Abstract
Nitrogen balance was measured in lysimeter experiments to clarify nitrate leaching in Ando and sandy soils. The amount of leaching water was increased in proportion to precipitation. The percentages of leaching water to precipitation was 39 in the Ando soil and 59 in the sandy soil. Crop uptake of the fertilizer nitrogen in the sandy soil was smaller than that in the Ando soil in all of the crops investigated. The percentage of leached fertilizer nitrogen was 25-32 in the Ando soil and 58-66 in the sandy soil. In the Ando soil, the leaching of fertilizer nitrogen under winter cropping was more than that under summer cropping. It was suggested from the hydrograph of upland rice cultivation that fertilizer nitrogen started to leach in the small-pore volume (amount of leaching water/whole pore space) in both the Ando and sandy soils.
