Improve Soil Health Research Articles

Response of agronomic and physiological traits of flue-cured tobacco (Nicotiana tabacum L.) to plant stem cell soil amendments

Black shank disease is an important factor limiting the yield of flue-cured tobacco. Soil amendments have the potential to improve soil health and increase crop yield and quality. However, the application effects of soil amendments have not been elucidated in flue-cured tobacco. Here, we conducted field experiments in the major tobacco planting area, Exploring the effects of plant stem cell soil amendments at different levels on the occurrence and physiological growth of tobacco black shank disease, The purpose is to evaluate the effectiveness of plant stem cell soil amendments and recommend feasible applied rates. Plant stem cell soil amendments are applied at four levels: T0 (0 kg ha−1), T1 (1500 kg ha−1), T2 (2250 kg ha−1), and T3 (3000 kg ha−1). Nutrient absorption, agronomic traits, dry matter quality, chemical composition, and economic benefits of flue-cured tobacco black shank disease were explored. The results showed that the application of plant stem cell soil amendments effectively reduced the incidence rate of tobacco black shank disease, and significantly improved the agronomic traits (leaf number, plant height, leaf length, and width) and dry matter quality of flue-cured tobacco. At the same time, the nutrient content (N, P, and K), the proportion of high-quality tobacco leaves, and the content of coordinated chemical components (total nitrogen, total plant alkali, total sugar, reducing sugar, potassium and chlorine) of flue-cured tobacco plants were increased. In addition, the application rate of stem cell soil amendment at 3000 kg ha−1 showed the best effect on reducing the occurrence of black shank disease, which resulted in improved tobacco yields and economic benefits to the greatest extent of flue-cured tobacco. The study indicates that plant stem cell soil amendments can significantly enhance the yield and quality of flue-cured tobacco and offers an effective method for sustainable crop production in the tobacco industry.

Biochar Amendment Alleviates the Combined Effects of Salinity and Drought Stress on Water Productivity, Yield and Quality Traits of Sugar Beet (Beta vulgaris L.)

Salinity and drought are two commonly occurring major threats to agricultural yields worldwide, including sugar beet production. Therefore, this work aimed to determine the effectiveness of biochar amendment in improving soil health and alleviating the combined effects induced by salinity and drought on morphological, physiological and biochemical responses of sugar beet plants. Two field studies were established at the experimental farm of Fayoum University, Egypt over two successive winter seasons (2019/2020 and 2020/2021). The experiments were carried out in a split-split plot design with triplicate including three factors: 1) soil salinity, with two levels of ECe (< 4 dS m−1 as control and 10 dS m−1) as main-plot factor; 2) deficit irrigation regimes (I100, I80, and I60) representing 100%, 80%, and 60% of crop evapotranspiration (ETc), respectively as sub-plot factor; and 3) biochar amendment with three application levels (B0 as control, B10, and B20) corresponding to 0, 10, and 20 t ha−1, respectively as sub-sub plot factor. Drought and salinity stress induced significant reduction in growth attributes, relative water content, membrane stability, relative chlorophyll content (SPAD), yield and yield components of sugar beet plants. Meanwhile, the contents of sucrose, proline, Na, K, α amino-N were substantially increased with increasing stress severity. The application of biochar amendment improved the soil physical and chemical properties, resulting in better morphological, physiological and biochemical responses of saline-drought stressed sugar beet plants. Biochar at level (B20) produced the highest values of root yield (95.02 t ha−1) and sugar yield (20.24 t ha−1) for full irrigated sugar beet plants in non-saline soil. Moreover, the application of biochar enhanced water productivity for drought and saline stressed sugar beet plants. Biochar amendment could be effectively used as a helpful agro-management strategy in alleviating the detrimental impacts of salinity and water stress on sugar beet plants, improving soil quality and enhancing water productivity to ensure water sustainability and food security, especially in areas of limited water supply.

