农牧交错带土地利用方式对土壤有机碳矿化的影响

Effects of land utilization types on soil organic carbon mineralization in agro-pastoral transitional zone

本研究以农牧交错带3种土地利用方式[苜蓿(Medicago sativa)栽培草地、莜麦(Avena nuda)-苜蓿轮作地、玉米(Zea mays)作物耕地]土壤为研究对象,通过测定土壤中有机碳的矿化量和矿化速率,以探索农牧交错带不同土地利用方式对土壤有机碳的积累和矿化的影响。结果表明,1)苜蓿栽培草地的土壤有机碳含量最高,莜麦-苜蓿轮作地最低;2)相同培养条件下,3种土地利用方式的土壤有机碳矿化量随着时间增加而减小;3)土壤有机碳月矿化量与有机碳含量呈极显著正相关(P<0.01)。土壤有机碳矿化随土壤全氮增加而增加,但是相关性不显著。

In order to study the impact of land utilization types on accumulation and mineralization of soil organic carbon mineralization in agro-pastoral transitional zone, the mineralization content of soil organic carbon and mineralization rate of three land utilization types soil （Alfalfa pasture, Naked oats-alfalfa rotation, Crop farmland） in agro-pastoral transitional zone have been investigated. The results showed that alfalfa field contained the highest organic carbon and naked oats-alfalfa rotation was the lowest. In the same humidity and temperature condition, the amount of soil organic carbon mineralization of three land utilization types were all decreased with the increment of time. Soil organic carbon mineralization showed a significant positive correlation with month mineralization content （P〈0.01）. Soil organic carbon minerali- zation increased with soil nitrogen and the correlation was not significant.