【摘要】 通过 1 1年的定位试验结果表明 ,典型黑土农田 1 1年不施N肥 ,N素的自然供给力由 92 %下降到 5 0 %～ 60 % ;不施P肥 ,P素的自然供给力由 98%下降到 80 %～ 90 % ;不施钾肥 ,K素的自然供给力也由 1 0 0 %缓慢下降接近 90 %。农田养分平衡盈亏及其变化决定了土壤养分消长规律 ,其中有效磷的消长与P素盈亏的相关模型为Y =2 895 +0 1 3 4x ,速效钾的消长与K素盈亏的相关模型为Y =1 8 81 +0 1 63x。更多还原

【Abstract】 Summary Results of an 11 year fixed experiment indicated that the spontaneous nutrient supplying capacity of the typical black soil farmland tested varied in the following way, its N supplying capacity declined from 92% to 50%～60% in the plot without nitrogenous fertilizer, its phosphorus supplying capacity decreased from 98% to 80%～90% in the plot of no phosphorous fertilizer, and its potassium supplying capacity dropped slowly from 100% to about 90% in the plot of no potassium fertilizer. Nutrient equilibrium of the soil and its changes controlled nutrient gain or loss in the farmland The correlation coefficient of the model between gain and loss of available phosphorus and of total phosphorus is Y =2 895+0 134 X , the correlation coefficient of the model between gain and loss of readily available potassium and of total potassium is Y=18 81+0 163X .更多还原