Utilization of carbon sources in the rice rhizosphere and nonrhizosphere soils with different long‐term fertilization management

Abstract

Carbon (C) plays an important role in the interaction between plant and rhizosphere microbial communities, but there is still limited information about how C source utilization soil microbial structure responds to soil fertility changes under the double‐cropping rice (Oryza sativa L.) system in Southern China paddy fields. Therefore, the effects of long‐term (33 years) fertilizer regimes on the characteristics of C utilization in both rhizosphere and nonrhizosphere soils under double‐cropping rice fields in Southern China were investigated by using the metagenome sequencing technology. The experiment began in 1986, and included five fertilizer treatments: without fertilizer input (CK), chemical fertilizer alone (MF), rice straw residue and chemical fertilizer (RF), 30% organic matter, and 70% chemical fertilizer (LOM), and 60% organic matter and 40% chemical fertilizer (HOM). The results showed that the relative abundance of Gemmatimonadetes and Planctomycetia in both the rhizosphere and nonrhizosphere soils was increased by application of rice straw residue and organic manure, whereas the relative abundance of Gammaproteobacteria and Nitrospira was promoted by application of inorganic fertilizers. The largest group of clusters of orthologous groups of proteins categories was “amino acid transport and metabolism” with 16.46% unigenes, followed by “general function prediction only” (12.23%). Regarding the gene ontology categories, biological process were the largest category (174 949, 46.40%), followed by cellular component (126 766, 33.62%), and molecular function (110 353, 29.26%). The principal coordinate analysis indicated that different parts of the root zone were the most important factors affecting the variation of C source utilization bacteria community, and the different fertilizer treatments were the second important factor affecting the variation of C source utilization bacteria community. As a result, the application of fertilization practices had significant effects on the abundance and community composition of C source utilization microbes in paddy soils. The results showed that the combined application of rice straw residue or organic manure with chemical fertilizer practices significantly increases the C source utilization of soil microorganisms in double‐cropping rice fields.

Microbial carbon source utilization in rice rhizosphere and nonrhizosphere soils with short-term manure N input rate in paddy field

“…At beginning of this experiment, the surface soil characteristics (0-20 cm) were as follows: pH 6.80, soil organic carbon (SOC) 22.75 g kg −1 , total N 2.24 g kg −1 , total phosphorous (P) 0.66 g kg −1 , total potassium (K) 14.45 g kg −1 , available N 178.90 mg kg −1 , available P 18.45 mg kg −1 , and available K 69.50 mg kg −1 . The climate condition (annual mean precipitation and evapotranspiration, monthly mean temperature) of this region, soil types and soil texture, and crop system were described by Tang et al 13 . and M100 treatments received the same total amount of N, phosphorus pentoxide (P 2 O 5 ), potassium oxide (K 2 O) (the total amount of N, P 2 O 5 , K 2 O were included chemical fertilizer and that from organic manure) during early rice and late rice growth period, respectively.…”

“…The rhizosphere and non-rhizosphere soils were collected and preprocessed according to the method described by Tang et al 13 . Briefly, rhizosphere soil was operationally defined as soil adhering to the total roots after gentle shaking.…”

“…Don et al 12 results indicated that organic C mineralization were decreased with decrease of C concentration. Tang et al 13 research found that C source utilization of soil microorganisms in paddy field were increased under combined application of organic manure or crop residue with inorganic fertilizer conditions. Fang et al 14 results showed that soil microbial biomass and C-use efficiencies were increased by applied with organic amendment and inorganic fertilizer.…”

“…The method for investigated soil microbial CUE in paddy ecosystem were accepted by more and more researchers 5 . Previous studies showed that soil microbial CUE were calculated by soil microbial incorporation and respiration of specific 13 C-labeled substrates 17 . However, this method found it was very different soil microbial CUE estimates for that this determination method confuses soil microbial CUE with the specific substrate 5 .…”

Variation in microbial biomass and community composition based on long-term fertilization regimes in paddy soil profiles

“…However, there is still limited information regarding the microbial-community change along the soil profiles of paddy soil supplied with equal amounts but different types of fertilizer based on long-term observation. It has been demonstrated that, unlike inorganic fertilizer, straw and manure addition increase the relative abundance ofGemmatimonadetes and Planctomycetia (Tang et al, 2019).…”