红萍对水稻及土壤的作用

稻田养萍作为水稻氮源有着很大潜力,本文论述了北京地区不同萍种、插秧方式、施氮水平综合处理下田间试验的产量结果和改土作用。亩施6000斤鲜萍作稻田有机肥,当季可增产稻谷35%左右,相当于60斤硫铵的增产效果,后季增产5-10%,红萍对水稻生长的影响可分为抑制,恢复和促进三个阶段,中后期促进作用十分明显。采用大行距方式插秧利于稻萍双丰收,养萍结合施用氮肥增产效果更为显著,一般以养萍加施45斤硫铵,大行距插秧效益最高,连年养萍加施30斤左右硫铵为宜,稻田养萍后土壤有机质、水解氮含量增加,利于维持稻田养分平衡,土壤结构明显改善,孔隙增加,容重下降,生物活性增强,水肥气热协调,达到增产培肥,并有助于抑制杂草,减轻病虫害,避免过量采用化肥农药污染环境

THE EFFECT OF AZOLLA ON RICE AND PADDY SOIL

Two Azolla species,three transplanting patterns and three levels a- pplication were studied in Beijing in relation to rice yield and the effect on soil.Incorporating 45 tons fresh Azolla/ha gave an increase of paddy yield by 35% in first crop,which is equivalent to that obtained from 90kgN/ha.An additional yield increase was followed in second crop for 5-10%.wide-row transplanting was beneficial to both rice and Azolla.The optimum way in using Azolla is mixed culture of A.filiculoides and A. imbricata in pa...