黄土丘陵区盛果期苹果树土壤水分利用策略

Water Use Source of Apple Trees with Full Productive Agein Loess Hilly Region

【目的】探讨黄土丘陵区不同栽植年限苹果树水分利用策略,为果园水分管理与可持续发展提供参考。【方法】以10龄、15龄、22龄苹果树为研究对象,利用天然氘同位素与人工氘同位素示踪技术以及MixSIR模型分析不同水分来源对果树生长的贡献比例,探明其水分来源的季节变化规律。【结果】3个树龄苹果树水分利用来源差异较大,10龄苹果树主要水分来源从开花坐果期的中、深层(88.9%)转变为着色成熟期的浅层(57.9%)。15龄苹果树在开花坐果期和果实膨大期水分来源均以中层土壤水为主(74.2%、70.2%);而在着色成熟期则主要吸收利用浅层土壤水(59.3%)。整个生育期22龄苹果树均主要吸收利用浅、中层土壤水(利用比例分别为74.34%、86.07%、87.77%),深层土壤水利用比例逐渐降低。苹果树木质部样品中氘同位素的显著增加,表明果树可以通过吸收利用更深层土壤水分以缓解水分胁迫。【结论】3个树龄苹果树生育期内水分利用来源差异明显,随着树龄增加,水分来源逐渐变浅,用水策略趋于保守。根据不同树龄苹果树水分来源的季节变化对其进行合理的水分管理,有效降低果树非生产性耗水及自身奢侈性耗水,实现苹果园的持续健康发展。

【Objective】The water use strategy of apple trees indifferent planting years in the loess hilly region wasdiscussed in this study, in order to provide a useful reference for water management and sustainable development of apple orchards. 【Method】In this study, 10-, 15- and 22-year-old apple trees were selected as the object and the natural and artificial deuterium isotope tracer techniques and MixSIR model were used to analyze the contribution ratio of different moisture sources to apple trees growth to investigate the seasonal variation of its moisture source. 【Result】The results indicated that the source of moisture utilization varied greatly among the three apple trees of different ages.The main source of moisture of the 10-year-old apple trees changed from the middle and deep layers of flowering and fruit-bearing stage（88.9%）to the shallow layeratthe coloring and ripening stage （57.9%）. The main source of moisture for the 15-year-old apple trees came from the middle layer during the blossoming and bearing fruits period and fruit expanding stage; but in the coloring and ripening period, the apple tree mainly absorbed the shallow layer soil moisture.During the whole growth period, the 22-year-old apple trees mainly used shallow and middle soil moisture （74.34%, 86.07% and 87.77% respectively）,and the ratio of deep soil moisture utilization was decreased gradually.The significant increase in deuterium isotopes in xylem samples of apple trees showed that apple trees could alleviate water stress by absorbing deeper soil moisture.【Conclusion】There was an obviously difference in water use source of three stand ages apple trees. The water source was shallower gradually and more conservative with stand age increasing. Reasonable water management measures should be adopted to effectively decrease nonproductive water consumption and extravagant water consumption to realize sustainable and healthy development of orchards on the basis of water source seasonal variations for different stand age apple trees.