Green manure and commercial organic fertilizers are widely used in agricultural production to improve the carbon reserves in farmland soil; however, their combined impact on soil organic carbon (SOC) turnover remains unclear. We designed a potted wheat–soybean green manure system to investigate the impact of different fertilization treatments on the content and structure of SOC, extracellular enzyme activity and microbial community characteristics in post-wheat harvest soil. For this analysis, fertilization treatment was considered as a single factor. Compared with chemical fertilization (CF), organic fertilization (OF) led to a 12.5

The soil ecosystem of oasis wheat fields is fragile, and excessive use of synthetic fertilizers has contributed to soil degradation. Commercial organic fertilizers and green manure can reduce reliance on synthetic fertilizers in agricultural production. However, the effects of combining these practices on wheat growth and soil health remain unclear. A 457-day in situ pot experiment involving spring wheat–soybean green manure–spring wheat rotations was conducted. Four treatments were applied during the wheat growing season: no fertilizer (CK), synthetic fertilizer providing N and P2O5 (CF), commercial organic fertilizer substituting 24

Context In oasis drip-irrigated wheat systems, optimizing fertilization strategies to reconcile productivity with soil sustainability remains challenging. Methods A two-year field experiment was conducted to evaluate the synergistic effects of organic substitution (OFS) combined with green manure species (soybean [SB], rape [RP], sunflower [SF]) on soil nutrient stoichiometry, microbial metabolism, and wheat yield formation. Results Compared to conventional fertilization, OFS enhanced wheat yield by improving leaf area (16.5-23.0 %), photosynthetic rate (26.0-28.6 %) and grain-filling duration (4.6-11.3 %), while boosting grain nutrient uptake (9.6-16.0 %) and quality. Under OFS, green manures differentially regulated soil properties: RP elevated soil organic carbon (SOC, 13.6-16.6 %), carbon-to-nitrogen ratio (C/N, 7.8-10.8 %), carbon-to-phosphorus ratio (C/P, 15.5-17.8 %), and available P (6.3-10.8 %), achieving maximum gain yield (5.4-31.7 %) via increased microbial biomass P (30.7-50.3 %); SF enhanced SOC (12.6-15.8 %), C/P (14.5-19.2 %), and available potassium (10.0-13.3 %) while maintaining grain yield comparable to RP; SB increased total N (8.7-9.9 %), N/P (6.7-9.1 %), and available N (11.5-15.1 %), but was constrained by high soil alkalinity (pH >8.5). Concurrently, SB reduced C/N (3.8-6.8 %) and showed yield parity with summer fallow. Conclusions Crucially, non-legume green manures outperformed legumes in oasis soils due to higher salt tolerance and nutrient activation efficiency. We propose a targeted green manure selection framework: salt-tolerant RP/SF for organic-amended fields to enhance P/K availability, and salt-resistant SB genotypes for reduced-fertilizer systems to sustain N supply. Significance These findings demonstrate that species-specific green manure integration with OFS reshapes soil-microbe interactions, offering a viable pathway to achieve yield stability and ecological intensification in arid oasis agriculture.

Acidic compost tea (CT) can provide nutrients for cotton in calcareous (alkaline) soil and improve soil properties; however, the responses of fungi to rhizosphere nutrient conditions and physicochemical properties remain unclear. In this study, the responses of phosphorus (P) morphology and fungal community structure and function to CT in cotton rhizosphere soil were examined. The results indicated that the contents of water P, NaHCO3-P, and NaOH-P in rhizosphere soil as well as the absorption and accumulation of nutrients by cotton were significantly increased following CT application. The diversity of rhizosphere fungi decreased; however, the species formed a more complex and stable community. Moreover, the relative abundance of oligotrophic species, such as Basidiomycota, decreased. Random forest distribution and Mantel tests revealed that the main driving factors in the compositional change of the fungal species were soil pH and the increasing proportion of labile P (water P and NaHCO3-P) and moderately labile P (NaOH-P and HCl-P), which directly affected the abundance of species with varying nutrient modes. A structural equation model revealed that the primary factor for dry matter accumulation and yield increase in cotton was increased P availability. This study revealed the changes in P morphology and fungal community in rhizosphere soil in response to CT and factors contributing to these changes as well as evaluated the relationship between efficient utilization of P in calcareous soil and rhizosphere fungal microecology.

