施氮对关中地区冬小麦农田土壤呼吸的影响及基于植被指数的估算模型

王锐; 蔡焕杰; 王晓云; 赵政鑫; 田雅洁; 彭青

Effects of nitrogen fertilizer application on soil respiration in winter wheat fields in Guanzhong region and estimation model based on vegetation index

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DOI：10.7606/j.issn.1000-7601.2023.06.11

Key Words: winter wheat soil respiration nitrogen fertilizer application amount estimation model vegetation index Guanzhong region

Author Name	Affiliation
WANG Rui	College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China Institute of Water\\|saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China
CAI Huanjie	College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China Institute of Water\\|saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China
WANG Xiaoyun	College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China Institute of Water\\|saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China
ZHAO Zhengxin	College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China Institute of Water\\|saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China
TIAN Yajie	College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China Institute of Water\\|saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China
PENG Qing	College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling, Shaanxi 712100, China Institute of Water\\|saving Agriculture in Arid Areas of China, Northwest A&F University, Yangling, Shaanxi 712100, China

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Abstract:

In order to explore the effects of different nitrogen application rates on farmland soil respiration (R_S) and quickly and accurately estimate R_S, this study took winter wheat in Guanzhong area as the research object, observed the changes of R_S under five nitrogen application rates, and examined the effects of environmental factors (soil temperature and soil moisture) and crop factors (leaf area index, above\|ground biomass, SPAD) on R_S. An estimation model of farmland soil respiration based on soil temperature and vegetation index was established in Guanzhong area. The experiment was set as five nitrogen application rates under straw returning. They were conventional nitrogen application SN200 (200 kg·hm^-2), optimal nitrogen application SN150 (150 kg·hm^-2), 60% optimal nitrogen application SN120 (120 kg·hm^-2), 50% optimal nitrogen application SN100 (100 kg·hm^-2) and no nitrogen application SN0 (0 kg·hm^-2). The results showed that R_S increased first and then decreased with the growth period under different nitrogen application rates, and the addition of nitrogen promoted R_S emission. The mean value of R_S in each treatment observation period was: SN200 (3.68 μmol·m^-2·s^-1) > SN150 (3.40 μmol·m^-2·s^-1) > SN120 (3.06 μmol·m^-2·s^-1) > SN100 (2.70 μmol·m^-2·s^-1) > SN0 (2.21 μmol·m^-2·s^-1). The near\|infrared reflectance of winter wheat canopy at jointing stage and heading stage was significantly different under different nitrogen application rates, and the reflectance from high to low was SN200>SN150>SN120>SN100>SN0, while the difference was not significant at filling stage and maturity stage. Soil temperature significantly affected R_S (P<0.01), but soil moisture had no significant correlation with R_S (P0.05). Leaf area index, aboveground biomass, SPAD and vegetation index were significantly correlated with R_S (P<0.05). Through multiple model evaluation, the optimal farmland soil respiration estimation model based on vegetation index and soil temperature was established, which was significantly higher than the single factor model based on soil temperature, and the accuracy of the model could reach more than 0.6 (n=120).