Production of Organic Matter In Situ for Sustainability High Productivity on Cassava Field

Abstract

Real productivity of cassava in Indonesia is 16.6-21.4 tons/ha whereas the potential productivity is 24.8-30.4 tons/ha. The low productivity has been a problem in developing cassavabased industries. Fonnation and enlargement of cassava tubers need loose, fertile and high C-organic of soil. C-organic of the soil should be not less than 2%. To increase C-organic of the soil at about 2-4% will be needed organic fertilizers of 20-40 tons/ha. Organic matter produced 'in situ' of the cassava field was 5.92-21.28 tons/ha (1.60-5.28 tons/ha in dry weight) which contributed average at 0.5% in increasing soil C-organic. Besides, the organic matter contains some important nutrients such are N, P, K, Ca, Mg. All nutrients produced 'in situ' were sufficient for Adira-1. All nutrients were also sufficient for Adira-4, except K. Nutrient of P and K were insufficient for Malang-4 and UJ-5. Nutrient of P and Mg were only sufficient Adira-1 and Adira-4.