Improve Soil Quality Research Articles

Soil quality evaluation for irrigated agroecological zones of Punjab, Pakistan: The Luenberger indicator approach

AbstractThis article describes the construction of the Luenberger soil quality indicator (SQI) using data on crop yield, non‐soil inputs, and soil profile from three irrigated agroecological zones of Punjab, Pakistan, namely, rice–wheat, maize–wheat–mix, and cotton–mix zones. Plot level data are used to construct a soil quality indicator by estimating directional distance functions within a data envelopment analysis (DEA) framework. We find that the SQI and crop yield relationships exhibit diminishing returns to improving soil quality levels. Using the constructed SQI values, we estimate linear regression models to generate weights that could be used directly to aggregate individual soil attributes into soil quality indicators without the necessity of fitting a frontier to the crop production data. For wheat and rice production, we find that SQI is most sensitive to changes in soil electrical conductivity (EC) and potassium (K). The SQI has direct relevance for site‐specific decision‐making problems where policymakers need to price land resources and conservation services to achieve agricultural and environmental goals.

Effects of food waste biogas residue composting on soil aggregates and its organic matter content in relocation site

Understanding the effects of food waste biogas residue composting and chemical amendments on soil aggregates composition of different particle sizes, stability, and organic matter distribution in relocation sites could provide primary data for improving soil quality and land utilization of food waste biogas residue composting. We analyzed the characteristics of soil aggregates distribution, stability of aggregates, and organic matter content in different particle sizes under treatments with different application amounts of food waste biogas residue composting, chemical amendments (β-cyclodextrin, calcium sulfate and ferric oxide were mixed at a mass ratio of 1:1:1), and control (100% soil). The results showed that 20% (soil: biogas residue composting=8:2) and 30% (soil: biogas residue composting =7:3) biogas residue composting significantly decreased the micro-aggregates content with the particle size of <0.106 mm and increased the large aggregates content with the particle size of 0.5-1.0 mm. All treatments significantly increased large aggregates content with the particle size of ≥2.0 mm, soil aggregate structure content, and mean weight diameter, but reduced the percentage of aggregate destruction. Among all the treatments, the effect of mixes application of 20% biogas residue composting and chemical amendments was the best. Biogas residue composting treatments significantly affected the distribution of organic matter in soil aggregates, with the strongest effect under 30% biogas residue composting treatment. Biogas residue composting treatments significantly increased soil organic matter content in all aggregates, with the maximal increase of organic matter content in soil micro-aggregates with the particle size of 0.106-0.25 mm. In conclusion, biogas residue composting could increase organic matter content of soil aggregates in different particle sizes, promote the formation of large soil aggregates, and improve the stability of aggregation. Specifically, the mixed application of biogas residue composting and chemical amendments performed better on soil improvement in relocation site.

Soil Stabilization Using Agricultural Waste (Wheat Husk, Rice Husk and Sugarcane Straw)

Abstract: For civil engineers, the safe disposal of both hazardous and non-hazardous waste is a challenge. This is because just a few states can securely deposit agricultural trash. This study includes studies on the safe disposal of agricultural wastes such as wheat husk (WH), rice husk (RH), and sugarcane straw (SCS). In this study, attempts were undertaken to improve soil quality by employing WH, RH, and SCS. The primary goal of ground improvement is to increase shear strength and reduce soil compressibility.The investigation was done utilizing the expansive soil by taking variable volumes, which are then mixed with the different stabilized material for Atterberg limit tests and California bearing ratio (CBR) test. These tests are tested and proven using the standard tests IS 2720, and it is ultimately decided that the test results improve the geotechnical qualities of the soil.

