Effects of Reclaimed Water Irrigation on Microbial Diversity and Composition of Soil with Reducing Nitrogen Fertilization

Abstract

Reclaimed water (RW) is an alternative water resource that has been utilized all over the world, but its environmental effects are not fully understood. Soil biodiversity is an important indicator of soil tolerance and resilience. In the present study, the impact of RW irrigation on the microbial community diversity and chemical properties of topsoil was investigated by monitoring nitrogen (N) rates. Tomato plants were grown on plots which had been irrigated with reclaimed water for 5 years with varying levels of N fertilization (N270, 270 kg ha −1 ; N216, 216 kg ha −1 ; N189, 189 kg ha −1 ; and N135, 135 kg ha −1 ). Soil bacterial community composition was analyzed by PCR amplification of the 16S rDNA gene and Illumina MiSeq high-throughput sequencing technology of a total of 770,066 quality sequences. The results showed that long-term RW irrigation altered the bacterial composition of soil in an N-dependent manner. RW irrigation increased the abundances of Gemmatimonadetes, Actinobacteria, Firmicutes, and Nitrospirae in soils. The Chao, ACE, and H indices revealed no significant difference under RW irrigation with varying levels of N fertilization. The tomato yield and partial factor productivity from applied N for RN216 increased significantly under RW irrigation with reducing N fertilization. RW irrigation increased the yield of tomato and the abundance of functional microorganisms, which eventually improved the practice of irrigating with reclaimed municipal wastewater. Meanwhile, the potential environmental and health risks of long-term RW irrigation warrant further investigation.

Response of soil characteristics and bacterial communities to nitrogen fertilization gradients in a coastal salt‐affected agroecosystem

“…For the alkaline soil, Zhou et al (2016) revealed that the change in straw chemical properties had impact on the bacterial communities associated with the decomposition of straw in agro-ecosystems. Interactions between soil fertilization and saline water irrigation or precipitation were also observed in soil bacterial communities and affected microbial metabolic activity, and the findings were similar to those of other studies where long-term saline water irrigation altered the bacterial composition of soil in an N-dependent manner (Guo et al, 2018), and alleviated the adverse effects of irrigation salinity on microbial metabolic activity (Chen et al, 2017). However, the non-synergistic effects of N fertilization and precipitation regimes on the microbial functional groups were reported by Sun et al (2018), and they also showed the negative effect of lower pH induced by N enrichment would be alleviated by precipitation regimes.…”

“…Actually, most previous studies revealed that field management practices, including irrigation, land use and straw returning, had greater impacts on the overall microbial community than fertilizer application. Evidences fromGuo et al (2018) andSun et al (2018) showed that no significant difference in bacterial composition occurred under slightly saline water irrigation with varying levels of N fertilization. The possible explanation was that bacterial community composition was more sensitive to soil moisture, salinity and C inputs than N fertilization rates, and N inputs prevailed in areas where soil moisture, salinity, organic carbon were not constraining factors and largely homogenous.…”

Interactive impacts of boron and organic amendments in plant-soil microbial relationships

“…Cyanobacterium is capable of atmospheric nitrogen fixation, which can lead to the production of ammonia; this probably contributed to the higher soluble N content in organically managed soils (OS) irrigated with the high B dose, relative to the rest of the soils. Further, Arenimonas, more abundant in soils treated with the higher B doses, contains members that are plant pathogens (Guo et al, 2018) and could take advantage of plants weakened by exposure to high B doses. In the case of the fungal community, the relative abundances of Fusarium and Alternaria were increased at the highest B dose.…”

Effects of Continuous Nitrogen Fertilizer Application on the Diversity and Composition of Rhizosphere Soil Bacteria

“…Previous studies have indicated that fertilization changes the diversity, community structure, and activity of soil microorganisms (Wei et al, 2018;Chen et al, 2019). The long-term application of chemical fertilizers can significantly alter the structure and diversity of bacterial communities (Ge et al, 2008), and numerous recent studies have used sequencing technology to examine the effects of fertilization on the diversity and structural composition of soil microbial communities (Mchugh and Schwartz, 2015;Sun et al, 2015).…”