Study of characteristic environments and increasing productivity of the field crops in sand dunes and arid lands

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In coastal sand dunes of Baja California, Mexico under very high temperature and very low humidity, we performed the basic research for the study with increasing productivity of vegetables: (Brassica campestris L. subsp.napus Hook. f.et Thoms. var.komatuna Makino), radish(Raphanus sativus L.), Bekana, Pak-choi (Brassica chinensis L.), head lettuce(lactuca sativa L. var capitata L.), and Greendebut. When we cultivated them, we tested many kinds of cultivation techniques for spending the less amount of water: the drip irrigation, the perforated irrigation, the use of water holding substances and controlling the irrihation with the frequency and the amount of water. At the same time we investigated the plants growth in seeding beds by the water of good quality, which was given from air humidity by dehumidifying machine.In Baja California the underground water had the value of E.C.,1442us/cm, but dehumidifying water was very good,E.C.,266us/cm. The plants growth by dehumidifying water was shown to be signifficantly better than that by underground water, with leaf weight by lettuse, 1.9 times and Pak-choi, 1.6 times. In 9 kinds of water holding substances the increase of the leaf weight, Pak-choi, arised and the greatest effect of them increased about 60%. Their result in Mexico mostly got the values less than the result in Japan. Because high salinity into irrigation water prevented plants growth.Then if we hope to plant trees in desert, we should quikly develop a new salt-tolerant water holding substances. When we gave the same irrigation water, we got more frequent irrigation, we got leaf weight, Pak-choi, more increasingly.