Improve Soil Quality Research Articles

Magnificent Bio-Management of Pesticides in Agriculture Soil

Following World War II, the agrochemical industry burgeoned, introducing diverse chemical agents like pesticides and herbicides to enhance crop production. These compounds, including herbicides, insecticides, and fungicides, are toxic and persist in the environment, causing soil, water, and air pollution and disrupting ecological balance. Farmers, heavily reliant on soil, initially use these chemicals to boost productivity, but over time, they become detrimental, accumulating in organisms and harming trophic levels. Addressing this challenge involves improving soil quality and eco-friendliness for maximum crop production. Indigenous microbial consortia, comprising bacteria and fungi, offer a cost-effective and eco-friendly solution by metabolizing and bio-remediating toxic compounds. This review focuses on their role in removing commercial xenobiotic pesticides that harm soil.

Residues of Symbiont Cover Crops Improving Corn Growth and Soil-Dependent Health Parameters

Cover crops have emerged as a crucial tool in promoting sustainable agricultural practices, particularly in improving soil quality and soil–plant health. This study investigates the impact of single cover crop plants each with varying fungal and/or bacterial symbiosis capacities in a pot experiment. The growth of non-symbiont Ethiopian mustard (Brassica carinata), the associative bacterium symbiont black oat (Avena strigosa) and the double (fungus–bacterium) endosymbiont broad bean (Vicia faba) was studied on three distinct soil types, namely a less-fertile sandy soil (Arenosol), an average value of loam soil (Luvisol) and a more productive chernozem soil (Chernozem). Beside the biomass production, nitrogen content and frequency of AM fungi symbiosis (MYCO%) of cover crops, the main soil health characteristics of electrical conductivity (EC), labile carbon (POXC) and fluorescein diacetate enzyme activity (FDA) were assessed and evaluated by detailed statistical analysis. Among the used soil types, the greatest biomass production was found on Chernozem soil with the relatively highest soil organic matter (2.81%) content and productivity. Double symbiotic activity, assessed by soil nitrogen content and mycorrhiza frequency (MYCO%), were significantly improved on the lowest-quality Arenosols (SOM 1.16%). In that slightly humous sandy soil, MYCO% was enhanced by 45%, indicating that symbiosis was crucial for plant growth in the less-fertile soil investigated. After the initial cover crop phase, the accumulated biomass was incorporated into the Luvisol (SOM 1.64%) soil, followed by the cultivation of corn (Zea mays, DK 3972) as the main crop. The results indicate that incorporating cover crop residues enhanced labile carbon (POXC) by 20% and significantly increased the FDA microbial activity in the soil, which positively correlated with the nutrient availability and growth of the maize crop. This study emphasizes the importance of selecting suitable cover crops based on their symbiotic characteristics to improve soil quality and enhance soil–plant health in sustainable agricultural systems.

Reducing Nitrogen Application Rates and Straw Mulching Can Alleviate Greenhouse Gas Emissions from Wheat Field Soil and Improve Soil Quality

Reducing Nitrogen Application Rates and Straw Mulching Can Alleviate Greenhouse Gas Emissions from Wheat Field Soil and Improve Soil Quality

Natural grassland restoration exhibits enhanced carbon sequestration and soil improvement potential in northern sandy grasslands of China: An empirical study

