Slow-release fertilisers increased microflora and nitrogen use efficiency and thus promoted peanut growth and yield

The effects of large granular slow-controlled release fertiliser prepared by a double coating of sulfur and sodium alginate on peanut growth, nitrogen fertiliser utilisation, and soil microbial community were investigated through peanut pot experiments, with a view to providing a theoretical and practical basis for the development of large granular slow-controlled release fertiliser. The results showed that the homemade large granular fertiliser could promote the root development of peanuts, and the root volume increased by 45.10% compared with the uncoated fertiliser at the fruiting stage. At the same time, the soil NH4+-N and NO3--N content were reduced at the seedling stage and increased at the fruiting stage to achieve the fertiliser's slow and controlled release effect. A significant contribution to the net photosynthetic rate was made for growth development and yield in the middle and late stages. Pod dry weight was significantly higher at the blooming stage than uncoated fertiliser, 4.8% higher at the fruiting stage, and 22.9% higher in nitrogen use efficiency (NUE). In terms of microbial bacterial communities, the large granular slow-release fertiliser promoted the diversity of the treated bacterial communities to some extent, with little difference in the relative abundance of soil bacterial communities. These results showed that a one-time application of homemade large granular slow-release fertiliser positively affected peanuts in terms of yield increase, promotion of nitrogen uptake and improved nitrogen utilisation under nitrogen application with urea equivalent, but the overall effect on soil microbial community was small.