一次和多次注射施肥对薄壳山核桃生长及品质的影响

Effects of one and multiple-injection fertilization on pecan growth and quality

【目的】探究同一施肥量下注射施肥次数对薄壳山核桃生长发育及品质的影响,为薄壳山核桃科学施肥提供技术依据。【方法】以13年生薄壳山核桃成年树‘马罕’为试材,在浙江金华进行田间试验。设置3个处理,分别为不注射对照、在树干基部距地面l5~25 cm处钻孔进行一次注射处理、多次(5次)注射处理,一次和多次注射处理的总施肥量相同。测定果实成熟期叶片和果实生物量及不同部位的养分含量,并调查果实外观和营养质量指标。用PLS-DA方法确定施肥处理对果实各指标差异的贡献。【结果】矿质元素在叶片中积累较多,其次是种仁,在木质部和韧皮部中积累较少。多次注射处理薄壳山核桃单果质量、单果径和核果高较对照分别显著增加了16.99%、7.52%和6.79%,较一次性注射处理分别提高了13.03%、4.50%和6.26%(P<0.05);种仁不饱和脂肪酸含量以及不饱和脂肪酸与饱和脂肪酸的比值均显著高于一次性注射处理(P<0.05);薄壳山核桃叶片Ca和Fe含量,种仁Mg、Mn、Cu和Zn含量,韧皮部Fe含量及木质部N和Ca含量均显著高于对照和一次注射处理(P<0.05);施肥处理对矿质元素在树体不同部位的分配没有显著影响。PLS-DA结果表明,一次和多次注射处理间存在显著差异,导致薄壳山核桃品质差异的主要物质为棕榈酸、棕榈油酸和种仁Cu含量。【结论】同一施肥量下,多次(5次)注射处理促进薄壳山核桃的生长,改善种仁品质,有助于树体各部位矿质营养元素的积累。

【Objectives】This study investigated the effect of the injection frequency of liquid fertilizer on pecan growth and quality.We aim to provide the technical basis for the fertilization of pecan.【Methods】A field experiment was conducted in Jinhua,Zhejiang Province,using 13-year-old pecan adult trees(Mahan)as test material.Fertilization treatments included no injection control,one injection,and multiple injections(5 times),drilling holes at the base of the trunk from l5 to 25 cm from the ground.Both injection treatments were applied at the same total fertilizer rate.The leaf and fruit biomass and the nutrient contents of the tree parts were determined at harvest.Further,the fruit appearance and nutritional quality indicators were investigated.The contribution of the fertilizer treatments to differences of the fruit indicators was determined by the PLS-DA method.【Results】The accumulation of mineral elements was highest in the leaves,followed by the kernels,with less concentration in the xylem and phloem.Multiple injections(P<0.05)increased pecan fruit weight,diameter,and nut height by 16.99%,7.52%,and 6.79%compared with the control,and by 13.03%,4.50%,and 6.26%compared with one injection.Multiple injections had(P<0.05)higher unsaturated fatty acid content in kernels and the ratio of unsaturated to saturated fatty acids than one-injection.Multiple injections recorded higher Ca and Fe content in pecan leaves,Mg,Mn,Cu,and Zn content in kernels,Fe content in phloem,and N and Ca in the xylem than the control.However,fertilizer treatments did not affect(P>0.05)mineral distribution in different tree parts.The PLS-DA results showed the significant differences(P<0.05)between one and multiple injection treatments;the main substances responsible for the differences in pecan quality were palmitic acid,palmitoleic acid,and kernel Cu content,respectively.【Conclusions】With the same fertilizer rate,multiple injections are more effective than one injection in promoting pecan tree growth,improving kernel quality,and accumulating mineral nutrients in various parts of the tree.