, groundwater flow from the aquifer to the sea were found to be higher than the inflows of seawater to the aquifer. Regarding climate change impact assessment, the results indicate that the variability in groundwater recharge posed by the high variability of precipitation during the projected periods is increasing the aquifer’s deterioration potential of both its quantity and quality status, the latter expressed by the increased groundwater Cl− concentration. This evidence becomes more significant because of the limited groundwater storage capacity of the aquifer. Concerning sea level rise, it was found to be less significant in terms of groundwater salinization impact compared to the decrease in groundwater recharge and increase in crop water needs.

A Soil Nematode Community Response to Reclamation of Salinized Abandoned Farmland.

Development from abandoned land to farmland after vegetation reestablishment for reclamation is an important salinization rehabilitation process in dryland ecosystems. While subsequent soil abiotic changes have been reported, few studies have focused on how reclamation affects the soil biota. Understanding the response of soil biota to reclamation is useful for evaluating the effect of agricultural management. We investigated soil physiochemical properties, the composition and structure of nematode communities, and nematode metabolic footprints in control and reclaimed farmland. The results showed that soil properties were significantly altered by reclamation. In particular, reclamation significantly increased pH, organic carbon, total nitrogen, and microbial biomass carbon. Conversely, electrical conductivity was significantly decreased. Shannon and Simpson indices were affected by reclamation. Reclamation significantly increased the Shannon index in the 10-20 cm soil layer. Reclamation significantly increased the Simpson index in the 0-10 cm soil layer, while the opposite was observed in the 10-20 cm soil layer. High basal index and fungal-based channel were found in the control. Total nematode abundance increased due to reclamation, which included fungivores, herbivores, and omnivores-predators. More nematodes could store more biomass carbon in the reclaimed farmland. Reclamation had an effect on the structure and function of soil food web, and increased the metabolic footprints of various trophic groups of nematodes. Nematode faunal analysis revealed that exogenous substances input led to the high level of communities structure, and the soil food web matured in the reclaimed farmland. The nematode communities were affected by reclamation. Furthermore, pH, EC, SOC, TN, and MBC were key driving factors affecting the nematode communities. Therefore, reclamation could effectively enhance the structure and function of soil food web through bottom-up effects in the cotton fields in Xinjiang, China.

Effects of Environmental Drivers and Agricultural Management on Soil CO2 and N2O Emissions

Understanding the roles of natural drivers and anthropogenic activities in greenhouse gas (GHG) emissions of arable fields is crucial for adopting the most appropriate agricultural management. This study investigated the effect of two tillage treatments of mouldboard ploughing (MP) and no-tillage (NT), and the environmental factors (soil water content and temperature, carbon content and nitrogen forms) on soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions. The research was conducted on chernozem soil under winter wheat cultivation. Besides field monitoring, several laboratory experiments took place to examine the effects of environmental drivers and fertilization management on soil GHG emissions. We observed no significant difference between the CO2 emission of MP and NT during a full year period. Nevertheless, significant differences were found in the sub-periods (more particularly during vegetation and then after harvest). NT had higher CO2 emission than MP in all laboratory experiments (p &lt; 0.001) and in the after harvest period of the field trial, measured on bare soil (p &lt; 0.0001). NT had significantly higher N2O emission both under laboratory (p &lt; 0.0001) and field conditions (p &lt; 0.0081). Different fertilization showed no distinguishable effect on N2O emission in the laboratory. This study confirms that N2O emission of the arable field depended more on soil water content than soil temperature, and vice-versa for CO2 emission.

Arable Weeds and Management in Europe

“Arable Weeds and Management in Europe” is a collection of weed vegetation records from arable fields in Europe, initiated within the Working Group Weeds and Biodiversity of the European Weed Research Society (EWRS). Vegetation-plot data from this scientific community was not previously contributed to databases. We aim to prove the usefulness of collection for large scale studies through some first analyses. We hope to assure other weed scientists who have signalled willingness to share data, and plan to construct a full data base, making the data available for easy sharing. Presently, the collection has over 60,000 records, taken between 1996 and 2015. Many more studies for potential inclusion exist. Data originate mostly from studies exploring the effect of agricultural management on weed vegetation. The database is accompanied with extensive meta-data on crop and weed management on the surveyed fields. The criteria for inclusion were a minimum amount of information on the cultivated crop, and a georeference. Most fields were surveyed repeatedly, i.e. transects, multiple random plots, or repeated visits. All surveys aimed to record the complete vegetation on the plots. Sometimes, taxa were identified only to genus level, due to survey dates very early in the vegetation period. Plant taxonomy is standardized to the Euro+Med PlantBase.

