Calcium application can prevent litchi from cracking.

In recent years, litchi (glutinous rice, cinnamon, March red, green yarn, sweet rock, etc.) fruit cracking phenomenon is more common, litchi fruit cracking often occurs in the fruit expansion period, the normal year is generally 20% to 30%, serious up to 50%. There are many reports about the cause and mechanism of litchi fruit cracking in China, among which many researchers mentioned that litchi fruit cracking is related to the mineral nutritional status of litchi, especially the calcitonin nutritional status. Our investigation shows that the soil in the south is acidic, and the maturity period is in the rainy season, and in the process of planting and management, fruit farmers pay more attention to nitrogen fertilizer, light phosphorus and potassium fertilizer, ignoring the supplement of medium and trace element fertilizers, resulting in severe soil acidification, poor hardening and poor tillage, lack of elements and root diseases, improper cultivation and diseases and insect pests are the main external factors of litchi fruit cracking. Therefore, we have arranged demonstration experiments in Zengcheng area of Guangzhou and Maoming to use soil conditioner and sugar alcohol chelating calcium fertilizer to improve mineral nutrition status of trees and calcium supplement to prevent fruit cracking. Among them, the soil conditioner is Futawei organic calcium powder, which is made from oyster shell powder calcined at high temperature, with an effective calcium content of 45%, and has the ability to neutralize acidity and improve soil. Sugar alcohol chelating calcium fertilizer is called fruit and vegetable calcium fertilizer, which solves the problem of calcium mobility in phloem and can improve the calcium absorption rate and utilization rate of calcium fertilizer in fruit trees. The litchi varieties tested were Nuomici, Guiwei and Bai Tang. Measures were taken as follows: measure 1, Zengcheng Sifeng, applying soil improver Fusuwei organic calcium powder in autumn, spraying sugar alcohol chelate calcium 5 times in young fruit stage and expansion stage; measure 2, Yincheng, Zengcheng, the second physiological fruit drop began to spray fruit and vegetable calcium fertilizer on the leaf, with an interval of 2 weeks, a total of 5 times. Measure 3, Maoming Huazhou, before the second physiological fruit drop, Fusuwei organic calcium powder was applied and foliar calcium fertilizer was sprayed, fruit and vegetable calcium fertilizer was sprayed once a week after fruit drop, and fruit and vegetable calcium fertilizer was sprayed every other week during the expansion period. The investigation shows that there are more fruit cracking in the control orchard of Sifeng demonstration area in Zengcheng, and the fruit cracking is obviously reduced when the fruit and vegetable calcium fertilizer is sprayed alone, and the outer part of the plant is less than the inside, which may be related to ventilation and light permeation. there is no significant difference between the application of soil improver and foliar spraying and single spraying of fruit and vegetable calcium fertilizer, and the fruits of these two treatments have begun to change color and are uniform in size. In the mature harvest period, the fruit cracking rate of the control reached 30%, but the fruit cracking rate of the two treatments was significantly lower than that of the control, and its appearance, color, luster, sweetness, taste and storage effect were better than those of the control orchard. In the demonstration area of Maoming area, the fruit cracking rate of litchi was 0.53% by applying Fusuwei organic calcium powder (soil improver) and leaf spraying fruit and vegetable calcium fertilizer (sugar alcohol chelate calcium), and 3.21% by spraying fruit and vegetable calcium fertilizer on leaves alone. the fruit cracking rate of the control reached 8.33%. Conclusion: soil improvement of Futawei organic calcium powder and foliar supplement of calcium fertilizer can effectively reduce litchi fruit cracking, which shows that exogenous calcium supplement plays a certain role in preventing litchi fruit cracking. In order to achieve the ideal effect, we should pay attention to the frequency and time of use. Futawei organic calcium powder had better be combined with autumn base fertilizer, and fruit and vegetable calcium fertilizer should be used for 4 or 5 times after physiological fruit drop. As the causes of litchi fruit cracking are various, involving comprehensive control techniques such as water and fertilization, it can not be controlled by the application of calcium fertilizer alone, and it is necessary to take comprehensive management measures.