Improve Soil Quality Research Articles

The effect of biochar obtained from waste filter coffee grounds on plant germination

Nowadays, coffee consumption is quite high, and the consumption of filter coffee is steadily increasing. Consequently, there is a significant increase in waste filter coffee. This study aims to evaluate waste filter coffee grounds using a zero-waste approach. In this context, the solid product of pyrolyzed waste filter coffee grounds was added to the soil in specific ratios to improve soil quality and increase yield. The effects on the root and stem development of arugula (Eruca vesicaria) and garden cress (Lepidium sativum) plants were investigated. Waste filter coffee grounds was homogeneously mixed with soil at application rates of 1, 2, and 4 tons/ha. The results of the study observed that the pyrolysis solid product positively affected plant growth. Comparing the data, the highest yield in plants was observed in soil with added biochar, while lower yields were seen in soil with added raw waste filter coffee grounds, and the lowest yield was found in soil without biochar. Among the soils with added biochar, the most significant root and stem development was observed in plants with 2 tons/ha of added biochar.

Utilizing sludge from catfish farming to produce vermicompost for improving soil quality

Abstract Earthworm organic waste is processed into vermicompost, which is of varying quality depending on the substrate. In vermicomposting, earthworms can promote nitrogen mineralization and effect nitrification. A challenging-to-absorb nutrient will be converted into a nutrient that plants can easily absorb to improve nutrients in soil and increase crop production. In this study, an experimental model of organic fertilizer production from catfish pond bottom sludge was implemented. Sludge from the bottom of catfish ponds is composted with water hyacinth in aquatic ponds to produce organic fertilizer, mature fertilizer is used as a substrate for vermicomposting. The impact of vermicompost on plant growth parameters was evaluated through its use to improve nutrients in soil. Sludge, compost, vermicompost, and soil quality were also evaluated for their physical and chemical properties. Results show that the growth coefficient of earthworms is 129.3±1.15% per 30 days, and the average amount of organic fertilizer created is 126±3.51 kg per 30 days. The quality parameters of vermicompost all meet national standards for organic fertilizer quality. The moisture and total organic matter content in mature fertilizer are 31% and 21.9%, respectively. The content of nutrients N and P increased compared to input materials, the corresponding values reached 2.84% and 0.96%. The C/N ratio is 7.7, microbiological and heavy metal indicators are within the accepted limits. In the experiment using vermicompost to cultivate Brassica rapa chinensis, the yield growth rate was the highest. After 21 days of planting, the growth rate is fast and the height reaches 25.0±0.38 cm. The biochemical composition ensures safety according to food regulations for leafy vegetables. Vermicomposting is recommended as a sustainable and suitable technique for catfish pond sludge utilizing.

Morphological characteristics of silica nanoparticles derived from rice husk for expected agricultural application

The study aimed to apply biosilica nanoparticles from renewable resources for improving soil quality as a type of fertilizer carier. The silica particles having a purity of about 98 % were extracted from rice husk at the calcination temperatures of 550 °C, 600 °C, 650 °C, and 700 °C. The required materials properties were investigated by advanced measurement techniques. All samples showed the amorphous structure with Si–O–Si bond and the particles’ agglomeration with the average size of 10–50 nm and principle electronic structures with the typical spectra of Si and O2. When the synthesized silica was used as the medium to release absorbed nutrients in a controlled manner, surface properties, including the Brunauer–Emmett–Teller area and the average pore diameter were evaluated between 179 m2/g to 570 m2/g, and 4 nm–40 nm, respectively. The measured electrokinetic potential of the synthesized particles was between −20 mV and −36 mV guaranteeing the stability when they are dispersed in the aqueous environment. The experimental results showed that the silica particles calcinated at 650 °C had the best properties.

Determination of dielectric properties of lead-contaminated soils: Potential application to soil remediation

This research investigated the effectiveness of radio frequency (RF) heating as a treatment for lead-contaminated soil, assessing its impact through dielectric constant measurements. Using water-soluble lead (II) acetate trihydrate, the study analyzed the impact of RF heating on soil dielectric properties under various soil moisture conditions (high, medium, and low) and electric field strengths (112.5, 150, 225, and 450 kV/m). The results indicated that soil temperature increased with lead concentration, highlighting significant changes in soil thermodynamics. Under high-humidity conditions, temperature increases were more pronounced, suggesting that higher lead concentrations elevate soil temperatures. Moreover, RF heating consistently reduced the dielectric constant as lead concentration increased, which was especially evident at higher electric field strengths. The study found that the soil resistivity approached that of uncontaminated soil, particularly at 450 kV/m electric field strength, with the highest removal rate of 46.154%. This investigation provides valuable insights into the application of RF heating for soil quality improvement in lead-contaminated environments, demonstrating how dielectric properties can reflect those of uncontaminated soil.