Physiological and microclimatic consequences of variation in agricultural management of maize

Background: Maize is cultivated under different agricultural management systems, which influence the ecological dynamics of the crop, and therefore the physiology of the plant.&#x0D; Questions: What is the effect of different agricultural management on the microclimate and the physiology of maize plants?&#x0D; Studied species: Zea mays L.&#x0D; Study site and dates: Nacajuca, Tabasco, Mexico; January to April 2017.&#x0D; Methods: Physiological performance of maize plants and microclimatic variation in the crop area was characterized under three management systems: maize monoculture, maize-bean, and maize-bean-squash intercropping. Each treatment was established in three 100 m2 plots (300 m2 per treatment). Four measurements were taken between days 33 and 99 after maize sowing, to characterize five microclimatic parameters (relative air humidity, air and soil temperature, vapor-pressure deficit and soil volumetric water content) and nine physiological parameters (photosynthesis, transpiration, water use efficiency, stomatal conductance, electron transport rate, quantum efficiency of photosystem II, non-photochemical quenching, foliar water potential and chlorophyll content).&#x0D; Results: Maximum soil temperature was up to 4.4 ºC less in the maize-bean system than in the monoculture at 15:00 h; soil in the maize-bean-squash intercropping retained up to 45 % more water than the monoculture throughout the day. Photosynthesis and electron transport rate in the maize-bean intercropping was up to 32 % higher than in the monoculture. The highest non-photochemical quenching and transpiration rate were observed in the maize-bean-squash system.&#x0D; Conclusions: The maize-bean and maize-bean-squash combination provides maize plants with lower soil temperature and higher water availability, allowing them better physiological performance compared to monoculture.

Biochemical signatures reveal positive effects of conservation tillage on arbuscular mycorrhizal fungi but not on saprotrophic fungi and bacteria

Since tillage can reduce the amount of organic C stored in soils, the use of conservation tillage practices, which exclude soil inversion, or include it less frequently, is often promoted. Soil microorganisms are closely linked to soil organic C (SOC), and they are assumed to respond quicker to management changes than SOC. Using two Swedish long-term tillage experiments, our aim was to determine whether (i) continuous conservation tillage (harrowing, H) increase microbial biomass (indicated by fatty acid signatures) compared to plowing (P), and if occasionally tilled soil (HP) was more like H or P. Also, the aim was to determine whether (ii) crop residue management has different effects on microbial biomass depending on tillage management, and whether (iii) conservation tillage and residue return increase SOC. We found that arbuscular mycorrhizal fungi (AMF) were stimulated by the H treatment compared to P treatment in the upper soil layer, and that occasional plowing resulted in intermediate amounts of AMF. The amount of microbial saprotrophs, on the other hand, was not affected by tillage treatment, and neither was the SOC concentration. Whether crop residues were returned in the autumn or not, had no direct effect on the microbial saprotrophs or the SOC after the winter, but crop residue removal stimulated AMF close to the surface in the P treatment. Although more research is needed to fully understand agricultural tillage and residue management effects on SOC dynamic, our study suggests that reducing or omitting plowing influence soil microbes, but does not necessarily result in more SOC.

Direct and indirect effects of agricultural practices, landscape complexity and climate on insectivorous birds, pest abundance and damage in olive groves

