SBR- Content.pmd - INBO

8 - AgricultureTable 19. Viet Nam* pesticide use (Metric tonnes)Item 1994 1995 1996 1997Fungic/Bacterial/Seed Treatment 3,139 3,465 8,188 7,684Herbicides 2,547 4,979 7,205 6,710Insecticides 15,226 16,452 17,352 17,851Plant Growth Regulators 667Rodenticides 107Total 20,912 24,896 32,745 33,019Note: “*” data are for the whole country rather than for just for the territory within the basin.Source: FAO 2002 (FAOSTAT Agriculture)3.5 Upland agriculture/shifting cultivationOne of the most important agricultural systems in the LMB is the group of farming techniquesknow as shifting cultivation. Shifting cultivation is practiced mostly in marginal upland areas. Inthe LMB it occurs most often in the Viet Nam Central Highlands, the northeast of Cambodia, andthe sloping land areas of Lao PDR. Because shifting agriculture occurs in remote areas and isalmost entirely removed from the formal economy, it is very difficult to measure its geographicextent and productive output. However, assessment of the phenomenon is important because itprovides the household consumption needs for large numbers of people, and is often deeply rootedin the culture of upland minority people. Shiftingcultivation is also of consequence because it is widelyconsidered to be a major contributor to deforestation.Estimates put the area under shifting cultivation in thebasin at about 2 million ha, with 25 percent of that landclassified as forest. 71Because of marginal soil fertility, manyshifting agriculture plots are cultivatedfor only 1-2 years and left fallow for 10-20 yearsA typical shifting cultivation system involves householdsin wooded or forested areas clearing and cultivating plotsof land on a rotational basis. At the beginning of the cyclea plot, typically 1.5 ha per household, will be cleared usingthe slash and burn method. 72 Rice and various other uplandcrops will be planted and the plot will be worked untilharvest. Because of marginal soil fertility, a second yearof cultivation on the plot would result in lower yields.The household therefore leaves the plot fallow and moveson to clear a second plot for the following year. The processis repeated until the original plot has been left fallow forlong enough for its fertility to be restored, generally 10-20 years. 73 Variations to this system include pioneeringcultivation where plots are worked for longer periods untilsoil fertility is completely exhausted, and semi-shifting cultivation, which involves greater numbersof people working from fixed homesteads on flatter land. 74 Most groups combine shifting cultivationwith other activities such as the gathering of non-timber forest products. 75165