Advancing Agricultural Sustainability: Vermicomposting as a Biochemical Pathway for Improved Soil Health and Climate Resilience

This comprehensive review explores the multifaceted role of vermicomposting in sustainable agriculture, emphasizing its biochemical processes and impact on soil systems. Beginning with the concept, the document delves into the intricacies of the vermicomposting process, including the selection of suitable earthworm species for vermiculture. It further examines the biochemical transformations that occur during vermicomposting, such as the optimization of the carbon to nitrogen ratio, alterations in organic carbon content, and the modulation of soil pH and electrical conductivity. The accumulation of heavy metals and the transformation of nitrogen and phosphorus are also discussed, alongside the process of humification. Subsequently, the profound effects of vermicompost on soil properties, highlighting its influence on physical characteristics, organic matter content, mineralization, and nutrient dynamics, as well as the enhancement of humus content was deeply reviewed. The document also investigates the implications of vermicomposting on plant growth and yield, providing insights into its potential to increase agricultural productivity. Additionally, the review addresses the impact of vermicomposting on greenhouse gas emissions, underscoring its significance in the context of climate-smart farming practices. Arising from detailed synthesis of the findings, vermicomposting is a pivotal component of climate-resilient agriculture, offering a pathway to healthier soil ecosystems and a sustainable future.

Strategies and Public Policies for Soil and Water Conservation and Food Production in Brazil

There is an urgent demand to change our intensive crop production systems, replacing them with soil use and management systems that recover, preserve, or improve soil health and are environmentally sustainable, producing healthy and good-quality food. In this work, we compile and present strategies and public policies aimed toward soil and water conservation and food production in Brazil. The results presented may help Brazilian farmers adopt practices to recover, maintain, or improve soil health and politicians to create or modify public policies for healthy soil and food, without the necessity of increasing agricultural areas. Food insecurity was also addressed, with family farming playing an important role in food production and decreasing food insecurity. But these challenges need the combined efforts and engagement of the whole society.

An assessment of Organic and Conventional Farming Practices for Yield, Pest Management and Soil Health

This study contrasts and compares conventional and organic farming. The purpose of the study is to assess the effectiveness and impact of each practice before deciding on the best crop-growing approach. Despite their agricultural systems can be categorized as conventional or sustainable depending on the techniques employed. Organic farming which cultivates a range of crops without the use of synthetic manures, the agricultural method that is most sustainable. While producing enough food, organic farming improves soil composition and supports biodiversity by relying on ecosystem services. The review compares the long-term effects of conventional and alternative organic farming practices on yield in which in short term organic yields were found to be 19.2% lower than conventional yield while in long term yields were lower in conventional systems by 31% and 50%, respectively, due to the long-term improvement in soil health. In soil health point of view long term practices of organic farming improves physical, chemical and biological properties of soil by increase soil carbon stock by 12 %, more nutrient release and microbial activity. Pest management is effectively controlled by crop rotation, increase beneficial population of pest in organic farming which reduce the dependency on chemical pesticides and maintain the sustainability of soil health and ecology. As a result, organic farming methods are being evaluated in a large number of research worldwide as an alternative due to their better physical, chemical and biological qualities than conventional farming methods.

Sandy soil reclamation technologies to improve crop productivity and soil health: a review

Sandy soils are characterized by low soil moisture content and nutrient retention due to high permeability, limiting crop productivity and threatening food security in arid and semi-arid regions worldwide. Various reclamation technologies have been developed to address these challenges, but their effectiveness has not been comprehensively evaluated. This systematic review evaluated the performance of 42 sandy soil reclamation technologies reported in 144 studies from 27 countries that met specified selection criteria. Performance was evaluated based on response ratio (RR) of aboveground biomass and grain yield, as indicators of productivity, and soil moisture content and soil organic carbon (SOC), as indicators of soil health. The 42 technologies employed four main soil amendments: biochar, organic amendments, organic amendments combined with biochar, and soft rock. Overall, all technologies increased productivity and improved soil health. Biochar application was found to be the most effective technology, increasing grain yield by 51.6%, aboveground biomass by 67.4%, soil moisture content by 17.3%, and SOC by 74.2%. Soft rock application increased grain yield by 20.3%, aboveground biomass by 27.6%, soil moisture content by 54.5%, and SOC by 12.8%. Organic amendments increased grain yield by 48.7%, aboveground biomass by 45.6%, soil moisture content by 20.8%, and SOC by 36.7%. However, the combination of biochar and organic amendments showed lower improvements, with increases of 25.4%, 15.6%, 1.3%, and 25.4% for grain yield, aboveground biomass, soil moisture content, and SOC, respectively. Our conclusion is that the findings provide strong evidence that sandy soil reclamation technologies can significantly improve crop productivity and food security. Considering the variability in technologies responses across continents, there is need for further research to determine the optimal technology for specific locations, crops, and management practices.