Pesticides used in agriculture to prevent yield and economic loss are a threat for the natural heritage worldwide. Finding win-win solutions for pest control management in sustainable and profitable agriculture is a current yet elusive challenge for human societies. The main alternative to reduce pest damage in a sustainable manner consists in fostering natural enemies through the extensification of agricultural practices or the promotion of heterogeneous landscapes. However, very few studies have analyzed the combined effects of these components on natural enemies and pests simultaneously.In this work, we fit meta-models (using Piecewise Structural Equation Models) aiming to understand the direct and indirect effects of agricultural management, landscape heterogeneity and climatic variables on insectivorous birds, pest abundance and crop damage. For this, we focus on olive groves, one of the most important woody agroecosystems worldwide, and its two main pest species.We found that management extensification and landscape heterogeneity benefited pest control and supported more insectivorous birds. Also, high temperatures diminished pest damage. Compared to landscape and temperature effects, abundance/richness of insectivorous birds were poor predictors of pest abundance and damage, suggesting that other natural enemies might be currently more important for pest control in olive groves. Lastly, we found a decoupled response of pest abundance and pest damage that may be attributed to insecticide use. This suggests that predation pressure by birds might predict better pest abundance than pest damage in our system.Current predation pressure by birds against pests in olive groves seems very low. Fostering extensive management and landscape heterogeneity increases the abundance of insectivorous birds in this system, potentially enhancing the pest control service.

Contrasting agricultural management effects on soil organic carbon dynamics between topsoil and subsoil

Agricultural practices (e.g. tillage, crop rotation and fertiliser application) have a strong influence on the balance between carbon (C) input and output by altering physicochemical and microbial properties that control decomposition processes in the soil. Recent studies suggest that the mechanisms by which agricultural practice impacts soil organic carbon (SOC) dynamics in the topsoil may not be the same as those in the subsoil. Here, we assessed SOC stock, soil organic fractions and nitrogen availability to 1.0 m in soils under a cotton (Gossypium hirsutum L.)-based cropping system, and assessed the impact of agricultural management (three historical cropping systems with or without maize (Zea mays L.) rotation) on SOC storage. We found that the maize rotation and changes in the particulate organic fraction influenced SOC stock in the topsoil, although the overall change in SOC stock was small. The large increase in subsoil SOC stock (by 31%) was dominated by changes in the mineral-associated organic fraction, which were influenced by historical cropping systems and recent maize rotation directly and indirectly via changes in soil nitrogen availability. The strong direct effect of maize rotation on SOC stock, particularly in the subsoil, suggests that the direct transfer of C into the subsoil SOC pool may dominate C dynamics in this cropping system. Therefore, agricultural management that affects the movement of C within the soil profile (e.g. changes in soil physical properties) could have a significant consequence for subsoil C storage.

Correction for Schmidt et al., "Effects of Agricultural Management on Rhizosphere Microbial Structure and Function in Processing Tomato Plants".

Volume 85, no. 16, e01064-19, 2019, [https://doi.org/10.1128/AEM.01064-19][1]. Figure 3 should appear as shown below. ![Figure][2] [1]: /lookup/doi/10.1128/AEM.01064-19 [2]: pending:yes

Subsoil Microbial Diversity and Stability in Rotational Cotton Systems

Microbial diversity has been well documented for the top 0–0.30 m of agricultural soils. However, spatio-temporal research into subsoil microbial diversity and the effects of agricultural management remains limited. Soil type may influence subsoil microbial diversity, particularly Vertosols. These soils lack distinct horizons and are known to facilitate the downward movement of organic matter, potentially supporting subsoil microbiota, removed from the crop root system (i.e., bulk soils). Our research used the MiSeq Illumina Platform to investigate microbial diversity down the profile of an agricultural Australian Vertosol to 1.0 m in bulk soils, as influenced by crop system (continuous cotton and cotton–maize) and sample time (pre- and in-crop samples collected over two seasons). Overall, both alpha- (Chao1, Gini–Simpson Diversity and Evenness indices) and beta-diversity (nMDS and Sørensen’s Index of Similarity) metrics indicated that both bacterial (16S) diversity and fungal (ITS) diversity decreased with increasing soil depth. The addition of a maize rotation did not significantly influence alpha-diversity metrics until 0.70–1.0 m depth in the soil, where bacterial diversity was significantly higher in this system, with beta-diversity measures indicating this is likely due to root system differences influencing dissolved organic carbon. Sample time did not significantly affect bacterial or fungal diversity over the two seasons, regardless of the crop type and status (i.e., crop in ground and post crop). The relatively stable subsoil fungal and overall microbial diversity in bulk soils over two crop seasons suggests that these microbiota have developed a tolerance to prolonged agricultural management.