Co-incorporating green manure and crop straw increases crop productivity and improves soil quality with low greenhouse-gas emissions in a crop rotation

In a nine-year field experiment in a wheat–maize–sunflower cropping system in Hetao Irrigation Area, Inner Mongolia, China, organic amendments applied as straw, manure, green manure, and the combination of green manure and straw increased wheat and maize yield, soil aggregate stability, and soil microbial activity in comparison with chemical fertilizer, without changing greenhouse gas emission intensity.

Effect of Land Use Type on Soil Moisture Dynamics in the Sloping Lands of the Black Soil (Mollisols) Region of Northeast China

This study investigates the spatial and temporal heterogeneity of soil moisture on slopes of China’s northeastern black soil region, focusing on the effects of terrain adjustment and vegetation. Soil moisture dynamics in the 0–60 cm soil layer were measured at 10 cm intervals using the TRIME-PICO64 TDR® device on slopes with similar gradients representing three land use types: transverse ridge tillage (TRT) farmland, terraced fields (TFs) farmland, and pure forest woodland (WL). The results indicate significant variations in soil moisture content and water storage across different land use types in the order of TF > TRT > WL. The study further identified that soil bulk density, porosity, and water-holding indicators were in the order of WL > TF > TRT, inconsistent with the soil moisture results, indicating that soil quality cannot be the sole reason for the differences in moisture. The moisture differences between farmland types (TRT and TF) and WL are substantial, especially during the rainy season. In the rainy season (0–60 cm) and the dry season (30–60 cm), significant differences in moisture content are observed (p < 0.05). Significant differences in moisture content between farmland types are found at 0–40 cm during the rainy season and at 0–10 cm during the dry season. In the rainy season, soil moisture for TRT and TFs first decreases from 26.76% and 30.85% to 22.44% and 25.38%, then slightly increases to 27.01% and 27.07% along the slope. Meanwhile, WL displays the opposite pattern on upper, relatively steep slopes, with soil moisture increasing from 16.66% to 17.81%, and exhibits a pattern of change similar to TRT and TFs on lower, gentler slopes. TFs consistently show higher soil moisture and water storage at all slope positions than TRT and WL. TFs improve soil quality, reduce erosion and sedimentation, and shift the lowest soil moisture content to a lower slope position. During the dry season, soil moisture differences between slope positions for TRT and WL were small. In general, terracing can effectively modulate moisture distribution along slopes, increasing moisture by an average of 0.26~12.43%, while afforestation, despite improving soil quality, leads to an 18.14~31.13% reduction in soil moisture content, with the impact being particularly significant during the rainy season. These findings provide important insights for optimizing land use and ecological construction, including keeping the balance between soil and water conservation, especially for sub-humid slope terrain areas.

Soil quality enhancement by multi-treatment in the abandoned land of dry-hot river valley hydropower station construction area under karst desertification environment.

