湄潭县抄乐乡农田土壤氮分布研究

Soil nitrogen distribution in farmland in Chaole Township of Meitan county

针对喀斯特区域农田生态系统村级氮含量以及影响因子研究比较缺乏的问题,文中以黔北喀斯特湄潭县抄乐乡为例,通过硒粉—硫酸铜—硫酸消化法测定总氮、扩散吸收法测定碱解氮及酸度计测定土壤pH的方法,研究其农田土壤总氮及碱解氮含量的变化。结果表明:(1)抄乐乡土壤总氮的平均含量为2.10 g/kg,变异系数为17.50%;土壤碱解氮的平均含量为208.16 mg/kg,变异系数16.60%。(2)不同土壤类型显著影响土壤总氮,水稻土的总氮含量最高为2.20 g/kg,其次是石灰土和紫色土比较接近在2.07~2.10 g/kg波动,黄壤最小为2.01 g/kg。(3)影响土壤总氮的因子有土壤有机质、pH、年降水量、有效积温和海拔高度;土壤碱解氮受pH、年降水量、有效积温、海拔高度、坡度和总氮的影响。说明抄乐乡农田土壤可以通过增加土壤有机质等相关措施增加农田氮肥力。

Soil nitrogen plays an important role for plants,especially the type of alkali hydrolyzable nitrogen. The amount of soil nitrogen affects the growth of crops and the emission of nitrogen oxide from farmland. There are lack of research on the content of nitrogen and its influence factors in the farmland ecosystem of Karst area. The contents of soil nitrogen and alkali nitrogen in farmland were studied in this study. The results showed that the average concentration of total nitrogen in soil was 2. 10 g/kg and the coefficient of variation was 17. 50%. The average concentration of soil alkali nitrogen was 208. 16 mg/kg and the coefficient of variation was 16. 60%. Different soil type significantly affected soil total nitrogen,and the total nitrogen content of paddy soil was the highest of 2. 20 g/kg,followed by lime soil and purple soil and with the fluctuation of 2. 07 ~ 2. 10 g/kg. Theminimum was 2. 01 g/kg in yellow loam. Soil total nitrogen is mainly affected by soil organic matter,p H,annual precipitation,effective accumulated temperature and altitude,and drought resistance ability. Soil alkali solution is mainly affected by p H value,annual precipitation,effective accumulated temperature and elevation,slope and total nitrogen content. This means that the country can increase the nitrogen fertilizer of farmland by increasing the soil organic matter and other related measures.