Evaluating the long-term effects of best management practices on pollution reduction and soil quality improvement in sloping farmland of the Three Gorges Reservoir area

Reducing nonpoint-source pollution and improving soil quality by applying best management practices (BMPs) on sloping farmland are essential for ensuring water environmental safety and sustainable agricultural development. However, little is known about the accumulative effect of the long-term application of BMPs on reducing pollution and improving soil quality in major land use types of sloping farmland in watersheds. We conducted a nine-year field experiment for citrus orchard and cropland of sloping farmland in the Three Gorges Reservoir area of China. The treatment settings for the citrus experimental plots were as follows: (1) citrus intercropped with white clover (WC), (2) citrus orchard soil mulched with straw (SM), (3) citrus intercropped with Hemerocallis flava contour hedgerows (HF) and (4) conventional citrus planting pattern (C-CK). The treatment settings for the crop experimental plots were as follows: (1) wheat-peanut rotation intercropped with Toona sinensis contour hedgerows (TS), (2) wheat-peanut rotation intercropped with alfalfa contour hedgerows (AF), (3) ryegrass-sesame rotation (RS) and (4) conventional wheat-peanut rotation (W-CK). We found that compared with C-CK and W-CK, (1) runoff, sediment, total nitrogen and total phosphorus losses were reduced by 18.0 %, 66.1 %, 35.6 % and 40.2 %, respectively, in WC; by 22.4 %, 61.2 %, 43.9 % and 52.4 %, respectively, in SM; by 25.4%, 69.5 %, 52.0 % and 58.1 %, respectively, in HF; by 45.1 %, 73.7 %, 64.6 % and 66.0 %, respectively, in TS; by 41.8 %, 67.4 %, 59.3 % and 60.8 %, respectively, in AF; and by 24.1 %, 42.9 %, 39.3 % and 40.3 %, respectively, in RS; (2) the soil quality index values of the BMP treatments increased; and (3) the application of these BMPs did not significantly affect yield or product value. We suggest the application of these BMPs on sloping farmland to (1) efficiently reduce total runoff, total sediment, and soil total nitrogen and total phosphorus losses; (2) improve soil quality; and (3) have no significant effect on output, of which the BMP HF applied to citrus orchard and the BMP TS applied to cropland are the most effective.

Inversion Tillage Combined with Organic Fertilizer Application Increased Maize Yield via Improving Soil Pore Structure and Enzymatic Activity in Haplic Chernozem

Inversion tillage and organic fertilizer application can break the plow pan and improve soil quality. However, the effects of combining these practices on the soil microbial resource limitation and maize yield in Haplic Chernozem are unclear. In this research, a field experiment was established in 2018, and soil samples were collected in 2021 in Longjiang County in Northeast China, which is a Haplic Chernozem region. Four treatments comprising conventional tillage (T15), conventional tillage with organic fertilizer (T15+M), inversion tillage (T35), and inversion tillage with organic fertilizer (T35+M) were randomly arranged with four replications. Compared with T15 and T15+M treatments, soil bulk density significantly decreased by 11.1–16.3% in the 15–35 cm layer under T35 and T35+M treatments, accompanied by the improvement in soil pore structure (e.g., soil porosity, circularity, and Euler number). T15+M treatment significantly increased soil organic carbon and soil nutrient contents by 11.1–16.3% and 3.9–24.5% in the 0–15 cm layer compared with other treatments. However, soil organic carbon, total nitrogen, available phosphorus content, microbial biomass, and enzymatic activities reached the maximum values in the 0–35 cm layer under T35+M treatment. In addition, T35+M treatment had the highest maize yield and sustainable yield index. Extracellular enzymatic stoichiometry suggested that soil microorganisms are generally co-limited by carbon and phosphorus in Haplic Chernozem. However, T35+M treatment significantly reduced soil microbial resource limitation, which was one important factor impacting maize yield and sustainability. Random-forest and partial least-squares path modeling showed that T35+M treatment could reduce soil microbial resource limitation and increase the stability and sustainability of the maize yield by improving soil available nutrients, microbial biomass, and pore structure. Therefore, the incorporation of inversion tillage and organic fertilizer is a suitable soil management practice in view of increasing soil quality and crop yields in a Haplic Chernozem region.

