Irrigation and Nitrogen Fertilization Alter Soil Bacterial Communities, Soil Enzyme Activities, and Nutrient Availability in Maize Crop

Abstract

Irrigation and nitrogen (N) fertilization rates are widely used to increase crop growth and yield and promote the sustainable production of the maize crop. However, our understanding of irrigation and N fertilization in the soil microenvironment is still evolving, and further research on soil bacterial communities under maize crop with irrigation and N management in subtropical regions of China is needed. Therefore, we evaluated the responses of two irrigation levels (low and high irrigation water with 60 and 80% field capacity, respectively) and five N fertilization rates [i.e., control (N0), N200 (200 kg N ha−1), N250 (250 kg N ha−1), N300 (300 kg N ha−1), and N350 (350 kg N ha−1)] on soil bacterial communities, richness, and diversity. We found that both irrigation and N fertilization significantly affected bacterial richness, diversity index, and number of sequences. Low irrigation with N300 treatment has significantly higher soil enzymes activities, soil nutrient content, and bacterial alpha and beta diversity than high irrigation. In addition, the Proteobacteria, Actinobacteriota, Chloroflexi, and Firmicutes were the dominant bacterial phyla under both irrigation regimes. The acidic phosphates, acidic invertase, β-glucosidase, catalase, cellulase, and urease were positively correlated with the Shannon index under both low and high irrigation. Therefore, low irrigation improves soil nutrient utilization by boosting soil enzyme activity, directly affecting soil bacterial communities. It was concluded that greater soil nutrients, enzyme activities with higher bacterial diversity are the main indicators of soil reactivity to low irrigation water and N300 for maintaining soil fertility and soil microbial community balance.

Effects of Biochar Amendment and Nitrogen Fertilizer on RVA Profile and Rice Grain Quality Attributes

“…Another possible explanation is that BC in combination with N application improves N uptake in rice [ 14 ]. Improving N uptake in plants consequently increases photosynthetic attributes and N metabolism enzymes in rice [ 14 , 21 , 33 ], thus improving grain yield. The variation among these two years might be due to BC being a slow-released fertilizer [ 34 ], which can contribute to soil up to several years because BC had long-term effects on soil [ 35 ].…”

Differential Response of Wheat Rhizosphere Bacterial Community to Plant Variety and Fertilization

“…Interestingly, ASVs affiliated to the uncultured phylum RCP2-54 were found more abundantly in Sieve and mainly in Verna, compared to Bologna and Andriolo. The functional role of this phylum is still unknown; however, previous works showed its presence in the rhizosphere and in differentiating tomato and maize varieties under water deficit conditions [ 42 ], again suggesting a possible genetic basis in the plant for its differential recruitment. At the level of ASVs it was relevant to find members of Blastocatellales and Pyrinomonadales.…”

Straw Return and Nitrogen Fertilization to Maize Regulate Soil Properties, Microbial Community, and Enzyme Activities Under a Dual Cropping System

“…Soil enzymatic activities are generated and released by soil microbes, which are responsible for organic matter degradation ( Burns et al, 2013 ). The activity of soil enzymes can provide insight into the processes of microbial sensitivity to added C and N ( Zhao et al, 2016 ; Muhammad et al, 2022 ). The addition of C and N to soil and field management approaches may affect different enzymes in different ways ( Gong et al, 2021 ; Huang et al, 2021 ).…”