Fruit color is an important appearance index to measure the commodity value of fruit, which mainly includes two aspects: fruit color and appearance gloss. The color of citrus fruit is mainly determined by the contents and relative proportions of chlorophyll, carotenoids, flavonoids, anthocyanins and other pigments in the peel. At the young fruit stage, the fruit accumulated a lot of chlorophyll and turned green. Carotenoids, flavonoids, anthocyanins and other pigments are mainly yellow, orange or red. As the fruit matures, chlorophyll gradually decreases, green gradually recedes, and carotenoids, flavonoids, anthocyanins and other pigments begin to accumulate in large quantities, making the fruit eventually become bright orange.
deep ploughing and applying organic fertilizer, intercropping green manure and increasing biological fertilizer to improve soil, so as to maintain the ecological balance of soil and improve the ability of dissolving phosphorus and potassium. Advocate the use of dried cake, peanut bran and bio-organic fertilizer.
Pay attention to pruning.
The density of orange orchards sweetened by light is changed to thin, and the crown height is changed to short, so as to ensure the formation of "independent trees". Tree pruning follows the principle of ventilation and light transmission. Controlling water 2-3 days before harvest and using reflective film on the ground cover can not only control water, but also supplement light, which is beneficial to improve fruit sugar content.
Applying more phosphorus and potassium fertilizer
Supplementing and sweetening phosphorus can improve the fertilizer absorption capacity, drought resistance and cold resistance of fruit roots, promote flower bud differentiation, improve fruit quality and increase fruit yield; Potassium can promote the thick growth of branches and developed mechanical tissue, improve the ability of cold resistance, drought resistance, pest resistance and improve fruit yield and storage performance. Boron fertilizer should be added in bud stage, and zinc, boron and magnesium fertilizers should be added to the leaves of soils lacking zinc, boron and magnesium from fruit expansion stage to color-changing maturity stage.
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using biological stimulators
high-quality amino acid biological stimulators contain plant extracts rich in oxygen fat, which exist as natural promoters of many physiological and metabolic reactions (directly driven by related DNA) during fruit ripening. At the same time, phenylalanine for anthocyanin synthesis and methionine for ethylene synthesis are provided. Anthocyanin is the main natural pigment affecting fruit coloring, while ethylene initiates and regulates physiological and metabolic reactions related to fruit ripening, including carotenoids and sugar accumulation. Promote the accumulation of sugar in fruit, make the fruit color evenly, quickly and brightly, improve the appearance of fruit and increase the sugar content.
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