Studies on irrigation management and water requirements of upland fields converted from paddy fields and those of protected cultivation fields
1999
Hashimoto, I. (Ishikawa Prefecture Coll. of Agriculture, Nonoichi (Japan))
In this country, upland fields converted from paddy fields have been increased since 1970s. On these converted upland fields, unique problems which are unable to be dealt with by conventional techniques have arisen in irrigation because of their different soil conditions and water-use conditions from those in ordinary upland fields. First of all, the problem is that in the converted upland fields where plowsole remains, the effective soil layer, soil moisture extraction pattern and starting time of irrigation differ from those in ordinary upland fields. Secondly, the problem is that irrigation, in the converted upland fields, is conducted by the method of ponding the furrow temporary or all the time by using the water from the irrigation canal in paddy fields, while utilization of water in those fields differs depending on the method of furrow irrigation. In the present study, the author elucidated the real situation of these problems through his field surveys. The recent years, greenhouse horticulture fields have increased sharply as well. Following this, the increase in sizes of facilities and installation of watering apparatus have been advanced. However, in the most of the crops whose culture is limited to protected culture, the changes of their growing stages differ and the demand for moisture in each stage differs delicately in each cropping type among those crops; and besides, they are harvested once in each cropping, so a very careful watering management is needed. Added to this, few cases of studies on the technique have been reported and only limited numbers of techniques reported so far are available, so the watering management has been mostly conducted according to the experiences and skills of farmers. The actual situations for the amount of each irrigation, irrigation intervals and management of soil moisture were made clear throughout the growing seasons of these crops from planting until harvesting
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