Understanding and exploring the diversity of soil microorganisms in tea (Camellia sinensis) gardens: toward sustainable tea production.

Leaves of Camellia sinensis plants are used to produce tea, one of the most consumed beverages worldwide, containing a wide variety of bioactive compounds that help to promote human health. Tea cultivation is economically important, and its sustainable production can have significant consequences in providing agricultural opportunities and lowering extreme poverty. Soil parameters are well known to affect the quality of the resultant leaves and consequently, the understanding of the diversity and functions of soil microorganisms in tea gardens will provide insight to harnessing soil microbial communities to improve tea yield and quality. Current analyses indicate that tea garden soils possess a rich composition of diverse microorganisms (bacteria and fungi) of which the bacterial Proteobacteria, Actinobacteria, Acidobacteria, Firmicutes and Chloroflexi and fungal Ascomycota, Basidiomycota, Glomeromycota are the prominent groups. When optimized, these microbes' function in keeping garden soil ecosystems balanced by acting on nutrient cycling processes, biofertilizers, biocontrol of pests and pathogens, and bioremediation of persistent organic chemicals. Here, we summarize research on the activities of (tea garden) soil microorganisms as biofertilizers, biological control agents and as bioremediators to improve soil health and consequently, tea yield and quality, focusing mainly on bacterial and fungal members. Recent advances in molecular techniques that characterize the diverse microorganisms in tea gardens are examined. In terms of viruses there is a paucity of information regarding any beneficial functions of soil viruses in tea gardens, although in some instances insect pathogenic viruses have been used to control tea pests. The potential of soil microorganisms is reported here, as well as recent techniques used to study microbial diversity and their genetic manipulation, aimed at improving the yield and quality of tea plants for sustainable production.

Fishpond Water Potential on Vineyard Soil Health: An Exploratory Study of a Circular System

Climate variabilities continue to hinder sustainable food production with an increasing need to use resources such as water and soil efficiently. The quest for these efficiencies in agriculture systems drives innovations among farmers. However, limited data on farm practices, such as irrigating with fishpond water and their effects on soil health, hinder their adoption as climate-smart innovations. In a nearly twenty-year-old vineyard with two distinct irrigation practices (irrigation with recycled fishpond water and irrigation with ditch water), this study was carried out as an exploratory study to investigate the influence of recycling fishpond water on soil health parameters and yield. Soil samples were taken from two different irrigation fields in summer and winter for lab analysis on soil health parameters (organic matter and carbon, nitrogen, phosphorus, microbial biomass, and microbial respiration). Averages over the two seasons of field measurements indicate that long-term irrigation using recycling fishpond water increased the measured soil health parameters (organic matter (13%), organic carbon (30%), nitrogen (17%), phosphorus (46%), microbial biomass (18%), and microbial respiration (56%)) in both summer and winter months when compared to fields receiving just ditchwater irrigation. Using water in a way that can improve soil health increases biodiversity and improves the efficiency of our limited water resources in semi-arid agricultural lands, and this strategy is a climate-smart tool that can help reduce water risks in dry agricultural regions such as Arizona.

