北热带亚高山土壤肥力垂直分异特征——以红河蝴蝶谷为例

Spatial Variation Characteristics of Soil Fertility in Northern Tropical Subalpine——A Case Study of Honghe Butterfly Valley

对北热带亚高山地区红河蝴蝶谷不同海拔(105~3012 m)单项肥力空间变异及综合肥力分布特征进行研究,通过区分表层(0~20 cm)和亚表层(20~40 cm),按同层五点混合法采集58个垂直土壤样本,测定土壤肥力指标含量,采用变异系数及修正内梅罗指数法计算单项肥力及土壤综合肥力。研究结果表明,研究区各层土壤单项肥力指标的变异系数在0.11~0.86范围,均属于中等变异,其中,亚表层的pH变异系数接近弱变异,有机质和全氮的变异系数接近强变异,有机质、速效钾、全氮在不同土层变异差异显著;蝴蝶谷土壤综合肥力一般(P为0.9~1.8),需密切关注,防止肥力下降导致森林生态效益降低;表层和亚表层土壤的综合肥力随着海拔的升高均呈上升趋势,在海拔2100 m以上区域,表层土壤综合肥力系数明显高于亚表层。以期为北热带山地土壤肥力及生态环境管护、保育、农业生产等提供参考价值。

The spatial variation of individual fertility and the distribution characteristics of comprehensive fertility at different altitudes(105-3012 m)in Honghe Butterfly Valley in the northern tropical subalpine areas were studied.By distinguishing the surface layer(0-20 cm)and subsurface layer(20-40 cm),58 vertical soil samples were collected according to the five-point mixing method in the same layer to determine the soil fertility index content,and the variation coefficient and the modified Nemero index method were used to calculate the individual fertility and comprehensive soil fertility.The results showed that the variation coefficient of individual soil fertility indicators in each layer was between 0.11 and 0.86,belonging to medium variation,and the variation coefficient of pH value in subsurface layer was close to weak variation,and the variation coefficient of organic matter and total nitrogen was close to strong variation,and the variation of organic matter,available potassium and total nitrogen was vary significantly in different soil layers;the comprehensive soil fertility of Honghe Butterfly Valley was average(P was 0.9-1.8),which should be paid close attention to prevent the decline of fertility from reducing the ecological benefits of the forest;the comprehensive fertility of surface and subsurface soils both showed an upward trend with the increase in altitude,the comprehensive fertility coefficient of surface soil was significantly higher than that of subsurface soil in the area above 2100 m.The results provides reference value for soil fertility,ecological environment management,conservation and agricultural production in northern tropical subalpine.