[Problems and conservation farming practice on the steeps land of the alley cropping system]

Alley cropping system is an alternative conservation farming practice on the steep land. The practice is claimed to be able to minimize soil erosion and to regenerate soil fertility. Many highland development projects, both governmental and non-governmental organizations, have introduced such practice to the farmers, but the adoption is not common. The on-farm research on alley cropping system was conducted at Ban Huay Som Sook, Amphur Mae Rim, Chiang Mai with three levels of studies. The field level concerned the measurement of the effects of leucaena hedgerow and fertilizer application on soil fertility, soil loss prevention soil moisture and crop yields in peanut-soybean pattern. The farm level study examined household activity to determine labour management and return to labour. At the village level, farmer opinion on problems of alley cropping practice was assessed. The leucaena mulching did not show evidence of soil loss prevention. The maximum soil loss of 112 ton/ha was estimated in the alley plot with peanut-soybean as sequential crops. This could have been lost if there were no hedgerow barriers. There was no indication of fertility improvement from the four-year old hedgerow plot. The application of phosphate fertilizer at 56 kg P2O5/ha in peanut and 16-20-0 at 281 kg/ha in soybean provided higher return than the control. Farmer who adopted the leucaena hedgrow required 30 percent of additional labour for the year round activity. The labour requirement for the alley field with peanut-soybean cropping pattern was 323 manday/ha with the return to labour of 38 Baht/manday. This was lower than the average daily wage in the village (50 Baht/manday). The adoption of alley cropping system in the village was still limited. The non-adopters did not consider soil erosion as a serious problem in their fields. They also saw no economic benefit from the leucaena hedgerows. However, those adopted the practice had the intention of establishing permanent land use system on the steep land. They were aware of erosion problems and were convinced the long term benefits of the alley cropping system.