In this study, we established a feasible fertilization programming method for wheat production by exploring the effects of the combined application of chemical and organic fertilizers on wheat yield, nutrient uptake, soil nutrient content, and fertilizer utilization. Six treatments, no fertilizer (CK), conventional fertilizer (CF), optimized fertilizer (with reduced fertilizer amount) (RF), chemical fertilizer with organic fertilizer extract (RPAE), partial replacement of chemical fertilizer with raw amino acid powder (RAF), and partial replacement of chemical fertilizer with raw humic acid powder (RHF), were set up for a field experiment. The fertilizer application rates for the RF treatment were calculated based on fertilization-monitoring techniques (30.3% nitrogen and 24.8% phosphorus reductions in 2022 and 23.0% nitrogen and 1.5% phosphorus reductions in 2023). The effects of different fertilizer treatments on yield, dry matter accumulation, plant nutrient accumulation, soil nutrients, and nutrient utilization in wheat were investigated. The results showed that, on the basis of 23% nitrogen and 1.5% phosphorus reductions, there was no significant difference in wheat yield between the RF and CF treatments and that the utilization rate of nitrogen fertilizer was improved. The application of organic fertilizer promoted dry matter accumulation in different organs of wheat; increased plant nutrient accumulation; improved soil nutrient content, nutrient utilization rate, nutrient partial productivity, and nutrient agronomic use efficiency; and ensured stable and increased crop yield. Specifically, compared with CF, the RPAE, RAF, and RHF organic fertilizer treatments increased wheat yield by 3.85%, 1.97%, and 0.67%, respectively, and the utilization of nitrogen and phosphorus fertilizers induced by these treatments significantly increased by 40.46%, 39.28%, and 37.46% (nitrogen) and by 9.83%, 8.91%, and 7.46% (phosphorus), respectively. As a result of our experiment, we concluded that RPAE exerted the best effects among the three organic fertilizer treatments (RPAE, RAF, and RHF) and that its use can result in a higher wheat yield and fertilizer utilization rate in drip-irrigated wheat fields. The results of this study provide a theoretical basis for the combined application of chemical and organic fertilizers, which is conducive to sustainable agriculture development.

Long-term excessive use of chemical fertilizers and continuous cropping in vegetable and cotton production lead to a decline in farmland soil quality and crop productivity, endangering sustainable agricultural development. Organic amendment substitution (OAS) or farmland use change or can potentially enhance soil quality and crop yield. However, it remains unclear whether their combined application can improve the sustainability of wheat fields when changing from cotton and vegetable fields. In this study, continuous cropping cotton and vegetable fields were changed to wheat fields (C-W and V-W), and then field fertilization experiments (non-fertilization, NF; chemical fertilizer alone, CF; chemical fertilizer reduced by 20%, RF; and organic amendment substituted 20% of inorganic nitrogen, OAS) were conducted for three years (2018–2020) to explore their effects on wheat productivity and soil quality. The findings revealed that the combined farmland use change and fertilization improved soil quality in wheat fields compared to pre-change cotton and vegetable fields. OAS improved soil quality index (SQI-TDS by 0.36–0.82 and 0.32–0.82; SQI-IDS by 0.37–0.90 and 0.40–0.88) by improving soil properties and increasing microbial diversity compared to NF, CF and RF in C-W and V-W. Meanwhile, OAS increased nutrient use efficiency, crop productivity index (CPI, by 13.69%−72.46% and 8.52%−41.45%) and the sustainability index (SI, by 14.14%−49.35% and 12.56%−40.00%). Moreover, microbial biomass carbon and nitrogen (MBC and MBN), pH, available nitrogen (AN), soil organic carbon (SOC) and ACE index were key soil factors affecting yield. These indicators can be used to construct important dataset to simplify soil quality evaluation systems. Overall, the present study revealed the mechanism by which OAS improved wheat field sustainability by increasing wheat productivity and soil quality after farmland use changes, contributing to sustainable agricultural development. Moreover, it provides valuable reference methods and evaluation ideas for future research on farmland soil quality and sustainability evaluation.

