不同耕作措施下稻茬直播冬油菜田土壤呼吸研究

Study on soil respiration of direct-sowing winter oilseed rape in paddy field under different tillage conditions

为探讨四川盆地稻茬田冬油菜生长季的土壤呼吸特征,采用LI-8100A土壤碳通量自动测量系统,于2012-11—2013-04对成都平原稻-油轮作系统不同耕作措施下直播冬油菜田的土壤呼吸进行测定。结果表明,观测期内直播冬油菜田土壤呼吸表现为旋耕处理(1.97μmol·m^(-2)·s^(-1))高于免耕处理(1.86μmol·m^(-2)·s^(-1)),但差异不显著(P>0.05)。直播冬油菜田土壤呼吸表现出先下降后升高的趋势,土壤呼吸速率最低值出现在1月份。旋耕与免耕条件下,直播冬油菜田土壤呼吸的温度敏感系数(Q10)分别为2.07和2.16。直播冬油菜田土壤呼吸与地上生物量呈显著(P<0.05)正相关,与土壤有机碳含量呈显著(P<0.05)负相关。耕层土壤温度是影响冬油菜田土壤呼吸的主要因素。

In order to explain the characteristic of soil respiration（ RS） during the growth season of direct-sowing winter rapeseed in the paddy field,a field experiment was carried out to examine the variations of soil respirations and soil temperature（ ST） and soil water content（ SWC） at the 5 cm depth of winter oilseed rape under rice-rapeseed rotation system in Chengdu Plain of Sichuan Province from November 2012 to April 2013. It was shown that there was no significant difference of RS between rotary tillage（ RT） treatment（ 1. 97 μmol·m^（-2）·s^（-1）） and zero tillage（ ZT） treatment（ 1. 86 μmol·m^（-2）·s^（-1）） during growth season of winter oilseed rape. The monthly variation trend of RS was first decreased and then increased and the minimum value appeared in January 2013. Temperature sensitivity（ Q10） of RS was 2. 07 and 2. 16 under RT and ZT,respectively. In addition,there was a significant（ P 〈0. 05） positive correlation between RS and above-ground biomass,yet a significant（ P 〈0. 05） negative correlation between RS and soil organic carbon. Soil temperature of topsoil was the main influencing factor of soil respiration in direct-sowing winter rapeseed.