Effects of nitrogen and phosphorus addition on litter
decomposition and soil enzyme activities with Salix cupularis in
an alpine desert ecosystem
Gang Chen 1, Nai-rui Yang 1, Yu-fu
Hu *, Hong-yu Qian, Fan Yang, Wei Wang, Jian-kai Lu
College of Resources, Sichuan Agricultural University, Chengdu 611130,
China
* Corresponding author: Yu-fu Hu
E-mail address: huyufu@sicau.edu.cn (Y. Hu).
Abstract: Nitrogen (N) and phosphorus (P) are important factors
controlling biogeochemical cycling in terrestrial ecosystems and
significantly affect the decomposition process of litter. However, N and
P addition effects on litter decomposition, especially biological
pathways in alpine grassland in northwest Sichuan, remain unclear.
Therefore, this study explored the response mechanism of Salix
cupularis litter decomposition and soil
enzyme activity to different
exogenous nitrogen and phosphorus additions and the inner relationship,
combined with field in situ experiments and laboratory analysis methods.
The results showed that: (1) In general, N, P and NP treatments
significantly promoted the decomposition of litter, lignin and
cellulose, and the addition of NP had a stronger effect in the same
concentration level. P addition could alleviate the inhibitory effect of
litter decomposition by high N concentration. (2) Litter C, N and P
basically showed a sustained release pattern, and NP treatment had the
strongest promoting effect. (3) Each treatment significantly increased
the activities of soil invertase, cellulase, polyphenol oxidase, urease
and phosphatase, and the NP treatment had the best effect. The rate of
litter decomposition was significantly influenced by nutrient content as
well as soil enzyme activity, where cellulose content and invertase
activity may be a key factor controlling the rate of litter
decomposition.
Keywords: Salix cupularis; litter quality; decomposition rate;
nitrogen and phosphorus additions; soil enzyme activities; alpine desert
ecosystem