玉米秸秆还田量对黑土区农田地面节肢动物群落的影响

为考察玉米秸秆还田量对黑土区农田地面节肢动物群落的影响,2016年6—9月在内蒙古兴安盟扎赉特旗研究了0(CK)、9000(SR1)、10500(SR2)、12000(SR3)、13500(SR4) kg/hm25个梯度对农田地面节肢动物群落影响。结果表明:共捕获地面节肢动物1820只,隶属于16个类群; SR4处理显著提高了地面节肢动物个体数(P0.05),SR3处理显著提高了地面节肢动物类群数(P0.05)。各处理样地地面节肢动物个体数最高值均出现在8月,类群数则出现在7月; SR4处理显著提高了地面节肢动物多样性指数和丰富度指数(P0.05),SR1处理显著提高了地面节肢动物优势度指数(P0.05),对照CK的均匀度指数最高(P0.05)。相关分析表明:农田地面节肢动物的个体数与土壤有机质呈极显著相关(P0.01),与平均入渗率呈显著正相关(P0.05),与土壤容重呈显著负相关(P0.05);类群数与土壤温度呈显著正相关(P0.05);丰富度指数与平均入渗率和土壤含水量呈显著正相关(P0.05)。主成分分析表明:地面节肢动物的个体数、多样性指数、蟋蟀总科、跳甲科和步甲科5个特征指标对玉米秸秆还田最为敏感,初步认为是衡量黑土区土壤玉米秸秆还田后肥力状况的评价指标。

Impact of quantity of returned corn straw on the cropland ground arthropod community in a black soil area

In order to understand the effects of returned corn straw on the cropland ground arthropod community in a black soil area, an experiment with five different amounts of corn straw returned to the field 0 (CK), 9000 (SR1), 10500 (SR2), 12000 (SR3) and 13500 (SR4) kg/hm² was carried out in Zhalaid Banner of Inner Mongolia from June to September 2016. The results showed that 1820 ground arthropod individuals were captured and these were classified into 16 taxonomic groups. The number of individuals of ground arthropods was significantly increased in SR4 (P < 0.05), and the number of taxonomic groups was significantly increased in SR3 (P > 0.05). The number of individuals of ground arthropods was highest in August, and the number of taxonomic groups of ground arthropods was highest in July. The diversity and richness indexes were highest in SR4 (P < 0.05). The dominance index was highest in SR1 (P < 0.05). The evenness index was highest in CK (P < 0.05). Correlation analysis showed that ground arthropod individuals were not only positively correlated with soil organic matter (P < 0.01), but also with average infiltration rate (P < 0.05), and negatively correlated with soil bulk density (P < 0.05). Soil temperature was obviously correlated with the number of ground arthropod taxonomic groups (P < 0.05). The richness index was obviously correlated with average infiltration rate and soil moisture content (P < 0.05). Principal component analysis (PCA) showed that ground arthropod individuals, the diversity index, and the taxa Grylloidea, Alticinae and Carabidae were most sensitive to the amount of straw returned, and could therefore be considered as evaluation indexes to judge the nutrient status after straw is returned in a black soil area in the future.