Vegetation restoration is an effective measure for restoring degraded ecosystems. Soil carbon mineralization, a crucial indicator for evaluating the effectiveness of vegetation restoration, is essential in soil carbon cycling. However, the response of soil carbon mineralization to different vegetation restoration types remains unclear. In this study, grassland (Leymus chinensis and Stipa bungeana), shrubland (Corethrodendron fruticosum), and forestland (Ulmus pumila) with 20 years of consistent restoration in the Xilingol sandy grassland were selected to determine the effects of vegetation restoration types on soil carbon mineralization. The results showed that the soil cumulative carbon dioxide emissions (CCE) and microbial respiration rate (SMR) in grassland and forestland were significantly higher than those in shrubland, while soil carbon mineralization efficiency (CME) and microbial metabolic quotient (MQ) were significantly lower than those in shrubland. Furthermore, soil organic carbon (SOC) and its fractions were influenced considerably by vegetation restoration types, with grassland exhibiting the highest SOC content. The ratios of soil total effective nutrients (C/N, N/P, and C/P) and the content of active organic carbon (DOC, MBC, EOC, and POC) can effectively reflect the changes in soil carbon mineralization and the stability of SOC pools. The variations in CCE were influenced by litter biomass, macroaggregates organic carbon, mineral-associated organic carbon (MAOC), and dissolved organic carbon (DOC), while the changes in SMR were affected by aboveground biomass (AGB), soil total nitrogen and phosphorus ratios (N/P), and microaggregate organic carbon and microbial biomass carbon. The changes in CME were affected by AGB, N/P, pH, MAOC, and DOC, while the changes in MQ were influenced by AGB, N/P, DOC, MAOC, and easily oxidizable organic carbon. Given the higher carbon sequestration benefits and soil quality improvement capability of naturally restored grassland, this study suggests that grassland could be considered the primary vegetation restoration type in the Xilingol sandy grassland.

Effects of Varied Tillage Practices on Soil Quality in the Experimental Field of Red-Soil Sloping Farmland in Southern China

Red-soil sloping farmland in southern China plays a crucial role in the local economy and food production. However, improper tillage practices have resulted in topsoil degradation and deteriorating soil quality. This study investigated changes in soil physico-chemical properties under four tillage methods—cross-slope ridge tillage (RT), down-slope ridge tillage (DT), plastic mulching (PM), and conventional tillage (CT)—on red-soil sloping farmland. The study applied the Soil Management Assessment Framework (SMAF) to assess the influence of these tillage practices on soil quality. Results indicated that PM can increase the total porosity of the soil, reduce soil bulk density, and simultaneously decrease soil surface-water evaporation, significantly improving the soil’s water-retention capacity. RT improved soil aggregate formation and stability, leading to increased macro-aggregate content, mean weight diameter, and soil water-stable aggregate stability rates. PM and RT effectively preserved soil nutrients like total nitrogen and organic matter, although PM lowered soil pH, potentially causing acidification. RT demonstrated the highest soil quality, with PM following. Crop growth positively impacted soil macro-aggregate content and stability, showing continuous improvement in soil structure and quality (p < 0.05). Priority should be given to RT in red-soil sloping farmland, followed by PM and CT, while avoiding DT if possible. This research furnishes valuable scientific substantiation for the selection of optimal tillage practices in the preservation of soil quality on red-soil slopes.

Deep Vertical Rotary Tillage: A Sustainable Agricultural Practice to Improve Soil Quality and Crop Yields in China

Deep vertical rotary tillage (DVRT) is an innovative soil tillage technology that has been widely adopted in China and shown significant potential in enhancing soil quality, optimizing water use efficiency, and increasing crop yields across diverse ecological and agronomic conditions. DVRT utilizes a vertical spiral drill bit for deep plowing, which preserves soil structure, reduces soil compaction, and improves water retention, making it particularly effective in regions facing climatic challenges such as drought. This review synthesizes the effects of DVRT on soil’s physical and chemical properties, crop root systems, photosynthesis, and water use efficiency, demonstrating its advantages in promoting robust root development and improving nutrient utilization. Although the technology has been applied successfully across various crops and regions, its nationwide adoption remains limited. This paper emphasizes the need for further research to refine the theoretical framework of DVRT and develop tailored strategies for different local conditions. Additionally, integrating DVRT with other agronomic practices and advancing machinery design, supported by policy measures, is essential for maximizing its benefits. In conclusion, DVRT presents a promising approach for sustainable agriculture in China, contributing to improved soil quality, increased crop yields, and enhanced food security.