Cover crop residue decomposition triggered soil oxygen depletion and promoted nitrous oxide emissions

Cover cropping is a promising strategy to improve soil health, but it may also trigger greenhouse gas emissions, especially nitrous oxide (N2O). Beyond nitrogen (N) availability, cover crop residue decomposition may accelerate heterotrophic respiration to limit soil O2 availability, hence promote N2O emissions from denitrification under sub-optimal water-filled pore space (WFPS) conditions that are typically not conducive to large N2O production. We conducted a 21-day incubation experiment to examine the effects of contrasting cover crop residue (grass vs legume) decomposition on soil O2 and biogeochemical changes to influence N2O and CO2 emissions from 15N labeled fertilized soils under 50% and 80% WFPS levels. Irrespective of cover crop type, mixing cover crop residue with N fertilizer resulted in high cumulative N2O emissions under both WFPS conditions. In the absence of cover crop residues, the N fertilizer effect of N2O was only realized under 80% WFPS, whereas it was comparable to the control under 50% WFPS. The N2O peaks under 50% WFPS coincided with soil O2 depletion and concomitant high CO2 emissions when cover crop residues were mixed with N fertilizer. While N fertilizer largely contributed to the total N2O emissions from the cover crop treatments, soil organic matter and/or cover crop residue derived N2O had a greater contribution under 50% than 80% WFPS. Our results underscore the importance of N2O emissions from cover crop-based fertilized systems under relatively lower WFPS via a mechanism of respiration-induced anoxia and highlight potential risks of underestimating N2O emissions under sole reliance on WFPS.

Agricultural Practices and Climate Resilience: Case Study in Vietnam

Purpose: To aim of the study was to analyze agricultural practices and climate resilience: case study in Vietnam. Methodology: This study adopted a desk methodology. A desk study research design is commonly known as secondary data collection. This is basically collecting data from existing resources preferably because of its low cost advantage as compared to a field research. Our current study looked into already published studies and reports as the data was easily accessed through online journals and libraries. Findings: In Vietnam, agricultural practices significantly enhance climate resilience amidst growing climate variability. Diversified cropping systems and climate-smart techniques like conservation agriculture and agroforestry help mitigate climate-related risks by spreading vulnerabilities and improving soil health and water retention. Promoting resilient crop varieties and livestock breeds further reduces susceptibility to pests, diseases, and extreme weather events. Integrating these strategies into agricultural policies is vital for ensuring food security and sustainability in Vietnam's changing climate. Unique Contribution to Theory, Practice and Policy: Social-Ecological Systems Theory (SES), Adaptive Capacity Theory &amp; Political Ecology Theory may be used to anchor future studies on agricultural practices and climate resilience: case study in Vietnam. Encourage diversification of crops and livestock to increase resilience to climate variability. Promote mixed cropping, agroforestry, and integrated livestock-crop systems, which enhance biodiversity, soil fertility, and pest resilience. Develop and implement policies that support climate-resilient agriculture.

Crop, livestock, and forestry integration to reconcile soil health, food production, and climate change mitigation in the Brazilian Cerrado: A review

Integrated crop–livestock (ICL) and crop–livestock–forestry (ICLF) systems have been widely adopted in the Brazilian Cerrado. In this study, we gathered the publications regarding the effects of the ICL and ICLF systems on soil health, plant and animal production, and carbon (C) balance and then synthesized them in comparable terms, aiming to evaluate the sustainability of these systems in a broader and comprehensive approach. On the basis of the evidence from 65 peer-reviewed publications, it was observed that adopting integrated systems can improve soil health in the Brazilian Cerrado. With a few exceptions, positive effects on chemical, physical, and biological indicators of soil health were observed in most of the studies that comprised our data. Accordingly, the results showed that the ICL and ICLF systems can improve plant yield and animal production, but special attention regarding the grazing regime and tree management (e.g., spacing, pruning, and thinning) is required. Moreover, soil C accumulation fully offsets soil N2O emissions, underscoring the feasibility of using the ICL and ICLF systems for decreasing the C footprint of agricultural commodities in this region. The research assembled in this review has undoubtedly advanced our knowledge regarding integrated systems in the Brazilian Cerrado. However, there are still significant knowledge gaps that should be addressed, such as their effects on soil physics and biology. Despite these shortcomings, our literature review demonstrates that the ICL and ICLF systems are essential strategies to intensify agricultural production in the Brazilian Cerrado while ensuring sustainability.

