Abstract
In the previous paper, it has been reported that the nitrate-reduction in paddy field soil is closely related with the formation of ferrous iron in soil. In this paper, the author conducted several experiments on the nitrate-reduction in the soil stood previously with water before nitrate-addition and the results obtained will be summarized as follows; 1) The amount of reduction was remarkably decreased by standing soil with water before nitrate-addition. (with both dry and paddy field soils) 2) The reduction of nitrate was fairly increased by stirring soil before nitrate-addition. 3) The potential of soil kept under stagnation previously before nitrate-addition was not entirely lowered farther, but increased gradually. 4) The % of the reduced nitrogen was greater, the smaller the quantity of nitrate applied and its actual amount was smallest in 2mg plat and was almost same with cases of 5 and 10mg. 5) The reduction of nitrate was markedly decreased in acid condition and at pH 5 and 2 weeks previous standing, this decrease was from 20.4% to 63.0%
