Dampak Abu Vulkanik Erupsi Gunung Kelud dan Pupuk Kandang terhadap Ketersediaan dan Serapan Magnesium Tanaman Jagung di Tanah Alfisol - Suntoro, Suntoro; Department of Soil Science, Faculty of Agriculture, Sebelas Maret University (Faculty of Agriculture, Universitas Sebelas Maret, 2015)