Intercomparison of Same-Day Remote Sensing Data for Measuring Winter Cover Crop Biophysical Traits.

Winter cover crops are planted during the fall to reduce nitrogen losses and soil erosion and improve soil health. Accurate estimations of winter cover crop performance and biophysical traits including biomass and fractional vegetative groundcover support accurate assessment of environmental benefits. We examined the comparability of measurements between ground-based and spaceborne sensors as well as between processing levels (e.g., surface vs. top-of-atmosphere reflectance) in estimating cover crop biophysical traits. This research examined the relationships between SPOT 5, Landsat 7, and WorldView-2 same-day paired satellite imagery and handheld multispectral proximal sensors on two days during the 2012-2013 winter cover crop season. We compared two processing levels from three satellites with spatially aggregated proximal data for red and green spectral bands as well as the normalized difference vegetation index (NDVI). We then compared NDVI estimated fractional green cover to in-situ photographs, and we derived cover crop biomass estimates from NDVI using existing calibration equations. We used slope and intercept contrasts to test whether estimates of biomass and fractional green cover differed statistically between sensors and processing levels. Compared to top-of-atmosphere imagery, surface reflectance imagery were more closely correlated with proximal sensors, with intercepts closer to zero, regression slopes nearer to the 1:1 line, and less variance between measured values. Additionally, surface reflectance NDVI derived from satellites showed strong agreement with passive handheld multispectral proximal sensor-sensor estimated fractional green cover and biomass (adj. R2 = 0.96 and 0.95; RMSE = 4.76% and 259 kg ha-1, respectively). Although active handheld multispectral proximal sensor-sensor derived fractional green cover and biomass estimates showed high accuracies (R2 = 0.96 and 0.96, respectively), they also demonstrated large intercept offsets (-25.5 and 4.51, respectively). Our results suggest that many passive multispectral remote sensing platforms may be used interchangeably to assess cover crop biophysical traits whereas SPOT 5 required an adjustment in NDVI intercept. Active sensors may require separate calibrations or intercept correction prior to combination with passive sensor data. Although surface reflectance products were highly correlated with proximal sensors, the standardized cloud mask failed to completely capture cloud shadows in Landsat 7, which dampened the signal of NIR and red bands in shadowed pixels.

Integrated parasite management (IPM) and the pasture ecosystem: Optimizing outcomes for cattle, insect biodiversity, and soil health

Concerns over the negative environmental impacts of livestock parasiticide treatments and the widespread development of resistance has precipitated a move towards integrated parasite management (IPM). However, within the pasture ecosystem management strategies are likely to impact multiple processes in complex ways. This study investigates the impacts of IPM strategies on pest flies, gastrointestinal nematode (GIN) parasites, beneficial dung insects, and soil health. Twenty-nine grazing dairy farms participated in the study, representing different chemical and nonchemical parasite management and grazing strategies (continuous, rotational, or management intensive rotational (MIG)). Cattle managed using rotational grazing and MIG had significantly lower FEC than continuously grazed cattle. Farms using chemical parasiticides had significantly fewer pest flies, however farms releasing parasitoid wasps as biological control also had reduced abundances. Dung inhabiting beetle abundance was significantly correlated with reduced pest flies and GIN. Beneficial insects were negatively impacted on farms that used parasiticides. Continuously grazed pastures had higher beneficial insect abundances only on farms that did not use chemical parasiticides. Pastures managed under MIG had lower soil bulk density and higher active carbon compared to continuous grazing. There were positive associations between soil health and tunneling dung insects (Onthophagus spp. dung beetles). Finding optimal strategies will be context dependent, however the results of this study indicate that grazing strategies can control gastrointestinal parasites and improve soil health outcomes, natural enemies such as parasitoid wasps and dung inhabiting beetles can suppress pest fly populations, and the impacts of chemical control strategies may be mitigated through thoughtful implementation.

