环渤海盐碱地“池-田”改进模式提高棉花产量的生理生态机理研究

Large area of coastal saline-alkali land is covered in China, whose development and utilization will be the main contents of improving medium and low-yield fields and the solution to resolve the planting contradictory between cotton and grain in China. The stress threatens in Bohai rim saline-alkali area, such as salinity-alkalinity, drought and waterlogging etc. severely inhibit and the yield improvement in cotton. Present research results showed that the improved model of “pool and raised-bed” significantly alleviated the adversity stress threaten in Bohai rim saline-alkali area. However, the physiological ecology mechanism of yield improvement in cotton was not clear. According to the change of groundwater and the soil physicochemical properties of water-salt migration under the improved model of “pool and raised-bed” and the distribution of water-salt in cotton, this project will study the photosynthetic performance in cotton and the variation of mass accumulation and distribution, expound ecology mechanism of photosynthetic production affected by the improved model of “pool and raised-bed”. Based on these researches, the canopy photosynthetic production and the transportation and partitioning efficiency of photosynthate will be improved by combining with sowing and density techniques, and the physiological mechanisms and the yield potential will be exploited fully in the pathways of photosynthetic production improvement.This research will be significant importance to enrich the theoretical system of cotton plantation in saline-alkali soil and provide important theoretical reference for improving the production technology of stress-resistant and high yield cotton in Bohai rim saline-alkali area.

我国拥有的大量滨海盐碱地，其开发利用是我国中低产田改造重要内容和解决粮棉争地矛盾主要出路。环渤海盐碱地旱涝盐碱等逆境胁迫严重阻碍棉花产量提高。本课题组研究表明，“池-田”改进模式显著缓解环渤海盐碱地逆境胁迫，但提高棉花产量的生理生态机理尚不清楚。本项目从环渤海盐碱地“池-田”改进模式棉田地下水变化及土壤水盐运移等理化性质和水盐在棉株体内分布入手，研究环渤海“池-田”改进模式棉花光合性能和物质积累与分配的变化，阐明环渤海“池-田”改进模式影响盐碱地棉花产量形成的生态机理；在此基础上，通过播种、密度等栽培技术提高铃期群体光合生产和运输分配效率，探寻充分挖掘光合增产潜力的生理机理与途径。研究结果对丰富盐碱地植棉理论体系具有重要意义，同时为探寻环渤海盐碱地抗逆高产棉花生产技术途径提供重要理论参考。

环渤海盐碱地盐碱旱涝严重，严重制约棉花生产发展。传统改良措施土壤改良效果难以持久，逆境胁迫容易反复。滨海地区坑塘数量及储水丰富，可以用来改变滨海盐碱地盐碱旱涝状况。本课题组在前人的研究基础上提出了“池-田”改进模式，但其缓解环渤海盐碱地逆境胁迫的机制及提高棉花产量的生理生态机理尚不清楚。本项目对“池-田”改进模式的特征进行研究总结，提出了环渤海盐碱地“池-田”蓄引水模式。该模式中台田和地下水抽提田浅层地下水位显著降低，延长了盐分表聚距离；地下水盐分台田降到6.0 g/L，地下水抽提田降到5.3 g/L；周围农田0～80 cm土层盐分和pH值显著降低，台田和浅层地下水抽提田盐分降至3.0 g/kg左右，pH值低于8.0；抑盐排涝田盐分低于5.0 g/kg。雨季（7－8月）pH值低于8.0；浅层地下水抽提田水分0～40 cm土层高于20%。棉花植株台田含氮和磷含量较高，钾和钠离子含量较低；氮和磷含量高铃中体现最为明显；抑盐排涝棉田铃中氮含量，叶和铃的钾含量以及叶的磷含量较高，茎的钠含量较低。台田在节水灌溉条件下棉花光合性能长期保持高值，光合物质积累直线增长期结束时间最迟，持续时间和积累活跃期最长。浅层地下水抽提棉田在无灌溉条件下光合光合性能高值较长，光合生产指标整个花铃期保持较高数值，光合物质积累情况较好。抑盐排涝棉田产量形成关键期7-8月份棉花光合性能明显提高，籽棉产量超过了2500 kg·hm−2。播期为4月28日、5月2日时，密度为4.50 万株·hm-2时，单株光合物质积累量最高，冠层各层次源库比上层略高于1.0，中下层为1.5左右。冠层中下层叶面积和叶倾角较大，冠层开度较小。冠层各层次单叶和群体光合速率最高，中下层叶绿素相对含量SPAD值显著较高；产量水平最高，皮棉产量均超过1200 kg·hm−2水平。环渤海盐碱地“池-田”蓄引水模式显著改善盐碱胁迫状况，在其他农艺措施的配合下为滨海盐碱地棉花高产提供充分条件，为滨海盐碱地区因地制宜实施生态改良提供了技术支撑和理论依据。

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