ABSTRACT

Rice straw (RS) and cow dung compost (CDC) are good sources of phosphorus (P) to support rice production. Our previous research found that CDC application in mixed crop-livestock systems supplied more total P to the paddy soil than RS, but available P did not differ significantly between the CDC and RS fields. To explain these results, we investigated the soil total P and soil P balance in RS and CDC fields. From the 79 paddy fields managed by farmers in Mamurogawa, Yamagata, Japan, which were investigated in previous research, we selected 10 pairs of adjacent RS and CDC fields, then measured soil total P, P inputs (RS or CDC and fertilizer), and P outputs (plant uptake and leaching), and calculated the resulting soil P balance. The result showed that soil total P did not differ significantly between treatments. The higher P input from CDC would let farmers apply less fertilizer P in CDC fields than in RS fields, but there was no significant difference in total P input between treatments. Plant P uptake and leaching did not differ significantly between treatments. The soil P balance was positive (i.e., net P accumulation) and did not differ significantly between treatments. The lack of differences in the total P input, total P output, and soil P balance between treatments explains the non-significant differences in soil total P and available P.

摘要

稻草 (RS) 和牛粪堆肥 (CDC) 是支持水稻生产的磷 (P) 的良好来源。我们之前的研究发现，CDC 在作物-牲畜混合系统中的应用比 RS 为稻田提供了更多的总磷，但 CDC 和 RS 田间的有效磷没有显着差异。为了解释这些结果，我们调查了 RS 和 CDC 田地的土壤总磷和土壤磷平衡。从前期研究调查的日本山形县真室川农民经营的 79 个稻田中，选取 10 对相邻的 RS 和 CDC 田，测量土壤总磷、磷投入（RS 或 CDC 和肥料），并P 输出（植物吸收和浸出），并计算得到的土壤 P 平衡。结果表明，不同处理间土壤全磷无显着差异。CDC 较高的磷输入将使农民在 CDC 田中比在 RS 田中施用更少的磷，但处理之间的总磷输入没有显着差异。处理之间植物磷吸收和浸出没有显着差异。土壤磷平衡是正的（即净磷积累）并且在处理之间没有显着差异。处理之间的总磷输入、总磷输出和土壤磷平衡没有差异解释了土壤全磷和有效磷的非显着差异。净 P 积累）并且在处理之间没有显着差异。处理之间的总磷输入、总磷输出和土壤磷平衡没有差异解释了土壤全磷和有效磷的非显着差异。净 P 积累）并且在处理之间没有显着差异。处理之间的总磷输入、总磷输出和土壤磷平衡没有差异解释了土壤全磷和有效磷的非显着差异。