2013 Volume 5 Issue 2 Pages 26-36
Questionnaires with farmers and field surveys were conducted in Hokuto City, Yamanashi Prefecture, to identify factors that contributed to successful organic vegetable cultivation. Cultural characteristics found are described below. (1) A few fruit and leaf vegetables were positioned as central items, although the farming was for planting multiple vegetables in principle. (2) Cultivars were selected on the basis of harmony with other vegetables in terms of cultivability, early/late-maturing, yield, disease resistance and so on. (3) Each ridge was arranged to form blocks so that a number of vegetables could be planted in a lot of field. (4) Problems for fruit vegetables were pests in general and problems for leaf vegetables were insects in particular. Following measures were implemented: use of resistant cultivars, planting at proper times, sparse planting, mixed planting, use of rain cover, use of covering materials, and the like. (5) Characters and effects were considered to use different organic fertilizers for different vegetables and to adjust their application volumes. (6) Sparse planting was practiced to keep passages wide and secure adequate lighting and aeration. Indigenous grasses were taken advantage of between and on ridges for weed control. (7) Field vegetation mainly consisted of annual grasses between ridges and perennial grasses on ridges while vegetables were grown. (8) Many indigenous natural enemies were found on crop leaves and between ridges in organic fields. (9) Vegetables were divided into a few groups for planting rotation. The groups were arranged for yearly transfers of planting fields. Solanacea vegetables were rotated at intervals of three years or longer in order to avoid damage by continuous cropping.
