水田滿江紅 Azolla pinnata研究II.土壤與肥料因子對滿江紅生長之影響

Abstract

At the rate of N 54kg/ha, urea, Taiwan compound fertilizer No.1 and Taiwan compound fertilizer No. 4 killed the azolla, but ammonium sulfate did not. Low rates of urea, i. e. N 15 and N 5kg/ha, retarted the growth of the azolla. At the rate of N 45 kg/ha of ammonium acetate, ammonium carbonate and ammonium nitrate, the azolla was killed also, but ammonium chloride and ammonium nitrate were helpful for the growth of the azolla. The nitrogenase activity of the azolla was hardly influenced either by the high or the low concentrations of nitrate nitrogen in Tollen's solution, but was seriously inhibited by the application of ammonium sulfate at the rates of N 18, N 36 and N 54 kg/ha. The addition of superphosphate was helpful for the recovery of azolla's nitrogen nase activity which was inhibited by ammonium sulfate application. With and without P addition, the azolla grew more vigoriously in acidic soilwater than in calcareous soil water. The soil water of acidic slate alluvial soil was found to be The most suitable for azolla growth, while the calcareolus slate alluvial soil water was found to be the most unsuitable one. Water depth around 3-5 cm were better than that of 1 cm for the superphosphate application. The N. P. K. fertility tests in field showed that the P had the dorminant effect among these three elments.