钾肥对苜蓿植株吸收氮磷钾的影响

Effects of potassium fertilizer on N,P_2O_5 and K_2O absorption of alfalfa

通过田间试验探讨钾肥对苜蓿植株吸收氮、磷、钾的影响。结果表明,在播种当年,施钾肥降低了苜蓿植株中N和P2O5的百分含量,增加了K2O的百分含量。苜蓿植株中N、P2O5和K2O的积累量均可用曲线方程Y=eb0+b1/X来表达,拟合良好。高钾处理降低了苜蓿干草中N和P2O5的积累量,施钾均增加了K2O的积累量,但K2O的积累量不随施钾量的增加而持续增加。施钾对N的吸收速率影响不明显,但有利于提高K2O的吸收速率;施相对低水平钾可提高磷的吸收速率,高水平钾则降低了磷的吸收速率。

A field trial was carried out in two years in order to investigate the effect of potassium fertilizer on N, P2O5 and K2O absorption of alfalfa . The result showed that basic potassium fertilizer application decreased N and P2O5 content of first- year alfalfa , and increased K2O content. Shape curve was used to simulate N, P2O5 and K2O accumulation in alfalfa. Low potassium fertilizer application increased N and P2O5 accumulation, while high potassium fertilizer application decreased N and P2O5 accumulation. Potassium fertilizer application increased K2O accumulation, but K2O accumulation didn＇t continuously increase with potassium fertilizer increment. Potassium fertilizer had no effect on N absorption rate but could improve K2O absorption rate. Low potassium fertilizer application increased P2O5 absorption rate, high potassium fertilizer decreased P2O5 absorption rate.