长期施肥下潮土速效钾含量与钾素投入水平关系

以郑州潮土肥力与肥料效益长期试验为基础，分析了长期施肥条件下土壤速效钾含量演变特征及其与钾素投入量的关系。结果表明，在不施钾肥条件下，土壤速效钾含量先逐年下降，810年后稳定在60 mg/kg左右; 施用钾肥和有机肥均可以显著提高土壤速效钾含量; 土壤速效钾含量与钾素投入量之间具有显著的正相关关系。单施化肥的NPK处理每投入钾1 kg/hm2，土壤速效钾含量增加0.007 mg/kg; 而化肥配施有机肥或玉米秸秆处理每投入钾1 kg/hm2，土壤速效钾含量分别增加0.025和0.014 mg/kg。从提升土壤钾素供应能力的角度而言，化肥配合施用有机肥或秸秆还田是值得推广的培肥措施。

Relationship between available K content and K input levels in fluvo-aquic soil under long term fertilization

Based on the long-term experiment of fertility and fertilizer effects in fluvo-aquic soil in Zhengzhou City of Henan Province,  the dynamic patterns of soil available potassium (K) content were investigated in different fertilizer treatments and the relationship between soil available K content and K input level was examined. The results show that when no K is applied,  soil available K contents gradually decline,  then maintain at the level of around 60 mg/kg after 8 to 10 years. Soil available K contents increase with the combining application of K fertilizer and organic amendments,  and a significant positive correlation between soil available K content and K input levels is observed. In treatment of pure chemical NPK fertilizers,  1 kg/ha of K input could lead to the soil available K content increase by 0.007 mg/kg.  In the treatment of combination of NPK with manure or straw,  the increase would be 0.025 mg/kg and 0.014 mg/kg,  respectively. Inorganic fertilizers combined with farmyard manure or maize straw are the best management strategy for increasing soil K supply.