Bayesian Belief Network models as trade-off tools of ecosystem services in the Guayas River Basin in Ecuador

Food production often leads to environmental degradation. Consequently, insights into ecosystem functioning in relation to exploitation are needed as a basis for socioeconomically acceptable mitigation of these impacts. A Bayesian Belief Network (BBN) model is developed to link three major ecosystem services (ES), i.e. food production, water provision and ecotourism, and determine the effect of local agricultural practices and management on the ES in the Guayas Basin (Ecuador). Several data sources were integrated into the BBN model, including processed spatial data from primary and secondary sources, sampling and survey data, and expert knowledge. The model suggests that banana and sugar cane generate the highest yield but provide low ecotourism benefits. In contrast, cacao produces the lowest yields but contributes to better water quality. Scenario analyses suggest that environmental gains are possible by optimising the land use (LU) based on the edaphoclimatic requirements of crops. Moreover, the integration of LU optimisation with upscaling and farming intensification can allow for additional advantages in water provision and ecotourism while mitigating productivity losses. The BBN development approach can serve as a reference for other case studies, where data scarcity plays a limiting factor in the assessment of interactions between key ES.

Simulation and evaluation of the spatial heterogeneity of shallow-groundwater environmental risk in an urban–rural fringe of megacity: a case study of Shenyang city, northeast China

Shenbei district of Shenyang city, Liaoning province, northeast China is a typical urban–rural (peri-urban) fringe of a megacity that is undergoing rapid urban expansion and the intensification of agricultural management, which threatens the quality of shallow groundwater in the area. This study selects proper indices relevant to vulnerability, stress, function, and adaptability based on the results of groundwater monitoring and the collection and processing of hydrogeological data. Based on the theory of natural disaster risk, an evaluation index system was then established, followed by constructing a groundwater environmental-risk assessment model. Next, the model was used to perform environmental risk grading and spatial pattern assessment on the groundwater based on the statistics and spatial analysis function of ArcGIS. The assessment results were then subjected to a correlation analysis with land use indices and socioeconomic indices, to explore the effects of natural geological conditions, urban expansion and intensive agricultural management on groundwater environment. The results of the study will provide support for land use optimization and water environmental management decision-making during the development and construction of the urban–rural fringe of the area. The results of the study showed that: (1) the spatial distribution of groundwater environmental risk of the Shenbei district is similar to that of groundwater vulnerability. At present, geological conditions are still the main influential factors of groundwater environmental risk in the region; (2) the scale and intensity of urbanization and intensive agricultural management have shown an obvious potential risk to the groundwater environment; (3) the large area paddy fields in the northwest have certain ecological function value, which should be further protected to ensure a win–win situation of agricultural production and environmental safety; (4) it is necessary to put more environmental protection efforts such as ensuring natural vegetation protection, strengthening artificial afforestation, and increasing the number of waste water treatment facilities during the urbanization process, as these measures are significantly effective in maintaining the groundwater quality.

Evaluation of the influence of cultivation on the total magnesium concentration and infusion extractability in commercial arabica coffee

Coffee is considered an important source of organic nutrients and minerals, and these resources are strongly affected by agricultural management. Among the minerals, the element Mg is important, which is essential for both plants and humans. In this work, the effects of agricultural management on the absorption and storage of Mg by commercial, ground, roasted Arabica coffee were investigated. For this purpose, some Mg and P fractions were evaluated. It was observed that Mg stored in the grain was concentrated in the inorganic fraction, with an average extraction of 102% and in conventional samples and 119% in organic samples. These results suggest that in these samples Mg is probably largely presented as different inorganic salts. Phytate and organic acid salts are two possibilities discussed in this work that could explain this hypothesis. This can be corroborated by the extraction of Mg in the infusion of hot water.

