Biophysical characteristics of dry-climate upland and agriculture development challenges in West Nusa Tenggara and East Nusa Tenggara Provinces

Abstract

Abstract West Nusa Tenggara (NTB) and East Nusa Tenggara (NTT) Provinces covered an area of about 6.6 million ha, of which largest part (95%) categorized has dry-climate with annual rainfall <2,000 mm and has 5-8 dry months. The study aimed to identify biophysical characteristics and propose development challenge of dryland agriculture in NTB and NTT. Biophysical land surveys have been conducted and soil samples have been analyzed for chemical and physical properties. The results showed good fertility status at three islands which was characterized by neutral to basic soil acidity, medium to high P and K total content, high cations content, high CEC and high to very high base saturation. Except for South West Sumba and West Sumba, several observation have indicated acidic pH due to andesitic lava parent material and have >2,000 mm rainfall that lead to high leaching. Soil texture may influence water content where the higher sand portion of soil, the lesser capacity to hold water and nutrients. Fertility status of the three islands is quite good but low in organic carbon content which indicated special attention to improve soil quality. Thus the land management of upland dry-climate area should be focused on surface water availability and conservation agriculture.