不同轮作模式农田钾养分表观平衡及其对土壤速效钾含量的影响

Potassium nutrient balance and its impact on soil available K content in Shanghai suburb farmlands

通过连续3年监测上海郊区43块定位农田,比较了50种作物以及5种不同轮作模式农田的钾养分表观盈余状况及其对土壤速效钾含量的影响。结果表明：（1）不同作物农田的钾养分盈余趋势为水生蔬菜类、果树类〉旱作蔬菜≥草皮〉大田作物;不同轮作模式农田钾养分盈余大小表现为作物轮作〉菜作轮作〉草皮单作〉菜菜轮作〉果树单作;（2）不同作物及轮作模式农田收获时土壤速效钾含量随土层的加深而逐渐增加,钾养分盈余多的农田土壤的表层速效钾含量也高;（3）不同作物及不同轮作模式农田钾养分盈余量与收获时土壤表层（0-30 cm）的速效钾含量呈正相关,但未达显著水平。

Potassium nutrient balances of the farmland soils in 50 varieties of crops and 5 types of rotation and its impact to soil available K nutrient content were studied in 43 site-specific locations over the past three years in Shanghai suburb. The result indicated that： （ 1 ） the potassium nutrient surplus tendency of different crops farmland was： the fewflower wildrice, the fruit 〉 the vegetables ≥ the greensward 〉 the crops ; The potassium nutrient surplus of different rotation farmland was ： the rotation of crops and crops 〉 the rotation between vegetable and crops 〉 the greensward only 〉 the rotation between vegetable and vegetable 〉 the fruit tree only ; （2） Content of soil available potassium after harvest gradually increased with the depths of soil profile in the farmlands of different fields and different rotation fields. The more soil available potassium contents were, the more potassium nutrient surplus had been in different planting patterns fields ; （3） Potassium nutrient surpluses of the farmland soil in different crops fields and different planting patterns were positive correlated with the content of available K content in the surface soil （0 -30 cm） in harvesting, but not significantly.