Enhance Soil Quality Research Articles

Unveiling the Impacts of Biochar, Manure and Their Optimal Combinations on Microbiological Soil Health Indicators and Lettuce Biomass

Continuous use of chemical fertilizers has deteriorated soil health and crop productivity. Replenishing soil nutrients and microbial activity with eco-friendly soil amendments such as biochar and manure is therefore necessary to sustain soil health for crop production. However, studies are limited regarding the evaluation of biochar and poultry manure effects on soil health, attributed mainly to microbial extracellular enzymes and respiration. Therefore, the present study was designed to investigate the effects of poultry manure and biochar on soil physico-chemical and microbiological properties and lettuce biomass accumulation in a pot experiment. The pots were amended with poultry manure either alone and or in combination with low (10%) and high (20%) rates of biochar. The treatments included were; (i) control, (ii) manure alone (M), (iii) manure plus 10% biochar (M + B10, and (iv) manure plus 20% biochar (M + B20). Results revealed that soil extracellular enzymes related to C, N, and P mineralization, soil basal (BR), and substrate induced respirations (SIR) were significantly affected by applied manure and manure–biochar. However, there were large differences observed for applied amendments regarding various soil and crop parameters. Specifically, the manure combined with a high rate of biochar (M + B20) enhanced total carbon (TC) content, dehydrogenase activity (DHA), BR, and all SIRs except Arginine-IR. On the other hand, manure combined with a low rate of biochar (M + B10) resulted in enhanced lettuce aboveground dry biomass (AGB-dry). The manure treatment alone (M), however, proved to be the most influential treatment in improving soil enzymes (β-glucosidase, N-acetyl-β-d-glucosaminidase and phosphatase) involved in C, N, and P mineralization compared to the other treatments and control. Thus, it was concluded that the sole application of M and M + B20 improved both fertility and soil health, which therefore could be a promising direction for the future to enhance soil quality and crop productivity.

Current Challenges and Pitfalls in Soil Metagenomics.

Soil microbial communities are essential components of agroecological ecosystems that influence soil fertility, nutrient turnover, and plant productivity. Metagenomics data are increasingly easy to obtain, but studies of soil metagenomics face three key challenges: (1) accounting for soil physicochemical properties; (2) incorporating untreated controls; and (3) sharing data. Accounting for soil physicochemical properties is crucial for better understanding the changes in soil microbial community composition, mechanisms, and abundance. Untreated controls provide a good baseline to measure changes in soil microbial communities and separate treatment effects from random effects. Sharing data increases reproducibility and enables meta-analyses, which are important for investigating overall effects. To overcome these challenges, we suggest establishing standard guidelines for the design of experiments for studying soil metagenomics. Addressing these challenges will promote a better understanding of soil microbial community composition and function, which we can exploit to enhance soil quality, health, and fertility.

Characterization of Poultry Litter Biochar and Activated Biochar as a Soil Amendment for Valorization

Biochar applications to soils may enhance soil quality, hydrological properties, and agronomic productivity. Modification of biochar by activation via introduction of heteroatoms at different pyrolysis conditions can alter physical and chemical characteristics, which may enhance soil properties, although the extent of this is unknown. The objective of this study was to investigate the impacts of pyrolysis temperature (400, 500, 600, and 700 °C) on activated (activated with methanesulfonic acid) and unactivated biochar produced from poultry litter to identify optimum production conditions for end use as a soil amendment. Physical, chemical, and surface properties of biochars were determined using wet chemistry and spectroscopic analyses. Results showed that activation with methanesulfonic acid increased biochars’ oxygen content, while decreasing its point of zero charge and electrical conductivity. Conversion of raw poultry litter to activated and unactivated biochar increased concentration of P (3-fold), K (1.8-fold), Ca (3-fold), Mg (2.3-fold), and S (4.8-fold), with concentrations increasing with increasing temperatures (p < 0.05) except for C and N. Activated biochar had lower recovery of C and N, but greater water-holding capacity than unactivated biochar. Concentrations of NH4-N, NO3-N, and water-soluble P were greater in unactivated biochar (p < 0.05). Among all biochars, activated biochar produced at 400 °C had the lowest bulk density, total P, K, Ca, and Mg, and greatest water-holding capacity, water-soluble P, Ca, and Mg concentrations, thereby suggesting improved soil amendment characteristics and subsequent soil health under poultry litter biochars produced under these conditions.