Excessive use of chemical fertilizers negatively impacts crop productivity and farmland ecosystem, impeding sustainable agricultural progress. Consequently, there is an immediate need for a chemical fertilizer reduction strategy that ensures crop productivity and improves soil quality and the ecological environment of farmland. This study implemented a three-year (2018-2020) field experiment with two chemical fertilizer reduction methods (direct fertilizer reduction and organic substitution) to investigate their effects on wheat productivity, soil quality, heavy metal pollution risk and microbial characteristics. The results showed that organic substitution treatments (OF1, OF2 and OF3) improved most wheat plant (nutrient uptake and yield and its components) and soil properties (soil nutrients and carbon and nitrogen fractions), leading to increased crop productivity index (CPI, by 9.18 %-16.39 % and 14.14 %-23.36 %) and soil quality index (SQI, by 84.67 %-138.86 % and 104.11 %-175.91 %) compared to conventional fertilization (CF) and direct fertilizer reduction treatments (RF1, RF2 and RF3) in 2019 and 2020. Additionally, organic substitution enhanced the diversity and network complexity of bacterial community, while raising the soil pollution index (SPI, by 9.30 %-12.84 % and 12.20 %-18.49 %) without causing soil heavy metal pollution. Thus, it is recommended to adopt organic fertilizer substitution as the primary chemical fertilizer reduction strategy for wheat production. This approach will ensure crop yield, and improve soil quality and microbial characteristics, but its long-term application requires monitoring changes in soil heavy metals. Overall, this study provides guidelines for implementing scientific fertilization in agricultural practices, thus contributing to the health and sustainability of farmland ecosystems.

BACKGROUNDImprovements in farmland soil organic carbon (SOC) stock enhance crop yield and soil fertility while mitigating climate change. Rational fertilization in agricultural production is crucial for safeguarding SOC stock. In this study, field experiments were conducted with different ratios of chemical fertilizer reduction and organic fertilizer substitution for three consecutive years (2018-2020) to explore their effects and interlinkages on SOC fractions, soil properties and SOC stock.RESULTSThe results showed that organic fertilizer substitution increased SOC and its fractions content, SOC stock (by 3.98-12.98% and 7.15-18.13%) and soil fertility index (by 11.76-49.26% and 33.33-91.47%) compared to conventional fertilization in 2019 and 2020, while chemical fertilizer reduction had the opposite effect. Moreover, soil properties (except total nitrogen to total phosphorus ratio, N/P) and SOC fractions significantly affected SOC stock, with SOC fractions contributing more than soil properties. The high sensitivity of microbial biomass carbon (MBC) and dissolved organic carbon (DOC) can indicate changes in soil carbon pool. Structural equation modeling (SEM) revealed that organic fertilizer substitution increased SOC content and stock by increasing SOC fractions [recalcitrant organic carbon (ROC) and labile organic carbon (LOC) fractions] content and soil fertility.CONCLUSIONSOur study revealed the corresponding mechanisms of the two fertilization modes affecting SOC stock changes. The use of organic fertilizer substitution is recommended to increase SOC stocks and soil fertility in wheat fields. (c) 2023 Society of Chemical Industry.