Distribution Characteristics of Soil Aggregate Stability and Organic Carbon of Different Grassland Types in the Temperate Desert of Longzhong Loess Plateau

Soil aggregate stability and organic carbon （SOC） are important indicators of soil structure and quality and play a key role in the improvement of soil quality in temperate deserts. This study aimed to investigate the distribution patterns, stability of soil aggregates, and variation characteristics of the content of aggregate organic carbon in different grassland types in temperate deserts and their interrelationships. Four grassland types in a temperate desert （Kalidium foliatum type, Reaumuria songarica type, Salsola passerina type, and Sympegma regelii type） in the Longzhong Loess Plateau as research objects, and the soil aggregate particle size distribution characteristics were determined using the wet sieving method. The stability of soil aggregates was analyzed by calculating aggregate stability indicators and the contribution of aggregate particle size SOC to bulk soil SOC content. Correlation analysis, principal component analysis, and linear fitting equations were used to reveal the relationship between the soil aggregate content and aggregate particle size SOC and aggregate stability. The results showed that the content of >0.25 mm aggregates （R0.25）, mean weight diameter （MWD）, geometric mean diameter （GMD）, and bulk soil SOC content in each soil layer （0-10, 10-20, and 20-30 cm） of the K. foliatum type grassland were significantly higher than that of the R. songarica type and S. regelii type （P<0.05）. The SOC content of 0.053-0.25 mm and <0.053 mm particle size in each soil layer of the K. foliatum type grassland were significantly higher than that of the S. regelii type （P<0.05）. Surface and subsurface soils （0-10 cm and 10-20 cm） had the significantly highest contribution of 0.25-2 mm particle size SOC to the bulk soil SOC content （P<0.05）. Additionally, as the soil layer deepened, the R0.25, MWD, GMD, bulk soil, and aggregate SOC contents of the K. foliatum type grassland showed a tendency to increase first and then decrease, with the highest contents from 10-20 cm. Kalidium foliatum type grassland aggregate content was dominated by 0.25-2 mm aggregates, whereas the other three grassland types were dominated by 0.053-0.25 mm aggregates. In addition, bulk soil SOC content was significantly correlated with R0.25, MWD, GMD, and ELT （P<0.01）, and the 0.25 mm aggregate was the critical size of positive and negative correlation. R0.25, MWD, GMD, and ELT values were the key factors influencing bulk soil SOC in grassland. The equation fitted to bulk soil SOC content, and GMD was the most suitable to describe the relationship between SOC content and the stability of soil aggregates. Therefore, compared with other grassland types, K. foliatum type grassland had a promoting effect on the soil aggregate stability and the improvement of soil quality.

Effects of Film Mulching on Soil Quality, Garlic Yield, and Garlic Quality

To determine the optimal film management technique for garlic planting, this study aimed to investigate the effects of various film cover methods on soil quality and garlic yield in garlic cropping systems. To achieve these goals, trials with different film cover methods were conducted at the Jiangsu Academy of Agricultural Sciences in Nanjing. To investigate the impact of changes in soil quality and garlic yield, we set up four treatments： no film treatment （CK）, black polyethylene film treatment （HPE）, black poly（butylene- adipate-co-terephthalate） （PBAT） with straw composite film treatment （HSJ）, and white PBAT film treatment （BJ） in a garlic cropping system. Our results indicated that specific mulch coverings had a positive effect on both soil quality and garlic yield. The film cover treatments resulted in significant changes in soil physicochemical properties and bacterial and fungal biomasses and indirectly improved soil quality. Compared to that under the no film treatment, the BJ treatment boosted soil quality by 70%, with the most significant impact, followed by that under the HPE and HSJ treatments, with improvements of 52% and 36%. Random forest modeling indicated that soil organic matter and total nitrogen were the most important factors influencing soil quality. The different film covers significantly increased the diameter of garlic bulbs and single quality. The HSJ treatment exhibited the most significant increase in garlic yield, with 46%, 19%, and 6% improvement compared to that in the CK, HPE, and BJ treatments, respectively. Correlation analysis showed that soil quality under film cover was significantly correlated with the starch content of garlic bulbs, garlic diameter, and single quality. This study highlights that selecting the appropriate mulch film aids in the production of garlic and helps to develop farmland that produces both high-quality and high-yield crops.

