우리나라 관개논에서 토양특성과 대형농기계를 사용한 경작년수에따른 여름 강우기 분산성 점토의 함량

BACKGROUND: This study was conducted to evaluate the water-dispersible clay content of paddy soils over the country in the summer rainy season as affected by cultivated years using heavy agro-machinery and soil properties such as texture and exchangeable sodium percentage. METHODS AND RESULTS: Water-dispersible clay content of 16 soil series of Korean paddy soils over the country were investigated in summer rainy season from July to August, 2006 by Middleton’s method. Waterdispersible clay content ranged from non-detected to 4.8%, showing maximum value from the fine textured soils and high clay dispersibility in average from the coarse textured soils. Longer cultivated years using agro-machinery more than 40 hp result in higer water-dispersible clay content for 60% of studied paddy soils with less than 5% of exchangeable sodium percentage (ESP). Exceptionally, soils with relatively big difference of ESP at about 10 percent showed higher water-dispersible clay content with higher ESP. CONCLUSION: Long years of cultivation using agromachinery with more than 40 hp enhanced waterdispersiblility of clay in approximately 60% of the studied paddy fields except for salt-affected soils. KCI Citation Count: 0