The medium-intensity karst desertification environment is typically characterized by more rocks and less soil. The abandoned land in the construction areas of the dry-hot river valley hydropower station has more infertile soil, severe land degradation, and very low land productivity. Therefore, it is urgent to improve the soil quality to curb the increasingly degrading land and reuse the construction site. Few studies have focused on the effect of soil restoration and comprehensive evaluation of soil quality with multi-treatment in abandoned land in the dry-hot valley hydropower station construction area. Here, 9 soil restoration measures and 1 control group were installed at the Guangzhao Hydropower Station construction in Guizhou Province, China, for physical and chemical property analysis. In total, 180 physical and 90 chemical soil samples were collected on three occasions in May, August, and December 2022. Soil fertility and quality were evaluated under various measures using membership functions and principal component analysis (PCA). This study showed that almost all measures could enhance soil water storage capacity (The average total soil porosity of 9 soil treatments was 57.56%, while that of the control group was 56.37%). With the increase in soil porosity, soil evaporation became stronger, and soil water content decreased. Nevertheless, no decrease in soil water content was observed in the presence of vegetation cover (soil water content: 16.46% of hairy vetch, 13.99% of clover, 13.77% of the control). They also proved that manure, synthetic fertilizer, and straw could promote total and available nutrients (Soil total nutrient content, or the total content of TN、TP、TK,was presented as: synthetic fertilizer (11.039g kg-2)>fowl manure (10.953g kg-2)>maize straw (10.560g kg-2)>control (9.580g kg-2);Total available nutrient content in soil, or the total content of AN,AP,A,was shown as:fowl manure (1287.670 mg kg-1)>synthetic fertilizer (925.889 mg kg-1)>sheep manure (825.979 mg kg-1)>control (445.486 mg kg-1). They could also promote soil fertility, among which the first two reached the higher comprehensive soil quality. Fertilizer was conducive to improve soil quality and fertility, yet long-term application could cause land degradation like soil non-point source pollution, compaction, and land productivity decline. Ultimately, combining fertilizer with biochar or manure is recommended to improve soil fertility. Biochar and green manure could play an apparent role in soil improvement only when there is abundant soil water. The above views provide theoretical support for curbing soil degradation, improving soil fertility and quality, enhancing land productivity, and promoting the virtuous cycle of the soil ecosystem.

Soil Bacteria Community Composition Indicating Soil Quality in Different Tillage Practices

Organic tillage practice of current study used fully cattle manure, while semi-organic tillage used cattle manure and 10% of synthetic fertilizers as transition to reduce chemical inputs in order to improve sustainable production and ecosystem health. Despite the important role of soil microbes in soil of agriculture, we still have limited understanding of the complex response of microbial composition to organic and semi-organic tillage practices. The aim of this work was to evaluate the impact of use of organic and semi-organic tillage practices on bacteria abundance, richness and functional diversity of microbial communities. Analysis of soil bacteria using nutrient agar by serial dilutions of soil suspension was performed to quantify bacteria abundance. They were further identified and categorized into IAA-producing bacteria and non IAA-producing bacteria groups in Tryptic Soy Agar (TSA). Bacteria abundance was significantly higher in semi-organic tillage than organic tillage. Even though bacteria richness did not show statistically significant, beneficial effect of organic tillage was reflected in higher bacteria richness in term of isolates. The assessment of their functional diversity on producing IAA hormone demonstrated higher IAA-producing bacteria than non IAA-producing bacteria in both tillage practices, indicating the availability of rich substrate through introduction of cattle manure improve soil quality and beneficial for soil bacteria. We observed that among all physicochemical properties, C-organic indicated highly significant, higher in organic tillage than semi-organic tillage. It has been proposed that the availability of organic carbon may favour bacteria as resource of energy. Keywords: Bacteria community composition; IAA-producing bacteria; Organic tillage; Semi-organic tillage

Microbial fertilizers improve soil quality and crop yield in coastal saline soils by regulating soil bacterial and fungal community structure

Salinization is a global problem affecting agricultural productivity and sustainability. The application of exogenous microbial fertilizer harbors great potential for improving saline-alkali soil conditions and increasing land productivity. Yet the responses to microbial fertilizer application rate in terms of rhizosphere soil biochemical characteristics, soil microbial community, and crop yield and their interrelationships and underlying mechanisms are still unclear. Here, we studied changes to rhizosphere soil-related variables, soil enzyme activity (catalase, sucrase, urease), microbial community diversity, and sweet sorghum (Sorghum bicolor (L.) Moench) yield under four fertilization concentration levels (0, 0.12, 0.24, and 0.36 kg m−2) in a saline-alkali ecosystem (Shandong, China). Our results showed that the best improvement effect on soil when the microbial fertilizer was applied at a rate of 0.24 kg m−2. Compared with the control (sweet sorghum + no fertilizer), it significantly increased soil organic carbon (21.50 %), available phosphorus (26.14 %), available potassium (36.30 %), and soil urease (38.46 %), while significantly reducing soil pH (2.21 %) and EC (12.04 %). Meanwhile, the yield of sweet sorghum was increased by 24.19 %. This is mainly because microbial fertilizers enhanced the diversity and the network complexity of bacterial and fungal communities, and influenced catalase (CAT), urease (UE), and sucrase (SC), thereby facilitating nutrient release in the soil, enhancing soil fertility, and indirectly influencing sweet sorghum productivity. Among them, Gemmatimonadota and Verrucomicrobiota may be the key microbial factors affecting sweet sorghum yield, while available potassium, soil urease and available phosphorus are the main soil factors. These findings provide valuable theoretical insights for preserving the health of coastal saline-alkali soils and meeting the agricultural demand for increased yield per unit of land area.

