Contents of Main Nutrients in Leaves of‘Jianyang Juyou’

[Objectives]This study aimed to understand and master the nutritional characteristics of‘Jianyang Juyou’growing in southern Guangxi,with a view to providing a theoretical basis for the rational fertilization of local orchards.[Methods]The leaves of 3-year-old‘Jianyang Juyou’were sampled according to the phenological characteristics,and the dynamics in the contents of macronutrients and main trace elements N,P,K,Ca,Mg,Fe,Zn and B in the leaves were analyzed.[Results]The average contents of N,P and K in the leaves of‘Jianyang Juyou’were in the order as N>K>P.Among them,the content of N reached the highest during the flowering period and then decreased;K maintained a high content around the fruit enlargement period;the Ca content of leaves is significantly greater than that of Mg,and the peak value of Ca content appeared during the flowering and color change periods;the Mg content increased from the germination stage to the late fruit enlargement stage,while decreased in the color change stage;the average contents of main trace elements in the leaves ranked as Fe>B>Zn;the Fe content gradually increased from the germination stage to the physiological fruit drop stage,and slowly decreased after the fruit enlargement;the Zn content peaked in the physiological fruit drop period and fruit maturity period;and the B content of the leaves was 81.6-87.2 mg/kg during the flowering period,the early period of fruit enlargement,the late period of fruit enlargement,and the color change period.[Conclusions]During the phenological period,the leaves of‘Jianyang Juyou’had a higher demand for N,and the peak absorption period was mainly concentrated from the germination period to the early period of fruit enlargement;the demand for K was second only to N,and the peak absorption period was concentrated in the early stage of fruit enlargement to the mature stage;and the demand for P was minimal.In the production of‘Jianyang Juyou’Mg played an important role in promoting budding and blooming,preserving flowers and fruits and promoting fruit enlargement,so attention should be paid to the application of Mg fertilizer before the color change period.During the flowering period,the early period of fruit enlargement,the late period of fruit enlargement,and the color change period,B fertilizer could be appropriately increased by soil application or foliar spraying.Due to the large fluctuation of Zn content in leaves and small mobility of Zn,it could be supplemented quickly by spraying on the leaf surface before the physiological fruit drop period and fruit maturity period.

建阳桔柚劣质果产生原因及防控措施

介绍了建阳桔柚劣质果的主要特征,分析了劣质果产生的主要原因,并从整形修剪、花果管理、土水肥管理、病虫害防治、采收等方面提出了劣质果的防控措施。

不同物候期建阳橘柚叶片主要营养元素的含量变化及其相关性

以3年生建阳橘柚为材料,采样不同物候期进行叶片,测定叶片中N、P、K、Ca、Mg、Fe、Zn、B含量,分析其不同生育期主要营养元素含量变化状况,以期为果园的合理施肥提供参考依据。结果表明:建阳橘柚叶片N、P、K平均含量的高低顺序为N>K>P,其中,N在开花期达到最高值之后降低,K在果实膨大前期后保持较高含量;叶片Ca含量明显大于Mg,Ca含量在转色期最高,Mg含量从萌芽期到果实膨大后期波动上升,转色期又有所降低;叶片主要微量元素平均含量表现为Fe>B>Zn,Fe含量从萌芽期到生理落果期逐渐增高、果实膨大后缓慢降低,B含量在开花期、果实膨大前期、果实膨大后期、转色期均维持较高水平(81.6~87.2mg/kg),Zn含量在生理落果期和果实成熟期较高;相关分析结果表明,叶片N含量与P、K、Ca、Mg含量呈负相关关系,P与Zn间呈负相关关系,K含量与Zn、B间呈负相关关系,Fe含量与B含量呈负相关关系。综上所述,建阳橘柚不同物候期叶片养分含量随物候期变化出现规律性波动,不同生育期内对不同养分元素需求有所差异,且各种营养元素含量存在不同程度的拮抗关系。