北方农牧交错带不同土地利用方式土壤呼吸速率探究

Research of Variations of Soil Respiration Rate among Different Land Use Types in the Agro-pastoral Ecotone of North China

农牧交错带地区土地利用方式多变,人为的改变土地利用方式会影响土壤释放CO2的速率.分别对新开垦农田、多年耕种农田、退耕还草草地、多年生草地4种利用类型的土壤温度、土壤有机碳含量、土壤呼吸速率进行监测和研究,结果表明:4种土地利用类型土壤呼吸速率的日变化图像呈单峰性曲线,其中草地平均呼吸速率最大,为0.85g·m-2·d-1.4种土地利用类型土壤温度与土壤呼吸速率呈正相关关系,其中新开垦农田变化明显,K值最高,达到0.045.从整个生长季来看,4种土地利用类型平均呼吸速率表现为新开农田>草地>还草草地>农田,分别为0.97g·m-2·d-1、0.85g·m-2·d-1、0.77g·m-2·d-1和0.56g·m-2·d-1.0-10cm和10-20cm土层土壤有机碳含量大小关系与土壤呼吸速率基本吻合.试验表明不论对草地进行开垦还是对农田进行退耕还草都会增加土壤CO2的释放.

The land use patterns was changeable in the agro-pastoral ecotone , and Artificial changes of land use pat-terns could affect the rate of CO2 released from the soil. the soil temporature, soil organic carbon content and soil respi-ration rate of four different soil type（new farmland, operated farmland of years, the grassland which has returned farm-land to grassland and the grassland growed for many years）were monitored and contrasted ,The result showed that diur-nal variation images of soil respiration rate of four different soil type was a single apex, and average respiration quantity of grassland reached the maximum for 0.85g·m-2·d-1.With the increase in soil temperature, soil respiration rate of four kinds of land-use types also immediately increase, Soil temperature and soil respiration rate was positively correlated for four different soil type, Among these,the newly opened farmland changed significantly, K value up to 0.045.From the point of view throughout the growing season, average soil respiration rate of different soil type were：farmland〉grassland〉also hastily〉farmland,andrespectively0.97g·m-2·d-1,0.85g·m-2·d-1,0.77g·m-2·d-1 and 0.56g·m-2·d-1. The change trends of soil organic carbon content in 0-10cm and 10-20cm soil layers was similar to soil respiration rate. which showed it could increase the soil CO2 release by returned farmland to grassland and the grassland growed for many years.