Rediscovering circularity in productive urban landscapes

The recycling of urban green waste generated from urban forests is important in enhancing urban circularity; however, most green waste remains underutilized. An effective way to recycle green waste is composting. Recent studies show the effectiveness of decentralized composting in home and community gardens; however, little is yet known about linkage to commercial urban agriculture, which could play a critical role in urban food supply. This study aims to investigate the community-scale composting system of green waste integrated into commercial farming, using Tokyo as a case study where urban and agricultural land uses are mixed historically. We conducted mailed questionnaire surveys and in-person semi-structured interviews with urban farmers. The results revealed that approximately one-third of professional urban farmers still produced compost from green waste, especially leaf litters, to improve soil quality. They have adapted urbanization by expanding leaf litter sources beyond their own woodlands to various neighboring urban forests within a few kilometers, including parks, schools, and shrines. Although urbanization has drastically changed the tangible landscape, urban farmers have handed down the intangible system for hundreds of years by retrofitting their system. While the system can contribute to reducing green waste and enhancing urban circularity, urban farmers are motivated by economic reasons rather than such environmental reasons. In cities that encompass productive urban landscapes, decentralized composting systems work effectively in commercial urban agriculture due to its geographic proximity of waste supply and demand sites. This study suggests the potential benefits of having urban farms in cities abundant in underutilized organic wastes. Further research is needed on how to scale up waste recycling through urban agriculture to foster urban circularity and sustainability.

Long-Term Effect of Rice and Non-rice Ecology on Pools of Carbon in Surface and Deep Soil in Farmer’s Field

The greatest terrestrial sink of carbon (C) is soil. In addition to improving soil quality, carbon absorption in soil helps reduce atmospheric CO2 loading. Not only the surface soil, but also the deep sub-soil act as a storehouse of C. Besides, the study of C dynamics in tropical rice soil is important in countries like India where rice is the predominant crop and soil C sequestration is at risk due to high temperatures. In this context, this study tried to understand the C dynamics in surface as well as deep soil under rice and non-rice ecology. Representative soil samples were collected from five sites of rice-rice (rice ecology) and vegetable-vegetable (non-rice ecology) cropping systems from three depths viz., 0-20 cm, 100-120 and 120-140 cm from long-term farmer’s field of Nadia district of West Bengal belonging to Alfisols to compare C dynamics of surface and deep soils as well as rice and non-rice ecology. Results indicated that surface soils exhibited higher amount of total C, total organic C and inorganic C in comparison to deep soil irrespective of crop ecologies. The rice ecology showed higher total C and total organic C in comparison to non-rice soil. As per water solubility, water-soluble (room temperature) C and hot water-soluble C which were highest in surface soil compared to deep soil as the former usually receives maximum amount of fresh C input compared to deep soil. Irrespective of crop ecology, water-soluble C (WSC), hot water-soluble C (HWC), recalcitrant C (RC) were highest in surface soil compared to deep soils. Again, irrespective of soil depth, WSC and RC were highest in rice ecology and lowest in non-rice ecology. But, HWC content was highest in non-rice ecology and lowest in rice ecology. Irrespective of crop ecology, per cent contribution of labile pool of C (WSC+ HWC) and that of RC pool towards TOC was the highest and the lowest respectively. However, irrespective of soil depth, per cent contribution of labile pool of C and that of recalcitrant pool of C towards TOC was highest and lowest in soils under non-rice ecology and rice ecology respectively. Thus, this study conclusively indicated the potential of subsoil layer to act as a C sink in comparison to surface soil. The rice soil also has been identified as a niche for soil C sequestration.

Feasibility of constructed soils for tree planting – A pilot study in New York City

