Application Effect of the Controlled Release Fertilizer Applied on Seedling Tray at Seeding Time in Rice

The optimal application rate of a controlled release fertilizer (CRF) on the growth, yield, and seeding time of rice grown on seedling trays was investigated. The experimental field was located at 37°22'10''N latitude and 127°03'85''E longitude in Hwaseong, Gyeonggi-do, Republic of Korea. The soil in the paddy field was a clay loam. The CRF used in the experiment contained 300 g kg of nitrogen, 60 g kg of phosphate, and 60 g kg of potassium, respectively. The CRF was applied at the rate of 0, 200, 300, 400, 500, and 600 grams on rice seedling tray compared with the field application based on soil testing (control), respectively. The CRF can be applied as single application(which can replace basal fertilizer application and two top dressing application) directly to the seedling tray, and showed the minimum release at the seedling period. Considering the plant growth, nitrogen use efficency and yield of rice, the optimal application rate of developed CRF was 500 g per seedling tray and the yield of rice at this application rate was 4.92~5.04 Mg ha-1. The regression formula between the rice yield and application rates of CRF was as follows ; Y=0.0002χ+0.0963χ+411.6(R : 0.9922) in 2010 and Y=8E-6χ+0.2723χ+344.04(R:0.9864) in 2011, Y : Rice yield (Mg ha), χ : Application rate (grams) of controlled release fertilizer . The optimum application rates of CRF per rice seedling tray by regression formula was 498 grams in 2010 and 513 grams in 2011.