System fertilization in integrated crop-livestock management favors microbial processes, soil quality and production profitability

Integrated crop-livestock systems with no tillage (ICLS-NT) have emerged as more responsible modes of production. Different fertilization strategies can optimize the productivity and profitability of ICLS-NT. However, it is necessary to understand how these strategies can change soil quality. This study aimed to investigate how different fertilization strategies within the ICLS-NT impact the biochemical and chemical attributes of the soil, as well as the productivity and profitability of the system. An ICLS-NT experiment was conducted with beef cattle grazing in winter and soybean cultivation in summer, structured in a 2×2 factorial arrangement, starting in 2019 and evaluated after 3 years (2021/2022 harvest). The first factor was the timing of fertilization: conventional Fertilization (CF - application of phosphorus and potassium during soybean sowing), and system Fertilization (SF - application of phosphorus and potassium in pasture). The second factor was the application of 100 kg ha–1 of nitrogen to the Brachiaria pasture: with application (+N) or without application (–N), resulting in four treatments distributed in three blocks. The system fertilization showed greater biochemical activity, nutrient availability, forage accumulation, increased animal stocking, and animal weight gain, regardless of the level of nitrogen. The strategy SF+N also provided an increase of 438 kg ha–1 in soybean grain productivity, which added to profits from animal production culminating in 407.35 US$ ha–1 of net income more than what was obtained in reference treatment (CF–N). The findings highlight that applying fertilizers after the crop phase is an effective strategy for replenishing soil nutrients, activating microbial processes and improving soil quality. This approach means a more sustainable agricultural practice, reducing environmental impact and at the same time reinforcing profitability in ICLS-NT.

Possibility of brewery wastes application to soil as an organic improver of biological and chemical properties

Soil degradation, marked by declining organic matter, threatens global food security. The impact of brewer's spent yeast (BSY) on clay and sand was analysed at varying application rates to assess its effectiveness in improving soil quality. A randomized complete block design with three replicates was employed. One kilogram of soil were mixed with BSY at application rates of 2 t/ha and 5 t/ha. The samples were incubated at 26 °C for 5 months with daily watering. We analysed pH, total nitrogen, organic carbon, total phosphorus, and electrical conductivity (EC); microbial activity (total heterotrophic bacteria, actinobacteria, and fungi) and soil enzyme activity (dehydrogenase, catalase, protease). BSY application improved soil quality, particularly in clay. Clay showed increased in pH, EC, N and C. BSY significantly boosted microbial populations (bacteria, fungi) in clay with a lesser effect in sand. Enzyme activity and a fertility index also improved in BSY-treated clay, while sand displayed increased activity of a different enzyme. Results suggest BSY holds promise as an organic fertilizer, especially for clay soils. Further research is needed to optimize application, understand long-term effects, and evaluate economic feasibility and social acceptance. This study contributes to the search for sustainable, local solutions to improve soil health and agricultural practices.

Açai seed biochar improves soil quality and black pepper seedling development in the Amazon region

Sustainable management of the Amazon rainforest is fundamental for supporting life on earth because of its crucial role in sequestering carbon. One of the species grown in the forest is açaí (Euterpe oleracea), which is an important food and income source for its inhabitant. The acai seed, resulting from the processing of the fruit, is a solid organic residue, which has been an agent of undesirable environmental impacts such as natural landscape modifications, clogging sewers and water courses, eutrophication of surface waters. In this research, we evaluated the use of wood chips as a source of energy in a rustic oven to produce acai biochar so that family farmers carry out sustainable management of the residue and use biochar to improve soil quality and produce seedlings of native plants to regenerate degraded forests. The experiment was conducted in Pará, Brazil, Amazon region, using a randomized complete block design. A factorial treatment structure was implemented consisting of four biochar particle sizes (3, 5, 7, and 12 mm), 4 application rates (4, 8, 16, and 32 t ha−1), and a biochar-free control, with 5 replications. The results showed that the methodology for biochar production was easy to apply and low cost, allowing its use by family farmers. The combination of biochar rate and particle size affected soil properties and the development of black pepper seedlings in different ways. The soil properties affected were water retention capacity, moisture, fluorescein diacetate hydrolysis and arylsulphatase activity. The growth parameters of the affected black pepper seedlings were height and root system development.

