Nitrate Movement, Transformation, and Accumulation Following Diverse Nitrogenous Fertilizer Regimes in Arable Soils

摘要

Arable farming with intensive agricultural practices causes severe damage to groundwater quality. Hence study on mechanisms of diverse nitrogenous fertilizer regimes were focused relate to nitrate movement, transformation, and accumulation in arable soils. Knowledge of effects of N-leakage from soils of different chemical and physical compositions fertilized by various organic and inorganic N-fertilizers is of upmost importance. Few studies have compared the fate of N in relation to the properties of soils and nitrifying denitrifying potential, when it is applied in the form of municipal solid waste (MSW), commercial organic fertilizer (COF), or commercial inorganic fertilizer (CIF). Tsukuba Kuroboku, Kagawa loamy clay, and Sizuoka sandy soil types were selected as representatives of Andisol, Andosol, and Sandy soils because most of the soils in Japan are based on volcanic ash. It is concluded that the N transformation and nitrate leaching strongly influenced by the soil’s chemical characteristics and secondarily by the physical characteristics in agricultural lands. Denitrification was increased markedly by readily available C. NO₃?N transport was influenced by fertilizer type and soil properties. Nitrogen transformation rates were higher in the Tsukuba Kuroboku soil than in the Sizuoka sandy soil and Kagawa loamy clay soil, however the nitrogen transport rate was lower. The differences were more pronounced between the Kagawa and Tsukuba soils. NO₃-N movement in Andisol columns treated with MSW and COF showed similar patterns however NO₃-N movement in sandy soil columns was more rapid than in the other soil types. Soils treated with COF showed slightly higher crop yield (10%) than soils treated with MSW compost fertilizer.