Mineralization of soil nitrogen and nitrogen absorption by rice plants derived from soil and from irrigation water in paddy fields with continuous application of rice straw compost
Takahashi, S.; Yamamuro, S.
Japanese Journal of Soil Science and Plant Nutrition 63(5): 505-510
In field experiments at Chugoku National Agricultural Experiment Station rice straw compost was applied at 0, 2 or 5 t/ha each year for 24 years. The rate of N mineralization and the amount of N taken up by rice plants increased with straw application rate. The amount of N mineralized between 27 June and 5 Sep. in plots given 2 and 5 tons straw/ha were 43 and 94% more, respectively, than that of the plots with no straw applied. The amount of N taken up by the plants gradually increased and reached the maximum level between 18 and 25 July, after which it gradually decreased. The amount of N absorbed from soil between 27 June and 29 Aug. in plots given 0, 2 and 5 t straw/ha was 3.49, 6.11 and 7.49 g/msuperscript 2, respectively.