Multiple Soil Health Assessment Methods for Evaluating Effects of Organic Fertilization in Farmland Soil of Agro-Pastoral Ecotone

The incorporation of organic fertilizer is an important practice to improve the sustainability and productivity of crop production and decrease environmental pollution from crop-livestock systems in global agriculture. However, establishing an evaluation dataset is still the main challenge for quickly and effectively assessing the effect of management measures on farmland soil health. Hereby, we developed a minimum dataset (MDS) using three methods (network analysis (NA), random forest analysis (RF), and principal component analysis (PCA)). Based on MDS and two scoring functions (nonlinear (NL) and linear scoring curve (L)), the SHI (soil health index framework) was constructed to assess soil health conditions under four fertilization treatments (no fertilization, CK; only chemical fertilizer, NPK; only cow manure, MF; 50% chemical fertilizer + 50% cow manure, NPKM) in the northern ecotone of China. The results showed that the MDS-based on SHIs were positively correlated with each other and SHI-TDS (total dataset), verifying the consistency of soil health assessment models. Higher R2 was observed in the fitting of SHIs based on NA and TDS, which suggested that nMDS (minimum dataset based on network analysis) could represent most of the information in the TDS. The SHI-NL-nMDS (based on network analysis and nonlinear scoring curve) has the highest ability of sensitivity and accuracy, which indicates that compared with PCA and RF, the SHI based on NA can better embody farmland sol ecosystem functions. In addition, crop yield was significantly positive relative to SHI (soil health index). The incorporation of cow manure and chemical fertilizer improved soil health and increased crop yield. These results indicate that network analysis was a reliable technology for determining the minimum dataset in the evaluation of farmland soil health, and incorporating livestock manure could improve soil health and crop yield in this study area.

Effects of ecological intensification of agriculture on soil fertility and carbon and nitrogen stocks: An 8‐year study in southern Brazil

AbstractEcological intensification (EI) of agriculture aims to optimize soil conservation, crop diversity and nutrient management. Despite growing interest in EI, its impact on soil properties, compared with conventional farming practice (FP), remains poorly understood as a result of limited field evidence. This study, conducted over eight seasons in southern Brazil as part of the ‘Global Maize Project’ of the International Plant Nutrition Institute, evaluated EI compared with FP, and FP with silage (FPS) using a split‐plot design. Four nitrogen application rates (0, 70, 140 and 210 kg ha−1) were applied to subplots with four replicates. Soil properties were measured to a depth of 1 m. The trial systems consisted of a maize–soybean rotation under no‐till during summer and cover crops and fertilizer application during winter. In the FP system, black oats and wheat were cultivated, while FPS utilized white oats and ryegrass. In the EI system, peas (without N application) and wheat were cultivated. In the 4‐years preceding the trial, the area was cultivated in a no‐till system with maize–soybean during summer and black oat–wheat in winter. Our results reveal distinct differences in soil properties among the systems, with FPS demonstrating greater soil acidity (pH of 4.4 at 0–5 cm) caused by higher N application than FP and EI systems. The lower soil pH altered soil nutrient dynamics, with decreased available Ca, Mg and K and increased Cu, Fe, Mn and Zn. Furthermore, nutrient availability varied, with EI having more inorganic N and DON at 0–40 cm compared with FP, but less in deeper soil (40–100 cm). Notably, EI system had more soil carbon (175 Mg ha−1) compared with FP (161 Mg ha−1), a relative annual increase of 1.8 Mg ha−1 year−1 over 8 years. These findings underscore the potential of EI to promote soil carbon, thereby contributing to climate change mitigation and soil health improvement.

