The Effects of Applied Organic Materials for Improving Soil Physico-Chemical Properties in Paddy Fields.
Yong Hwan Lee, Sang Min Lee, Jwa Kyung Sung, Young Ho Kim, Du Hoi Choi, and Gab Hee Ryu. Organic Farming Division, NIAST(National Institute of Agricultural Science and Technology), Kwongsungu Seodundong 249, Suwon, 441-707, South Korea
This experiment was conducted to estimate the values of applied organic materials as alternative mineral nutrients and a soil conditioner. We transplanted rice seedlings on May 23th, 2004. Rice straw, hairy vetch residue and compost were applied to 1,200-2,000-500 kg 10a-1 as organic materials, respectively, and phosphate rock, lime-magnesia and ash were supplied with 10-3-3 kg 10a-1 as fertilizers, respectively. pH and organic matter of soil before and after experiment did not changed. A small quantity of available phosphorus among applied organic materials and fertilizers remained in soil despite energetic uptake via rice roots. Compared to soil before experiment, exchangible cations in soil slightly decreased. Soil physical properties after harvesting were investigated. Organic materials such as compost, rice straw and hairy vetch residues increased soil porosity up to three percent, therefore, an increase of liquid and gaseous phase of soil highly elevated root expansion and an uptake of mineral nutrients. Key words : organic materials, soil nitrogen, soil property, rice.