S Agriculture (General) wet tropical area Ilmu Tanah Fresh organic matter QH Natural history Ultisols nutrient paddy soil soil aggregate stability - 5. Inceptisol Agrikultura Available P Bioteknologi Bobot umbi CSR Caldera maninjau Corporate Social Responsibility Efficiency Environmental Guidance Erosi Gizi H Social Sciences (General) Ilmu Pertanian Ilmu Tanah dan Sumber Daya Lahan Jerami jagung Kesehatan Kulit kopi Land use Land-Use Change Manajemen National Company-Care Partnership Program Pembinaan Physico-chemical characteristics Potensial air tanah Satellite image interpretation Sifat fisik tanah Soil Science Soil chemical characteristics Sub-Watersheed Sumpur Singkarak Sungai Batang Tanaman aren Teknologi Ultisol Umur tanaman West Sumatra acid soil acidity