氮磷钾对红花草固氮根瘤菌生长及种植后土壤肥力的影响

Effect of NPK on Clover Nitrogen-fixing Rhizobia Growth and Soil Fertility after Plantation

为了发展有机水稻,以红花草-有机水稻轮作培肥水田土壤肥力,研究氮、磷、钾对红花草固氮根瘤菌生长及种植后土壤肥力的影响,为红花草的合理种植、培肥地力提供依据。2012—2013 2年稻后茬种植红花草,过冬前分别单独施用不同用量的氮肥、磷肥、钾肥,以不施肥为对照,探讨不同肥料不同用量对红花草产草量、固氮根瘤菌数量、固氮根瘤菌重量的影响及种植后的土壤肥力变化状况。研究结果表明:红花草前期补施氮、磷、钾,氮素对红花草的影响较大,在施氮75 kg/hm^2(N 46%)时,产草量最高,固氮根瘤菌数量最多,固氮根瘤菌重量大;种植后土壤全氮变化表现为不同施氮量增幅随肥料用量增加而增加,施磷、施钾各处理增幅随肥料用量增加而先降后升;土壤速效磷变化为施氮、施磷各处理增幅随肥料用量增加而增加,施钾各处理增幅趋势表现不明显;土壤速效钾变化表现为施氮、施磷各处理增幅变化趋势是随肥料用量增加先升后降,在施氮150 kg/hm^2(N 46%)、施磷300 kg/hm^2(P_2O_512%)时,土壤速效钾增幅达最大;土壤有机质变化表现为增幅随肥料用量增加而增加。所以,种植红花草,前期适当补施氮、磷、钾,可以提高红花草产草量,有效提高土壤肥力。

In order to develop organic rice and increase paddy soil fertility by clover-organic rice rotation, theauthors studied the effect of N, P and K on the growth of clover nitrogen-fixing rhizobia and soil fertility afterplantation, aimed to provide reference for the reasonable plantation of clover and soil fertility increase. A two-year experiment was conducted from 2012 to 2013, clover was cultivated after rice every year and differentlevels N, P and K fertilizer were applied before winter, CK treatment was without fertilizer. The effects ofdifferent fertilizers and different application amounts on clover yield, nitrogen-fixing rhizobia quantity,nitrogen-fixing rhizobia weight and soil fertility after plantation were analyzed. The results showed that theapplication of N, P and K in the earlier stage had significant effect on the growth of clover, when the nitrogenapplication amount was 75 kg/hm2（N 46%）, clover yield, nitrogen fixing rhizobium quantity and weightreached the maximum. Soil nitrogen content after plantation increased with the increase of the applicationamount of nitrogen fertilizer, while phosphorous and potassium content decreased and then increased with theincrease of the application amount. The content of available P increased with the increase of N and Papplication amount and had significant change with the application of K. The content of available K first increased and then decreased with the increase of N and P application amount, when N was 150 kg/hm2（N46%） and P was 300 kg/hm2（P2O5 12%）, the available K content reached the maximum. Soil organic mattercontent increased with the increase of fertilizer application amount. So, N, P and K should be applied in theearlier stage in clover plantation, which could increase clover yield and soil fertility.