盐氮效应对棉花氮素分配、转运和利用效率的影响

Effects of Salt and Nitrogen Synergism on Nitrogen Distribution,Transport and Use Efficiency in Cotton

探究盐氮效应对棉花氮素动态积累、运转及利用效率的影响机制。以棉花“新陆中68号”为材料,设置土壤盐分含量为S1(2.5~3 g/kg)、S2(5~6 g/kg)和S3(8~9 g/kg),施氮量分别N1(105 kg/hm^(2))、N2(210 kg/hm^(2))、N3(315 kg/hm^(2))处理进行田间小区试验。通过Logistic生长函数模型对各器官生物量氮素累积进行拟合,以V m(最高累积速率)和Δt(持续时间)为2个动态特征指标分析盐氮对棉花生物量氮素快速累积时间和速率的影响。结果表明,营养器官(根、茎、叶)生物量S1N3处理最大,棉铃生物量S1N2处理最大,S3条件下棉铃生物量表现为N3>N2>N1。各营养器官积氮量S2处理均达到较大,在S1和S2中茎积氮量为N2>N3>N1。在S2和S3中叶积氮量为N3>N2>N1,棉铃积氮量为S1>S2>S3和N3>N2>N1,根积氮量N3>N2>N。N1S3处理各营养器官生物量积氮量Δt最小,V m最大。盐分显著抑制棉花各器官生物量和氮素积累量及V m(P<0.5)。施氮量与土壤盐分存在明显的互作效应。氮肥在盐分S1和S2中N2和在盐分S3中氮肥N3最利于生殖器官生物量积累及V m。盐分越高,氮素运转率越低。施氮量促进氮素运转率。各器官积氮量累积和营养器官氮分布使作物氮分布更均衡,导致产量的最优。S1N2产量最大达到6683 kg/hm^(2)。氮肥在盐分S1和S2中N1氮利用效率最优,盐分S3中氮肥N2最利于氮利用效率。因此在盐分<6 g/kg土壤施用氮肥105 kg/hm^(2)或210 kg/hm^(2),最利于棉花生产和效益。盐分在8~9 g/kg土壤应施用氮肥315 kg/hm^(2)。研究结果为合理利用盐碱土和施肥管理提供科学依据。

The objective of this study was to explore the effects of salt and nitrogen on the dynamic accumulation,transport and use efficiency of nitrogen in cotton.Taking cotton Xinluzhong 68 as material,afield plot experiment was carried out under threesoil salt contents of S1(2.5~3 g/kg),S2(5~6 g/kg)and S3(8~9 g/kg),respectively,also with three nitrogen levels of N1(105 kg/hm^(2)),N2(210 kg/hm^(2))and N3(315 kg/hm^(2)),respectively.The results showed that the biomass of vegetative organs(root,stem and leaf)under S1N3 was the largest,while the biomass of cotton boll under S1N2 was the largest,and the biomass of cotton boll was N3>N2>N1 under S3 condition.In S1 and S2,nitrogen accumulation in stem was N2>N3>N1.In S2 and S3,N3>N2>N1.Nitrogen accumulation of cotton boll was S1>S2>S3,N3>N2>N1.Root nitrogen accumulation was N3>N2>N1.Logistic growth function model was used to fit the accumulation of biomass nitrogen in each organ,R 2>0.9.The maximum cumulative rate V m and durationΔt were two dynamic characteristics.In N1S3 treatment,Δt was the smallest and V m was the largest.Salt significantly inhibited the biomass,nitrogen accumulation and V m incotton organs.There was an obvious interaction between nitrogen application and soil salinity.The results showed that N2 in S1 and S2,and N3 in S3 were the best for biomass accumulation and V m of reproductive organs.The higher the salinity,the lower the nitrogen transfer rate.The amount of nitrogen applied promoted the nitrogen transfer rate.The maximum yield of S1N2 was 6683 kg/hm^(2).The accumulation of nitrogen accumulation in various organs and the distribution of nitrogen in vegetative organs madethe distribution of crop nitrogen more balanced,resulting in the optimal yield.The nitrogen use efficiency of N1 was the best in S1 and S2,and N2 was the best in S3.Therefore,applying 105 or 210 kg/hm^(2) nitrogen fertilizer in soil with salinity less than 6 g/kg is most beneficial to cotton production and benefit.315 kg/hm^(2) of nitrogen fertilizer should be applied when the soil salinity is 8~9 g/kg.These findings could provide scientific basis for rational utilization of saline alkali soil and fertilization management.