Effects of Long-Term Sustainable Inorganic Fertilization on Rice Productivity and Fertility of Quaternary Red Soil

Soil microbial communities play a critical role in soil fertility and crop productivity. The present study investigated the impact of long-term chemical fertilization on microbial communities, rice productivity, and fertility of Quaternary red soil. A long-term experiment was conducted from 1984 to 2018 with the following treatments: unbalanced nitrogen (N), phosphorus (P), potassium (K) fertilization (NP, NK, and PK) and balanced inorganic fertilization (NPK) and non-fertilization (CK) as control. The results indicate that alkaline hydrolyzed nitrogen (AhN), available phosphorus (AP), and available potassium (AK) were higher with the application of NPK fertilizers than in the initial stage of the experiment. The crop yield of fertilizer groups was also higher than that of CK, and the maximum yield was observed in the NPK group. The relative abundance of dominant bacteria, such as Acidobacteriaceae and Proteobacteria, was significantly different among different fertilizer treatments. Different fertilization strategies also had significant effects on soil fungi. For instance, Mortierella had a positive correlation with the soil N content, and Arnium showed a negative correlation with the balanced fertilization of N and P. Therefore, long-term balanced inorganic fertilization can effectively improve rice productivity and fertility of Quaternary red soil.