Estimation of N- and P-Mineralization of Organic Materials under a Paddy Condition
2012
Lee, Y., National Academy of Agricultural Science, RDA, Suwon, Republic of Korea | Choi, H.S., National Academy of Agricultural Science, RDA, Suwon, Republic of Korea | Lee, S.M., National Academy of Agricultural Science, RDA, Suwon, Republic of Korea
Various organic materials, such as compost and crop residues, were used to identify the characteristics of N- and P-mineralization of the materials. Non-destructive (analysis for mineralized N in leachate periodically extracted with CaCl₂ at a measure date) at a constant temperature chamber were conducted in a paddy (water-logged) condition. The constant chamber was continued at 25℃ in 0, 1, 2, 3, 4, 6, 8, 16, 21 weeks using extracting to obtain sufficient time and data points to adequately describe the relation between cumulative N and P mineralized and chamber period. Organic materials included maize residue, alfalfa, sudan grass, millet, perilla residue, rice straw, cabbage, Stellaria media (L.) Ville, clotararia, compost Ⅰ, compost Ⅱ, compost Ⅲ, soybean oilcake, tomato residue, watermelon residue, and castor oilcake, and urea also was used in this experiment. Alfalfa material produced the highest N-mineralization rate. NO₃-N content was not accumulated in soil by the material input during the periods. Higher net accumulation of NH₄-N in most organic materials was obtained from the lower C/N ratio of them. P-mineralization in soil was little affected by application of most of organic materials, except for compost Ⅰ and Ⅱ, and rice straw.
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