Thesis Abstract of AGS Students

Problems and prospect of alley cropping on the steep land

Suporn Amaruekachoke (1992)

Soil erosion and nutrient deficiency are the major physical factors that limit crop productivity on the highlands. The alley cropping system is regarded as an effective integrated conservation practice for the steep land agriculture. However, farmer adoption is found to be less encouraging. Therefore, the on-farm agronomic and economic evaluation of alley cropping system and the study related to farmer adoption were conducted at Ban Huay Som Sook, Amphur Mae Rim, Chiang Mai in 1990 growing season.

The study consisted of three levels. The field level concerned the agronomic investigation on the effect of alley cropping system and fertilizer application on soil fertility, soil loss prevention, soil moisture and crop yields in a peanut-soybean pattern. The farm level study examined household activity to determine labor management and analyze economic return to labor. At the village level, farmer assessment on erosion problems and alley cropping system as an approach of conservation practice was conducted.

The application of phosphate fertilizer at 56 kg P2O5/ha had increased peanut kernel yield to 694 kg/ha, and 16-20-0 at 281 kg/ha had increased soybean yield to 1529 kg/ha. The treatments also provided higher economic return than the control, with marginal rate of return of 557 percent for peanut and 717 percent for soybean. At soybean harvest, the soil analysis indicated that the available phosphorus in the alley and non-alley plots was low for legumes, averaging 6.50 and 9.94 ppm., respectively.

The leucaena mulching did not provide a concrete evidence of soil loss prevention as the cumulative soil loss as determined by the staking technique was highly variablle. However, the mulching had higher available soil moisture than the nonmulching treatment, but it showed non-significant effect on peanut kernel yield. The maximum soil loss of 112 t/ha was found in the alley plot. This could have been lost if there were no hedgerow barriers.

The labor allocation of the farmer adopter revealed that for agriculture activities in the lowland paddy fields and on the steep land, the farmer required an addition of 30 percent of total labor. The labor requirement for the alley field with peanut-soybean cropping pattern was estimated to be 323 manday/ha, and the return to labor was 38 Baht/ manday. This was lower than the average daily wage in the village (50 Baht/manday).

The non-adopters did not consider the occurrence of soil erosion as a serious problem in their fields. In addition, they saw no economic benefit which could be derived 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 by the long term benefits of the alley cropping system.

The practice of alley cropping system has to be considered within the context of a farm system. Its prospect on the steep land rests on the integration of nutrient management and cropping system between the hedgerows.

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