TEHNOLOGII ȘI SOLUȚII CONSTRUCTIVE PRIVIND MANAGEMENTUL INTERVALULUI DINTRE RÂNDURILE DE VIȚĂ DE VIE ȘI POMI FRUCTIFERI

The management of inter-row space of vineyards and fruit trees has emerged as an essential approach in sustainable agriculture, optimizing resource use and improving ecosystem services. This paper reviews a range of innovative technologies and solutions aimed at revolutionizing line management practices. Modern sensing and monitoring systems provide real-time data on soil moisture, nutrient levels, and plant health, facilitating precision row-to-row management. Furthermore, techniques for grassing the space between rows of vines and fruit trees are important for space management, ensuring good air circulation and facilitating agricultural activities such as maintenance and harvesting. In addition, the advent of inter-row seeding machines simplified the implementation of cover crops. These machines use advanced seed delivery mechanisms, precisely distributing the cover seed into the spaces between the rows. This not only encourages soil health and erosion prevention but also mitigates weed competition, increasing the overall resilience of the agroecosystem. The purpose of this review is to discuss the combination of state-of-the-art technologies such as 3D LIDAR technology, intelligent systems used for inter-row management of vines and fruit trees, and inter-row solar panel systems, all these examples have revolutionized inter-row management in vineyards and orchards. This holistic approach optimizes resource allocation, improves soil health, and encourages sustainable agricultural practices, paving the way for greener and more resilient inter-row spaces in modern agroecosystems.

Effect of manure co-digestion on methane production, carbon retention, and fertilizer value of digestate

Anaerobic digestion can provide benefits not only from the perspective of renewable energy production but also in the form of fertilization effect and increased retention of C in soils after digestate application. This study consisted of two phases, where the first phase assessed the suitability of carbon-rich co-feedstocks for methane production via laboratory testing. The second phase assessed the balance and stability of C before and after anaerobic digestion by systematic digestate characterization, and by evaluating its carbon retention potential using a modeling approach. The results indicated that pyrolysis chars had a negligible effect on the methane production potential of cattle manure, while wheat straw expectedly increased methane production. Thus, a mixture of cattle manure and wheat straw was digested in pilot-scale leach-bed reactors and compared with undigested manure and straw. Although the total amount of C in the digestate was lower than in the untreated feedstocks, the digestion process stabilized C and was modeled to be more effective in retaining C in the soil than untreated cattle manure and wheat straw. In addition, digestion converted 23–27 % of the C into valuable methane, increasing the valorization of the total C in the feedstock. Considering anaerobic digestion processes as a strategy to optimize both carbon and nutrient valorization provides a more holistic approach to addressing climate change and improving soil health.

Developing causal loop diagrams for the perusal of soil health in agricultural practices – A case study of rice nursery cultivation practices in India

CONTEXTSoil is a key component of the agriculture–livestock–forestry nexus. However, it has been reported that 40% of the agricultural soil is being degraded globally; in India, 70% of the agricultural soil is undergoing degradation despite various efforts to improve soil health. Hence, the current study takes a paradigmatic shift by applying the approach of systems thinking for understanding soil health. OBJECTIVEThis study aims to present an alternative methodology to study the impact of agriculture practices on soil health with a systems approach. METHODSA practice of soil parching for rice nursery cultivation, called raab, representing the agriculture–livestock–forestry nexus, was taken as a case study. The study included field visits to rice farms in Maharashtra, India, soil sample collection at three stages of raab practice, and soil samples from non-raab fields. Thirty-one soil samples were tested for four properties: pH, electrical conductivity, available potassium, and permanganate oxidizable carbon (POXC) in raab and non-raab nursery fields. Further, a causal loop diagram of the soil ecosystem was developed based on farmer interactions, soil testing results, and literature to identify the key system archetype in this case study. RESULTS AND CONCLUSIONStatistical analysis of the results showed a significant difference in soil properties at different stages of cultivation and in comparison to the control group. The mean pH of raab fields had increased due to the raab practice from 5.76 to 7.01, and the mean electrical conductivity increased from 0.218 dS/m to 0.745 dS/m. The mean available potassium increased from 229.9 kg/ha to 1239 kg/ha in the raab fields, while direct nursery fields had a mean of 487 kg/ha at the time of sowing. The mean POXC increased from 0.02 to 0.04 mol of MnO4− reduced. The causal loop diagram developed had 17 loops, 15 of which were favorable-reinforcing loops, and two were unfavorable-balancing loops. The system archetype of “Limits to growth” was identified in this study, based on which recommendations are suggested for maintaining soil health. SIGNIFICANCEThe systemic approach aids in decision-making regarding sustainable agriculture practices considering soil ecological processes with judicious use of resources available from the forest and livestock. The direct impact of soil health on five UN Sustainable Development Goals (SDGs) and the indirect impact on seven other SDGs underscores the global significance of the novel approach discussed in this study.