This study aimed to elucidate the mechanism of substituting organic fertilizer for mineral fertilizer to increase calcareous fluvisol soil organic carbon. Four years of soil culture experiments were conducted, wheat yield, soil nutrients, soil organic carbon (SOC) and SOC fractions were measured and the compositional changes of SOC was analyzed by attenuated total reflectance-fourier transform infrared (ATR-FTIR) spectroscopy. Treatments included applying no fertilizer (CK), mineral N and P fertilizers (CF) and organic fertilizers to replace 6% (OF6), 12% (OF12), 18% (OF18) and 24% (OF24) of N and P under the same nutrient conditions. The results showed that the OF24 treatment was the best among the treatments employed. Compared with CF, wheat yield, SOC, microbial biomass carbon (MBC), labile fraction 1 (LOC1) and recalcitrant fraction (ROC) of OF24 increased by 10.4%, 24.4%, 66.3%, 43.2% and 30.7%, however, the labile fraction 2 (LOC2) decreased by 16.8%. ATR-FTIR results showed that the relative absorption intensity of OF24 treatment at 1,000 cm-1 band is lower than CK and CF treatment, other bands are higher than CK and CF treatment. Overall, OF24 treatment not only significantly increased wheat yield, but also increased the content of LOC1 and MBC. The increase of MBC can improve the soil microbial environment and promote the decomposition of LOC2, while also accelerate the turnover rate of soil carbon and then show the increase of ROC content and improve the proportion of the recalcitrant carbon pool.

Organic fertilizer substitution (OFS) technology effectively mitigates the adverse effects of excessive synthetic fertilizer application while promoting soil organic carbon (SOC) sequestration in farmlands. However, how the permanganate oxidizable carbon fractions (KOCs) transformation affects SOC under OFS remains unknown. In this study, two typical farmland soils (grey desert soil, GS; meadow soil, MS) were selected for a 3-year field fertilization experiment (no fertilization, NF; synthetic fertilizer alone, SCF; and organic fertilizer substituted 20% synthetic N fertilizer, OFS). Field experiments conducted from 2018 to 2020 showed that SOC could be used to evaluate wheat yield and soil quality, so further study the effects of OFS on SOC and KOCs and their corresponding C pool management index (CPMIs). The results showed that OFS in GS and MS increased SOC (by 3.37%-15.62%, 4.92%-20.28%) and its fractions content (except low-activity KOC, LKOC) and CPMIs (except CPMI-L) year by year compared to SCF and NF. The recalcitrant organic C (ROC), KOC, high-activity KOC (HKOC), and medium-activity KOC (MKOC) were the key fractions affecting SOC. Moreover, HKOC and MKOC and their corresponding CPMIs (CPMI-H and CPMI-M) showed higher sensitivity. Structural equation modeling revealed that OFS in GS and MS increased SOC by increasing ROC and KOC (by regulating KOCs transformation) content, and increased CPMI-H and CPMI-M by increasing HKOC and MKOC content. Overall, the process of OFS promoted SOC sequestration and improved soil C pool in two soils were revealed from the perspective of KOCs transformation. Also, we proposed corresponding fertilization recommendations and showed that HKOC and MKOC could be used to evaluate and monitor soil quality and SOC. This study provides guidance for SOC sequestration, crop yield, and soil quality improvement in oasis wheat fields, contributing to the sustainable development of farmland.

Acid compost tea (CT) is an acidic liquid organic fertilizer, which can be used for topdressing throughout the period of cotton growth in drip irrigation cotton fields with calcareous soil. However, its effects on soil bacteria and cotton roots are not clear. This study investigated the response of cotton roots and rhizosphere bacteria to CT application. Compared with organic fertilizer, the total root length, surface area, and volume were found to increase by 18.9%, 19.9%, and 20.7% upon CT treatment, respectively. However, the abundance of rhizosphere bacteria decreased upon CT treatment. The relative abundance of bacteria associated with root growth and rhizosphere environmental health, such as Micrococcaceae, Nocardioidaceae, and Sphingomonadaceae, increased significantly, whereas the relative abundance of oligotrophic bacteria, such as Methylmirabilota, decreased. Random forest distribution showed that the cotton root was the main factor affecting rhizosphere bacterial abundance and diversity, while soil properties (pH, total nitrogen, and organic carbon) and roots affect the relative abundance of some species together. The gene expression associated with metabolism, environmental adaptation, and immune system in rhizosphere bacteria increased. In conclusion, CT can improve soil properties and promote the growth of cotton roots, and cotton roots in turn exert regulatory effects to promote the growth of beneficial bacteria in the rhizosphere and affect their functions. CT has considerable application potential for the sustainable development of cotton fields with calcareous soil.