No-tillage with straw retention influenced maize root growth morphology by changing soil physical properties and aggregate structure in Northeast China: A ten-year field experiment

Conservation tillage, particularly the implementation of no-tillage and straw retention (NTS), has been proposed as an effective practice to enhance soil structure and improve soil quality in Northeast China. However, the impact of NTS on maize (Zea mays L.) root growth morphology and the influence of tillage practices on maize root morphology through soil physical properties and structure in Northeast China remain understudied. To address this knowledge gap, a continuous ten-year experiment was conducted to assess the effects of NTS on soil physical properties, aggregate structure, maize root morphology, and their interconnections. Our findings demonstrate that the NTS treatment significantly increased soil water content and soil bulk density at depths of 0–5 cm (1.6%) and 5–10 cm (2.2%), while decreasing soil porosity at depths of 0–5 cm (1.4%) and 5–10 cm (2.0%) compared to conventional tillage (CT). Additionally, NTS resulted in a higher content of soil macro-aggregates (> 0.25 mm) and improved soil aggregate stability compared to CT. Notably, root length, root surface area, root volume, and root biomass in the NTS treatment were 6.04%, 22.15%, 10.04%, and 9.29% higher than those in CT, respectively. However, there was no significant difference in root diameter between the two tillage practices. These results reveal that NTS induces alterations in soil physical properties, aggregate size distribution and aggregate stability, thereby affecting maize root growth morphology.

Phacelia and Buckwheat Cover Crops’ Effects on Soil Quality in Organic Vegetable Production in a High Tunnel System

Cover crops (CCs) are regarded as beneficial to agricultural practice as an option for soil quality improvement in field production systems. The main goal of this study was to assess the impact of spring phacelia (Phacelia tanacetifolia Benth.) and buckwheat (Fagopyrum Mill.) in a crop rotation (CC–leek–parsley, 2020–2021) on the physicochemical and biological properties of the soil in an organic high tunnel system. Soil analyses involved measurements of bulk density, water capacity, soil aggregation, soil organic carbon (SOC), available soil nutrients, as well as microbial abundance and diversity. Phacelia generated more aboveground biomass (58.2 t fresh matter ha−1) than buckwheat (33.0 t ha−1), and their biomass contained 161 kg N ha−1 and 67 kg N ha−1, respectively. A large quantity of elements, such as N, Ca, P, S, B, and Cu, were found in phacelia biomass. More Mg and Na were found in buckwheat plants. The results showed that CC biomass significantly improved some of the soil physical and chemical properties, such as soil organic carbon stock and wet aggregate stability, and decreased soil bulk density. Cover crop treatments changed the dynamics of soil bacterial and fungus populations in a high tunnel system. Phacelia increased the quantity of ammonifiers and nitrifiers in the soil substantially. Further research with a long-term focus is needed to assess the impact of cover crops on soil properties, soil quality, and subsequent crop yields in high tunnel crop rotation and management systems.

Willingness to Pay for Agricultural Soil Quality Protection and Improvement

Understanding and estimating the economic value that society places on agricultural soil quality protection and improvement can guide the development of policies aimed at mitigating pollution, promoting conservation, or incentivizing sustainable land management practices. We estimate the general public’s willingness to pay (WTP) for agricultural soil quality protection and improvement in Spain (n = 1000) and the UK (n = 984) using data from a cross-sectional survey via Qualtrics panels in March–April 2021. We use a double-bound dichotomous choice contingent valuation approach to elicit the individuals’ WTP. We investigate the effect of uncertainty on the success of policies aiming at achieving soil protection. In addition, to understand the heterogeneity in individuals’ WTP for agricultural soil quality protection and improvement, we model individuals’ WTP through individuals’ awareness and attitudes toward agricultural soil quality protection and the environment; trust in institutions; risk and time preferences; pro-social behavior; and socio-demographics in Spain and the UK. We found that there is significant public support for agricultural soil quality protection and improvement in Spain and the UK. We also found that the support does not vary significantly under uncertainty of success of policies aiming at achieving soil protection. However, the individual’s reasons for supporting agricultural soil quality protection and improvement are found to depend on the level of uncertainty and country. Hence, promoting public support for soil protection needs to be tailored according to the level of the general public’s perceived uncertainty and geographic location.