Constructed soils are soils that are created with a mixture of various materials. An innovative soil exchange program - the Clean Soil Bank (CSB) in New York City allows recycling of clean glacial outwash sediments excavated from depth at construction sites. One previous study showed that soils constructed from CSB sediment and compost can effectively support crop growth in community gardens, but no research has been conducted on its potential usage as a medium for tree growth. Moreover, biochar has been used to improve soil quality, but its efficacy for street trees incorporated into constructed soils has largely not been quantified in the field. The objective of this project was to evaluate the feasibility of using soils constructed from the CSB and compost for tree planting and to investigate the impact of biochar on tree performance. Thirty-six trees of two species (Maackia amurensis and Zelkova serrata) were planted in 2019, on the sidewalks of a residential-business neighborhood in Bronx, New York. Each tree pit contains one of three soil types: type A - existing and purchased topsoil mixed with 33% compost and biochar, type B - CSB sediment mixed with 33% compost, and type C - CSB sediment mixed with 33% compost and biochar. Soil samples were collected in 2019 (before planting) and in 2021. Tree health assessments were conducted in September 2020 and July 2021 using a protocol developed by the USDA Forest Service. Other tree health parameters collected include diameter at breast height (DBH), crown diameter, tree height, photosynthetic capacity, and foliar chemistry. Significant differences in bulk density, water holding capacity, and K, Fe, and Zn concentrations were found among the three soil types. However, comparison of tree performance and foliar chemistry showed no systematic differences among the three soil types. The results indicate that CSB sediment mixed with compost can be an effective replacement for purchased topsoil for tree growth. No evidence was found that biochar provides additional benefits to street tree performance. Considering the abundant availability of glacial outwash sediment at low cost to the city, as well as access to locally produced compost, constructed soils can be a reliable source of material for urban forestry programs.

Selective Modifier-Assisted Humic Acid Extraction: Implications for Soil Quality Enhancement.

Efficient use of humic acid (HA) for eco-friendly farming and environmental remediation requires further understanding of how targeted modification of HA affects the chemical structure of HA and thereby its effectiveness in enhancing soil quality. We developed novel selective modifiers (SMs) for extracting HA by codoping sodium and copper elements into the birnessite lattice. The structure of SMs was thoroughly examined, and the HAs extracted using SMs, referred to as SMHs, were subjected to a detailed evaluation of their functional groups, molecular weight, carbon composition, flocculation limits, and effectiveness in saline soil remediation. The results showed that replacing manganese with sodium and copper in SMs alters the valence state and reactive oxygen species. In contrast, SMHs exhibited increased acidic functional groups, a lower molecular weight, and transformed aliphatic carbon. Furthermore, the saline soil was improved through increased salt leaching and an optimized soil aggregate structure by SMHs. This research highlights the importance of targeted modification of HA and demonstrates the potential of these modifiers in improving soil quality for eco-friendly farming and environmental remediation.

Straw pyrolysis for use in electricity storage installations

A concept has been proposed for an installation designed to store excess electricity periodically occurring on the grid. Excess electricity will be used for straw pyrolysis. The main pyrolysis product, gas, will be used to generate electricity using a combustion generator to feed back power into the grid during periods of shortage. The resulting biochar from the pyrolysis can be introduced into the soil to improve soil quality and play a significant role in carbon sequestration. The system uses an electrically heated reactor with a screw conveyor.To preliminarily assess the feasibility of this system, experiments were carried out using wheat straw at temperatures of 300, 400, 500, 600, and 700 °C for the pyrolysis reactor. The resulting gas-to-feedstock mass ratio ranged from 29.04 % at 300 °C to 52.7 % at 700 °C reactor temperature, the biochar mass yield ratio to feedstock varied from 39.41 % to 27.36 % (at 700 °C), and the pyrolysis liquid ranged from 31.55 % to 27.36 % (at 700 °C). The pyrolytic liquid contained a high water content relative to its mass, reaching up to 95.2 % at 700 °C, rendering it less suitable as an energy feedstock.At a reactor temperature of 700 °C, the energy value of the gas produced from the feedstock was twice that of the electricity used for the pyrolysis process. These results suggest the feasibility and operation of the proposed installation.

