| Title |
Studies on the Behavior of N , P , K Fertilizers Applied in Paddy Soils and the Water Pollution Caused by the Leachate |
| Authors |
이창호 ; 임수길 ( Chang Ho Lee ; Soo Kil Lim ) |
| Abstract |
In order to investigate the behavior of N,P,K fertilizers applied in submerged paddy soils and the water pollution caused by these leachate, Ammonium sulfate(AS), Urea, Superphosphate(SP), Fused phosphate(FP), Potassium chloride(PC) were applied in three levels in the columns filled with silty clay loam(SiCL) and sandy loam(SL), respectively. Distributions of N,P,K in soil were detertmined, and concentrations of N,P,K in leachate were also analyzed, separately. The obtained results were summarized as follows. In terms of residual amounts in soils, AS induced decreasing amount NH₄-N from top to bottom whereas Urea revealed reverse phenomenon. SL soil rather than SiCL soil and AS rather than Urea had a much effect on the water pollution. Residual amount of NO₃-N showed higher amount in SL soil than in SiCL soil regardless of fertilizer and application rates. In SiCL soil, main source of soluble phosphorus was SP whereas FP was the one in SL soil. Conc. of phosphorus in leachate were very small due to high adsorption ability of soils for phosphorus, the soil pollution was more considered than the water pollution. Leaching conc. of K^+ was higher from SL soil than SiCL soil, leaching conc. of K^+ increased as fertilizer application rates increasing on both SiCL and SL soils. Leaching concentrations(Y) of K^+ decreased with increasing leaching frequency(X), fitting the equation of exponential function could be expressed as Y=aX^b egardless of soil textures and potassium fertilizer application rates. The value of b is in between 0.41 and 0.63. |