Molecular-level insight into the effect of fertilization regimes on the chemodiversity of dissolved organic matter in tropical cropland

Fertilization is a critical agronomic measure for croplands in tropical regions, owing to their low fertility. However, the effects of fertilization on the quantity and chemodiversity of latosolic dissolved organic matter (DOM) in tropical regions remain largely unknown. Therefore, in this study, the variations in latosol DOM concentrations and chemodiversity induced by inorganic fertilization and the co-application of inorganic fertilization with straw return, sheep manure, biochar, and vermicompost fertilizers at a molecular level were systematically investigated using multispectral techniques and ultrahigh-resolution mass spectrometry. In line with our expectations, the results showed that combined inorganic-organic fertilization improved soil quality by increasing soil organic carbon content compared to that under inorganic fertilization. However, as the most active and bioavailable organic carbon pool, dissolved organic carbonconcentrations between the fertilization treatments were not significantly different (p = 0.07). However, the dissolved organic carbon concentrations under combined inorganic-organic fertilization treatment (NPK plus straw return, 263.45 ± 37.51 mg/kg) were lower than those under inorganic fertilization treatment (282.10 ± 18.57 mg/kg). Spectral analysis showed that the DOM in the combined inorganic-organic fertilization treatments had a higher degree of humification and lower autogenetic contributions. Furthermore, Fourier transform ion cyclotron resonance mass spectrometry analysis indicated that the combined inorganic-organic fertilization increased the chemodiversity of latosolic DOM and promoted the production of large, oxidized, and stable molecules, including lignin, aromatic, and tannin compounds, which potentially benefits soil carbon sequestration in tropical regions. This study could provide a theoretical basis for elucidating on the potentially relevant ecological functions and environmental effects of DOM under fertilization regimes.

Effects of Terracing on Soil Aggregate Stability and Erodibility in Sloped Farmland in Black Soil (Mollisols) Region of China

Soil aggregates are important indicators of soil structure stability and quality. The black soil region of northeast China, known for its high agricultural productivity, faces significant challenges due to soil erosion. This study investigates the impact of terracing on the stability and erodibility characteristics of soil aggregates in sloped farmlands, which is crucial for this important agricultural area. Three research sites with the same basic management modes were selected along a latitudinal gradient, from the mid-temperate zone to the cold temperate zone, in the black soil region of northeast China. The Savinov method was used to analyze the differences in soil aggregate size distribution, stability characteristics, and soil erodibility between terraced and non-terraced slopes at each research site. The results showed that terracing increased the content of large soil aggregates (>0.25 mm) by 5.38–6.35%, with the increase becoming more pronounced from north to south. The improvement in soil structure varied by location and slope position, with the most significant improvement at the middle slope position. Terracing enhanced soil aggregate stability, reduced soil erodibility, and improved soil structure by increasing clay and soil organic matter (SOM) content and reducing soil bulk density (BD), promoting the conversion of small aggregates to large aggregates. Soil stability indicators such as water-stable aggregates (WSAs), mean weight diameter (MWD), and geometric mean diameter (GMD) were dominated by aggregates > 5 mm, while erodibility indicators such as fractal dimensions (Ds) and the soil erodibility factor (K values) were mainly influenced by aggregates < 0.25 mm. Terraces can improve the soil structure and stability of sloping farmland by increasing the content of large soil aggregates and enhancing overall soil quality. The benefits of these improvements increase with latitude. These findings provide critical insights for determining effective management practices for sloped farmlands in the black soil region under various site conditions. They offer scientific evidence for preventing soil erosion and improving soil quality, thus supporting the sustainable development strategy for protecting black soil and ensuring long-term agricultural productivity.

