| 摘要: |
| 【目的】探明土壤水氮盐耦合对膜下滴灌棉花生理生态指标及产量、水氮利用效率的影响，明确不同程度盐渍化土壤中适宜的水氮措施。【方法】基于膜下滴灌棉花盆栽试验，采用“3414”试验方案，分别设置灌水量（W0：1 575 m3/hm2、W1：2 100 m3/hm2、W2：2 625 m3/hm2和W3：3 150 m3/hm2）、施纯氮量（N0：0、N1：150、N2：300和N3：450 kg/hm2）、土壤盐分（S0：非盐化土、S1：轻度盐化土、S2：中度盐化土和S3：重度盐化土）三因素试验，研究水氮调控对不同程度盐渍化土壤膜下滴灌棉花生长发育及水氮利用效率的影响。【结果】水氮盐耦合效应对棉花株高、茎粗、叶面积指数、净光合速率、蒸腾速率及气孔导度均有显著影响（P<0.05）。在土壤施氮量、含盐量或灌水量、含盐量相同时，适当增加土壤灌水或施氮量，可显著促进棉花株高、茎粗、叶面积指数的增加及产量的提高；在土壤灌水量、施氮量相同时，土壤含盐量对棉花生长存在阈值。水氮盐单因素及施氮量与土壤含盐量的交互作用均对棉花生长指标及产量、水分利用效率、氮肥偏生产力有极显著影响（P<0.01）。各处理中，N1S1W2处理的产量、水分利用效率和氮肥偏生产力最大，分别比较低的N2S2W0处理高172.01%、60.71%、444.08%；N2S2W3处理的产量较N1S2W1处理高71.46%，即土壤盐渍化相对较重时，增加灌水量及适度的增加施氮量可促进棉花产量的提高。通径分析发现，灌水量对棉花产量的正向促进作用最大；土壤含盐量则产生负向的抑制作用。【结论】土壤处于轻度盐渍化时，灌溉定额2 625 kg/hm2、施纯氮量150 kg/hm2最适宜棉花的生长；土壤盐渍化较重时，灌溉定额3 125 kg/hm2、施纯氮量300 kg/hm2可以有效改善土壤盐渍化对棉花生长的负面影响，最大程度提高棉花产量。 |
| 关键词: 棉花；盐碱地；膜下滴灌；生长指标；产量 |
| DOI：10.13522/j.cnki.ggps.2022001 |
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| Improving Soil Water and Nitrogen Management to Facilitate Growth and Water-nitrogen use Efficiency of Cotton in Saline-alkali Soils |
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WANG Peihua, SHI Wenjuan, ZHANG Yanchao
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State Key Laboratory of Eco-hyraulics in Northwest Arid Region of China, Xi’an University of Technology, Xi’an 710048, China
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| Abstract: |
| 【Objective】Soil salinity is an abiotic stress faced by agricultural production in many countries. Improving agronomic practices to alleviate the detrimental effect of soil salinity is essential to sustaining crop production in salt-affected areas. This paper aims to study the combined effect of soil water, nitrogen and salt content on physiological and ecological indexes as well as yield of cotton under mulched drip irrigation in saline-alkali soils.【Method】The study was based on pot experiment. It consisted of four irrigation amounts: 1 575 (W0), 2 100 (W1), 2 625 (W2) and 3 150 m3/hm2 (W3); four nitrogen fertilizations: 0 (N0), 150 (N1), 300 (N2) and 450 kg/hm2 (N3), and four salt stress treatments: non-salinity (S0), light salinity (S1), moderate salinity (S2) and heavy salinity (S3). All pots were irrigated by mulched irrigation and for each pot, we measured the growth, water-nitrogen utilization efficiency of the cotton.【Result】Change in irrigation amount, nitrogen application and soil salinity had a significant impact on plant height, stem diameter, LAI, Pn, Tr and Gs (P<0.05). When soil nitrogen application, soil salinity and irrigation amount were the same, increase in soil water or nitrogen content boosted plant height, stem diameter, LAI and cotton yield significantly. When soil irrigation amount and nitrogen application were the same, there was a threshold soil salt content beyond which the effect of soil salinity on cotton growth ushered in. Interaction analysis showed that soil water, nitrogen and salt content had a combined significant effect on growth index, yield, WUE and PFP of the cotton (P<0.01). Among all treatments, N1+S1+W2 gave the highest yield, WUE and PFP, while N2+S2+W0 was the worst, with its yield, WUE and PFP reducing by 172.01%, 60.71% and 444.08%, respectively, compared to CK (without salinity). The yield of N2+S2+W3 was 71.46% higher than that of N1+S2+W1. That is, when soil salinization was high, increasing irrigation amount and nitrogen application could offset the detrimental impact of soil salinity and increased cotton yield. Path analysis showed that irrigation amount and soil salt content had the most positive and negative effect on cotton yield, respectively.【Conclusion】For the slightly salinized soil, irrigating 2 625 kg/hm2 of water coupled with 150 kg/hm2 of nitrogen fertilization was effective to alleviate the effect of soil salinity, while for the severely salinized soils, irrigating 3 125 kg/hm2 of water combined with 300 kg/hm2 of nitrogen fertilization worked better to ameliorate the effect of soil salinization and maximize cotton yield. |
| Key words: cotton; saline-alkali land; mulch drip irrigation; growth target; yield |