Dissolved organic matter (DOM) assists in the phytoremediation of heavy-metal-contaminated soils, but the effect of synergistic remediation of DOM on plants is unclear. This study investigated the effect of two DOM sources (cotton straw (CM) DOM and farmyard manure (FM) DOM) on cadmium (Cd) accumulation in Cd-contaminated soil by cotton and evaluated the phytoremediation effect of DOM. The results showed that adding DOM reduced the available nitrogen and increased organic matter, available phosphorus and available potassium. Applying DOM increased the proportions of Cd acid soluble fractions and reduced the proportions of Cd residual fractions by 1-7%. DOM application increased root length, root surface area and root volume compared to the control and had a promoting or inhibiting effect on cotton biomass, depending on the soil Cd concentration. Furthermore, applying DOM improved the Cd content and bioconcentration factor of cotton. The lower the molecular weight, hydrophilic components and aromaticity of DOM, the more conducive to Cd accumulation is in cotton. The correlation and random forest analyses also showed that CM showed high remediation potential. According to our study, DOM can improve the phytoremediation efficiency of cotton, especially in low-concentration contaminated soils. This study provides a basis for applying DOM in the phytoremediation of Cd-contaminated soils.

To reveal the effects of dissolved organic matter (DOM) on the remediation of cadmium (Cd)-contaminated soils by cotton, the effects of cotton straw dissolved organic matter (CM) and farmyard manure dissolved organic matter (FM) on soil available Cd (DTPA-Cd) content, cotton biomass, photosynthetic characteristics, and Cd accumulation were investigated in a pot-based experiment under three exogenous soil Cd levels (mg·kg-1) of 0 (C0), 5 (C5), and 10 (C10). The results showed that the application of CM and FM increased the content of available Cd in soil, with the maximum increase of 30.89% and 8.51%, respectively, and that of CM was higher than that of FM. The effects of CM and FM application on total biomass and photosynthetic characteristics in cotton showed that biomass accumulation and net photosynthetic rate were promoted at the C0 level, there was no significant difference compared to that in the control (CK) at the C5 level, and total biomass accumulation and net photosynthetic rate were inhibited at the C10 level; however, transpiration rate both showed higher than the CK treatment at the same Cd level. The application of DOM altered the Cd content of all parts of the cotton compared to that in the CK treatment, where the application of CM resulted in significantly higher Cd content in all parts of the cotton (except for lint) than that in the CK treatment at the same Cd level; however, the application of FM mainly increased the Cd content in the root. The root was the main organ for the increase in total Cd accumulation, the application of CM and FM significantly increased the total Cd accumulation in cotton, and the total Cd accumulation increased by 27.76%-113.05% and 17.77%-93.79%, respectively. Therefore, DOM can be used as an additive to repair Cd-contaminated soil, which has certain application potential. It is recommended to apply cotton straw DOM to repair Cd-contaminated soil.

Organic fertilizer substitution (OFS) is an effective strategy for reducing the chemical fertilizer usage; however, the effects of different OFS ratios (OFSRs) on maize yield, soil fertility, and heavy metal pollution risk are still unclear. Therefore, determining a suitable OFSR is important. Through the pot experiment, no fertilizer (CK) and organic fertilizer substituting 0% (CF, chemical fertilizer alone), 8% (OF8), 16% (OF16), and 24% (OF24) of the chemical N fertilizer were set to investigate the effects of different OFSRs on maize growth and yield, soil properties (available nutrients, carbon fractions, and carbon pool indices), and nutrients and heavy metals in grain and soil. The results showed that OF8, OF16, and OF24 improved soil fertility by increasing soil organic carbon (SOC, by 10.05–16.26%) and its fractions, most middle- and micro-nutrients content, and carbon pool management index (CPMI, by 17.45–30.31%) compared with CF, while improving grain nutritional quality. However, they increased heavy metals content in grain and soil and their Nemerow comprehensive pollution index (NCPI, by 4.06–16.56% in grain and 2.55–5.57% in soil) but did not cause pollution. Among them, throughout the growth period, only OF8 treatment increased soil available nitrogen (AN), phosphorus (AP), and potassium (AK) content by 3.04–11.15%, 7.11–8.05%, and 0.12–6.05%, respectively, compared with CF, which thus significantly promoted maize growth and increased yield (by 35.65%); the NCPI of grain and soil was however lower than that OF16 and OF24. In conclusion, substitution ratio of 8% was considered ideal for promoting maize growth, improving yield and soil fertility, with a low pollution risk. The results of this study would aid in guiding the scientific application of OFS technology to agricultural production, thereby contributing to resource utilization of organic waste and sustainable agricultural development.

