砂土における塩水点滴かんがいによる作物栽培

Grain sorghum(Sorghum vulgare L.)，cabbage (Brassica oleracea L.)and Japanese radish(Raphanus sativus L.)were grown in sandy soil under a plastic house，and irrigated either with fresh water， or with brackish water containing 2995 ppm of several dissolved salts，a nd using five kinds of drip irrigation emitters. The soil moisture contents of the brackish water plots were slight1l higher than those of the fresh water plots. In the brackish water plots，the pH values of soil suspension (H₂0，1:2.5) were high，and differences in the pH values of each type of emitter were observed. The electrical conductivity(EC) values of soil water extract (1:2) were much higher in the soil irrigated with brackish water，and some differences were observed between emitter types. Salt was concentrated in the surface of the soil at places distant from emitters near the wetting front. With brackish water irrigation，dicreases in culm length，leaf age，and weight of culm and leaves of grain sorghum were observed，but grain yields were somewhat increased. Neither the brackish nor the fresh water showed a difference in the mineral composition of the plants and grains. In Japanese radish，l eaf length，leaf age，top weight and edible root weight decreased with brackish water irrigation，and the degree of decrement differed between the types of emitter. With brackish water irrigation，malformation of the edible root and the EC value of the juice of the edible root increased; in the mineral composition of the top and the edible root，Na increased while the other minerals decreased. 1n cabbages irrigated with brackish water，growth of the outer leaves and head much decreased，and abnormal tightening of the head was observed，while in mineral composition，Na of the head increased but the other minerals did not differ.