Mycorrhizal effects on crop yield and soil ecosystem functions in a long-term tillage and fertilization experiment

The Effect of the Application of Chemical Fertilizer and Arbuscular MyCorrhizal Fungi on Maize Yield and Soil Microbiota in Saline Agricultural Soil

The overuse of chemical fertilizers not only leads to resource wastage but also causes problems such as environmental pollution and soil degradation. In particular, crop growth in saline-sodic soils is severely restricted due to high salinity and alkalinity, further exacerbating challenges in agricultural production. The aim of this study was to investigate different fertilization strategies that combine chemical fertilizer reduction with arbuscular mycorrhizal fungi (AMF) for improving saline-sodic soils and to assess the effects of these protocols on crop yield, soil properties, and microbial communities. Field experiments across two sites (BeiWuLao and XuJiaZhen) demonstrated that integrating AMF with CF reduction (AHCF treatment) significantly enhanced maize yield by 23.5% at BeiWuLao (from 11,475 to 14,175 kg/ha) and 81.2% at XuJiaZhen (from 7245 to 13,125 kg/ha) compared to conventional fertilization (CK) (p < 0.01). Soil nutrient analysis revealed substantial improvements: available potassium (AK) increased by 77.7% (61.35 vs. 39.33 mg/kg), available phosphorus (AP) by 33.9% (20.50 vs. 15.50 mg/kg), ammonium nitrogen (AN) by 57.3% (64.17 vs. 40.83 mg/kg), and soil organic matter (SOM) by 96.4% (46.98 vs. 23.91 mg/kg) under AHCF treatment (p < 0.05). Although pH and electrical conductivity (ECe) remained unaffected, AMF inoculation shifted microbial composition, elevating salinity-tolerant taxa such as Actinobacteria (+24.7%) and Anabaena. Beta diversity analysis (PCoA) confirmed distinct microbial community structures between treatments, with ECe and AN identified as primary drivers of bacterial (RDA variance: 74.08%) and fungal (RDA variance: 54.63%) communities, respectively. Overall, the combination of chemical fertilizer reduction and AMF effectively improved soil fertility, microbial community structure, and crop yield. These findings have important implications for improving saline soils and promoting environmental sustainability.

Trade-off between soil enzyme activities and hotspots area depends on long-term fertilization: In situ field zymography

Mineral fertilizers and livestock manure have been found to impact soil enzyme activities and distributions, but their trade-off and subsequent effects on soil functioning related to nutrient cycling are rarely evaluated. Here, we investigated the long-term effects of manure and mineral fertilization on the spatial distribution of enzyme activities related to carbon, nitrogen, and phosphorus cycling under field-grown maize. We found that the legacy of mineral fertilizers increased the rhizosphere extension for β-glucosidase and N-acetylglucosaminidase by 16-170 %, and the hotspots area by 37-151 %, compared to manure. The legacy of manure, especially combined with mineral fertilizers, increased enzyme activities and formed non-rhizosphere hotspots. Furthermore, we found a trade-off between hotspots area and enzyme activities under the legacy effect of long-term fertilization. This suggested that plants and microorganisms regulate nutrient investments by altering spatial distribution of enzyme activities. The positive correlation between hotspots area and nutrient contents highlights the importance of non-rhizosphere hotspots induced by manure in maintaining soil fertility. Compared to mineral fertilization, the legacy effect of manure expanded the soil functions for nutrient cycling in both rhizosphere and non-rhizosphere by >1.7 times. In conclusion, the legacy of manure expands non-rhizosphere hotspots and enhances soil functioning, while mineral fertilization expands rhizosphere extension and intensifies hotspots area for nutrient exploitation.

Conservation agriculture improves soil health and sustains crop yields after long-term warming

Climate warming threatens global food security by exacerbating pressures on degraded soils under intensive crop production. Conservation agriculture is promoted as a sustainable solution that improves soil health and sustains crop yields in a changing climate, but these benefits may be affected by long-term warming. Here, we investigate the effects of conservation agriculture compared to conventional agriculture on 17 soil properties, microbial diversity and crop yields, during eight-years' experimental warming. An overall positive effect of warming on soil health over time under conservation agriculture is characterized by linear increases in soil organic carbon and microbial biomass carbon. Warming-triggered shifts in microbial biomass carbon and fungal diversity (saprogen richness) are directly linked to a 9.3% increase in wheat yields over eight years, but only under conservation agriculture. Overall, conservation agriculture results in an average 21% increase in soil health and supports similar levels of crop production after long-term warming compared to conventional agriculture. Our work provides insights into the potential benefits of conservation agriculture for long-term sustainable food production because improved soil health improves resilience to the effects of climate warming.

Enhanced Soil Fertility and Carbon Dynamics in Organic Farming Systems: The Role of Arbuscular Mycorrhizal Fungal Abundance

Arbuscular mycorrhizal fungi (AMF) are critical for soil ecosystem services as they enhance plant growth and soil quality via nutrient cycling and carbon storage. Considering the growing emphasis on sustainable agricultural practices, this study investigated the effects of conventional and organic farming practices on AMF diversity, abundance, and ecological functions in maize, pepper, and potato-cultivated soils. Using next-generation sequencing and quantitative PCR, we assessed AMF diversity and abundance in addition to soil health indicators such as phosphorus content, total nitrogen, and soil organic carbon. Our findings revealed that, while no significant differences in soil physicochemical parameters or AMF diversity were observed across farming systems when all crop data were combined, organic farming significantly enhances AMF abundance and fosters beneficial microbial ecosystems. These ecosystems play vital roles in nutrient cycling and carbon storage, underscoring the importance of organic practices in promoting robust AMF communities that support ecosystem services. This study not only deepens our understanding of AMF's ecological roles but also highlights the potential of organic farming to leverage these benefits for improving sustainability in agricultural practices.