[目的]研究镉胁迫对作物生长及富集特性的影响,探寻更适宜修复镉污染的植物.[方法]设计水培试验,以德高小白菜、新陆早42号棉花、野生龙葵为供试材料,人工模拟不同浓度镉胁迫条件,测定不同浓度镉胁迫下3种植物生长、镉吸收与积累.[结果](1)镉胁迫下,棉花株高生长显著受到抑制;随镉胁迫浓度的增加,龙葵及棉花生物量下降尤为显著.(2)各处理下,棉花和小白菜地下部镉含量大于地上部,根系表现出较强的耐性与镉吸收能力;龙葵在低浓度镉(10和20 mg/kg)处理下地上部镉含量大于地下部,此时,根至茎叶表现出较强的镉转移能力.(3)高浓度镉胁迫下,龙葵的镉积累能力高于小白菜和棉花.[结论]镉胁迫下,小白菜生长无显著抑制.镉处理浓度分别为5、3.5和50 mg/kg时,对应的小白菜、棉花和龙葵镉积累量达到最大.3种植物对镉污染的修复能力表现为龙葵>小白菜>棉花.

Abstract Compost tea comes from a wide range of sources and can provide nutrients for crops and improve soil quality. In order to explore the effects of fertilization frequencies of compost tea on the spatial distribution of nutrients and the uptake by cotton, a trial comprised no fertilization treatment (CK) and three fertilizer treatments, that is, the application of a fixed amount of fertilizer at four (F3), two (F5), or one (F9) irrigation cycle, and each irrigation cycle was 10 days. The total amount of nutrients (N, P2O5, K2O) in fertilization treatment were all 18 g, and their amount of fertilization each time was 1/3, 1/5 and 1/9 of the total fertilizer, respectively. The results showed that in 0–10 cm soil layers, high-frequency fertilization (F9) reduced the soil pH by 5.6% compared with F3, the soil nutrient content of F3 treatment at seedling stage was significantly higher than that of the other two treatments by 71.9%–272.3%, however, the 20–40 cm soil layer was hardly affected by fertilization; The nutrient accumulation of cotton in F3 treatment was 17.1%–32.4% higher than that in the other two treatments, and the highest dry matter and recovery efficiency were also obtained under the F3 treatment. In conclusion, increasing the proportion of fertilization in seedling stage (F3) can increase the uptake and utilization of nutrients by cotton; While high-frequency fertilization (F9) can reduce the pH of calcareous soil. This study provides a basis for fertilizer optimization and soil quality improvement of composted tea.