Effect of raw sewage sludge and sewage sludge biochar on soil physicochemical properties and seed germination of Solanum lycopersicum

AbstractVarious experts have been concerned about the safety usage of sludge generated during wastewater treatment and its disposal in the environment. Biochar made from sewage sludge was studied for its efficiency in enhancing soil quality, reducing heavy metal uptake, and potential benefits in agriculture areas to enrich the soil. The objectives of the present study were to examine the feasibility of raw sewage sludge (RSS) and sewage sludge biochar (SSB), which were produced at 400 and 500°C, as a soil amendment, and the effect of sewage sludge biochar on seed germination of Solanum lycopersicum. Present study included seven treatments: (i) T0 (Control); (ii) T1 (RSS, 1%); (iii) T2 (RSS, 2.5%); (iv) T3 (SSB400°C, 1%); (v) T4 (SSB400°C, 2.5%); (vi) T5 (SSB500°C, 1%); and (vii) T6 (SSB500°C, 2.5%). The addition of sewage sludge and its biochar enhanced electrical conductivity (EC), total organic carbon (TOC), sodium (Na) and potassium (K), and soil enzymatic activity when compared to control. The pH value of the soil amended with RSS increased by 0.04–0.1 units as compared to control. The treatments with the higher concentration (2.5%) of RSS and SSB significantly increased the concentration of Na whereas, SSB400°C, 2.5% significantly increased the K concentration in soil in comparison to control. The TOC in soil increased in all the RSS and SSB amended treatments and ranged between 1.16 and 1.83 %. Seeds of Solanum lycopersicum treated with SSB at 500°C had shown maximum germination (90%) and germination index (103.01 ± 1.41). The increase in the alkaline phosphatase activity was significant and was maximum 25.2 μg 4‐nitrophenol g−1 soil h−1 for T2 followed by T4 which was 24.9 μg 4‐nitrophenol g−1 soil h−1. The results demonstrate that the RSS and SSB at 2.5% concentration are potential organic amendments to promote the soil nutrients.

Soil Quality Enhancement with Orchard Age in Pecan Orchards of the Southeastern U.S. Coastal Plain

Pecan (Carya illinoinensis) orchards in Georgia and throughout the southeastern United States are commonly established from land that had previously been used for row cropping systems. Soil quality is characteristically low in the loamy-sand, low pH soils of the southeastern Coastal Plain. Changes in land use are known to exhibit different effects on soil quality; however, no studies specifically address soil enhancement from converting row crop land to pecan orchards in this region. Sampling was conducted in eight counties throughout the coastal plain of South Georgia in 2020 and 2021. The objectives of this study were to analyze and compare soil quality indicators of pecan orchards of varying ages and adjacent row crop fields. Soil quality indicators analyzed include soil organic matter (SOM), active carbon or permanganate oxidizable carbon (POXC), aggregate stability, cation exchange capacity (CEC), bulk density, porosity, Solvita CO2-Burst, SLAN (Solvita labile-amino nitrogen), pH, and total N. Results from this study demonstrate that pecan orchards under commercial management had higher soil quality compared with row crop fields based on the indicators measured. Active carbon and Solvita CO2-Burst measurements suggest that pecan orchards exhibited significantly higher rates of microbial activity and soil respiration. Indicators of soil microbial activity such as active carbon and Solvita CO2-Burst were strongly correlated with SOM, which explained much of the variation observed in these measurements of soil microbial activity. Selected soil quality indicators also provide evidence that the soil quality of commercial pecan orchards in this region improves with orchard age.

