20 years of alley cropping research and extension in the slopes of Northern Thailand
1996
Somchai Ongprasert | Turkelboom, F. (Maejo Univ., Chiang Mai (Thailand). Faculty of Agricultural Production. Dept. of Soils and Fertilizers. Soil Fertility Conservation Project)
Research and extension of alley cropping with grass strips and nitrogen-fixing tree hedgerows on sloping land of Northern Thailand was reviewed. The research was and has been done since 1985 by four organizations at eight locations, in areas with slopes of 18-55 percent and altitudes between 480-1100 m. Such areas are not unusual shifting cultivated areas of the almost seven hundred thousand ethnic minority population in Northern Thailand. A review was done on the effects of alley cropping on soil erosion, terrace forming, soil fertility gradient, long term soil fertility dynamics, weed pressure and crop yields. Ten years of research have suggested that alley cropping can effectively control erosion but can not maintain soil fertility. Pruning biomass was too low to be used as mulch to control weeds and enhance soil fertility. Terrace and soil fertility gradient forming within alleys were the inherent consequences of alley cropping on sloping land. Distinctive better yields from alley cropping over those from traditional cropping could not be identified. Extension of alley cropping in the highlands of Northern Thailand has been done for a decade before research started. Adoption rate of cropping system was low. The major constraints were the extra required labour and the lack of short-term benefits of alley cropping. Another important reason is that the farmers are still capable to shift their cultivated lands.
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