Optimizing native vegetation establishment in urban soils: Assessing the impacts of organic amendments on specific growth parameters

Following soil disturbances, establishing healthy roadside vegetation can reduce surface water runoff, improve soil quality, decrease erosion, and enhance landscape aesthetics. This study explores the use of organic soil amendments (OAs) as alternatives to conventional vegetation growth approaches, aiming to provide optimal compost mixing ratios for poor soils, and clarify guidelines for OAs’ use in roadside projects. Three sandy loam soils and one loam soil were chosen for the study. Organic amendments included yard waste (Y), food waste (F), turkey litter and green waste-based (T) composts, and wood-derived biochar (B). Treatment applications targeted specific increases in the organic matter (OM) percentage of the soils. A selection of seven native species (grasses and forbs) in a total of 156 pots (4 control soils + 4 soils x 4 OAs x 3 application rates, all prepared in triplicates) was used for the pot study experiment. A significant correlation between electrical conductivity (soluble salts) in soil-OA blends and corresponding percent green coverage (%GC) was found. High salts from the T compost either delayed or curtailed growth. Notably, 3 out of the 4 soils amended with biochar exhibited rapid vegetation coverage during initial growth stages compared to other soil-OA blends but reduced the nitrogen (N) uptake and leaf area in black-eyed Susan (BES) plants. In contrast, N uptake was higher in the BES plants emerging from composts T, F, and Y compared to biochar. It is recommended to minimize concentrated manure-based (e.g., turkey litter) composts for roadside projects as an OM source, and alternatively, enriching wood-based biochar with nutrients when used as a soil amendment. Within the current study, composts such as F and Y were well-suited to establish healthy and long-lasting vegetation.

Enhancing Maize Yield and Nutrient Utilization through Improved Soil Quality under Reduced Fertilizer Use: The Efficacy of Organic–Inorganic Compound Fertilizer

Objectives: The substitution of chemical fertilizers with organic alternatives presents a viable strategy for enhancing soil quality and boosting agricultural productivity. However, the question remains whether organic–inorganic compound fertilizers (COIFs) can sustain improved soil quality and crop yields while reducing chemical fertilizer use. The underlying mechanisms of COIF’s impact still warrant further exploration. Methods: In this study, a long-term fertilization trial was conducted from 2020 to 2023 at two sites with different soil textures and types in the Huang-Huai-Hai Plain, China. The experiment involved three fertilization treatments, each replicated three times: (1) LCF (conventional fertilizer treatment); (2) COIF1 (COIF applied at 90% of the recommended rate); and (3) COIF2 (COIF applied at 80% of the recommended rate). The objective was to assess the effects of COIF on summer maize growth, grain yield, nutrient uptake and utilization, and soil quality. Results: Compared to LCF, COIF1 in Yantai and Dezhou increased biomass by 6.4% and 8.1%, grain yield by 5.9% and 4.12%, PFP (N, P, and K) by 17.6% and 15.7%, and soil quality by 563.6% and 462.5%, respectively. No significant differences in biomass and grain yield were observed between COIF2 and LCF, yet COIF1 in Yantai and Dezhou enhanced PFP (N, P, and K) by 19.7% and 18.6%, and soil quality by 109.1% and 175.0%, respectively. In conclusion, COIF improved soil quality by enhancing soil organic matter (SOM), available nutrients, pH, and other soil indices. It promoted summer maize growth, increased grain yield, and improved nutrient utilization. COIF was a practical and effective measure to reduce chemical fertilizer use, enhance field soil quality, and ultimately increase maize yield and nutrient utilization.

Valorization of treated wastewater from the soaking of baby alpaca skin fur

Baby alpaca fur industry generates considerable wastewater during the soaking process, which contains high levels of total suspended solids (TSSs), proteins, and salts, among other components. The valorization of wastewater after precipitation, coagulation–flocculation, and aeration treatments was evaluated for use in irrigation water, fertigation, groundwater recharge, concrete construction, and disposal. The precipitation treatment sludge and the coagulation–flocculation treatment were evaluated as a protein source, soil quality improvement, and disposal. The treatment system included evaluations of nine pH levels, seven coagulant doses, and seven aeration times. The contents of TSSs, chemical oxygen demand (COD), total Kjeldalh nitrogen (TKN), ammonia nitrogen (N–NH3), and oils and fats (O&G), among other parameters, were determined in the treated and untreated wastewater. Before entering the treatment system, the physicochemical characterization of the wastewater showed a high concentration of parameters related to organic matter and dust, such as O&G, five-day biological oxygen demand (BOD5), COD, TSSs, TKN, and N–NH3. The optimal removal parameters were pH 12 for the chemical precipitation of proteins, a dose of 480 mg/L FeCl3 as a coagulant for TSSs removal, and 150 min of aeration; removal efficiencies of 99.02 %, 77.49 %, 79.93 %, and 64.62 % for TSSs, Cod, TKN, and N–NH3, respectively, were obtained. The wastewater after treatment can be used for groundwater recharge and concrete construction, and the wastewater with 2 % dilution can be used for irrigation water and fertigation. The sludge after precipitation is rich in protein and can be used as a protein source or soil quality improver.