Anthropogenic restoration exhibits more complex and stable microbial co-occurrence patterns than natural restoration in rubber plantations

Forest restoration is an effective method for restoring degraded soil ecosystems (e.g., converting primary tropical forests into rubber monoculture plantations; RM). The effects of forest restoration on microbial community diversity and composition have been extensively studied. However, how rubber plantation-based forest restoration reshapes soil microbial communities, networks, and inner assembly mechanisms remains unclear. Here, we explored the effects of jungle rubber mixed (JRM; secondary succession and natural restoration of RM) plantation and introduction of rainforest species (AR; anthropogenic restoration established by mimicking the understory and overstory tree species of native rainforests) to RM stands on soil physico-chemical properties and microbial communities. We found that converting tropical rainforest (RF) to RM decreased soil fertility and simplified microbial composition and co-occurrence patterns, whereas the conversion of RM to JRM and AR exhibited opposite results. These changes were significantly correlated with pH, soil moisture content (SMC), and soil nutrients, suggesting that vegetation restoration can provide a favorable soil microenvironment that promotes the development of soil microorganisms. The complexity and stability of the bacterial-fungal cross-kingdom, bacterial, and fungal networks increased with JRM and AR. Bacterial community assembly was primarily governed by stochastic (78.79 %) and deterministic (59.09 %) processes in JRM and AR, respectively, whereas stochastic processes (limited dispersion) predominantly shaped fungal assembly across all forest stands. AR has more significant benefits than JRM, such as a relatively slower and natural vegetation succession with more nutritive soil conditions, microbial diversity, and complex and stable microbial networks. These results highlight the importance of sustainable forest management to restore soil biodiversity and ecosystem functions after extensive soil degradation and suggest that anthropogenic restoration can more effectively improve soil quality and microbial communities than natural restoration in degraded rubber plantations.

Productivity and health of soil cultivated with forage cactus (Opuntia cochenillifera (L.) Mill.) with combined use of topsoil and biochar

Agricultural production in semi-arid environments represents a significant challenge, as these are areas that have soils with limited nutrient availability and scarcity of precipitation, which require adaptive and innovative strategies. The application of biochar to improve soil quality and increase productivity has been well studied. However, there is still a gap regarding the use of biochar with the technique of incorporating different topsoils on plant development and soil health. This technique has emerged as an alternative for producers to increase soil fertility. This technique is emerging as an alternative for producers to enhance soil fertility. The hypothesis of the present study is that the use of biochar associated with the topsoil technique increases the productivity and yield of cactus, mainly by changing the properties of the soil and its microbiological interactions. To test this hypothesis, we used different sources of biochar (bean husk, coffee grounds and soursop residue) in association with two types of topsoil (Acrisol and Luvisol). Our analyzes revealed changes on plants development, chemical and microbiological soil attributes. The topsoil technique significantly interfered with mean cladode length (COM), stem diameter (DI), plant height (AL), pH, Na+, K+ and urease enzymatic activity, while biochar had a significant effect on microbial respiration rate. In general, our results expand the knowledge about the use of biochar associated with topsoil, suggesting it as a promising, low-cost way that guarantees the conservation and health of the agroecosystem, contributing with important information for the development of alternative technologies to conventional ones.

Effects of humic acid application on bacterial diversity under maize cultivation

AbstractThe fundamental ecosystem processes in soil are regulated by microbial communities, and community diversity is implicated by soil environmental conditions. Humic acid (HA) improves soil quality and fertility, stimulating the microbial environment, but the detailed effects remain poorly understood. We investigated the effects of HA rates on soil bacterial diversity, particularly on species richness and community composition in the rhizosphere of corn (Zea mays). Inorganic fertilizer (T2), HA 0.5% (T3), HA 1.0% (T4), HA 1.5% (T5), and HA 2.0% (T6) were applied in soil. Initial soil (O1) and control after harvesting (T1) were included. A total of 3601 operational taxonomic units were captured from the overall sample, and analysis of 16S ribosomal ribonucleic acid amplicon sequencing data indicated that HA did not notably impact species richness. Intriguingly, HA induced changes in bacterial community composition, along with the relative prevalence of specific taxa. Certain associations between soil chemical properties and abundance distribution have been uncovered. Notably, exchangeable Mg2+, Ca2+, and available phosphorus were strongly related to the relative abundance of bacterial phyla. Furthermore, HA potentially shaped the specific bacterial taxa, as the application of HA at different rates had distinct effects on the member of bacterial abundance of each taxon. These findings enhance our understanding of communities potentially being increased or shifted by HA rate addition in short‐term corn cultivation.