Relationships of priming effects with organic amendment composition and soil microbial properties

• We assessed for interactions between priming effects, soil microbial dynamics, and organic amendment (OA) composition. • Priming effects correlated closely with OAs’ hot water to total carbon concentrations. • Priming effects can be reduced by composting, but not fermenting, OAs before application. • Microbial properties correlated better with energetic than stoichiometric OA characterizations. • Relationships can be used in the preliminary approximation of OA sequestration efficiency. Soil organic carbon (SOC) sequestration through the application of organic amendments (OAs) is considered an important strategy to offset anthropogenic CO 2 emissions while simultaneously enhancing soil quality and food security. The efficiency of SOC sequestration, however, depends on the priming effect which is influenced by interactions of OA composition with soil microbial response variables (MRVs). Yet, there remain large uncertainties surrounding the mechanisms and relationships defining these interactions, hampering the identification of OAs most effective for SOC sequestration and hindering the inclusion of OA dynamics in soil carbon models. In this study therefore, we performed an integrated assessment of these interactions for a cropland soil amended with wood chips, waterway residues, and isotopically enriched road-verge grasses, compost, and bokashi. Changes in 11 microbial properties and priming effects (for isotopically labelled OAs) were monitored for 150 days and related to 22 characterizations of OA composition. We demonstrate that i) hot water extractable to total carbon ratios of OAs are superior predictors of priming effects, ii) dissolvable to hot-water extractable carbon ratios are most closely related to variation in MRV expressions, and iii) priming effects correlate significantly with changes in several MRVs. Findings advocate for the adoption of energetic principles in modelling and predicting microbially-mediated soil carbon dynamics and suggest that application of OAs with high hot water to total carbon concentrations – potentially achievable by composting, but not fermenting, OAs prior to application – can allow for more efficient SOC sequestration.

Response of soil carbon fractions and enzyme activities to mowing management on in a coastal wetland of the yellow river delta

Coastal wetlands are considered as important “blue carbon” sink, and mowing management induced by anthropogenic activities is anticipated to profoundly affect soil carbon stocks in coastal wetlands. However, the impacts of mowing management on soil organic carbon (SOC) and enzyme activities and the mechanisms responsible for associated changes in Phragmites australis wetland remain uncertain. We conducted a field mowing manipulation experiment [control (CK), mowing and returning straw in December (12MS), mowing and removing straw in December (12MR), mowing and returning straw in March (3MS), and mowing and removing straw in March (3MR)] in P. australis wetland of the Yellow River Delta and quantified their impacts on soil quality, SOC, SOC fractions, and enzyme activities. Results showed that mowing treatments led to overall increases in soil nutrients [total carbon (TC), total nitrogen (TN), total phosphorus (TP), NH4+, and NO3−] and decreases in soil C/N ratio. The effects of mowing treatments on soil nutrient content were pronounced on topsoil than deep soil, and the maximum value of TC, TN, and TP reached in the 12MR treatment. Compared with CK, the 12MS, 12MR, 3MS, and 3MR treatments at 0–10 cm depth significantly enhanced SOC content by 8.78%, 32.9%, 16.5%, and 30.1%, respectively, but only the 3MS treatment enhanced SOC by 16.5% at 10–20 cm depth. Mowing treatments increased dissolved organic carbon (DOC), microbial biomass carbon (MBC), particulate organic carbon (POC), and labile organic carbon (LOC) and the contents of DOC, MBC, POC, and LOC decreased with soil depth. Mowing treatments stimulated the activities of sucrase and urease in topsoil, but only the 3MR treatment improved alkaline phosphatase activity in topsoil. Path analysis indicated that mowing management dominantly modulates SOC by changing sucrase activity, alkaline phosphatase activity, TN, TP, NH4+, NO3−, DOC, and LOC in 0–10 cm depth. However, SOC was significantly controlled by sucrase activity, urease activity, TC, TN, TP, LOC, and POC in 10–20 cm depth. Collectively, our results indicate that the continuous mowing management is beneficial to enhance soil quality and carbon storage capacity of P. australis wetlands, which will contribute to enhance carbon sequestration and sink capacity of coastal wetlands.

Nano-biofertilizers on soil health, chemistry, and microbial community: benefits and risks

Nano-biofertilizers are the biologically synthesized nano-fertilizers from the microbes and plants employed in the agricultural fields to promote crop production and protection. For instance, specifically, the plant growth-promoting microbes (PGPM) having significant growth promotion and antagonistic traits, have led to their wide range of applications as nano-biofertilizers. In the agricultural scenario, the soil, crops, microbiome and nano-biofertilizers often influence one another and their ecological systems. The application of these PGPM nano-biofertilizers often promised enhanced soil quality and crop protection during both abiotic and biotic stress conditions through their bioactive compounds. This made the PGPM nano-biofertilizers as key players of yield enhancers and an advantage to the ever-increasing global food demand. However, day by day, nanotechnology being more beneficial and economical, many researchers and agriculturalists are shifting towards their wide range of applications in modern agricultural practices. This challenges the nanoparticles (NPs) dosage, toxicity, and their environmental footprint in the agricultural soils over a long time. This chapter highlights the key features of the PGPM nano-biofertlizers, their type and time of application, their dynamics on plant soil health, and the necessity for better and safer marketing applications of these NPs in the agricultural fields.

