节水减肥对苹果果实品质形成的影响机理及多目标综合评价研究

Irrigation and fertilization are the two big controllable factors of fruit quality which affecting the formation. And how to use integrated technology of water and fertilizer to explore reasonable irrigation and fertilization system has become an urgent scientific problem in modern orchard production. The present study on the integration of water and fertilizer in orchards did not consider the influence of water and fertilizer on the formation process of fruit quality, nor did it establish a multi-objective comprehensive evaluation method based on quality. This project takes apple as research object to exploring the influence of water-saving irrigation and fertilizer reduction on apple tree roots zone moisture and nutrients migration, effectiveness, absorption, especially the nutrient elements in apple leaves migrate and transform into fruits and the formation of quality under integration of drip irrigation and fertilization conditions in northern semi-arid region. Meanwhile, it will reveal the influence mechanism of water saving and fertilizer reducing on apple dynamic formation process to achieving the goal of maximally improve fruit quality by changing different irrigation and fertilizer. At last, building a multi-objective optimal control strategy based on apple quality comprehensive evaluation method to seeking the optimal irrigation and fertilization system in multiple targets (irrigation, fertilization, quality) for providing a scientific basis of apple water and fertilizer management, fruit quality regulation and comprehensive evaluation.

灌溉和施肥是影响果树果实品质形成的两大可调控因素，如何利用现代的水肥一体化技术探索合理的灌溉和施肥制度已成为现代果园生产中迫切需要解决的科学问题。现有的水肥一体化研究并未考虑水肥对果实品质形成过程的影响，也没有构建一种基于品质的多目标综合评价方法。本项目以苹果为研究对象，在滴灌施肥一体化条件下探索节水灌溉和肥料减施对北方半干旱地区苹果树根区水分养分迁移、有效性、水分养分的吸收、特别是苹果叶片营养元素向果实中迁移和转化以及对品质形成的影响，揭示节水减肥对苹果果实动态形成过程的影响机理，达到通过改变不同的滴灌和施肥量，实现最大限度的提高果实品质的目的，构建一种基于苹果品质的多目标最优控制策略的综合评价方法，寻求在多种维度目标上（灌水、施肥、品质）均到达较优的最佳灌水和施肥制度，为苹果水肥管理和品质调控与综合评价提供科学依据。

灌溉和施肥是影响果树生长发育和果实品质形成的两大可调控因素，目前果园灌溉施肥管理较为粗放，大水漫灌方式依然存在，过量施肥造成的面源污染问题也日益突出，如何利用现代的滴灌施肥一体化技术探索合理的灌溉和施肥制度已成为现代果园生产中迫切需要解决的科学问题。本项目采用果园滴灌施肥一体化试验和室内分析试验相结合的方法，开展了节水减肥调控水肥处理对苹果生长、生理指标、水肥利用效率以及产量和果实品质的影响研究，重点探究了相关指标间的关系，特别是节水减肥调控下各指标对果实品质形成的影响机理以及采用各指标建立多目标综合评价模型。不同水肥调控下苹果树各生育期植株生长量最大值均出现在F1W2处理，F1W2与F1W1处理相比净光合速率、蒸腾速率、气孔导度分别降低了2.1%、11.5%和3.0%，F1W2与F1W1处理间产量差异不明显。单果质量最大值出现在F1W2处理，节水处理和增加施肥量有利于提高苹果果实硬度和维生素C含量，增加灌水有利于提高着色指数和果形指数，可降低可滴定酸含量和一定程度提高糖酸比，增加施肥量有利于提高果实可溶性固形物和可溶性糖。干物质量和水分生产率在F1W2处理下均达到了最大值，与F1W1相比分别增加了0.6%和11.1%，耗水量却减少了9.4%，水分利用效率最大值出现在F1W2处理，与F1W1相比提高了10.6%，肥料偏生产力轻度节水调控与充分供水差异不明显。通过分析节水减肥对苹果生长发育指标的影响规律和果实品质形成机理，采用AHP层次分析法和熵权法对各单一指标进行主观赋权和客观赋权，然后利用组合赋权法计算出各个指标综合权重值，最终基于TOPSIS法构建了以高效、高产和高品等为目标的苹果综合指标评价模型，得出F1W2水肥调控处理是苹果种植的最佳水肥耦合制度。本研究结果对制定科学合理的灌溉和施肥制度与品质调控策略和保障北方半干旱地区果树产业健康发展都具有重要的意义。