Managing Residue Return Increases Soil Organic Carbon, Total Nitrogen in the Soil Aggregate, and the Grain Yield of Winter Wheat

Soil tillage and maize residues return are important practices for tackling and promoting soil quality and improving crop yield in the North China Plain (NCP), where winter wheat production is threatened by soil deterioration. Although maize residues incorporation with rotary tillage (RS) or deep plowing tillage (DS) is widespread in this region, only few studies have focused on rotation tillage. Four practices, namely RT (continuous rotary tillage without maize residues return), RS, DS, and RS/DS (rotary tillage every year and deep plowing interval of 2 years), were evaluated under field conditions lasting a period of 5 years. After a 5-year field experiment, the mean soil bulk density of the 0–30 cm soil layer decreased significantly with RS, DS, and RS/DS, i.e., by 4.19%, 6.33%, and 6.71% compared with RT, respectively. The treatments greatly improved the total soil porosity, soil aggregate size distribution, soil aggregate stability, and the root length density in the 0–30 cm soil layers. Residues return with DS and RS/DS treatments significantly increased the soil organic carbon (SOC) and total nitrogen (TN) storage in the 0–30 cm soil layer, mainly owed to the increases in the SOC and TN pool associated with the macro-aggregate. A positive trend in the grain yield was noted under both DS and RS/DS conditions, whereas a decreasing tendency was presented in continuous rotary treatments. In summary, RS/DS treatment significantly increased the amount of SOC and TN, improved the particle size distribution of soil aggregates, and thus improved the soil’s physicochemical properties, which is beneficial for wheat to achieve high yields. Our results suggested that RS/DS was a highly efficient practice to improve soil quality and increase crop production in the NCP.

Assessing the Alteration of Soil Quality under Long-Term Fertilization Management in Farmland Soil: Integrating a Minimum Data Set and Developing New Biological Indicators

The key role of soil quality improvement in achieving sustainable agricultural development based on highly intensive use of farmland is increasingly being recognized, as is the ponderance of suitable evaluation of the soil quality. The overarching goal of this study was to determine an accurate assessment framework by the comparison of the scoring function (linear and non-linear) and integration method (area and weighted additive), which integrally evaluates the soil quality of an eleven-year field fertilization experiment (including CK, no fertilizer; CF, conventional fertilization; SF, formulated fertilization; SFO, SF with organic fertilizer). Thirty-three properties, including eighteen physiochemical-related and fifteen biological-related properties, associated with soil functions were measured as potential soil quality indicators, and the soil multifunctionality (SMF) was applied to validate the soil quality indices (SQIs). Principal component analysis and relationship analysis were used with indicators sensitive to management to determine a minimum data set (MDS). The results showed that the electrical conductivity, large macroaggregate-associated total nitrogen, small macroaggregate-associated organic carbon, carbon fixation, and enzyme activities of phenol oxidase and cellulase were chosen as the MDS. All the SQIs were significantly correlated with the SMF (p < 0.05). The fertilization strategies affected most indicators in different ways, and the index developed using the non-linear function and weighted additive integration method (SQI-NL) had the best sensibility and discriminability. The SQI value with the SQI-NL-MDS method was higher following the fertilization treatments than that of no fertilizer (p < 0.05), and the treatment of the organic fertilizer had the highest SQI value (0.66). Soil quality evaluation in long-term fertilized farmland suggested that the soil quality constraints between treatments of synthetic and organic fertilizer are related to the soil functions of nutrient cycling and sustain biological activity due to their higher contribution rates to the SQI in the organic fertilizer treatment, which provides insights into ways to reduce the gap in soil quality. The framework method can provide an accurate quantitative tool for the evaluation of soil quality from the target indicators by bridging management objectives and field-level actions.