Soil Quality Index as Affected by Integrated Nutrient Management in the Himalayan Foothills

Soil quality assessment serves as an index for appraising soil sustainability under varied soil management approaches. Our current investigation was oriented to establish a minimum data set (MDS) of soil quality indicators through the selection of apt scoring functions for each indicator, thus evaluating soil quality in the Himalayan foothills. The experiment was conducted during two consecutive years, viz. 2016 and 2017, and comprised of 13 treatments encompassing different combinations of chemical fertilizers, organic manure, and biofertilizers, viz. (i) the control, (ii) 20 kg P + PSB (Phosphorus solubilizing bacteria), (iii) 20 kg P + PSB + Rhizobium, (iv) 20 kg P + PSB + Rhizobium+ FYM, (v) 20 kg P + 0.5 kg Mo + PSB, (vi) 20 kg P + 0.5 kg Mo + PSB + Rhizobium, (vii) 20 kg P + 0.5 kg Mo + PSB + Rhizobium + FYM, (viii) 40 kg@ P + PSB, (ix) 40 kg P + PSB + Rhizobium, (x) 40 kg P + PSB + Rhizobium+ FYM, (xi) 40 kg P + 0.5 kg Mo + PSB, (xii) 40 kg P + 0.5 kg Mo + PSB + Rhizobium, and (xiii) 40 kg P + 0.5 kg Mo + PSB + Rhizobium + FYM. Evaluating the physical, chemical, and biological indicators, the integrated module of organic and inorganic fertilization reflected a significant improvement in soil characteristics such as the water holding capacity, available nitrogen, phosphorus, potassium, and molybdenum, different carbon fractions and soil biological characteristics encircling microbial biomass carbon (MBC), and total bacterial and fungal count. A principal component analysis (PCA) was executed for the reduction of multidimensional data ensued by scoring through the transformation of selected indicators. The soil quality index (SQI) established for different treatments exhibited a variation of 0.105 to 0.398, while the magnitude of share pertaining to key soil quality indicators for influencing soil quality index encircled the water holding capacity (WHC), the dehydrogenase activity (DHA), the total bacteria count, and the available P. The treatments that received an integrated nutrient package exhibited a higher SQI (T10—0.398; T13—0.372; T7—0.307) in comparison to the control treatment (T1—0.105). An enhanced soil quality index put forth for all organic treatments reflected an edge of any conjunctive package of reduced synthetic fertilizers with prime involvement of organic fertilizers over the sole application of inorganic fertilizers.

A comprehensive assessment of diversified cropping systems on agro-environmental sustainability in three Mediterranean long-term field experiments

The intensification of agricultural systems has caused a noticeable impact on agro-ecosystem services. Thus, the adoption of more sustainable agricultural practices such as crop diversification and reduction of external inputs represent an alternative strategy to minimize the impacts of intensive agricultural systems to the environment. This study aimed at evaluating the effects of crop rotation, conservation tillage, and low-input strategies on soil quality and farming performance using a set of 7 indicators based on a fuzzy logic approach. Data were collected from three Mediterranean long-term field experiments (LTEs) mostly oriented on cereal-based and vegetables cropping systems, located in Spain and Italy. The selected agro-environmental indicators clearly discriminated both from a geographical point of view and between monoculture and diversification, showing their suitability for the evaluation of diversified cropping systems. Such indicators highlighted that implementing crop diversification and reducing soil disturbance and chemical inputs enhanced soil quality. In this context, the most significant effects of diversified cropping strategies were the increase of crucial variables such as soil organic carbon (SOC), total nitrogen (TN), available phosphorus (Pav), and bulk density (BD) maintaining a stability of yields in all the three LTEs. These results provide strong evidence for the benefits of crop diversification in Mediterranean areas, highlighting that diversification represents a very promising strategy for more sustainable land management. Simple and composite indicators calculated using fuzzy method can be proposed as tool to assess the effects of diversification strategies on cropping systems performance. This approach can be used to define local solutions to help the re-design of cropping system through crop diversification transition across Europe.