Carbon, water and energy fluxes in agricultural systems of Australia and New Zealand

A comprehensive understanding of the effects of agricultural management on climate–crop interactions has yet to emerge. Using a novel wavelet–statistics conjunction approach, we analysed the synchronisation amongst fluxes (net ecosystem exchange NEE, evapotranspiration and sensible heat flux) and seven environmental factors (e.g., air temperature, soil water content) on 19 farm sites across Australia and New Zealand. Irrigation and fertilisation practices improved positive coupling between net ecosystem productivity (NEP = −NEE) and evapotranspiration, as hypothesised. Highly intense management tended to protect against heat stress, especially for irrigated crops in dry climates. By contrast, stress avoidance in the vegetation of tropical and hot desert climates was identified by reverse coupling between NEP and sensible heat flux (i.e., increases in NEP were synchronised with decreases in sensible heat flux). Some environmental factors were found to be under management control, whereas others were fixed as constraints at a given location. Irrigated crops in dry climates (e.g., maize, almonds) showed high predictability of fluxes given only knowledge of fluctuations in climate (R2 > 0.78), and fluxes were nearly as predictable across strongly energy- or water-limited environments (0.60 < R2 < 0.89). However, wavelet regression of environmental conditions on fluxes showed much smaller predictability in response to precipitation pulses (0.15 < R2 < 0.55), where mowing or grazing affected crop phenology (0.28 < R2 < 0.59), and where water and energy limitations were balanced (0.7 < net radiation ∕ precipitation < 1.3; 0.27 < R2 < 0.36). By incorporating a temporal component to regression, wavelet–statistics conjunction provides an important step forward for understanding direct ecosystem responses to environmental change, for modelling that understanding, and for quantifying nonstationary, nonlinear processes such as precipitation pulses, which have previously defied quantitative analysis.

Soil acidification in Chinese tea plantations.

Soil acidification is a major problem in intensive agricultural systems and is becoming increasingly serious. Most research has reported the soil acidification of cereal crops, forests, and grasslands. However, there is no information about soil acidification under tea cultivation on a national scale. Therefore, we conducted a nationwide survey of soil acidification in the major tea-planting areas of China and used two nationwide surveys in three Chinese counties to evaluate changes in soil acidity over the past 20-30years. Finally, the acidity of soil from forests and traditional and organic tea plantations was compared to evaluate the effects of agricultural management on soil acidification in tea plantations. Our results show that: (1) the average soil pH was 4.68 nationally and ranged from 3.96 to 5.48 in different provinces. Overall, 46.0% of the soil samples had a pH <4.5, which is too acidic for tea growth and only 43.9% had a soil pH of 4.5-5.5, which is optimal for tea growth. (2) In the past 20-30years, the greatest soil acidification was observed in tea plantations; the pH decreased by 0.47 to 1.43, which is much greater than the decrease seen in fruit and vegetable systems (0.40 to 1.08) and cereals (0.30 to 0.89). (3) Compared with forests, tea cultivation with chemical fertilizer application caused serious soil acidification, while no significant acidification was observed at organic tea plantations. In conclusion, serious soil acidification occurs nationally in China, and organic management is an adaptive choice for sustainable tea growth.

Impacts of climate change and agricultural activities on water quality in the Lower Kaidu River Basin, China

In the context of climate change and over-exploitation of water resources, water shortage and water pollution in arid regions have become major constraints to local sustainable development. In this study, we established a Soil and Water Assessment Tool (SWAT) model for simulating non-point source (NPS) pollution in the irrigation area of the lower reaches of the Kaidu River Basin, based on spatial and attribute data (2010–2014). Four climate change scenarios (2040–2044) and two agricultural management scenarios were input into the SWAT model to quantify the effects of climate change and agricultural management on solvents and solutes of pollutants in the study area. The simulation results show that compared to the reference period (2010–2014), with a decline in streamflow from the Kaidu River, the average annual irrigation water consumption is expected to decrease by 3.84x108 m3 or 8.87% during the period of 2040–2044. Meanwhile, the average annual total nitrogen (TN) and total phosphorus (TP) in agricultural drainage canals will also increase by 10.50% and 30.06%, respectively. Through the implementation of agricultural management measures, the TN and TP in farmland drainage can be reduced by 14.49% and 16.03%, respectively, reaching 661.56 t and 12.99 t, accordingly, and the increasing water efficiency can save irrigation water consumption by 4.41 x108 m3 or 4.77%. The results indicate that although the water environment in the irrigation area in the lower reaches of the Kaidu River Basin is deteriorating, the situation can be improved by implementing appropriate agricultural production methods. The quantitative analysis results of NPS pollutants in the irrigation area under different scenarios provide a scientific basis for water environmental management in the Kaidu River Basin.

