覆蓋作物吸水型態及根系分佈調查

Abstract

欲明瞭覆蓋作物喜多豆及現行推廣最多之百喜草吸水型態及根系分佈情形舉行本調查。茲將調査結果摘要如下：1.氣候因素及生長階段均能影響覆蓋作物吸水量，且以後者影響較大。2.種植後五個月之總吸水量以喜多豆最多（597.24mm），百喜草A44品系次之（491.55mm），百喜草USA品系最少（431.37mm）。3.刈草有抑制覆蓋作物吸水之效果，刈割後能使吸水量迅速下降至初植時相近之程度。4.百喜草A44品系，雖然吸水量較大，但主要吸水區域在土壤表層（0〜25cm），百喜草USA品系之吸水量於植後第三個月開始，第二層（25〜50 cm）多於表層（0〜25㎝）。5.喜多豆根系最深到達第三層（50〜75 cm），第四層未發現有根系生長其中。6.二種品系之百喜草刈割後，第三層（50〜75 cm），第四層（75〜100 cm）兩層停止吸水。需經半月後恢復吸水，其根系已有部份腐爛現象，將可增加土壤有機質，孔隙率及滲透量。 We designed this experiment in order to understand the water absorption and distrbution of root system of cover crops and it's effect on fruit trees possibly and find out the true absorption of two kinds of Bahia grass (A44 and U.S.A.) The results obtained were as follow: 1. The absorption of cover crops were effected by climatic factors and stages of growth, the latter is more effective than the former. 2. Five months after planting, Desmodium required and absorbed water is both597.24 mm., Bahia grass (A44.) is 491.55 mm., Bahia grass (U.S.A) is 431.37 mm. ting grass the rate and the consumption of water went down rapidly as starting planting. 4. This two kinds of Bahia grass stopped water absorption in third layer (50-75 cm.) and forth layer (75-100 cm.) after cuttin g grass. It is hot till half-month that water absorption had restored, the root system had partly decayed within this period so that will increase organic matter, porosity and infiltration rate. 5. Bahia grass A44. absorbed water is more than Bahia grass U.S.A.. The Bahia grass A44. main absorption of water was needed in first layer (0-25 cm.). The absorption of water that Bahia U.S.A. needed in second layer (25-50 cm.) is more than in first layer (0-25 cm.) after planting three months. According to this experiment we come to the conclusion that Bahia grass A44. use in orchard is more ideal than other two kinds of cover crops.