施氮量对膜下滴灌棉花氮素吸收、积累及其产量的影响

2004年在膜下滴灌条件下,研究了施氮量0,180,270,360kg/hm2对膜下滴灌棉花氮素的吸收、累积和产量及氮肥利用率的影响。结果表明:施用氮肥可以显著提高棉花的生物和经济产量及地上部分总吸氮量,但过量施用氮肥对经济产量和生物产量增产不显著,各施氮处理氮肥利用率在27.6~33.8%之间,随施氮量的增加而降低。植株中氮素含量随生育延长而降低,氮素累积总体呈增加趋势,施氮量对棉花氮素吸收有显著影响,同一生育时期,氮素含量和累积量都随着施氮量增加而提高。本试验条件下,棉花的合理施氮量应控制在270 kg/hm2左右。

Effect of N Rates on N Uptake, Accumulation and Yield of Cotton under Drip Irrigation and Mulch

A field experiment was carried out to study the effects of N application on N uptake,accumulation yield and apparent N recovery in cotton under drip irrigation with mulch.Four N rates employed(0,180,270,360kg/hm2).The experiment was designed randomly.Each treatment was with 3 replications.The area of each plot was 48.6m2(13.5m×3.6m).30% of N fertilizer was used as basal fertilizer and 70% was used as topdressing fertilizer during the growth stage from bud to flowering_boll.Total P(P_2O_5) was 245kg/hm2,and K(K_2SO_4) was 2275kg/hm2.The results showed that N fertilizer application significantly increased yield,biomass yield and total N uptake of shoot of cotton in maturity,but expect over N fertilizer made yield decreasing.The apparent N recovery of all N treatments was ranged from 27.6%to 33.8%,which decreased with increasing of N application rates.N content in plant was decreased with the growth stages of cotton,but N accumulation in the tissue showed an upward tendency,N application rates influenced N uptake of cotton plant significantly.Both N content and N accumulation were increased with N rates increasing in the same growth stage.The recommendatory N rate for cotton should be 270 kg/hm2 under the experimental condition.