Characterization of Bacterial and Fungal Communities in Soils under Different Farming Systems. The Cacao Plantation in Sulawesi Island—Indonesia

The cacao plantations in Sulawesi Island, Indonesia are responsible for a great part of the local economy; however, their soils still need to be deeply explored. Our study focused on evaluation of the microbial communities in cacao soils according to their location and applied management system. Four soil samples were taken from six cacao farms under two kinds of systems (conventional and organic). 16S and ITS rDNA amplicon sequencing analyses of soils were also performed to identify bacteria and fungi, respectively, whereby their relative abundance and diversity were determined. In general view, the bacterial and fungal communities were affected by management system at the local and general levels. Bacterial analyses indicated that the number of operational taxonomic units and bacterial diversity were higher under the organic system in Kulawi, Palolo, and Poso farms. The composition and biodiversity of fungi were clearly different between organic and conventional systems and between different places (coastal and inland). The effect of agricultural management was observed in each location individually and in general.

Spatial structure and soil properties shape local community structure of plant-parasitic nematodes in cultivated olive trees in southern Spain

Numerous studies have documented the distribution of plant and animal communities with respect to spatial structure; however, relatively little is known about the involvement of spatial structures in the diversity of soil organisms such as plant-parasitic nematodes (PPN). Host plants such as olive trees are of particular interest because they host a large number of PPN and have a high economic and cultural importance. In this study, we investigated how different aspects of the environment (i.e. the factors soil, above-ground environment, and agricultural management) and spatial structure shaped the variation of species composition (expressed as beta diversity) and species richness of plant-parasitic nematodes infesting the soil rhizosphere in 376 commercial olive orchards in the south of Spain. We used variation partitioning to assess the relative importance of the unique and shared contributions of the factors describing the environment and spatial structure. To identify sites and species of particular interest, we partitioned beta diversity into local and species contributions.Contrary to our expectation that soil and agricultural management would largely determine the community structure of PPN, more than two-thirds of the variation remained unexplained. Spatial structure and soil were the most important factors shaping species richness and beta diversity. Surprisingly, the effects of agricultural management on species richness were lower than expected, and null [or nonexistent, or nonsignificant] on beta diversity. We found relatively high levels of shared contributions of the different factors, especially in combination with spatial structure, indicating the presence of spatial gradients of the variables describing the environmental factors.Species contributions to beta diversity (SCBD) were positively correlated with nematode prevalence and density range; thus, SCBD could be related to the niche position as reported in other ecosystems. Local contributions to beta diversity (LCBD) were mainly related with habitat filtering mechanisms (e.g. soil physiochemical and agronomic management predictors), suggesting a relationship between nematode total biomass and ecological gradients. Overall, we revealed novel insights into the spatial structure of PPN communities and showed that its beta diversity is less structured by spatial and environmental factors compared to other organism types.

Effect of fertilizers and irrigation on multi‐configuration electromagnetic induction measurements

AbstractElectromagnetic induction (EMI) data are often used to investigate spatial and temporal patterns of soil texture, soil water content and soil salinity. We hypothesized that the EMI methodology might thus also offer potential to detect agricultural legacy effects originating from fertilizer application and irrigation of different fields. Therefore, we performed EMI measurements on two long‐term field experiments (LTFE) at Thyrow near Berlin (Germany) that differed in agricultural management with regard to long‐term irrigation in combination with mineral (NPK and lime) and organic amendments (straw and farmyard manure). Two different rigid‐boom multi‐coil EMI instruments were used to measure simultaneously the apparent electrical conductivity (ECa) over nine different depth ranges to study the entire soil profile from topsoil to deep subsoil. Additionally, soil samples were taken from the different treatments to ground‐truth the measurements and disentangle the nutrient application or irrigation effects from natural soil heterogeneity. The soil samples indicated a rather homogenous soil and the correlation between soil parameters or states were not significant. However, the treatments showed significant differences in measured ECa values. In general, ECa values were largest on regularly irrigated as well as on mineral and organic fertilized plots, with regular irrigation exhibiting the largest impact on EMI records even though the last application was months before the EMI measurement. Overall, this study reveals that EMI data can support the classical in situ assessment of agricultural management effects within LTFE, while offering new potentials in detecting and understanding legacy effects of agricultural management on spatial soil properties at farm level.