Objectives This study explored the effects of organic materials on nutrient accumulation in maize, and provide nutrient management techniques for maintaining soil microbial ecosystems and sustainable agricultural development.

Methods A positioning field experiment was carried out in Heilongjiang for two consecutive years. The experiment included one chemical fertilizer control ( CK ) and three chemical fertilizer combined with organic material treatments ( decomposed straw, humic acid, chicken manure ). During the maize harvest period, the study investigated the accumulation of nutrients in the upper part of the maize field, the activity of soil enzymes, and the microbial diversity of soil bacteria and fungi.

Results Compared with CK, all the three combined organic material application increased the yield and accumulation of nitrogen and phosphor and potassium in maize plant. The chicken manure treatment resulted significantly different bacteria and fungal community structures, relative to the other treatments. In all the treatment soils, the number of differential microbial species specific to bacteria was higher than that to fungi. The four bacterial phyla with a relative abundance greater than 5% are Proteobacteria, Acidobacteriota, Gemmatimonadota and Actinobacteriota. Three bacterial families are Sphingomonadaceae, Gemmatimonadaceae and Vicinamibacteraceae, and one bacterial genus is Sphingomonas. The three fungal phyla with a relative abundance of more than 5% are Ascomycota, Basidiomycota and Mortierellomycota, and one fungal family is Chaetomiaceae. One genus of fungi is Podospora. All the organic material treatments, except for humic acid on sucrase and straw on catalase, did not significantly change the activities of soil enzymes. The relative abundance of Basidiomycota was negatively correlated with maize N and K accumulation, and the relative abundance of Mortierellomycota was positively correlated with maize K accumulation.

Conclusions At the base pf conventional chemical fertilizer, combined application of organic materials further inproved the nitrogen and phosphor and potassium accumulation and yield of maize. Chicken application resulted significantly different bacteria and fungal structures. Chicken and maize straw application increased the differential bacteria number, but decreased the differential fungal number, and humic acid did bit have impaction on them. Enzyme activities showed close relative relationship with soil microbial composition, especially Sphingomonas in bateria phylum and Podospora in fungal phylum. Maize nitrogen and phosphorous uptake are correlated with soil sucrase activity.