云南元阳梯形稻田土壤碳氮空间分布及其影响因素

 采用地统计、方差分析方法，研究了云南元阳土壤有机碳（SOC）、全氮（TN）的空间分布及其影响因素。该区域内水田土壤表层（0~20 cm)有机碳、全氮含量分别为21.38 g/kg和1.65 g/kg，变异系数分别为36.90%和32.95%，属于中等程度变异。土壤有机碳、全氮的半方差模型均为球型，具有中等程度的空间自相关性（块金/基台值分别为0.67和0.71）。土壤有机碳、全氮含量均随海拔上升而增加。土壤有机碳和全氮含量均随着肥料投入水平上升而降低，过量施肥使土壤有机碳、全氮含量略有增加，但会影响肥料利用效率。因此，应根据土壤养分空间分布格局加强农业生产管理措施调控，以提高土地生产力。

Spatial Distributions of Soil Organic Carbon and Total Nitrogen Concentrations,and Their Influencing Factors in Terraced Paddy Fields of Yuanyang County,China

Spatial distributions of soil organic carbon(SOC) and total nitrogen(TN) concentrations,and their influencing factors in terraced paddy fields of Yuanyang County were analyzed by geostatistics and variance analysis.The SOC and TN concentrations in the surface layer(0-20 cm) were 21.38 g/kg and 1.65 g/kg,and moderately variation(36.90% and 32.95%),respectively,and demonstrated moderate spatial dependence according to the nugget ratios(0.67 and 0.71).The semi-variogram of SOC and TN were best-fitted by spherical models.SOC and TN concentrations increased with rising elevations,while decreased with increasing fertilizer inputs.SOC and TN concentrations were improved with the excessive fertilization,but had a negative impact on the fertilizer use efficiency.In all,attentions should be paid to strengthening agricultural production management for improving land productivity according to spatial distributions of soil nutrients.