基于暗管埋设的农田生态工程对运东滨海盐碱地的改良原理与实践

Principle and practice of saline-alkali soil improvement via subsurface pipe engineering in coastal areas of East Hebei Province

  • 摘要: 我国具有丰富的盐碱地资源, 滨海盐碱地是其重要组成。运东滨海平原盐碱地具有地下水埋深浅, 土壤盐分重, 土壤水盐季节性变化强烈等特点。基于上述特点, 该区域农作物限制因子为盐分胁迫、干旱和涝渍害。针对限制因子总结了各种农田生态工程手段的实施及原理。通过对当地常见作物3种胁迫的敏感时期分析, 结合农田生态工程原理, 在河北省南大港管理区的荒地进行了农田生态工程改良盐碱地实践研究。结果显示, 棉花、玉米的产量可分别达到2.23~3.98 t·hm-2和4.6~6.7 t·hm-2, 接近当地耕地的平均水平。小麦 玉米一年两熟粮食总产量可达9.6~10.8 t·hm-2, 小麦 谷子一年两熟粮食总产量达到9.1~11.9 t·hm-2。农田生态工程显著地增加了作物的种植适宜性, 使多种轮作制度成为可能。但是单项的生态工程技术都有一定的局限性, 如咸水结冰灌溉会增加土壤盐分, 暗管工程会降低土壤养分含量和有效性, 因此农田生态工程应系统化和体系化。多种技术手段互补, 最终实现调整盐碱地土壤水分、盐分季节性分配, 使作物避开盐分、水分胁迫敏感期, 使作物生长与土壤水盐季节变化耦合, 完成作物生命周期并形成产量, 最后在周年内达到土壤积盐与排盐平衡。暗管工程必将取代明沟作为盐碱地区排水的基础, 也是各项生态工程的基础。而农田生态工程技术的多样化、系统化和体系化是未来改良盐碱地的发展趋势。

     

    Abstract: Coastal saline-alkali soils form a critical component of the abundant saline soils in China. Shallow groundwater, highly saline soils and strong seasonal changes in soil water and salt are the main characteristics of saline coastal plains in East Hebei Province. Given these characteristics, salt stress, drought and water logging have been the main limiting factors to crop production in this area. This study summarized the principles and implementation of various farmland eco-engineering methods to overcome these limiting factors. It studied the improvements in saline soils via eco-engineering using sensitivity analysis of three kinds of stresses in local common crops in Nandagang. The results of the field experiment showed that yields of cotton and maize were respectively 2.23~3.98 t·hm-2 and 4.6~6.7 t·hm-2, which were close to the average level for local farmlands. Total wheat-corn yield at harvest was 9.6~10.8 t·hm-2 and the yield of wheat-millet reached 9.1~11.9 t·hm -2. Farmland eco-engineering significantly increased the suitability land for cropping and multiple crop rotation systems. However, single eco-engineering technology showed some limitations, for example, iced salt-water irrigation increased soil salinity and underground pipe system reduced soil nutrient content and effectiveness. Eco-engineered farmlands were systematic and circulative so that it enhanced redistribution of soil water, reduced soil salt content and prevented salt/water stress. However, there was still the need for more functional technologies to adjust crop to environment for optimal yield. Eco-engineering aimed at producing high crop yields and balanced soil salt content. For that purpose, underground pipe systems replaced the open-ditch systems as the basis of drainage and eco-engineering. Furthermore, eco-engineering was gradually becoming abundant, systematic in the saline-alkaline farmlands of East Hebei Province.

     

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