The prosperous spring shoots of apples are also the period of young fruit growth, which is a period of simultaneous vegetative growth and reproductive growth, and the competition for nutrients is fierce. Generally, when new shoots grow vigorously, the photosynthetic products produced by the lower mature leaves mainly supply the growth of the young and tender parts of the top, and are basically not exported. Therefore, in order to avoid the competition of nutrients between the vigorous shoots of apples and the expansion of young fruit, the branches and leaves are lush, the orchard has poor ventilation and light transmission, insufficient nutrient supply, poor flower bud differentiation, and hindered fruit expansion. During the prosperous period of spring shoots of apples, it is necessary to control the prosperous growth in time.
The length of the new shoots of fruit trees is fixed. Generally, the spring shoots grow long, and the autumn shoots grow shorter. On the contrary, the spring shoots grow shorter, and the autumn shoots must grow vigorously. The new shoots can only become the fruiting shoots in the second year after turning into old shoots, laying the foundation for high and stable yields in the next year. Therefore, in the early management of orchards, from the beginning of spring to mid-May, proper water and nitrogen control should be used to control the vigorous growth of spring shoots, reduce nutrient consumption, and promote the capping of new shoots. At the same time, plant growth regulators can be used to inhibit the growth of new shoots. Chlormequat chloride and Mepiquat can inhibit the synthesis of GA3, inhibit the vigorous growth of branches, regulate the hormone levels in apple trees, and promote the differentiation of flower buds. In the long-term growth of new shoots of apples (the length of shoots is 10-15cm), use 50% Chlormequat chloride SL to dilute 400-500 times or 98% Mepiquat to dilute 1500 times, and focus on spraying the top of shoots to control the growth of new shoots. Long, promote the purpose of flower bud differentiation.