[Response of Soil Respiration to Extreme Precipitation in Semi-arid Regions].

Evaluating the response of soil microbial respiration to extreme precipitation event is significant for a better understanding about the influence of the change of precipitation regime on soil carbon cycling under global warming. A simulated experiment of extreme precipitations was conducted during the rainy season (July-September 2015) in the Changwu State Key Agro-Ecological Station, Shaanxi, China. The treatments consisted of three total precipitations in rainy season (600 mm, 300 mm, and 150 mm) and two precipitation regimes (10 mm, 150 mm; P10, P150). Soil microbial respiration varied differently in the same single rainfall event among three precipitations. The variation coefficient of soil microbial respiration under 600 mm total precipitation was 36% (P150) and 33% (P10), and 28% and 22% under 300 mm total precipitation, 43% and 29% under 150 mm total precipitation. Under 600 mm total precipitation, the cumulative soil microbial respiration under P150 was 20% less than that under P10; however, the cumulative soil respiration of P150 under 150 mm total precipitation was 22% more than that under P10; and there was no significant difference between P10 and P150 under 300 mm total precipitation. Therefore, the duration in soil water stress must be considered to estimate soil microbial respirations under extreme precipitations.