水分管理對水稻生育及米質之影響

Abstract

本研究一系列田間試驗結果顯示，適度減少灌溉水，提高土壤水分張力至0.01 MPa，可以提昇土壤氧化還原電位，有助於提昇水稻幼苗根活性及乾物質累積速率。若於高張力提早晒田後，適量補量磷肥，有助於提高根活性，增加分蘗數，增加稻穀產量18%。營養生長期提昇灌溉起點之土壤水分張力至0.02 MPa，對臺中秈10號並未造成產量降低，但臺中189號產量顯著降低25%，顯示品種間對乾旱忍受性有相當大之差異。建議在容易缺水地區，推廣適當品種種植，可以獲得較高之灌溉水利用效率。穀粒充實期可施以間歇性灌溉，一期作以0.018 MPa，二期作提高至0.027 MPa做爲灌溉地點，可以獲得最高產量。 Results from a series of field experiments showed that reduced irrigation water for rice cultivation is feasible. During seedling stage, increased soil moisture tension to 0.01MPa enhanced soil redox potential, and thus a higher root activity and dry weight accumulation rate resulted. Supplementary phosphate fertilizer applied after 0.08 MPa intermittent drying practiced during the 10-tiller stage promoted root activity and tiller number, and thus a 18% grain yield increased. During vegetative growth stage, increased soil moisture tension to 0.02 MPa reduced 25% grain yield in rice cultivar Taichung 189, but no such effect occurred in the cultivar Taichung Sen 10. Results suggest that Taichung Sen 10 has a higher drought tolerance and water use efficiency. During grain filling stage, 0.018 MPa in the first crop and 0.027 MPa in the second crop as the irrigation starting point of soil moisture tension gave the highest grain yield.