When the apple tree is in the "big year", nutrients are consumed in large quantities as a result, nutrients accumulated in the later stages of the tree are small, and the nutrient composition is also changed. The general soluble sugar content is higher, the starch content is lower, the protein content and the proportion of starch and total nitrogen are low, the organic phosphorus content is low, and the inorganic phosphorus content is high. As a result, flower buds are differentiated late, the differentiation rate is slow, the number of flower buds is small, and the quality is also poor. In fertilizing the “Big Year†tree, we must pay attention to three issues: First, we must apply enough fertilizer according to the yield so as to avoid undernutrition of the tree and affect growth and fruit development. The second reason is that due to the large amount of flowers used in the "Year of the New Year", the early spring fertilizers before germination and flowering should be managed flexibly according to the amount of basal fertilization in autumn and the level of nutrient storage in the trees. In the case that the amount of basal fertilizer is relatively sufficient and the storage of nutrients in the tree is relatively high, it is not necessary to chase fertilizer before sprouting or flowering to avoid too much fruit set and to increase the pressure of thinning and thinning fruit to further increase the magnitude of “size yearâ€. However, when the application amount of basal fertilizer is insufficient, or the nutrient level of tree storage is low, a small amount of available nitrogen fertilizer may also be applied before germination and flowering to make up for the need for flowering. The third is to take advantage of the favorable timing of flower buds before flowering, and appropriate topdressing of available nitrogen fertilizer to promote flower bud differentiation, increase the number of flower buds, and increase the output of the coming year (“small yearâ€).
The fruit trees of the "small-year" tree had low fruit load, weak early growth, more accumulation of nutrients in the middle and late trees, early differentiation of drug buds, rapid differentiation, and a large number of flower buds. Therefore, early application of nitrogen fertilizer before budding, flowering, to increase the rate of fruit set, increase the output of the year. Before the differentiation of flower buds, it is generally not necessary to chase fast-acting nitrogen fertilizer so as to avoid excessive formation of flower buds and further increase the magnitude of “small and large yearsâ€.
The fruit trees of the "small-year" tree had low fruit load, weak early growth, more accumulation of nutrients in the middle and late trees, early differentiation of drug buds, rapid differentiation, and a large number of flower buds. Therefore, early application of nitrogen fertilizer before budding, flowering, to increase the rate of fruit set, increase the output of the year. Before the differentiation of flower buds, it is generally not necessary to chase fast-acting nitrogen fertilizer so as to avoid excessive formation of flower buds and further increase the magnitude of “small and large yearsâ€.