Enhancing soil fertility, inorganic fertilizer efficiency, and oil palm productivity through bio-compost application in oxium biodegradable sacks on former mining land-podzols: Insights from a field study in Indonesia

Sandy podzolic soils, prevalent on former mining lands, present significant agricultural challenges due to their coarse texture, depth, acidity, and low fertility. This study evaluated the impact of bio-compost fertilizer, delivered in biodegradable oxium sacks, on soil quality and oil palm productivity in these soils. Conducted over 12 months in a 4-year-old oil palm plantation in East Belitung Regency, Indonesia, the research compared various combinations of bio-compost and inorganic fertilizers with a control group. The findings revealed that the integration of bio-compost with reduced doses of inorganic fertilizers markedly improved soil quality and decreased dependence on chemical inputs. Specifically, applying 50 kg or 75 kg of bio-compost per palm along with 50 % or 75 % of the standard inorganic fertilizer dose was particularly effective. This approach increased oil palm productivity to 14.50–15.87 tons per hectare per year. The method provides a sustainable solution for the palm oil industry and small farmers, improving soil fertility and productivity in degraded podzolic soils. The use of oxium biodegradable sacks allowed for a gradual release of nutrients. Future research should further explore the potential of bio-compost as a soil conditioner and its long-term environmental impacts across various soil types.

Divergent responses of aggregate breakdown by slaking to nitrogen forms in solution for contrasting soil types

Aggregate stability strongly affects many soil processes and is critical to maintain sustainable agriculture. Aggregate breakdown is controlled by the interaction between soil intrinsic properties and solution characteristics. Nitrogen fertilization including different forms is well known to influence aggregate stability; however, relative to their long-term effects, there is little recognition on the rapid response of aggregate breakdown to nitrogen solutions. This study aimed to examine the effects of nitrogen form and concentration on aggregate stability for different types of soils. Aggregate breakdown against slaking of three soil types (Phaeozem, Luvisol, and Acrisol) and three horizons (organo-mineral (A), illuvium (B), and parent material horizons (C)) was determined subjected to nitrogen solutions of three forms (CO(NH2)2, NH4+, NO3–) and five concentrations (0.05 ∼ 1.0 mol/L). Among nitrogen forms, urea solution almost had non-significant effect irrespective of soil type and horizon (p > 0.05); for NH4+ and NO3– solutions, aggregate stability showed little variations (MWD of 0.19 ∼ 0.26 mm) with electrolyte concentration for Phaeozem in B and C horizons, overall increased for Luvisol and Phaeozem in A horizon, and decreased first and then reached a steady state for Acrisol. The effects of nitrogen forms on aggregate breakdown were dependent on soil aggregation status or cementing agents (mainly organic matter, clay mineralogy). Electrolyte nitrogen solutions (NH4+ and NO3–) inhibited aggregate breakdown mainly through reducing electrostatic repulsive forces for moderately developed soils rich in swelling clays, and promoted aggregate breakdown by both weakening particle cohesion and enhancing compression pressure of entrapped air for highly developed soils rich in non-swelling clays and Fe/Al oxides. These results facilitate an improvement of fertilizer management and irrigation to improve soil quality on different soil types.

