浙江金华地区水稻土养分供应能力研究

Analysis on the Indigenous Nutrient Supply Capacity of Rice Soils in Jinhua, Zhejiang Province

自 1997年早稻开始 ,在浙江省金华市农业科学研究所试验区稻田设立了监测水稻土生产力及肥力变化的长期肥料定位试验 ,并在试验区周围 10 km范围内选择了 2 1户农民的稻田进行相应的监测试验。试验区内农户间稻田土壤的养分供应能力相差很大 ,氮供应能力变化于 49～ 116 kg/ hm2 ,磷供应能力变化于 13～ 32 kg/ hm2 ,钾供应能力变化于 6 8～ 183kg/ hm2 。农民常规施肥区的氮肥利用效率很低 ,氮表观回收率的平均值为 14%～ 2 6 % ,氮肥农业效率平均值为 4.6～ 8.2 ,且农户之间、早晚稻之间均存在较大差异。肥料定位试验结果表明 ,在连续种植水稻条件下 ,缺肥区土壤相应的有效养分消耗很快。与 NPK全肥区比较 ,NP区从第 2季水稻起 ,NK区从第 3季水稻起 ,即开始出现减产。针对当地农民现行养分管理的实际情况 。

On farm experiments involving 21 rice growing farmer families and a long term NPK fertilizer experiment since 1997 in Jinhua of Zhejiang Province to assess the current status of soil fertility and productivity under intensive rice rice cropping. Soil indigenous supply of N, P and K was estimated in nutrient omission plots (PK, NK, NP). Among the 21 farms located within a small domain, the indigenous N supply capacity ranged from 49 to 116 kg/ha, indigenous P supply capacity ranged from 13-32 kg/ha, indigenous K supply capacity ranged from 68-183 kg/ha. Farmers applied high fertilizer rates, but current average rice yields of about 6 t/ha were only about 60% of the climatic and genetic yield potential. N use efficiency was low and very variable among farms. On average, the apparent recovery efficiency of applied N was only 14%-26%. The average agronomic efficiency was only 4.6-8.2 kg grain yield increase per kilogram N applied. The long term fertilizer experiment showed that soil available nutrient pool depletion might occur very fast under consecutive crops grown without fertilizer application. Implications for developing a new approach of site specific nutrient management were also discussed.