极端干旱区矮化密植大枣对滴灌的适应性及水肥耦合作用研究

Turpan-Hami area is located at the extreme arid area. The developed industry of fruit and horticulture is the pillar industry with local characteristics. Dwarfing and closely spaced planting of the local jujubes have been developed a new horticultural technology based on drip irrigation，and application area is growing in this area. In this project, based on water movement under different layout pattern of drip irrigation, experimental study and numerical simulation were made. Combining with the characteristic of root distribution, we will fix layout pattern of drip irrigation and formulate the corresponding irrigation system. We will observe the microclimate in the field after dwarfing and close planting the drip irrigation jujubes. And we'll combine the changes of flowering rate and fruit rate of jujubes in order to locate the main factors affecting the fruiting rate on field microclimate. We also try to reveal the influence law that flowering and fruiting are affected by the field climate, to put forward to the management method of water and fertilizer to improve the fruiting rate of jujube; We will do a plot experiment on controlling water and fertilizer, meanwhile we'll study the effect on the yield and quality of jujubes caused by water and fertilizer Interactively. With the aim of yield, quality, comprehensive benefits, the water and fertilizer coupling model of dwarfing and close planting jujube is established, and efficient management schedule will be formulated. The expected research achievement will provide theoretical and technical support for the innovation of water-saving technology and horticultural techniques, which is significant for the development of water-saving technology on local fruit industry.

吐鲁番哈密地区处于极端干旱区，当地林果园艺产业发达，是吐哈地区的特色支柱产业。当地大枣矮化密植是基于滴灌技术发展起来的园艺新技术，在该地区的应用面积越来越大。本项目针对滴灌不同布置模式下的水分运动规律进行试验研究和数值模拟，结合矮化密植大枣的根系分布特点，确定田间滴灌系统布置模式，并制定对应灌溉制度；监测滴灌大枣矮化密植后的田间气候，结合大枣开花坐果率变化，确定田间气候对坐果率影响的主要因素，揭示田间气候对大枣开花坐果的影响规律，提出提高大枣坐果率的田间水肥管理对策；开展小区水肥控制试验，研究水肥交互作用对大枣产量、品质的影响，以产量、品质、综合效益为目标，建立滴灌矮化密植大枣的水肥耦合模型，形成滴灌矮化密植大枣的田间水肥高效管理制度。预期研究成果对节水技术与园艺技术相互促进创新提供理论和技术支持，对当地林果业节水技术的发展具有重要意义。

项目通过试验研究了不同水肥条件下矮化密植大枣根系分布规律、水肥耦合效应对大枣生理特性的影响、不同水肥条件下土壤和枣树中全氮含量及N15同位素丰度变化、水肥耦合效应对矮化密植大枣的影响。研究得出以下结果：.1. 土壤中全氮含量随深度的增加而减少，在20 cm以上深度土层全氮含量值较大；N15丰度值由于分馏作用而表现为深度越大值越大。枝条和根系中的全氮含量相对较为稳定，N15丰度变化幅度不大。叶片和大枣中全氮含量和N15丰度变化较大，能够反映N在叶片和大枣中有富集现象。在适宜的灌水定额时，氮肥的吸收利用率最高；生育初期施入氮肥，贡献率在灌溉定额较低时对作物的贡献率较高；氮肥的偏生产力随施肥量增加而降低。.2. 相同灌水量情况下，浅层土壤容易与外界进行热交换，土壤温度更容易受到气温的影响，波动范围大，深层土壤受大气温度影响小。灌水量越大，土壤温度下降值就越大，土壤表层温度下价值最大；深层土壤下降值较小且变化相对稳定。滴灌技术可以使土壤的温度相对稳定，有利于大枣的生长。.3. 在施肥量较低的情况下，灌溉定额较低的处理，叶片气孔导度出现峰值的时间早于灌溉定额大的处理；在施肥量较高的情况下，灌溉定额较大的处理，叶片气孔导度更早出现较大值。较大的灌溉定额或较高的施肥量处理，对枣树叶片的维持较高蒸腾速率更为有利。相同灌溉定额时，光合速率随施肥量增大而变大；而灌溉定额对光合速率影响相对较小。不同水肥条件下，矮化密植大枣光合特性与水肥条件之间的关系，并不表现为单一的线性关系，而是表现出耦合关系。.4. 在水平方向上，距离树干越近，根系分布越密集；采用漫灌方式进行灌溉时，根系分布与滴灌相比更加均匀；在垂直方向上，根系分布较为密集的区域为20 cm~30 cm和60 cm~80 cm两个深度土层。较低灌溉定额和适宜的灌溉定额时，增加施肥量有利于提高产量；过高的灌溉定额时，增加施肥量产量反而降低。相同施肥量时，矮化密植大枣产量随灌溉水量的增加而增加。.项目研究成果对节水技术与园艺技术相互促进创新提供理论和技术支持，对当地林果业节水技术的发展具有重要意义。结合本项目培养硕士研究生4名，发表论文10篇，其中核心期刊8篇，EI 检索1篇，SCI 检索1篇，申请国家实用新型专利5项，国家发明专利8项。