Studies on the dynamics of 15N-labeled animal manure nitrogen applied to fields

Kagoshima Prefecture is one of the largest production centers of livestock in Japan. The manures coming from these production centers can be utilized for agricultural production as these animal manures contain nutrients such as N, P, and other nutrient elements. On the other hand, it is pointed out that animal manure causes nitrate nitrogen pollution of ground water. Therefore, it is important to study the dynamics of animal manure N applied in soil. Sup(15)N labeling can be useful for studying the dynamics and fate of animal manure N. Recently, sup(15)N labeling of an inorganic pool of cattle slurry (Paul and Beauchamp, 1995; Sorensen et al., 1995) and organic pool of animal manure (Kirchman, 1985; Sorenson et al., 1994) has been reported. The objectives of this research work were to produce sup(15)N-labeled animal manure, and investigate the fate of nitrogen in sup(15)N-labeled animal manure applied to both paddy and upland field.