future harv/est - Search CIMMYT repository

374 Adisak Sajjiapollgse, Amado Maglillao alld C/wimsit AlleksamphalltThe ASIAL4ND Management of Sloping LandsetworkThe ASIA!. ND Management of Sloping Lands Network has been organized to assist theparticipating national agricultural research centers (NARCs) in conducting research on themanagement of sloping lands. The main objective of the network is to help NARCs in conserving soilresources on sloping lands in the region through research and promotion of the application ofappropriate land management technologies to achieve a sustainable form of agriculture. Currently,seven countries, i.e. China, Indonesia, Laos, Malaysia, Philippines, Thailand, and Vietnam, areparticipating in the network. To achieve the mentioned objective the following technologies werevalidated in the different participating countries: alley cropping, hillside ditches, agroforestry and thefarmers' practice. The network established the following parameters as indicators to identifyappropriate technologies for sloping lands.• Soil loss and runoff• Plant growth and crop yield• Change in soil property (chemical and physical)• Socioeconomic indicatorsThe research of the network has been going on since 1988. Currently, data and information fromthe experiments in the different network-participating countries have been gathered. Following are thetechnologies validated and the results obtained from China, Philippines, Thailand and Vietnam.Technologies ValidatedAlthough many soil-conservation measures were validated by the network, only the resultsobtained from alley cropping and the farmers practice in China, Philippines. Thailand, and Vietnamwill be reported in this paper.For the alley cropping treatment, hedgerows crops are Tephrosia cal/dida in China and Vietnam,Glirieidia septulIl in the Philippines, and a mixture of Leuwel/a lel/eocephala and Cajol/lls ('(ljol/ inThailand. The width of alleyways was 5 m. As for the farmers' practice, planting crop up-and-downthe slope without soil conservation measure was the main practice. Corn was employed as indicatorcrop.Suil Loss and RunoffTo measure the soil loss and runoff under different systems, individual plots were equipped withsoil erosion-measurement system having erosion-collecting trough and tanks at the lower end of theplots. After a significant amount of sediment had been collected, measurement of soil loss was made.The result showed that soil loss was significantly affected by soil-conservation practices (Table l).For year I, soil loss under alley cropping was lower than the farmers' practice in all countries, exceptfor the Philippines. From year 2 and onwards, the loss under alley cropping was lower than thefarmers' practice in all countries. Alley cropping reduced the soil loss practically to nil after year 2 inChina and the Philippines. The difference in soil loss between alley cropping and the farmers' practicewas so striking after year I, when hedgerows were established fully and effective in filtering out runoffsediments. In the field, it was observed that microsteps had been created along the hedgerows, due tothe accumulation of the filtered sediments.Similar results were obtained with the effect of alley cropping and the farmers' practice on runoff(Tablel). Less runoff amounts were received under alley cropping than the farmers' practice and theeffect was more remarkable after year l.