How to apply spring fertilizer?

When the average temperature in spring is stable at about 65438 02℃, mulberry trees begin to sprout and grow. At this time, the germination and growth of mulberry bud mainly depend on the nutrients stored in the trees. With the continuous increase of air temperature and ground temperature, the ability of mulberry roots to absorb water and nutrients is enhanced, the nutrients supplied by soil are gradually increased, and the growth rate of mulberry branches and leaves is accelerated. Generally, the utilization time of spring fertilizer after germination of mulberry leaves, that is, spring fertilizer has little relationship with germination rate, but it can obviously promote the late growth of bud leaves, increase and grow new shoots, make leaves thicker and darker, increase mulberry leaves and improve leaf quality. The effect of spring fertilizer can even continue into summer and autumn, which can promote the germination and branch growth after summer transplanting.

Spring fertilizer is applied too early, mulberry roots absorb less, and fertilizer loses more; However, late fertilization had little effect on the yield increase of spring leaves. Generally, spring fertilizer is applied twice in Jiangsu and Zhejiang provinces. The first time was in late March. Urea 15 ~ 25 kg+calcium superphosphate 20 ~ 30 kg+potassium chloride 10 ~/5 kg, or compound fertilizer 50 ~ 80 kg+urea10 kg per mu was applied deep in the ditch. The second time, in late April, urea 10 ~ 20kg was applied per mu, and then the land was lightly mowed and mixed with fertilizer. The secondary spring fertilizer accounts for 30% ~ 35% of the annual fertilization. Mulberry in Guangdong and Guangxi germinated early, and the time of applying spring fertilizer was more than one month earlier than that in Jiangsu and Zhejiang. Spring drought is more common in the western region, which grows slowly after germination, so the application amount of spring fertilizer should be reduced appropriately, and mulberry orchards without irrigation conditions should be fertilized when the soil is wet after rain.