Effect of Long-Term Annual Dressing of Organic Matter on Physico-Chemical Properties and Nitrogen Uptake in the Paddy Soil of Fluvio-Marine Deposit

This study was carried out to investigate the effects of fertilizer and organic resource annual dressing for 30 years of Jeonbug series (silt loam) on soil properties and rice N uptake in paddy field soil. In the study field, treatments including control (NPK), NPK+rice straw, NPK+rice straw compost and nitrogen fertilization levels at 0, 100, 150, 200, 250 kg have been imposed for 30 years. Soil hardness and bulk density decreased from 15.7 mm and 1.381 Mg in the control to 12.5 mm and 1.244 Mg in NPK+rice straw compost treatment, respectively, indicating improvement of soil physical conditions such as porosity. Co-application of straw compost with NPK also result in a better chemical properties than NPK alone as it increased available phosphate (from 96 to 133 mg ), available silicate (from 81 to 116 mg ), and cation exchange capacity (from 9.8 to 11.4 ). Soil organic matter concentration of top soil (0 to 7.5 cm in depth) was higher in NPK+rice straw and NPK+rice straw compost than in control. Fertilizer N uptake amount was much higher in NPK+rice straw (nitrogen fertilization level; 250 kg ) and NPK+rice straw compost (nitrogen fertilization levels; 200, 250 kg ) plots compared to the control (nitrogen fertilization level; 100 kg ) plot. Nitrogen use efficiency was showed significantly high in the NPK+rice straw compost (nitrogen fertilization levels; 100, 150 kg ) plot compared to the control (nitrogen fertilization level; 100 kg ) plot. Therefore, it was suggested that application of organic inputs is helpful in improving soil fertility and physical conditions and thus in N uptake.