The aim of this study was to investigate the effects of organic fertilizer replacing part of the nitrogen fertilizers on the structure and diversity of the inter-root soil fungal communities of potatoes. By carrying out a field trial in Gaoquan Village, Tuanjie Town, Dingxi City, Gansu Province, the main potato-producing area in China, the optimal proportion of organic fertilizer to replace nitrogen fertilizer was determined to provide a scientific basis for the rational use of organic fertilizer to improve the structure and function of soil fungal communities. The experiment was laid out with six treatments: CK (no nitrogen fertilizer, phosphate and potash fertilizer applied), CF (nitrogen fertilizer alone, control), T1 (25% replacement of nitrogen fertilizer), T2 (50% replacement of nitrogen fertilizer), T3 (75% replacement of nitrogen fertilizer), and T4 (100% replacement of nitrogen fertilizer). A systematic study of the inter-root soil fungal community structure, diversity, and soil physicochemical properties during potato harvesting was conducted using high-throughput sequencing technology. The results show that the organic fertilizer replacing part of the nitrogen fertilizer significantly increased the content of alkaline dissolved nitrogen, quick-acting potassium, quick-acting phosphorus, and organic matter in the inter-root soil of the potatoes, and significantly reduced the pH value of the soil. There was a trend of decreasing soil fungal abundance and a significant decrease in the Alpha diversity of the soil fungi. The treatment groups in the soil had as their core fungi Acomycota, Mortierellomycota, Basidiomycota, and others. The organic fertilizers replacing the nitrogen fertilizers significantly altered the structural composition of the inter-root soil fungal community of the potatoes, and increased the differential fungi in the soil. The number of functionally diverse and complex fungi in the soil gradually increased, and the function of the fungal community gradually changed from Singularity to diversification and complexity. A redundancy analysis showed that the soil pH was the main environmental factor affecting the inter-root soil fungal communities of potatoes under organic fertilizer replacing N fertilizer.

Different fertilization measures affect the soil’s physical and chemical properties and bacterial community structure, which in turn affects the growth environment and yield of maize seed production. Therefore, rational fertilization measures are important in maintaining and improving soil fertility and promoting maize crop growth. Research on fertilization practices in maize fields for seed production can help to increase agricultural productivity while protecting and enhancing soil health and achieving sustainable agricultural development. To clarify the effects of different fertilization measures on soil bacterial communities in seed corn fields, 16S rRNA high-throughput sequencing technology and PICRUSt method were used to explore the soil under different fertilization measures (CK as control, effects of single application of liquid organic fertilizer (M), single application of bacterial agents (BF), and combined application of liquid organic fertilizer and bacterial agents (M + BF)) on soil bacterial community structure characteristics and ecological functions. Proteobacteria (20.14–25.30%), Actinobacteriota (18.21–20.47%), Actinobacteriota (13.55–22.00%), and Chloroflexi (14.24–17.59%) were the dominant phyla. Bacillus, RB41, Arthrobacter, and Sphingomonas were the dominant genera. M + BF treatment significantly increased the relative abundance of Planctomycetota. The relative abundance of Bacillus and PaeniBacillus in M treatment decreased considerably, while the relative abundance of Turicibacter increased significantly. The relative abundance of Sphingomonas was reduced considerably in M and M + BF treatments. The relative abundance of Subgroup 10 decreased significantly after BF and M + BF treatments. BF treatment significantly increased the relative abundance of Skermanella. Redundancy analysis showed that alkali-hydrolyzed nitrogen (p = 0.044) was the main environmental factor affecting soil bacterial communities under different fertilizer treatments. PICRUSt function prediction results showed that metabolism was the main functional component of bacteria, accounting for 78.45–78.94%. The abundance of functional genes for terpenoid and polyketone metabolism, the endocrine system, the excretory system, and the immune system of the soil bacterial community was significantly increased under M treatment, while the abundance of functional genes for the digestive system was decreased considerably. Different fertilizer cultivation measures changed soil bacterial community composition and ecological function in maize fields. These results can provide a theoretical reference for the study of bacterial community succession characteristics in maize fields and the determination of appropriate fertilizer cultivation measures.

Pingliang City has a complex topography and diverse soil types. To realize the improvement of soil according to local conditions and the reasonable and sustainable use of soil resources, an evaluation of soil quality in Pingliang City was carried out, based on the soil distribution situation in Pingliang City, adopting a method combining fuzzy mathematics and cluster analysis of the main evaluation factors, such as soil organic matter, topsoil depth, soil erosion intensity, soil moisture regime, effective soil thickness, soil texture, soil profile structure, soil nutrient status and topographical parts, to carry out a comprehensive evaluation. A comprehensive evaluation of soil quality was conducted in seven counties under the jurisdiction of Pingliang City, and the evaluation results were compared and analyzed against the national standard, “Cultivated land quality grade”, to provide a basis for the selection of scientific soil improvement methods. The results of the arable land quality grades indicate that the quality of farmland in Pingliang City is divided into three to ten grades, and the average quality grade of farmland is 6.83, which is in the middle–lower level, and the overall grade distribution shows the characteristics of low in the middle and high in the east and west. The results of fuzzy mathematics combined with cluster analysis indicated the following trends in soil quality for the 12 soil genera: Chuan black gunny soil > yellow moist soil > sandy soil > silt soil > mulching helilu soil> loessal soil> loamy soil > slope loessal soil > arenosol > tillage leaching gray cinnamon soil > calcareous gray cinnamon soil > red clay soil. The results of the combination of fuzzy mathematics and clustering were significantly correlated with the results of the evaluation of the soil quality of arable land; the correlation coefficient was 0.884. This indicates that the method can accurately and objectively review the advantages and disadvantages of arable land soil and can be effectively applied to the evaluation of the soil quality of agricultural soils in other regions. It is a complement to the existing evaluation of the soil quality of arable land and at the same time provides a reference for the improvement of soil quality in agricultural regions.