冬春季节,若防寒措施不当,果树常因低温影响而发生冻害。其主要症状表现如下:主干皮层开裂;树体分枝交叉处皮层下陷,且内部变黑;枝条(尤其是嫩枝)的形成层或髓部、木质部变褐;树干基部皮层变褐或黑色;根系皮层变褐,皮层与木质部分离甚至脱落;花芽的花器畸形,冻后局部变褐。 果树遭受冻害会导致树势衰弱,产量下降。生产上,可采取以下3个措施进行护理补救: 一、追肥浇水 果树受冻后,吸肥水能力相对减弱,应在花前及早追施腐熟的人粪尿或速效氮,以改善树体营养,促进新梢前期生长。同时进行叶面喷肥,喷施浓度在发芽前可高些,生长季节则低些,落叶前又可稍高些。以尿素为例:在发芽前1个月, Winter and spring, if the improper cold measures, fruit trees often freeze damage due to the impact of low temperature. The main symptoms are as follows: the main cortex cracking; cortical subsidence at the branches of the tree branches, and the internal black; branches (especially shoots) forming layer or pulp, xylem brown; base brown cortex brown or black; Root cortex brown, cortex and xylem separation or even off; flower bud flower deformity, local browning after freezing. Frost damage to fruit trees can result in weakening of the tree and declining production. Production, can take the following three measures for nursing recovery: First, topdressing watering fruit trees after freezing, suction capacity is relatively weak, should be in the pre-flowering topdressing manure urine or available nitrogen to improve the tree nutrition , To promote the early shoot growth. At the same time foliar fertilizer, spray concentration can be higher before germination, growing season is lower, before the leaves can be slightly higher. Take urea as an example: one month before germination,