Resettlement and conservation policies may result in concentrating populations as exemplified in northern Lao PDR. Whereas the national population density is less than 15 inhabitants per km2, natural growth coupled with these resettlement conservation policies have led to a population density that exceeds 350 inhabitants per km2 of arable land in a representative village of Ban Lak Sip, northern Laos. Because of this very high pressure on arable land, this village is rapidly approaching the limit of upland rice cropping without external inputs. Weed infestation and low yields are problems resulting from too short fallow periods. The work load (228 days ha-1) in this rotational slash and burn cultivation system makes it no longer sustainable.

These conservation policies have also favoured, paradoxically, an increase in soil losses (4.7 tons ha-1in 2002, 11.3 tons ha-1 in 2005). Such erosion had an immediate impact on soil fertility, organic matter being removed preferentially. Cost of nutrient losses has been estimated to amount to 68 US$ ha-1 yr-1 in a 0.9 ha cultivated sub-catchment of the Philippines MSEC site. At the Vietnamese MSEC catchment, the predominant land-use has gradually changed from cassava (40% in 2001 to 0.5% in 2004) to tree plantations from 2000. Forest and fodder cover effectively eliminated erosion one year after establishment, decreasing soil loss from 3.6 t ha-1 yr-1 to 0.1- 0.3 t ha-1 yr-1 in 2004. With this change in land use, the opportunity for livestock introduction into the catchment has arisen. Similar results have been obtained in the Laotian MSEC and in the Indonesian MSEC catchment also. Factorial analysis of the data collected from the 27 catchments and sub-catchments clearly showed that the land use management and in particular the areal percentage of annual crops were the main predictors of runoff and sediment yields. Models showed that simulated land use changes are expected to have a greater impact than predictable climatic change.

Among some of the other key findings was that on very steep cultivated slopes, tillage erosion increases with slope and can even exceed sheet erosion (true for over 60%). In a simple evaluation of the off-site effects of erosion at the Philippine site it was estimated that total of 84 685 m3 of sediment was transported into the system since 1995 (equivalent of over US$ 50,000 in terms of dredging). Similarly in Thailand the amount of sediment accumulated in the reservoir since the construction a dam due to very intensive cultivation has caused the reduction of the reservoir volume by 10% within seven years.

The major impacts that are visible from this project are in Vietnam, the evaluation of fodder crops as an alternative to annual crops such as cassava has stimulated an interest in improved livestock production based on the introduction of adapted pasture species by farmers from the surrounding villages. In Indonesia, the conversion of arable land into fodder banks combined with livestock production was based on the lesson learned that farmers’ adoption and improvement of conservation measures is determined by the economic contribution of the measure to the household economy. In the Philippines, natural vegetative strips were introduced as suggested by the farmers. About half of the landowners, but no tenant farmers, have adopted some conservation measures so far. The major reason for the lack of adoption by farmers interested in the practice is the cost of establishment.