N Addition Overwhelmed the Effects of P Addition on the Soil C, N, and P Cycling Genes in Alpine Meadow of the Qinghai-Tibetan Plateau

Abstract

Although human activities have greatly increased nitrogen (N) and phosphorus (P) inputs to the alpine grassland ecosystems, how soil microbial functional genes involved in nutrient cycling respond to N and P input remains unknown. Based on a fertilization experiment established in an alpine meadow of the Qinghai-Tibetan Plateau, we investigated the response of the abundance of soil carbon (C), N, and P cycling genes to N and P addition and evaluated soil and plant factors related to the observed effects. Our results indicated that the abundance of C, N, and P cycling genes were hardly affected by N addition, while P addition significantly increased most of them, suggesting that the availability of P plays a more important role for soil microorganisms than N in this alpine meadow ecosystem. Meanwhile, when N and P were added together, the abundance of C, N, and P cycling genes did not change significantly, indicating that the promoting effects of P addition on microbial functional genes abundances were overwhelmed by N addition. The Mantel analysis and the variation partitioning analysis revealed the major role of shoot P concentration in regulating the abundance of C, N, and P cycling genes. These results suggest that soil P availability and plant traits are key in governing C, N, and P cycling genes at the functional gene level in the alpine grassland ecosystem.

Effects of biochar and arbuscular mycorrhizal fungi on winter wheat growth and soil N2O emissions in different phosphorus environments

“…In addition, compared to low P supply, the abundance of nirK and nirS genes associated with N 2 O production decreased by 17% to 59%, but the nosZ genes associated with N 2 O consumption (N 2 O→N 2 ) in denitrification were increased by 34% to 1340% at the high P supply, which result in the nosZ/(nirK+nirS) ratio at the high P supply was 2.72 to 7.56 times greater than that at the low P supply ( Figure 4 and Table 2 ), suggesting a strong influence of P addition on N cycling genes involved in denitrification ( Xiao et al., 2022b ). In the present study, among the top five factors affecting the N 2 O emission, nosZ/(nirK+nirS) , nirS , leaf Mn concentration and stem P content were closely related to soil Olsen P across all the treatments ( Figure 5B ).…”

“…Different P conditions can influence soil N pools and cycling processes via regulating plant growth and microbial activity ( Xiao et al., 2022a ; Xiao et al., 2022b ). In P-limited environments, P addition enhanced soil N immobilization and retained more N in the plant-soil system by promoting plant and microbial growth, thus suppressing N 2 O emission ( Shen and Zhu, 2022 ; Wang et al., 2022 ).…”

The Impact of Nitrogen Application on Leaf and Root Functional Traits of Davidia involucrata Saplings

“…The increased leaf C content may be attributed to stimulated leaf photosynthetic rates [49], as indicated by the significant increases in LL, LW (Figure 1a,b), and accumulated leaf biomass (Figure 3a) under N application. In addition, N application may increase soil P availability, promoting leaf P absorption and further increasing leaf P content [50]. N application may also increase root phosphatase activity, thereby increasing the absorption and utilization of soil available P [51,52], leading to an increase in leaf P content.…”

The response of nutrient cycle, microbial community abundance and metabolic function to nitrogen fertilizer in rhizosphere soil of Phellodendron chinense Schneid seedlings

“…In addition, N addition significantly increases the abundances of soil nirK , nirS, narG and ppx genes, while distinctly decreases the soil nifH abundance in Metasequoia glyptostroboides plantations ( Wang et al, 2022 ). However, N addition does not significantly affect the abundances of soil N and P cycling genes in the Alpine Meadow ( Xiao et al, 2022 ). Therefore, N input plays a crucial role in regulating soil physicochemical properties, enzyme activities and gene expressions, with outcomes depending on factors such as plant types, N concentration and agrotype ( Tu et al, 2014 ; Peng et al, 2017 ; Xu et al, 2022 ).…”