苜蓿和草木樨腐解及养分释放规律的研究`

秋季将苜蓿、草木樨地上部茎叶(鲜样)剪碎,装入200目尼龙网袋中,水平埋置于土中10 cm深处,第二年春季开始至秋季分12次取样测定其干物质、碳、氮、磷、钾的残留量,得出干物质分解率、碳的矿化率及养分释放率。结果表明:苜蓿干物质的年分解率为75.4%,高于草木樨5.1个百分点;苜蓿碳的年矿化率为73.8%,高于草木樨4.4个百分点;苜蓿氮的年释放率为74.4%,高于草木樨18.6个百分点;苜蓿磷的年释放率为74.7%,高于草木樨23.3个百分点;苜蓿钾的年释放率为96.8%,低于草木樨0.1个百分点;2008年10月~2009年4月苜蓿、草木樨干物质的分解率分别占全年分解率的54.2%和46.4%,钾的释放率分别占全年的94.5%和92.8%。

Study on the Decomposition and Nutrient-Releasing Regulation of Alfalfa and Sweet Clover

Stems and leaves of alfalfa and sweet clovers＇（fresh samples） were cut into pieces and were put into 200 mesh nylon net bag, then were embedded into the underground at 10 cm deep horizontally in autumn. The next year sampling from spring to fall a total of 12 times to analyse their dry matter, residues of Carbon, Nitrogen, Phosphorus and Potassium, and obtained the decomposition rate of dry matter, the mineralization rate of Carbon and nutrient-releasing rate. The results showed that the annual decomposition rate of alfalfa＇s dry matter was 75.4%, 5.1 percentage point higher than that of the sweet clover＇s; the annual Carbon mineralization rate of alfalfa was 73.8%, 4.4 percentage point higher than that of the sweet clover＇s; the annual Nitrogen-releasing rate of alfalfa was 74.4%, 18.6 percentage point higher than that of the sweet clover＇s; the annual Phosphorus-releasing rate of alfalfa was 74. 7%, 23. 3 percentage point higher than that of the sweet clover＇s; the annual Potassium-releasing rate of alfalfa was 96.8%, 0. 1 percentage point lower slightly than that of the sweet clover＇s ; the decomposition rates of alfalfa and sweet clovers＇ dry matter from october in 2008 to april in 2009 were accounted for the annual decomposition rates＇ 54.2 % and 46.4%, respectively; and the Potassium-releasing rates of alfalfa and sweet clover from october in 2008 to april in 2009 were accounted for the annual decomposition rates＇ 94.5 % and 92.8 %, respectively.