云南元阳哈尼梯田土壤养分垂直变异特征研究

 元阳哈尼梯田有着上千年农耕历史，本文对元阳梯田不同海拔、不同土层土壤进行实地采样调查，并分析测定了有机质和碱解氮，结果表明：（1）元阳梯田表层土壤有机质含量总体达到二级水平，含量比同区域平坝区的水稻土还高；而梯田中的碱解氮含量较低，含量低于同区域平坝区的水稻土；（2）元阳梯田相同土层中有机质含量随着海拔的降低而减少，但在谷底低海拔区含量突增；同一海拔段土壤有机质随着土层深度增加而呈下降趋势，但谷底低海拔区上层土壤中有机质含量相对均匀；（3）元阳梯田相同土层中碱解氮含量随着海拔的降低而减少，但在离村庄最近的中高海拔位置，碱解氮含量最高；同一海拔段土壤碱解氮含量随着土层深度增加而增加，但在离村庄最近的中高海拔位置却随深度增加先减后增。

Soil Nutrient Vertical Variance of Hani Terraced Field in Yuanyang County of Yunnan Province

Under the unique natural environment of mountainous region in subtropical zone, the agricultural ecosystem of terraced field that came of the coordinating development of ethnic cultural and natural environment, not only develops the agricultural production, but also protects the environment, and it is the typical case of harmonious development of human with natural environment. With altitude varying sharply and ecological environment being unique, the Yuanyang terraced field shows own unique soil nutrient variation feature under the influence of traditional farming civilization for more than 1000 years. With the sampled soils from Yuanyang terraced field which is the typical case of subtropical terraced field landscape after fieldwork, we analysed the alkali-hydrolyzed N and organic matters of soil in different altitude and different soil layers. It is showed that:(1) the soil organic matters content in the first soil layer of terraced field more than that of the soil of plain area in the mountainous region, up to “second” level in average; but the soil alkali-hydrolyzed N content in the first soil layer of terraced field is low and lower than that of the soil of plain area in the mountainous region; (2) the soil organic matters content of the same soil layer in different altitude of terraced field decreases along with the reduction of altitude, but the content increases suddenly in grain base of low altitude district; the soil organic matters content in different layers in the same altitude section submit to drop tendency along with the increase of depth, but the organic matters content is relatively even in grain base of low altitude district; (3) the soil alkali-hydrolyzed N content of the same soil layer in different altitude of terraced field decreases along with the reduction of altitude, but the alkali-hydrolyzed N content is highest near the village location in mid-high altitude; the soil alkali-hydrolyzed N content in different layers in the same altitude section increases along with the increase of depth, but the alkali-hydrolyzed N content increases after reducing firstly near the village location in mid-high altitude.