Abstract:

To investigate the effects of different new-type fertilizers on soil nutrients, soil microbial community, and crop yield in the typical ancient course area of Yellow River, a field location experiment was conducted in this study. Four treatments were set up, including CK (conventional fertilization), NM (additional application of nitrogen fertilizer at 187.5 kg·hm^-2 and microbial agent at 30 kg·hm^-2), F (application of bio-organic fertilizer at 6 000 kg·hm^-2), and FE (application of bio-organic fertilizer at 6 000 kg·hm^-2+soil enzyme preparation at 15 kg·hm^-2). After crop harvest, indicators such as soil physicochemical properties, soil enzyme activities, and crop yield were determined, and 16S rRNA high-throughput sequencing technology was used to analyze the composition of the soil bacterial community. The results showed that, compared with CK: the contents of soil organic matter and available phosphorus under the F and FE treatments increased significantly (p<0.05) by 16.90%-22.17% and 78.39%-207.70%, respectively; in contrast, the contents of soil organic matter and available phosphorus under the NM treatment decreased significantly by 22.64% and 24.91%, respectively. The soil pH values under the NM, F, and FE treatments all decreased significantly by 1.55%-2.46%. The activities of soil β-glucosidase and β-D-cellobiohydrolase under the NM treatment increased significantly by 56.42% and 139.26%, respectively; however, the activities of α-glucosidase, β-glucosidase, and acid phosphatase under the F and FE treatments decreased significantly by 73.50%-78.42%, 33.15%-36.72%, and 23.72%-28.64%, respectively. In terms of soil bacterial community richness, the NM treatment showed a significant decrease compared with CK, while the F treatment showed a significant increase compared with CK. At the phylum level, compared with CK: under the F treatment, the relative abundance of Proteobacteria decreased from 33.3% to 27.8%, the relative abundance of Chloroflexi increased from 19.3% to 22.3%, and the relative abundance of Bacteroidetes increased from 7.3% to 9.2%; under the FE treatment, the relative abundance of Bacteroidetes increased from 7.3% to 8.4%. Compared with CK, all treatments could increase the yield of rice and wheat. Among them, the FE treatment had the largest yield increase and showed obvious advantages in improving yield components such as 1 000-grain weight.

Key words: bio-organic fertilizer, microbial agent, enzyme preparation, crop yield, soil nutrients, soil microbial community