盐氮效应对棉花氮素分配、转运和利用效率的影响

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/hm2)、N2(210 kg/hm2)、N3(315 kg/hm2)处理进行田间小区试验.通过Logi...

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

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/hm²), N2 (210 kg/hm²) and N3 (315 kg/hm²), 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, R²>0.9. The maximum cumulative rate V_m and duration Δt 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 6 683 kg/hm². 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/hm² nitrogen fertilizer in soil with salinity less than 6 g/kg is most beneficial to cotton production and benefit. 315 kg/hm² 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.