内蒙古羊草草原土壤净氮矿化研究

Soil Net Nitrogen Mineralization in an Aneulolepidium Chinensis Grassland, Inner Mongolia

采用树脂芯方法于2004年雨季期间对内蒙古锡林河流域羊草草原土壤的净氮矿化进行了研究,探讨了雨季期间田间培养时间长度对测定结果的影响,分析了实验方法对土壤氮转化过程的干扰。结果表明,研究期间羊草草原土壤净氮矿化量为4.44KgN.ha-1,平均净氮矿化率为0.12KgN.ha-1.d-1;土壤湿度是控制土壤净氮矿化率的重要环境因子之一,土壤净氮矿化率与水分变化呈正相关关系(R=0.67,P=0.22);雨季期间,培养时间的长度对净氮矿化测定影响较大,连续培养37天土壤净氮矿化量测定值明显偏高;树脂芯方法对实验土壤干扰较小,是田间条件下研究温带草原土壤净氮矿化的有效方法。

Nitrogen mineralization is one of the most important processes in the nitrogen cycling. The soil net nitrogen mineralization in an Aneulolepidium Chinensis grassland was studied using the resin-core technique from July 20 to August 26, 2004. Influences caused by different length of incubation intervals and the experimental disturbance to soil nitrogen transformation processes were also discussed in the paper. The Aneulolepidium Chinensis grassland locates in the Xilin River Basin of Inner Mongolia, China. The results showed that the accumulated amount of net nitrogen mineralization was 4.44 KgN.ha-1 during the study period; average daily rate was 0.12 KgN.ha-1.d-1. The length of incubation intervals brings significant impact on net N mineralization measurement. After 37 day continued incubation, the amount of net nitrogen mineralization was 14.07 KgN.ha-1; the measurement was influenced greatly by the root decomposition. The net N mineraliazation rate correlated with soil moisture (R=0.67, P=0.22). Resin-core incubation technique causes little disturbance to the grassland soil and is a good method to study the net N mineralization of the temperate grassland in field.