休耕水稻田蓄水对土壤肥力影响试验

Influence of irrigation methods on soil fertility during the sabbath period

主要探讨水稻田休耕期间蓄水对休耕后土壤肥力之影响。选择两块水稻田区 ,在水稻收割后 ,将田区翻耕一次。一田区以人工连续灌溉 ,蓄存水量于田区 ;另一田区则为天然蓄水。在每一田区四边及中央处 ,以 1 0cm为一层采取土样 ,取至 60cm。再将每一层土样气干后 ,通过 0 42mm筛网土样混合 ,分析田区同一层在不同时段与不同深度下之pH值、电导度值、有机质、全氮、有效磷、钙离子、镁离子、钾离子及钠离子之变化。试验结果显示 :休耕后水稻根系腐化 ,造成土壤有机质以及有效磷显著的增加。蓄水后天然蓄水田区有机质和有效磷分别增加 5 1 %及 88% ,连续蓄水田区分别增加 1 3 %和 69%。而天然蓄水田区镁、钾、钠分别降低3 5 %、 2 4%和 47% ,连续蓄水田区分别降低 2 9%、 1 4%及 41 %。

The purpose of this study is to investigate the influence of irrigation methods on soil fertility during the sabbath period This study chose two blocks of paddy field, whose soil were turned over after the harvest One of the blocks was irrigated continually to maintain ponding water and was called continual irrigation field The other was without irrigation except natural precipitation and was called natural irrigation field The sampling locations were at four corners and the center of the block Each location was withdrawn six samples at six layers Each layer was 10 cm in depth to a totality of 60 cm below ground surface. The soil samples in each layer were air dried and mixed homogeneously by passing 0 42 mm sieve. The mixed soils were analyzed for their pH, EC, organic matter, total nitrogen, effective phosphorous, Ca, Mg, K, and Na The results showed that organic matter and effective phosphorous increased significantly after sabbath period due to the decay of rice roots In natural irrigation field, the organic matter and effective phosphorous increased 51% and 88%, respectively In continual irrigation field, the organic matter and effective phosphorous increased 13% and 69%, respectively However, in the natural irrigation field, Mg, K, and Na decreased 35%, 24%, and 47%, respectively In continual irrigation field, Mg, K, and Na decreased 29%, 14%, and 41%, respectively