During the ten years of experiment, the effect of recycled nutrients on crop yields appeared an increasing trend, implying the existence of an accumulative effect from successive application of recycled compost on crop yields.

• 养分循环再利用的作物增产效益在试验的10 a中有着逐年增长的趋势，表明以堆肥形式循环回田养分的作物增产作用有着明显的残效叠加效应。