MODELLING THE EFFECT OF WOOD AND MAIZE COB-DERIVED BIOCHAR APPLICATION ON SOIL DYNAMICS AND MAIZE GROWTH FOR SUSTAINABLE AGRICULTURE

Intensive agriculture has degraded global agricultural land and resulted in a food crisis. The application of biochar in agricultural soil has been proven effective at improving soil quality and increasing crop yield. This study aims to develop a simulation and investigate the effect of wood-derived biochar (WBC) and maize cob-derived biochar (MBC) at different application rates on soil pH, soil cation exchange capacity (CEC), soil organic carbon (SOC) and the productivity of the maize cropping system. The prediction regarding the effect of biochar on soil pH was the most accurate of all the parameters studied. The simulation was good at predicting the change of properties in calcareous clay soil for both WBC and MBC, as well as WBC in acidic, sandy soil. The results demonstrated that amendments to both WBC and MBC successfully improved the soil pH, SOC and CEC. The effect was more significant when higher biochar application rates were applied. The biochar amendment enhanced the properties of acidic sandy soil more significantly as compared to calcareous clay soil. Overall, WBC and MBC are potential green fertilisers capable of enhancing soil quality for the sustainable development in agriculture.

Field-Scale Evaluation of the Soil Quality Index as Influenced by Dairy Manure and Inorganic Fertilizers

Long-term addition of manure increases soil organic carbon (SOC), provides nutrient supply, enhances soil quality and crop yield (CY), but may also increase global warming potential (GWP). In this study, a long-term experiment was conducted to investigate impacts of organic dairy manure and inorganic fertilizer on the spatial distribution of soil quality indicators in field scale. The experiment was initiated in 2008 (seven years), and includes three manure and two inorganic fertilizer treatments along with a control (no manure or no inorganic fertilizer addition). The study was set into a randomized complete block design with six treatments and four replications in a total of 24 plots with an equal size each of 6 × 18 m (108 m2). Soil physical, chemical and biological properties (total 26 properties) were considered as the total data set and principal component analysis (PCA) was used to determine long-term organic and inorganic fertilizer-induced changes in soil quality. Ordinary kriging interpolation methods were used to predict the spatial distributions of soil quality index (SQI) and mean soil quality values were compared with fertilization treatments by using Duncan’s test. Results showed that most measured soil quality index parameters showed significant differences (p < 0.05). The long-term dairy manure applications had positive impacts on soil quality index parameters where overall SQI scores were higher under high manure (HM) compared to medium manure (MM), low manure (LM), medium fertilizer (MF), high fertilizer (HF), control (CK) by 25%, 27%, 47%, 55% and 92%. A similar trend was observed for CY and GWP. This indicates that long-term dairy manure can be an option to increase SQI values and provide higher CY, however, this may lead to greater GWP.

Enhancing soil quality makes crop production more resilient to climate change

Enhancing soil quality makes crop production more resilient to climate change

Effect of nutrient optimization on growth, yield and quality of sunflower under southern Odisha conditions

Oilseed crops can be cultivated widely in different agro-ecological conditions for the oil content in their seeds. Among different oilseeds, sunflower, is a vital edible oilseed that needs well-balanced nutrition for achieving enhanced oil quality and productivity. Considering the above, a field experiment was conducted during the rabi season of 2021-22 on sandy loam soil at Experimental Farm of Centurion University of Technology and Management to investigate the effect of nutrients on growth yield and quality of sunflower under southern Odisha conditions. The field experiment was carried out in randomized block design with ten treatments, viz., T1 : N100P100K100S100, T2: N0P100K100S100, T3: N100P0K100S100, T4: N100P100K0S100, T5: N100P100K100S0, T6: N100P0K0S0, T7: N0P100K0S0, T8: N0P0K100S0, T9: N0P0K0S100 and T10: Control. The findings revealed that the application of 80, 60, 40, 25 kg/ha N: P2O5: K2O: S (T1) registered superior performance in terms of growth, yield and yield attributes as compared to the control plot (T10). Interestingly, experimental results from treatment T5 (N100P100K100S0) were statistically at par with the results of Treatment T1 (N100P100K100S100) in enhancing growth and yield parameters and seed yield of sunflower. The yield enhancement in the omission treatments was in the order of NPKS> S>K>PKS>P>N>NPS>NKS>NPK>Control. The research findings clearly showed the importance of primary nutrients and sulphur on the growth and productivity of sunflower.

