The Plain of Jars is an acid, infertile savannah grassland covering an area of about 60,000 ha in the western region of Xieng Khouang Province, northeastern Lao PDR. In this ecology, farming systems are mainly based on lowland rice cultivation and extensive livestock production. Paddy rice and big ruminants represent respectively 20 to 50% and 50 to 80% of families' annual monetary income (Lienhard et al, 2006). An increase in rice production and intensification of the livestock industry are two key components in the Lao government's poverty alleviation strategy for this area. The main agronomic constraints for developing crops and forage systems are related to serious unfavorable soil chemical characteristics. As reported by Hacker et al. (1998) and Gibson et al. (1999), low pH, along with nutrients deficiencies (in nitrogen, phosphorus, potassium, calcium and magnesium) and high levels of aluminum saturation have a negative effect on food crops growth as well as on forage species development. Severe phosphorus deficiency generates also animal health problems (Gibson et al., 1999). In relation with these mineral deficiencies the PRONAE has organized market chains to import thermophosphate from Vietnam, macro (S) and micronutrients (Zn, Mn, Bo) from Thailand.