Exploring the driving forces and digital mapping of soil biological properties in semi-arid regions

Soil biological properties (SBPSs) are crucial for soil health and ecosystem functioning. Mapping these properties can provide insights into soil ecosystems and help develop management and conservation strategies. The objective of this study was to map five important indicators of SBPSs, namely urease (Ur), acid phosphatase (ACP), alkaline phosphatase enzyme (ALP) activity, metabolic quotient (qCO2), and soil microbial biomass to soil organic carbon ratio (MBC: SOC) using machine learning algorithms (MLA) and to identify the most important driving factors of these properties. The study was conducted in Honam sub-basin, Lorestan, Iran, on an area of 14,000 ha. 90 surface soil samples (0–30 cm) were collected and analyzed in the laboratory. 60 soil and environmental covariates, including soil, topography, and remote sensing data (RS), were used to represent influencing factors. The most relevant covariates were selected based on correlation and recursive feature elimination (RFE) analysis using two state-of-the-art MLAs, Random Forest (RF) and Extreme Gradient Boosting (XGBoost) trees, were used to predict SBPSs based on the selected covariates. Relative importance analysis and partial dependence plots were used to evaluate the effects of different factors on the prediction of SBPSs. The results showed that 28 soil and environmental covariates were selected as relevant factors. Both RF and XGBoost models performed well and achieved acceptable accuracy (as measured by R2 value). XGBoost outperformed RF on qCO2 (R2 = 0.61), ALP (R2 = 0.73) and Ur (R2 = 0.75), while RF performed better on ACP (R2 = 0.65) and the MBC: SOC (R2 = 0.81). Relative importance analysis showed that ACP and Ur were most strongly associated with the soil variables at 79 % and 42 %, respectively. ALP and qCO2 were strongly correlated with topographic attributes at 56 % and 52 %, respectively. MBS: SOC was about 40 % associated with the RS indices. The influence of each SBPS varied depending on the specific types of covariates. These results highlight the potential of targeted strategies for effective management and protection of soil ecosystem leading to improved soil health and ecosystem function. Further research should focus on developing methods that encompass a broader range of indices that influence soil microbial activity in drylands.

Soil C:N impacts on soil biological health and consequences on weed control in soybean and corn systems

Abstract Nitrogen availability has an important influence on agricultural weed growth, because many weeds in annual cropping systems are more competitive in high-nitrogen soils. A potential method to control nitrogen availability is through soil carbon amendments, which stimulate soil microbial growth and immobilize nitrogen. Additionally, carbon amendments may alter soil microbial community composition, increase soil biological functioning, and improve soil health. In a 2-yr field experiment in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.], we implemented five amendment treatments to test their ability to alter weed and crop growth through soil nitrogen availability and soil biological functioning. The treatments included: an untreated control, an unamended weed-free control, rye hay adding 3,560 kg C ha−1 and 3,350 kg C ha−1 in 2020 and 2021, respectively, sawdust adding 5,030 kg C ha−1 and 4,350 kg C ha−1 in 2020 and 2021, respectively, and a rye hay and sawdust combined treatment adding 8,590 kg C ha−1 and 7,700 kg C ha−1 in 2020 and 2021, respectively. Each treatment was replicated five times in corn and six times in soybean. Each season, we explored correlations between crop and weed biomass and weed community composition and nitrogen immobilization measured through soil respiration and nitrogen availability. We also explored changes to the soil microbial community composition and soil health as a secondary result of the carbon amendment treatments. Nitrogen availability was lowest in plots treated with the highest C:N amendment. Increasing carbon improved soil health metrics, but the microbial community composition was most affected by the rye hay treatment. Amendments with high C:N reduced weed growth in both soybean and corn plots but only selected for specific weed communities in soybean, leading to improved soybean competitiveness against weeds. In corn, crop growth and weed community composition remained consistent across amendment treatments. Targeted nitrogen immobilization may improve leguminous crop competition in some weed communities as part of an integrated weed management program.