Bacillus amyloliquefaciens strain enhances rhizospheric microbial growth and reduces root and stem rot in a degraded agricultural system

The aim of this study was to evaluate the ability of Bacillus amyloliquefaciens B14 to improve the quality of a degraded soil in Lerma Valley, northwestern Argentina, as well as crop growth and yield, when inoculated on seeds of common bean (Phaseolus vulgaris L.) black cv. Nag 12. The effect on this soil infected with Macrophomina phaseolina (Tassi) Goidanich (Order: Botryosphaeriales) was also evaluated because in a previous work, B. amyloliquefaciens B14 was found to have an antagonistic effect against this pathogenic fungus. The strain effect was also compared with that of an agrochemical commonly used in the region (thiabendazole-fludioxonil-metalaxyl M). B. amyloliquefaciens B14 strain improved the nutrient availability, increasing soil organic carbon, total nitrogen and extractable P. In addition, B14 strain increased the activity of soil enzymes (AP, DHA and FDA), microbial respiration (MR) and microbial biomass carbon (MBC). This strain also significantly increased Trichoderma spp., Gliocladium spp., Pseudomonas spp. and actinomycete soil populations, and increased fungal and bacterial gene abundance. An increase in crop growth and yield was also determined. B. amyloliquefaciens B14 also reduced disease incidence caused by M. phaseolina, showing a greater effect than that of the agrochemical. Therefore, B. amyloliquefaciens B14 strain is a potential bioinoculant for bean in northwestern Argentina, where it may not only improve and protect common bean crop, but also enhance soil quality.

Arbuscular mycorrhizal colonization increases plant above-belowground feedback in a northwest Chinese coal mining-degraded soil by increasing photosynthetic carbon assimilation and allocation to maize.

A three-compartment culture system was used to study the mechanism by which the AM fungus Funneliformis mosseae influences host plant growth and soil organic carbon (SOC) content in a northwest China coal mining area. A 13CO2 pulse tracing technique was used to trace the allocation of maize photosynthetic C in shoots, roots, AM fungus, and soil. Carbon accumulation and allocation in mycorrhizal (inoculated with Funneliformis mosseae) and non-mycorrhizal treatments were detected. AM fungal inoculation significantly increased the 13C concentration and content in both above- and below-ground plant parts and also significantly enhanced anti-aging ability by increasing soluble sugars and catalase activity (CAT) in maize leaves while reducing foliar malondialdehyde content (MDA) and leaf temperature and promoted plant growth. AM fungi also increased P uptake to promote maize growth. Soil organic carbon (SOC), glomalin, microbial biomass carbon (MBC), and nitrogen (MBN) contents increased significantly after inoculation. A mutually beneficial system was established involving maize, the AM fungus and the microbiome, and the AM fungus became an important regulator of C flux between the above- and below-ground parts of the system. Inoculation with the AM fungus promoted plant growth, C fixation and allocation belowground to enhance soil quality. A positive above-belowground feedback appeared to be established.

Plant Growth Stimulating Bacteria and Filter Mud Cake Enhance Soil Quality and Productivity of Mango (Mangifera indica L.)

Plant Growth Stimulating Bacteria and Filter Mud Cake Enhance Soil Quality and Productivity of Mango (Mangifera indica L.)

