Long-term Effects of Inorganic Fertilizer and Compost Application on Rice Sustainability in Paddy Soil

Sustainability index was calculated to determine the best management for rice productivity under long-term inorganic fertilizer management's practices. It is based on nutrient index, microbiological index and crop index related to sustainability as soil function. Indicators for calculating sustainability index were selected by the comparison of soil properties and rice response in paddy soil with fertilization. Total twenty two indicators were determined to assess nutrient index, microbiological index and crop index in order to compare the effect of different fertilization. The indices were applied to assess the sustainability with different inorganic fertilizer treatments such as control, N, NK, NP, NPK, NPK+Si, and NPK+Compost. The long-term application of compost with NPK was the highest sustainability index value because it increased nutrient index, microbial index and crop index. The use of chemical fertilizers resulted in poor soil microbial index and crop index, but the treatments like NP, NPK, and NPK+Si were maintained sustainability in paddy soil. These results indicate that application of organic and chemical fertilizer could be a good management to improve rice sustainability in paddy soil.