利川市现代烟草农业基地单元土壤基本养分现状及变化趋势与土壤改良建议

为了解利川市国家级现代烟草农业基地单元的土壤基本养分状况与演变趋势，指导该地区土壤改良与烤烟平衡施肥，分2年对该基地单元开展土壤普查分析与定点调查分析。结果表明，柏杨与汪营基地单元土壤酸碱度平均值均呈下降趋势，但两者变化特点不一致，前者向有利于烟叶生长适宜区间发展，后者酸化趋势较为明显；两大基地单元有机质与碱解氮2项指标接近中等水平，柏杨基地单元呈下降趋势，汪营基地单元呈上升趋势；2个基地单元速效磷均处于中等水平，但柏杨基地单元呈下降趋势，下降幅度较大，汪营基地单元呈上升趋势，幅度稍偏大；2个基地单元速效钾含量均有不同程度的增加，但仍有超过50%的土壤田块缺钾，且区域含量差异呈增大趋势。根据基地单元养分现状及演变趋势，结合地区的生产实际，分析了各养分指标变化的原因，同时对土壤速效磷与其他养分进行了相关性研究，提出相应的改良建议。

Status and Variation Trend of Principal Soil Nutrients and Soil Improvement Suggestion of Modern Tobacco Agriculture Base Units in Lichuan

In order to better realize status and variation trend of principal soil nutrients of state-level modern tobacco agriculture base units in Lichuan, and guide the soil conservation and tobacco balanced fertilization, soil survey analysis and fixed-point investigation analysis have been developed divided into two years. The results showed that average pH values in soil of both Baiyang and Wangying base units were tending to decline, but the changes were different; the former has been moving toward optimum interval for tobacco growth, and the latter trends evident toward further acidified. The contents of alkali-hydrolyzable nitrogen and organic matter of both base units were close to medium level, and the Baiyang base unit showed a drop tendency while the Wangying base unit was just on the contrary. Available phosphorus values of both base units were at medium level, and the former declined clear while the latter increased clear. The contents of available potassium of both base units were increased by some extent, but soil K deficiency was still over 50%. Difference between regional distributions of the content tended to increase. According to status and variation trend of principal soil nutrients, the change causes of soil nutrient indexes have been analyzed combined with the actual production condition in this area. The relationships of available phosphorus and other nutrient indexes have been investigated, and some suggestions to soil improvement were put forward.