The effect of soil erosion control by pineapple vegitation on pineapple orchard (2) (Fundamental studies on farmland conservvation in Okinawa XII.) (Department of Agricultural Engineering)

1.パイナップル根の緊縛強度は生育令50ケ月頃までは増大する傾向にある。2.パイナップル根の長さの総和は引き抜きの際の根の付着土量と高い相関関係がある。3.パイナップル畑は根の影響により裸地畑よりも侵食抑制に対して物理的に効果がある。4.パイナップルの被覆率は生育令20ケ月頃までは急速に増大する。5.ネピアグラス, ローズグラスはパイナップルやさつまいもに比べ土壌保定作用が極めて大である。The purpose of this study is to investigate the effect of erosion control by pineapple vegitation. In preparing the present paper the authors measured mainly the soil holding capacity of pineapple roots and the degree of vegitative cover of pineapples. The root strength of rhodes grasses, napier grasses and sweet potatoes was also measured in order to compare with that of pineapples. The results obtained are as follows : 1. The soil compact strength of the pineapple roots becomes larger with their growth by the age of around 50 months. 2. There is a high correlation between the total length of pineapple roots and their soil holding capacity. 3. In reducing erosion the roots of pineapples help improve aggregation and porosity of the soil. 4. The covering ratio of the sample increases rapidly by the age of around 20 months. 5. Rhodes grasses and napier grasses have a very high soil protection compared with pineapples and sweet potatoes