Effect on Soil Properties and Crop Yields to Long-Term Application of Superabsorbent Polymer and Manure

Intensive farming leads to soil degradation, and poses a serious threat to agricultural yield sustainability and soil ecology. Superabsorbent polymer (SAP) and organic manure (OM) are amendments that can remediate the soil, and improve soil structure and soil pore characteristics, thereby enhancing soil quality and promoting crop growth. These benefits may be enhanced through long-term continuous application of the amendments. X-ray computed tomography (CT) was used to determine the number, connectivity, and locations of pores (160–1,000 μm, >1,000 µm) in the soil at depths of 0–100 cm. Soil organic carbon content, proportion of water-stable macroaggregates (>0.25 mm) (WSM), soil bulk density, field water capacity, available water content, wilting point content, and saturated hydraulic conductivity were also determined. Compared to the control, long-term SAP and OM treatments significantly increased the number of 160–1,000 µm and >1,000 µm soil pores (5–20 cm depths), >1,000 µm and >160 µm soil porosity (at 0–20 cm depths), total organic carbon (10–20 cm and 40–50 cm), field water capacity (0–20 cm), available water content (0–20 cm), wilting point (10–30 cm), saturated water content (10–70 cm), saturated hydraulic conductivity (0–90 cm), and WSM (0–30 cm and 40–50 cm) while decreasing the soil bulk density (0–70 cm). Compared to OM, SAP had greater beneficial effects on the total organic carbon, soil field water capacity, available water content, saturated water content, saturated hydraulic conductivity, and WSM in soil at 0–20 cm depth. The improvements to soil quality resulted in an increase in the yields of wheat and maize. Therefore, although SAP and OM were both effective at improving soil properties and increasing the economic yield of wheat and maize, the effectiveness of SAP was greater than that of OM.

Organic management enhances soil quality and drives microbial community diversity in cocoa production systems

Maintaining soil quality for agricultural production is a critical challenge, especially in the tropics. Due to the focus on environmental performance and the provision of soil ecosystem services, organic farming and agroforestry systems are proposed as alternative options to conventional monoculture farming. Soil processes underlying ecosystem services are strongly mediated by microbes; thus, increased understanding of the soil microbiome is crucial for the development of sustainable agricultural practices. Therefore, we measured and related soil quality indicators to bacterial and fungal community structures in five cocoa production systems, managed either organically or conventionally for 12 years, with varying crop diversity, from monoculture to agroforestry. In addition, a successional agroforestry system was included, which uses exclusively on-site pruning residues as soil inputs. Organic management increased soil organic carbon, nitrogen and labile carbon contents compared to conventional. Soil basal respiration and nitrogen mineralisation rates were highest in the successional agroforestry system. Across the field sites, fungal richness exceeded bacterial richness and fungal community composition was distinct between organic and conventional management, as well as between agroforestry and monoculture. Bacterial community composition differed mainly between organic and conventional management. Indicator species associated with organic management were taxonomically more diverse compared to taxa associated with conventionally managed systems. In conclusion, our results highlight the importance of organic management for maintaining soil quality in agroforestry systems for cocoa production.

Impact of Balanced Fertilization on Carbon and Nutrient Dynamics under Long-Term Jute-Rice-Lentil Cropping System in Alluvial Soils of Eastern India

ABSTRACT A long-term experiment was conducted for 8 years to assess the impact of imbalance and balance fertilization based on soil test-based nutrient management practices on different carbon fractions, carbon (C) stocks, sequestration, C indexes and soil quality under Jute-rice-lentil cropping system in subtropical India. The 10 treatments were laid out in a randomized block design. Treatments included the use of farm yard manure (FYM), bio-inoculants and inorganic fertilizers at different rates and combinations. Results revealed that conjunctive use of inorganic fertilizer based on soil test and targeted yield approach, organic manure (FYM) and bio-inoculants was found to be superior in comparison to other nutrient management practices in terms of sustaining crop productivity and enhancing soil quality. Integrated soil test-based nutrient management increased total soil organic carbon (TSOC) by 16.9% compared to initial values and permanganate oxidizable C (KMnO4-C) to the extent of 26.2% over the control. Soil microbial biomass carbon (SMBC) (374 μg g−1 soil) and microbial quotient (3.3%) were also found highest in integrated soil test-based nutrient management treatment. SMBC and KMnO4-C constituted to the TSOC to the extent of 1.7 to 3.34% and 12.6 to 13.8%. The highest carbon management index value (129) was obtained in the treatment with integrated application of balanced fertilizes based on soil test and targeted yield, indicating that this system has better soil quality than the other management systems. C sequestration rate in the study varied from 0.015 to 0.16 Mg C ha−1 yr−1 under different treatments.