Nutrients balance under organic rice farming system in Central Java, Indonesia

Abstract

Understanding and calculation the net nutrient balance in an organic rice farming system is crucial to determine its ability to maintain soil fertility in the long term. The objective of this study is to calculate simple nutrient balances of nitrogen (N), phosphorus (P), and potassium (K) under different sources of organic fertilizer in organic rice farming. The results indicated an imbalance between nutrients, a general surplus for P budget +0.8 to +43.5 kg ha-1 season-1 and deficit for N budgets from -49.2 to +38.5 kg ha-1 season-1; and K -56.8 to +38.6 kg ha-1 season-1. The application of 5t ha-1 of chicken manure combined with 500 kg ha-1 of azolla and 2 t ha-1 of straw compost gave better growth, yield and positive N, P, K balance for local rice variety Mentik Wangi.