Organic Fertilization on Wetland Rice for Sustainable Agriculture: Organic Matters for Crop Nitrogen Sources

Rice (Oryza sativa L.) is the main staple food crop in Asia. Wetland rice systems in Asia make a major contribution to global rice supply. In this modern age with increasing population, rice production has to be intensified simultaneously with no or the least environmental degradation. Chemical fertilizers application is costly and gradually leads to environmental problems. Cheap and environmentally saved organic manure application might be essential for sustainable soil fertility and rice production. By conducting trials in pots and fields, animal manures such as poultry manure showed its superiority on crop yield, nutrient availability and soil fertility sustainability. It can be used as an environmentally and economically suitable fertilizer in paddy production especially in developing countries with little capability of investments. Sustainable crop production should maintain the optimal condition, avoiding high external application and high crop removal, and is sound for human and environmental health.