NUTRIENT CYCLING IN WHEAT-RICE AND BARLEY-RICE-RICE ROTATION SYSTEMS OF THE TAI LAKE REGION I.REMOVING AND REMAINING OF NUTRIENTS IN THE CEREAL GRASSES
Abstract:Field experiments were made on the three fertilizer treatments, such as native fertilizer, no fertilizer and pig manure, in the rotation systems of wheat-rice and barley-rece-rice in three different soils-wushan, Huanni (yellow loam) and Shanxuebeitu (white soil with Fe-humus coatings) Plots of the field experiments were taken as models of paddy field ecosystems. The total amount of nutrients removed by crop harvest in most systems during the rotation from Oct. 1982 to Oct. 1983 were in the sequense ofSi>N>...