ENVIRONMENTAL SAFETY OF THE TECHNOLOGY OF HANDLING DIGESTATE OF DIFFERENT GENESIS

In the modern world, biogas technology is gaining momentum as an ecological alternative to the production of biofertilizer after anaerobic fermentation of various types of waste. Due to the large amount of organic, nutrient and biologically active substances, biogas digestates are often applied directly to the soil as an organic fertilizer to improve soil quality and increase yield. The purpose of the article is to determine the ecological safety of the digestate obtained after anaerobic fermentation of chicken litter and sewage sludge, as part of a biocomposite for soil purification from heavy metals. The methodological basis of this study are experiments on the phytotoxicity of digestate samples based on the results of the germination of pepper seeds in Petri dishes using aqueous solutions of untreated digestate and digestate treated with phosphogypsum. The expediency of choosing a phosphogypsum treatment method was due not only to the possibility of reducing the presence of pathogens in digestates, but also to obtain a biocomposite capable of adsorbing harmful elements from the soil and feeding it with necessary substances. Using the germination index, the level of phytotoxicity of digestate based on various organic wastes was assessed, the effectiveness of the use of digestate as a biological fertilizer was substantiated. It was determined that digestate based on sewage sludge became an ecologically safe substrate for the germination of pepper seeds. Digestate from chicken litter treated with phosphogypsum on the 20th day of anaerobic fermentation showed a phytotoxic effect on pepper seeds. Indicators of the germination index increased on the 30th day of anaerobic fermentation, which indicates a decrease in the toxicity of the material after the end of the anaerobic fermentation process. In general, a germination index higher than 50% was observed in all samples of untreated digestate and a greater number of samples of treated digestate for both substrates. The article provides recommendations for evaluating the maturity of digestate using the seed germination index as a quick indicator for determining the phytotoxicity of substrates and, accordingly, the level of environmental safety of the material for soil and plants.

Potential of Effective Microorganisms in the Aspect of Sustainable Development

Human activity has been impacting the environment for thousands of years. Progressing environmental pollution caused by human economic activity is associated with an increase in the concentration of trace elements and the formation of an excess of polycyclic aromatic hydrocarbons (PAHs). PAHs have always been present in the environment, but the development of civilisation and technology has resulted in their increase. PAHs easily penetrate plants, animals and the human body, which makes them a serious threat to human health and agriculture. Reducing the amount of polycyclic aromatic hydrocarbons in the soil is possible by introducing a microbiological preparation in the form of Effective Microorganisms (EM) into the soil. Some strains of microorganisms in EM can decompose chemical compounds, including PAHs. Through biodegradation, EM transforms harmful substances into less toxic forms. EM stimulates the activity of soil microflora, which naturally participates in the decomposition processes of organic substances, which contributes to improving soil quality and environmental protection. The following work presents the results of own research on analysing the impact of Effective Microorganisms on changes in the content of PAHs in the soil. It was observed that 75% of test samples in the form of soils after wheat cultivation in which EM was added had lower contents of 3,4,5-ring PAHs than their control samples. The work aims to analyse the potential of EM as a preparation that supports the natural capabilities of the ecosystem to reduce the amount of pollutants in the form of PAHs in the soil.

Investigating the synergistic effects of biochar, trans-zeatin riboside, and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat

BackgroundWater stress is a major danger to crop yield, hence new approaches to strengthen plant resilience must be developed. To lessen the negative effects of water stress on wheat plants, present study was arranged to investigate the role of synergistic effects of biochar, trans-zeatin riboside (t-ZR), and Azospirillum brasilense on soil improvement and enzymatic activity in water-stressed wheat.ResultsIn a three-replication experiment comprising of four treatments (T0: Control, T1: Drought stress (DS), T2: DS + t-ZR with biochar, T3: DS + A. brasilense with biochar), we observed notable improvements in soil quality and enzymatic activities in water-stressed wheat plants with the application of t-ZR and A. brasilense with biochar. In drought stress, Treatment having the application of A. brasilense with biochar performs best as compared to the other and significant increased the enzymatic activities such as peroxidase (7.36%), catalase (8.53%), superoxide dismutase (6.01%), polyphenol oxidase (14.14%), and amylase (16.36%) in wheat plants. Different enzymatic activities showed different trends of results. Soil organic C, dissolved organic C, dissolved organic N also enhanced 29.46%, 8.59%, 22.70% respectively with the application of A. brasilense with biochar under drought stress condition.ConclusionsThe synergistic action of A. brasilense and biochar creates an effective microbiological environment that supports essential plant physiological processes during drought stress. This enhancement is attributed to improved soil fertility and increased organic matter content, highlighting the potential of these novel strategies in mitigating water stress effects and enhancing crop resilience.

