广西柑橘叶片微量营养元素含量状况研究

【目的】研究广西柑橘主产区树体微量营养元素含量状况，为柑橘平衡施肥提供依据。【方法】2017年在广西壮族自治区15个柑橘主产县 (区) 选择207个代表性果园采集叶片样品，对5种必需微量营养元素进行定量分析。【结果】柑橘叶片的Fe、Mn、Zn、Cu和B含量分别为37.9～278.5 mg/kg (均值99.6 mg/kg)、13.5～588.6 mg/kg (均值79.4 mg/kg)、5.4～68.2 mg/kg (均值20.1 mg/kg)、1.2～196.1 mg/kg (均值18.8 mg/kg) 和32.9～281.1 mg/kg (均值111.3 mg/kg)。叶片 Fe、Mn、Zn、Cu和B不足 (缺乏或低量) 的比例分别占11.6%、5.3%、84.1%、33.3%和0.5%，处于适量水平的比例分别占67.6%、72.5%、15.9%、34.8%和41.5%，处于超标 (高量或过量) 水平的比例分别占20.8%、22.2%、0.0%、31.9%和58.0%。叶片Fe含量大部分果园处于适量水平，全州县、德保县、阳朔县和兴安县Fe含量不足的程度较严重，而永福县、来宾市、西乡塘区、隆安县、马山县Fe含量超标的比例较高。叶片Mn含量大部分果园为适量水平，仅荔浦县、灵川县、德保县、隆安县和马山县存在Mn含量不足的果园；除兴安县和上林县外，其他县 (区) 都存在Mn含量超标的果园，其中永福县、阳朔县、富川县、钟山县、灵川县、来宾市、隆安县和马山县Mn超标程度较为严重，均超过25%。Zn不足的果园多且普遍，每个采样县 (区) 的柑橘叶片Zn含量不足的比例均很高，全州县、富川县、兴安县、灵川县、德保县、隆安县、马山县和上林县的叶片Zn含量处于不足的比例均达到100%。叶片Cu含量波动大，不足、适量、超标的样本数约各占1/3，全州县、荔浦县、灵川县和德保县叶片Cu含量主要处于不足水平；永福县、阳朔县、兴安县、钟山县和马山县叶片Cu含量主要处于适量水平；富川县、武鸣县、来宾市、西乡塘区、隆安县和上林县叶片Cu含量主要处于超标水平，超标果园种植的主要是溃疡病敏感品种，与长期使用含铜杀菌剂有关。叶片B含量超标的果园比例最大，达到58.0%；全州县、阳朔县、钟山县、德保县和上林县果园叶片B含量主要处于适量水平，永福县、荔浦县、兴安县、武鸣县、来宾市、西乡塘区、隆安县和马山县果园叶片B含量主要处于超标水平。【结论】广西柑橘主产区大部分柑橘园存在一种或多种微量元素不足或过量的问题。总体上Fe、Mn、Cu养分状况良好，但同时存在不足和超标问题；Zn不足问题突出，B超标比例较高。生产上特别需要重视补充Zn肥，控制B肥施用。

Status of microelement nutrition of citrus in Guangxi

【Objectives】Leaf microelement contents were analyzed to evaluate the microelement nutritional status of citrus trees in Guangxi Zhuang Autonomous Region, the biggest citrus production region in China, and to provide a theoretical basis for balance fertilization of citrus in this area.【Methods】 207 representative citrus orchards in 15 main citrus production counties were selected for collecting leaf samples in 2017, and 5 essential microelements were quantitatively analyzed.【Results】The ranges of the contents of Fe, Mn, Zn, Cu and B in citrus leaves were 37.9–278.5 mg/kg, 13.5–588.6 mg/kg, 5.4–68.2 mg/kg, 1.2–196.1 mg/kg and 32.9–281.1 mg/kg, respectively. The average contents of Fe, Mn, Zn, Cu and B elements were 99.6 mg/kg, 79.4 mg/kg, 20.1 mg/kg, 18.8 mg/kg and 111.3 mg/kg, respectively. The proportions of leaf Fe, Mn, Zn, Cu and B in the insufficient levels (deficient or low levels) accounted for 11.6%, 5.3%, 84.1%, 33.3% and 0.5%, respectively, and those in the optimum levels accounted for 67.6%, 72.5%, 15.9%, 34.8% and 41.5%, respectively, and those in the high or excess levels were 20.8%, 22.2%, 0.0%, 31.9%, and 58.0%, respectively. The leaf Fe contents were generally in the optimum level, except Quanzhou, Debao, Yangshuo and Xing'an County where the leaf Fe contents were relatively insufficient, and in Yongfu, Laibin, Long’an, Mashan County and Xixiangtang District where they exceeded the optimum levels. Insufficient leaf Mn contents were detected in orchards of Lipu, Lingchuan, Debao, Long’an and Mashan County. Except for Xing'an and Shanglin County, the orchards in the other 13 counties were excessive in leaf Mn contents, and in Yongfu, Yangshuo, Fuchuan, Zhongshan, Lingchuan, Laibin, Long'an and Mashan County, more than 25% of orchards were exceeding in leaf Mn contents. The percentage of orchards with insufficient leaf Zn contents were the highest among the five micronutrients. The Zn contents in leaf samples of Quanzhou, Fuchuan, Xing’an, Lingchuan, Debao, Long’an, Mashan and Shanglin County were 100% insufficient. The leaf Cu contents fluctuated greatly in different orchards, and the percentages of leaf samples with insufficient, appropriate, and excessive levels, each represented around one third. The Cu contents of leaf samples of Quanzhou, Lipu, Lingchuan and Debao County were mainly in the insufficient level, and the contents in Yongfu, Yangshuo, Xing’an, Zhongshan and Mashan County were mainly in the optimum level. However, the Cu contents of leaf samples of Fuchuan, Wuming, Laibin, Xixiangtang, Long’an and Shanglin County were mainly in the excess level. Orchards with excess leaf Cu contents were mainly planted with varieties susceptible to canker disease, which was related to the frequent application of copper containing bactericide. The proportion of leaf B contents exceeding the optimum level was the largest, reaching 58.0%. The leaf B contents in Quanzhou, Yangshuo, Zhongshan, Debao and Shanglin County were mainly in the optimum level, while the leaf B contents in Yongfu, Lipu, Xing’an, Wuming, Laibin, Xixiangtang, Long’an and Mashan County were mainly in the excess level.【Conclusions】Most of the analyzed citrus orchards have one or several micronutrients in insufficient or excessive status. In general, Fe, Mn and Cu nutrition in most citrus orchards is in optimum level, and insufficient and excessive contents are also detected. Zn deficiency is widely happened while B contents often exceed optimum level. In production practice, special attention should be paid to supply Zn fertilizer and reduce the application of B fertilizer.