稻田有机肥的分解动态研究

RESEARCH ON DECOMPOSITION DYNAMICS OF ORGANIC MATTER IN RICE FIELDS

用网袋法研究了早稻稻杆,晚稻稻杆,红萍(Azolla imbricata (Roxb)Nakai)及紫云英(Astragalus sinicus L.)在水田耕作层的分解动态,结果表明干物重、含氮量、含磷量和含钾量的残存百分率(y)均可用y=a·t描述,其中t为分解时间,a、b为回归系数,有机物中氮的释放速度慢于磷钾的释放速度,分解残留物的氮含量趋向1％。有机物氮含量(％)与干物重消失50％所需时间之间的相关系数R=-0.997 5。

Decomposition dynamics of rice ( Oryza sativa L. ) straw of early rice and late rice.azolla ( Anolla imbricata (Roxb) Nakai) and Chinese vetch ( Astragalus sinicus L. ) were studied by a plastic net bag method. Result showed that the equation y = a·t could be used to describe the percentage of dry matter .nitrogen , phosphorous and potasium remaining in the residue (y) after t days of decomposition. The 'a' and 'b' are regression parameters. The releasing rate of nitrogen was slower than the releasing rates of potasium and phosphrous. The nitrogen contained in the residues from different materials converged to 1 % during the decomposition processes. The correlation coefficent between the nitrogen content of organic matters and the number of days required for 50% loss of the dry matter was - 0. 997 5.