Exploring the spatial relationship between soil quality index and soil ecosystem services driven by social-ecological factors: A peri-urban case study in central China

Urban expansion has profound impacts on soil quality in peri-urban areas. Understanding the intricate spatial relationship between soil quality index (SQI) and soil ecosystem services (SESs) in response to social-ecological factors is crucial for achieving sustainable soil utilization and management. In this study, a total of 485 soil samples were collected from different land-use types (including paddy field, dry land, orchard, and forest) in peri-urban areas of a city (Nanchang) in central China. The assessments of soil quality based on SQI and SESs were conducted using multi-source heterogeneous data. We determined the spatial relationships between SQI and six SESs using bivariate spatial autocorrelation analysis, and deciphered the role of 11 social-ecological factors in driving SQI–SES relationships across different zones. The results showed that SQI and SESs exhibited significant spatial clustering (P<0.01), despite certain variations in their distribution patterns. SQI had significant positive spatial correlations with soil organism habitat, food provision, erosion control, carbon storage, and filtering and buffering (r = 0.16–0.48, P<0.05). Two-step clustering categorized 183 villages with distinct SQI–SES relationships into four zones, i.e., soil ecological protection zone, food production core zone, soil quality enhancement zone, and soil ecological restoration zone. The impacts of various social-ecological factors on different zones were unveiled and corresponding development recommendations were presented. Results of this study facilitate the formulation of peri-urban-specific soil conservation policies and management strategies. Our work provides guidance on the improvement of soil quality and soil ecosystems, contributing to the future achievement of sustainable development goals.

Karakteristik limbah pertanian dan dampaknya: Mengapa pengelolaan ramah lingkungan penting?

Background: Agricultural waste is a significant by-product of the agrarian sector, with the potential for substantial environmental and economic impacts. This study aims to examine the characteristics of organic agricultural waste and analyze its effects on the environment, both in terms of threats and its potential utilization. Method: This study employs a systematic literature review method. The literature search focuses on articles discussing agricultural waste, its characteristics, and its environmental impacts. Findings: The results show that agricultural waste has diverse characteristics based on fiber composition, physical form, and protein content. The main threats from agricultural waste include water pollution due to nutrient runoff and greenhouse gas emissions, especially methane. However, this waste also holds significant potential as a source of organic mulch, animal feed, and raw material for bioenergy. Utilizing agricultural waste as mulch can improve soil quality and crop yields, while its use as animal feed supports the integration of agricultural and livestock systems. In the context of energy, converting waste into biogas and biofuel offers an effective solution. Conclusion: This study emphasizes the importance of integrated and sustainable agricultural waste management to minimize negative impacts and optimize its economic potential. Novelty/Originality of this article: By providing a comprehensive analysis of the characteristics and impacts of agricultural waste, this study offers insights into the importance of a holistic approach to agricultural waste management to support sustainable agriculture.

The advantage of afforestation using native tree species to enhance soil quality in degraded forest ecosystems

Different vegetation restoration methods have improved soil quality to varying degrees. This study, focused on the forest–grassland–desert transition zone in the Hebei–Inner Mongolia border region, and employed a systematic grid sampling method to establish fixed monitoring plots in the Saihanba Mechanized Forest Farm and the Ulan Buh Grassland. The differences in soil quality evolution across various vegetation restoration methods under the same climatic and soil historical conditions were analyzed, elucidating the roles of these vegetation restoration methods in degraded forest ecosystems, with the aim of providing a reference for ecological restoration under similar land conditions. This study used a grid method to establish sample points in the forest–grassland–desert transitional zone and assessed five methods of vegetation restoration sites: artificial forest composed of native species of Larix principis-rupprechtii (FL), artificial forest composed of exotic Pinus sylvestris var. mongolica (FP), natural secondary broad-leaved forest (FN), open grassland (GO), and enclosed grassland (GC). The differences in soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), total potassium (TK), alkaline hydrolysis nitrogen (AN), rapidly available phosphorus (AP) and rapidly available potassium (AK) among the different vegetation restoration sites were compared via variance analysis, and the soil quality index (SQI) was calculated to assess the soil quality at the sample points. The SOC, TN, and AN contents of forest soil were significantly greater than those of grassland, and the TN, TP, AN, AK, and SOC contents of FL, FN, and GC were significantly greater than those of FP and GO. Among them, the TN, TP, and SOC contents were the highest in the FL, reaching 2.74, 0.39, and 47.27 g kg−1, respectively. In terms of ecological stoichiometric characteristics, the average N:P ratio in the study area was 6.68, indicating a serious lack of N in the study area. Among the different types of restoration sites, the effect was stronger in the FP than in the FL, and the TN and AN contents were only 1.48 g kg−1 and 116.69 mg kg−1, respectively. The SQI in the FL was not significantly different from that in the FN or GC, but it was significantly greater than that in the FP and GO. These findings indicate that native tree species restoration in degraded forest ecosystems significantly improved soil quality, while the introduction of exotic tree species for afforestation had a minimal effect on improving soil quality.

