薄壳山核桃叶面喷锌效果的评价

  目的  探明叶面喷锌肥对薄壳山核桃Carya illinoensis生长的影响，为果树施肥提供科学依据。  方法  以6年生薄壳山核桃‘波尼’‘Pawnee’为试材，设置乙二胺四乙酸锌钠(EDTA-Zn)、硫酸锌(ZnSO₄·7H₂O)、硝酸锌Zn(NO₃)₂·6H₂O]等3种锌肥和50、100、150 mg·L?1锌等3个质量浓度水平，共10个处理组(以不喷锌为对照组)进行叶面喷施，分析生长指标(叶长、叶宽、叶面积、含水率、比叶重、树高、胸径)和叶片矿质营养元素(氮、磷、钾、钙、镁、锌、铁、锰、铜)的质量分数变化，并采用主成分分析和加权隶属函数相结合的方法对叶面喷锌效果进行评价。  结果  随喷锌质量浓度递增，薄壳山核桃叶片及树高、胸径指标均有一定程度增大。与对照相比，150 mg·L?1硝酸锌处理的各项形态生长指标增长显著(P＜0.05)，特别是叶长、叶宽、叶面积和比叶重，分别超出对照26%、37%、25%、17%。随喷锌质量浓度递增，叶片氮、钾、锌、锰质量分数均呈上升趋势；磷、铁质量分数不断下降；钙、镁质量分数先升高后下降。相关分析表明:叶片中锌质量分数与叶长、叶宽和氮、钾质量分数呈显著正相关(P＜0.05)，与叶面积和钙、锰质量分数呈极显著正相关(P＜0.01)。  结论  在一定范围内叶面喷锌肥能显著促进薄壳山核桃叶片生长(P＜0.05)，并促进叶片矿质营养元素的积累。因此，建议薄壳山核桃喷锌肥可选用150 mg·L?1硝酸锌或100 mg·L?1硫酸锌或100 mg·L?1乙二胺四乙酸锌钠。图2表4参30

Evaluation of foliar spraying of zinc in Carya illinoensis

  Objective  With the effect of foliar spraying of zinc (Zn) on leaves growth and mineral elements of pecans (Carya illinoensis) explored, the study is aimed to provide scientific basis for the fertilizer control of fruit trees.  Method  Using 6-year-old ‘Pawnee’ pecans as the research material under field conditions, a field experiment was conducted with 3 types of zinc fertilizers, such as EDTA-Zn, zinc sulfate (ZnSO₄·7H₂O), zinc nitrate Zn (NO₃)₂·6H₂O)] sprayed at 3 levels of concentrations (50, 100, 150 mg·L?1 Zn) in terms of 10 treatments (with 0 mg·L?1 Zn as control). Treatments were replicated three times in a randomized complete block design to measure the growth parameters (leaf length and width and area, rate of water content, specific leaf weight, tree height and diameter) and leaf mineral elements nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), zinc (Zn), iron (Fe), manganese (Mn), copper (Cu)]. These parameters were initially evaluated with the employment of principal component analysis (PCA) and weight subordinate function (WSF).  Result  The leaf growth parameters and tree height and diameter increased to a certain extent with the increased concentration. The leaf length, width, area, specific leaf weight increased by 26%, 37%, 25%, 17% with the 150 mg·L?1 of zinc nitrate treatment respectively, which was significantly higher than that with other treatments (P＜0.05). With the increased concentration, the N, K, Zn, Mn contents of pecan leaves increased and the P, Fe content decreased while the Ca and Mg contents first increased and then decreased. As was shown in the correlation analysis, the length, width, N, K were significantly and positively correlated (P＜0.05) to Zn in leaves while the coverage, Ca, Mn were significantly and positively correlated (P＜0.01) to Zn in leaves.  Conclusion  Foliar spraying of zinc has significantly improved the leaf growth of pecans (P＜0.05) and increased the accumulation of mineral elements in leaves. Thus, it was suggested that 150 mg·L?1 of zinc nitrate or 100 mg·L?1 of zinc sulfate or 100 mg·L?1 of EDTA-Zn could be used for foliar spraying of zinc fertilizers in pecans. Ch, 2 fig. 4 tab. 30 ref.]