Temperature sensitivity of soil respiration: Synthetic effects of nitrogen and phosphorus fertilization on Chinese Loess Plateau.
Nitrogen (N) and phosphorus (P) fertilization has the potential to alter soil respiration temperature sensitivity (Q10) by changing soil biochemical and crop physiological process. A four-year field experiment was conducted to determine how Q10responded to these biochemical and physiological changes in rain-fed agro-ecosystems on the semi-arid Loess Plateau. Soil respiration, as well as biotic and abiotic factors were measured in winter wheat (Triticum aestivum L.), with three fertilization treatments: (no fertilization (CK), 160kgNhm-1(N), and 160kgNha-1with 39kgPha-1(N+P). Mean annual soil respiration rate (calculated by averaging the four years) in the N treatment and N+P treatment was 18% and 48% higher than that in the CK treatment, respectively; and it was increased by 26% (14%-48%) in the N+P treatment as compared with that in the N treatment. The decrease of Q10in the N and N+P treatments against the CK treatment was not stable for each year, ranging from 0.01 to 0.28. The maximum decrease of Q10in the N and N+P treatments was 10% and 15% in 2014-2015, while in other years the decrease of Q10was numerical but not significant. Soil microbial biomass carbon (SMBC) was increased by 10% and 50%, dissolved organic carbon (DOC) was increased by 6% and 21%, and photosynthesis rate was increased ranging from 6% to 33% with N and N+P fertilization. The relative abundance of Acidobacteria, Actinobacteria and Chloroflexi were significantly higher by 32.9%-54.1% in N addition soils (N and N+P) compared to CK treatment, whereas additional P application into soils increased the relative abundance of the family Micrococcaceae, Nocardioidaceae and Chitinophagaceae. Soil respiration was positively related to SMBC, DOC and photosynthesis rate (p<0.05). However, variation in Q10may be related to the increase of soil mineral N content and variation of the relative abundance of soil microbial community in our study. Nitrogen and additional phosphorus fertilization regimes affect soil respiration and temperature sensitivity differently.
College of Resources and Environment, Northwest A&F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China.
Rui
R
Wang
Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China.
Qiqi
Q
Sun
College of Resources and Environment, Northwest A&F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China.
Ying
Y
Wang
College of Resources and Environment, Northwest A&F University, Yangling 712100, China.
Qingfang
Q
Liu
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China.
Lanlan
L
Du
College of Resources and Environment, Northwest A&F University, Yangling 712100, China.
Man
M
Zhao
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China.
Xin
X
Gao
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China.
Yaxian
Y
Hu
College of Resources and Environment, Northwest A&F University, Yangling 712100, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A&F University, Yangling, Shaanxi 712100, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China. Electronic address: slguo@ms.iswc.ac.cn.
Shengli
S
Guo
DOC; Photosynthesis rate; Q(10); SMBC; Soil microbial community; Soil mineral N