Effects of different reclamation measures on soil quality restoration in open-pit mines: A meta-analysis based on the Chinese Loess Plateau

In the Loess Plateau region, ecological restoration projects have been implemented to restore the ecological environment of open-pit mines. However, no consistent conclusion has been reached regarding the response of soil remediation efforts to different ecological measures and restoration years. A meta-analysis was performed on the results of studies published over the past 30 years for open-pit mining areas on the Loess Plateau in China. The findings reveal that land rehabilitation considerably improved soil quality in open-pit mining areas on the Loess Plateau. Different ecological measures revealed a significant variability in soil quality restoration. Specifically, forestland reclamation affected soil organic matter and microbial carbon the most. Grassland reclamation substantially influenced soil total potassium, organic carbon, enzyme activity, and microbial abundance. Plowland caused the most effective improvement in soil total nitrogen and physical properties. However, total phosphorus and pH were unaffected by restoration measures. In addition, the period of land reclamation and soil nutrients showed a high correlation in the early stage of reclamation. After long-term reclamation, a decreased rate of soil quality improvement by remediation measures occurred after the soil quality returned to its premining level. A relatively lag was observed in the response of soil microbial indicators to environmental changes, and the premining level was reached after longer-term reclamation.

The Use of Products from Leonardite to Improve Soil Quality in Condition of Climate Change

Abstract The principle of sustainable fertilisation in modern agriculture, which ensures that the soil is maintained in a fertile state requires the search for alternatives to manure fertilisation for products based on humic substances to increase the organic matter content of soils.The advantage of leonardite over conventional natural and organic fertilisers is mainly due to its high content of organic matter and humic substances (humic and fulvic acids). Leonardite, due to the presence of humic acids in it, can be suitable for soil amendment and yield of barley. In the conducted studies, the yield increase after adding Rosahumus fertilizer to the soil at a rate of 6 kg.ha−1 + NPK (Nitrogen, Phosphorus, Potasssium) was found to be 11% compared to the control (NPK).There were no changes in the Corg. content of the soil as a result of the application of Rosahumus fertilizer with NPK. The fertilizer only slightly modified the fractional composition of humus. In the future, we should expect an increase in the use of leonardite-derived humic substances in fertilizers and soil conditioners to stabilize soil organic matter.

Development of Regenerative Tea Cultivation Models through Dual Approach of Soil and Plant Health Management towards Crop Sustainability, Soil Quality Development, Pesticide Reduction and Climate Change Mitigation: A Case Study from Lakhipara Tea Estate,