Availability of Recycled Phosphorus on Biochar Reacted with Wastewater to Support Growth of Lactuca sativa

The use of biochar in water resource and recovery facilities (WRRF) shows promise for recovery of phosphorus (P) to use as a biochar-based fertilizer (BBF) that can replace conventional fertilizers, promote carbon sequestration, and improve soil quality. In this study, biochar was recovered after being dosed into secondary-treated discharge from a municipal WRRF. The value of the recovered biochar as a BBF was tested in a lettuce (Lactuca sativa) growth trial. The BBF was compared to an inorganic fertilizer, raw biochar, and controls that had either only nitrogen (N) fertilizer or no amendment. The ability of the treatments to support plant growth was determined by measuring plant height, biomass, leaf tissue total N and P concentration, and plant quality. Plant quality for the Fe-modified biochar used in the WRRF was 9.05 (±0.44) on a 10-point scale compared to 9.61 (±0.46) for the inorganic fertilizer treatment and 2.22 (±0.82) for the untreated control. Plant tissue P concentrations were 6.28 (±0.83), 9.88 (±0.90), 15.46 (±2.54), and 6.36 (±1.91) g plant−1 for the raw biochar, Fe-modified biochar used in the WRRF, inorganic fertilizer, and no amendment treatments, respectively. Soil P availability and P uptake amount in the leaves indicated that the BBF released P more slowly than the inorganic P fertilizer; however, it was sufficiently available for uptake to support plant growth to maturity. Results from these experiments show that Fe-modified biochar used in WRRF can supply adequate P to plants. The slow release will reduce P leaching into surface waters.

Effects of Different Living Grass Mulching on Soil Carbon and Nitrogen in an Apple Orchard on Loess Plateau

Living grass mulching (LMG) is a modern, environmentally friendly, practical, and efficient production management technology that improves the ecological environment, quality, and efficiency of the orchard. However, in arid and semi-arid areas, the effects of different grass species mulching on soil carbon composition, carbon pool stability, and nitrogen content are still unclear. Therefore, in order to explore the impact of different LMG on soil carbon, nitrogen, and its component content, as well as the related soil carbon pool management index in an apple orchard located in the semi-arid region of the Loess Plateau, a control experiment was conducted. The experiment involved different grass species cover treatments on an 11-year-old semi-dwarf Qinguan apple orchard from 2019 to 2022. Soil carbon and nitrogen content were measured under each treatment. The results indicated that the application of LMG treatment and depth of the soil had a significant impact on the soil organic carbon (SOC), particulate organic carbon (POC), inactive organic carbon (NAOC), total nitrogen (TN), and carbon-to-nitrogen ratio (C/N). Planting Vulpia myuros mulches significantly enhanced 39.6% surface soil organic carbon, 61.7% surface particulate organic carbon, 20.3% surface dissolved organic carbon (DOC), 75.8% surface inactive organic carbon, and 20.6% surface soil total nitrogen compared to clean tillage. Mulching treatment with the planting of Vulpia myuros boosted surface soil organic carbon and decreased soil carbon pool activity (CPA) and carbon pool activity index (CPAI), ultimately improving the stability of the soil carbon pool. The findings will have a beneficial impact on improving soil quality, carbon sequestration, and emission reduction in arid and semi-arid regions.