(1) According to the timeliness of winter fertilizer, it is applied in winter. Judging from the role of this fertilization, on the one hand, it is to use the nutrients in the fertilizer to make plants recover quickly after fruit picking. On the other hand, the applied fertilizer can maintain the plants to extract the basic nutrients needed for flowering and fruiting in spring shoots for a relatively long time. So winter fertilizer is also called base fertilizer. According to the fertilization mentioned above, the collocation of winter fertilizer should be the collocation of quick-acting fertilizer and organic fertilizer. Fertilization time should generally be applied before and after fruit picking. If there are relatively many fruits on the plant, the nutrient consumption of the tree is relatively large, and the leaves are seriously faded, the fertilization time should be placed before the fruit picking 1 ~ 2 weeks. On the contrary, it can be done immediately after fruit picking. Because your planting has a certain scale, it is recommended to treat different plants differently, and also because the application of organic fertilizer is to reduce nutrient loss and reduce the root floating due to fertility. Organic fertilizer can also be applied in shallow ditches or holes under the crown drip line around the fruit after harvest in severe cold.

② Prevention and treatment of lipomatosis: firstly, the diseased branches are cut off and collected in winter, and then buried or burned. The second is to increase the overall balance of plant nutrients through winter shearing and improve the disease resistance of plants themselves. 3. Start drug protection before the leaves of spring shoots are about to unfold or after the flowers wither, and spray 1 time every 20 days, alternately for 2-3 times. Selected drugs: 800 times of 60% Duofu wettable powder, 600 times of 6: 4 mixture of carbendazim and chlorothalonil, or 800 times of 70% Fulong wettable powder, etc.

(3) The methods of preserving citrus fruits are basically the same, such as increasing the accumulation of organic nutrients in the plants; Improve the quality of flowers; Moderately thinning flowers and fruits, applying plant growth regulators to inhibit the formation speed and quantity of abscisic acid causing fruit drop; Using physical carving to inhibit the development of root system and reduce the competition between summer shoots and fruits for nutrients; Spraying foliar fertilizer and other measures to supplement the nutrients of trees in time, especially trace elements.