Climate change is a reality and its impact on the tea plantations is apparent in the rise of pest intensity, higher agrochemical use, inconsistent crop yields, declining grand growth period, increased abiotic stress and various other challenges; that threaten long-term sustainability of the Indian tea sector. The urgency to adopt sustainable practices is increasing by the day but to gain time bound results a comprehensive focus encompassing soil and plant health development will be crucial. To deal with climate challenge head-on, the Indian tea industry is making changes at various levels of operations. The sustainable tea initiative at Lakhipara tea estate, was one such attempt by the Goodricke Group Limited in their Dooars tea growing region of West Bengal. The program was initiated in 2014 with an aim to reduce pesticide use, improve soil quality, and produce quality teas while sustaining crop yields, improving renewable energy use and lowering the carbon footprint. Adoption of Inhana Rational Farming (IRF) Technology and taking the essence from ‘Trophobiosis Theory’ of French Scientist F. Chaboussou, the program focused on management of soil and plant health. Three years evaluation of crop yields in respect of the budgeted crop, revealed on an average an excess of 78 kg/ha/year in the project area. In rest of the garden area a contrasting crop loss of 118 kg was recorded per ha during the same period. The higher crop performance positively correlated with the higher nutrient use efficiency which was 17.7 percent higher in the project area (NUENPK : 8.86) as compared to the general garden area (NUENPK : 7.53), which reflected the impact of plant health management towards enhanced nutrient uptake, assimilation and utilization. Assessment of pesticide usage, revealed up to 77% decrease in usage in the project area during 2014-16, as compared to the pre- project year. Comparison with pesticide usage of the Dooars tea growing region during this same period, indicated a 62% lower Crop Pesticide Pollution Index (CPPI) in the project area. The finding indicated a 52 to 77% reduction in the accumulated toxicity potential of the applied pesticides in the project area; thereby accrediting safer tea development under this program, when adjudged in terms of pesticide residue. Assessment of soil quality revealed an overall eight percent increment in Soil Fertility Index (FI) value, with significant improvement in soil microbial activity potential (MAP) values i.e., by almost four times. The finding pointed towards the favourable impact of soil health management primarily through Novcom composting towards enhancement of soil microbial interactions. Post three years of experimentation the overall Soil Quality Iindex (SQI) value increased by 6% in the project area. The finding corroborated a concurrent 6.72% increase in the soil organic carbon stock during the same period. Reduction in use of non- renewable inputs viz. chemical fertilizers and pesticides in the project area was indicated by approximately 40 percent enhancement in energy use efficiency and energy productivity post the assessment period. Carbon assessment in terms of kg CO2 equivalents/ kg made tea (using ACFA version 1.0) indicated approx. 65 to 70 % lower footprint in the project area, primarily due to 20 to 30 % reduction in chemical fertilizers and 60 to 70 % reduction in the use of synthetic pesticides. The results indicated that while integrated soil management is the pre-requisite criteria towards rejuvenation of soil health and for restoration of the habitat for predators, it does not play a direct role in reducing the pest pressure and simultaneously the requirement of pesticides. Physiologically activated plants/ bushes on the other hand; due to their higher nutrient assimilation capacity and efficient protein synthesis are always lesser susceptible to pest attack. Hence, focus on activation of plant physiology can reduce the plant- pest interaction leading to a natural reduction in the requirement for pesticides vis-à-vis the pesticide usage.

Effects of Different Organic Fertilizer Substitutions for Chemical Nitrogen Fertilizer on Soil Fertility and Nitrogen Use Efficiency of Foxtail Millet

Conventional fertilizer management can destroy the structure of soil. Replacing chemical fertilizers with organic fertilizers can improve soil quality and nitrogen use efficiency. We aimed to study the effects of organic fertilizer substitutions for chemical nitrogen fertilizer on soil fertility and nitrogen use efficiency in order to clarify the effectiveness of the available nutrient management measures in improving soil quality and increasing foxtail millet yield. A field experiment was carried out over two consecutive years, and a total of six treatments were set up: no fertilizer (CK), chemical nitrogen fertilizer alone (N), the substitution of 25% of chemical nitrogen fertilizer with bio-organic fertilizer (N25A1), the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure (N25B1), the substitution of 50% of chemical nitrogen fertilizer with bio-organic fertilizer (N50A2), and the substitution of 50% of chemical nitrogen fertilizer with fermented mealworm manure (N50B2). The results of this study show the following: (1) Compared with chemical nitrogen fertilizer, the substitution of organic fertilizer for nitrogen fertilizer reduced the bulk density and solid phase of the soil, and it increased the total porosity, water content, liquid phase, and gas phase of the soil. (2) Compared with nitrogen fertilizer, the use of an organic fertilizer increased the contents of nitrate nitrogen, ammonium nitrogen, and total nitrogen in the soil by 13.59~52.56%, 4.47~18.27%, and 4.40~12.09%, respectively. The content of alkaline nitrogen increased by 1.70~32.37%, and the contents of soil available potassium, available phosphorus, and organic matter also increased. (3) The activities of sucrase, urease, glutaminase, and asparaginase were improved by replacing chemical nitrogen fertilizer with organic fertilizer. The N25 treatments performed better than the N50 treatments, and fermented mealworm manure performed better than biological organic fertilizer. (4) A moderate application of organic fertilizer (N25) can increase the grain yield, ear weight, grain weight, and 1000-grain weight of foxtail millet, whereas excessive application of organic fertilizer (N50) can reduce foxtail millet yield. (5) Replacing chemical nitrogen fertilizer with organic fertilizer can improve the agronomic use efficiency, physiological efficiency, biased productivity, harvest index, and apparent use efficiency of nitrogen fertilizer. In this study, the substitution of 25% of chemical nitrogen fertilizer with fermented mealworm manure was the best combination for restoring crop productivity and soil quality.