植物提取修复作为镉污染土壤修复的理想方法,探究植物的富集规律和探寻更适合石灰性土壤镉污染修复的植物是提高修复技术和效率的关键.本研究采用盆栽模拟试验,以小白菜、棉花和龙葵为试验材料,设置4个镉添加浓度;0、1、5、10 mg/kg,以不加镉为对照(CK),称重法测定3种植物收获时的干物质量、根系扫描仪扫描得到根系形态参数以及用HNO3-HCL-HF酸先微波消解,后用日立-Z2000原子吸收分光光度计法测定镉含量,并通过计算植物对镉的生物富集系数、转移系数和镉积累量,分析植物镉积累量与生物富集系数和转移系数等之间的关系.结果表明:(1)随着外源镉添加量的增加,除小白菜,棉花和龙葵地上部生物量均显著降低.(2)10 mg/kg镉处理下,棉花根系平均直径增大;不同程度镉胁迫下,小白菜根表面积、直径和根体积减小,龙葵的根长、根表面积、根体积和平均直径均降低.(3)小白菜和龙葵地上部、棉花地上和地下部富集系数均随镉处理浓度的增加先升高后降低,小白菜和龙葵地下部富集系数则随镉处理浓度增大而减小,3种植物的富集系数均大于1.(4)棉花的转移系数随外源镉添加浓度的增加逐渐减小,小白菜的逐渐上升,龙葵表现为先升高后降低.(5)棉花和小白菜地上部镉积累量在镉浓度为10 mg/kg时达最大,分别为393.2、630.3μg/盆,在5 mg/kg镉处理下龙葵地上部镉吸收量达最大,为202.1μg/盆.3种植物中,棉花在1 mg/kg镉胁迫下镉富集能力最大;龙葵在5 mg/kg镉处理下积累量仍较大;镉胁迫下小白菜镉吸收与转移能力仍较强,小白菜在10 mg/kg镉胁迫下地上部积累量最大,为630.3μg/盆;因此,棉花、龙葵和小白菜分别适用于植物提取修复为1、5和10 mg/kg的镉污染石灰性土壤.

Traditional organic fertilizer substitution is an effective measure for increasing crop yield and soil quality while reducing chemical fertilizer input. However, the effects of commercial organic fertilizer substitution (COFS) on soil quality and wheat yield, and the underlying mechanisms, are unknown. In this study, agricultural fields with low fertility (LF) and high (HF) fertility soils were selected for a two-year (2018-2019) field experiment in the oasis region of Northwest China. Three fertilization treatments with three replications (no fertilization, CK; local conventional chemical fertilizer application, LCF; and 20 % of inorganic nitrogen (N) was substituted by commercial organic fertilizer, COFS) were established to study the effects of COFS on wheat growth, yield, nutrient-use efficiency and soil quality. The results showed that compared with LCF in 2018 and 2019, COFS in LF and HF promoted wheat growth, improved nitrogen use efficiency (NUE) and phosphorus use efficiency (PUE), and increased yield (by 1.52 %-3.05 % and 1.16 %-1.39 %) and soil quality (by 15.09 %-28.63 % and 22.53 %-64.82 %) by improving most soil indicators (e.g., soil organic matter (SOM) and available nutrients). Moreover, SOM and available nutrients significantly affect soil quality and wheat yield, which can monitor changes in soil quality and wheat yield. In conclusion, our study revealed that the mechanism of COFS in HF and LF increased wheat yield by improving soil quality. COFS is recommended for agricultural production, but its continuous application requires monitoring changes in SOM and available nutrients to adjust fertilization to guarantee soil quality and crop yield. This study provides guidance for the scientific application of COFS to improve farmland productivity and soil quality and helps to promote healthy and sustainable agricultural development.

Organic fertilizer substitution technology is an effective measure to solve the excessive application of chemical fertilizers in agricultural production. A pot experiment was set up with 5 treatments: no fertilizer (CK) and organic fertilizer substituting 0% (CF), 8% (OF8), 16% (OF16), and 24% (OF24) of chemical N fertilizer to analyze their effects on maize yield, soil organic carbon (SOC) and its fractions, carbon pool management index (CPMI), nutrients and heavy metals to provide a scientific basis for safe fertilizer application to maize. This study found that OF8, OF16, and OF24 all increased the content and proportion of SOC and labile organic C (LOC) fractions, CPMI, most of the middle and trace elements, and heavy metals content and their pollution indices in soil and grain compared to CF. Grain was more vulnerable to pollution compared to soil. There was a strong positive correlation between the content of middle and trace elements, and heavy metal, SOC and its fractions (except LLOC), and organic fertilizer substitution ratio, all with no significant correlation with yield. OF8 and OF16 promoted maize growth with a significant increase yield of 35.65% and 30.28% ( P <0.05), respectively. A comprehensive analysis determined the optimum substitution ratio of 8% (OF8), which can reduce chemical fertilizer and increase yield, improve soil fertility, low heavy metal pollution risk, is beneficial to promote sustainable agricultural development.