Long-term effects of biochar one-off application on soil physicochemical properties, salt concentration, nutrient availability, enzyme activity, and rice yield of highly saline-alkali paddy soils: based on a 6-year field experiment

Biochar application can alleviate the adverse effects of saline-alkali stress on crops. However, the long-term effects of one-off biochar application on soil physicochemical properties, salt concentration, nutrient availability, soil enzyme activities, and rice yield under highly saline-alkali paddy soils remain unclear. Here, a 6-year paddy field study was conducted in a saline-alkali paddy field using two nitrogen application levels (0 and 225 kg ha−1) and four biochar application rates [0 (T0), 1.5% (T1.5), 3.0% (T3.0), and 4.5% (T4.5) biochar, w/w]. The results showed that compared with T0, the bulk density (BD) under T1.5, T3.0, and T4.5 treatments significantly decreased by 11.21%, 16.33%, and 25.57%, while total porosity (Tp) and saturated hydraulic conductivity (Ks) increased by 19.15–27.34% and 3217.78–5539.83%, respectively. Biochar consistently improved soil macro-aggregates, mean weight diameter (MWD), and the percentage of water-stable aggregates (PWSA) over the years. Additionally, one-off application of biochar continuously reduced the soil Na+ concentration, Na+/K+ ratio, Na+/Ca2+ ratio, saturated paste extract (ECe), exchangeable sodium percentage (ESP), and sodium adsorption ratio (SARe). However, it reduced the pH in 2021 and 2022 only. It enhanced the concentration of K+, Ca2+, Mg2+, and cation exchange capacity (CEC) over the 6-year study, indicating its longer-term positive impact. Furthermore, the one-off biochar application, especially under high application rate treatments (T3.0 and T4.5), significantly and continuously improved nutrient availability and soil enzyme activities. However, alkali-hydrolysable nitrogen (AN) decreased in the initial year of biochar application. The grain yield of T1.5, T3.0, and T4.5 surpassed that of T0 by 116.38%, 141.24%, and 145.20%, respectively. Notably, the rice yield reached its peak with the treatment of 3.0% (w/w) in all 6 years of study period. These findings offered new perspectives on repairing and improving soil quality and production ability of highly saline-alkali paddy soils.Graphical

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.

Influences of tobacco straw return with lime on microbial community structure of tobacco-planting soil and tobacco leaf quality.

Soil amendment is an important strategy for improving soil quality and crop yield. From 2014 to 2019, we conducted a study to investigate the effects of tobacco straw return with lime on soil nutrients, soil microbial community structure, tobacco leaf yield, and quality in southern Anhui, China. A field experiment was conducted with four treatments: straw removed (CK), straw return (St), straw return with dolomite (St+D), and straw return with lime (St+L). Results showed that after 5 years of application, the St+L significantly increased the soil pH by 16.9%, and the contents of soil alkaline nitrogen (N) and available potassium (K) by 17.2% and 23.0%, respectively, compared with the CK. Moreover, the St+L significantly increased tobacco leaf yield (24.0%) and the appearance (9.1%) and sensory (5.9%) quality of flue-cured tobacco leaves. The addition of soil conditioners (straw, dolomite, and lime) increased both the total reads and effective sequences of soil microorganisms. Bacterial diversity was more sensitive to changes in the external environment compared to soil fungi. The application of soil amendments (lime and straw) promoted the growth of beneficial microorganisms in the soil. Additionally, bacterial species had greater competition and limited availability of resources for survival compared to fungi. The results showed that soil microorganisms were significantly influenced by the presence of AK, AN, and pH contents. These findings can provide an effective method for improving the quality of flue-cured tobacco leaves and guiding the amelioration of acidic soil in regions where tobacco-rice rotation is practiced.