We need to consider the soil and tree nutrient level and the fertilization characteristics of the prune. First of all, the fertilizer demand characteristics of the prune, should pay attention to the use of nitrogen and potassium fertilizer.
1、The demand of potassium for prune
Adult plum trees have a high demand for potassium fertilizer. Potassium fertilizer application has a better effect on improving fruit quality.
2、Prune demand for phosphorus
The demand for phosphorus of poppy prune is low, and the use of insufficient or excessive amount will have adverse consequences. Too much will cause too much fruit in a particular year. Even all the fruit are deformed, stiff, small fruit, sour taste, poor coloring, etc.. Too little is not conducive to flower bud differentiation, affecting the results.
3、Prune requirements for the soil
Next is the soil conditions. We have measured the soil nutrition of Zhejiang prune garden. We found that the nitrogen, phosphorus and potassium content of the soil is low, 0.09% for nitrogen, 0.04% for phosphorus and 0.047% to 0.0056% for potassium. Planted on hillside land, the topsoil of poplar is easily lost, and the utilization rate of nitrogen, phosphorus and potassium fertilizers are only 40%, 20% and 30%, respectively. Therefore, the actual amount of fertilizer should be greater than the theoretical projection.
4、Nutrient level of the prune tree
In addition, we also need to consider the nutrient level of the tree, the tree growth potential is strong, nutrient accumulation is also more. On the contrary, if the growth potential is weak, the nutrient accumulation will be less. Therefore, the fertilization of plum should be based on the fertilization characteristics, the nutrient level of the tree and soil conditions, from the balance of the tree nutrients, a reasonable ratio of use. The ratio of the three elements of poplar, nitrogen, phosphorus and potassium ratio of 1:0.5:2.6. The amount of fertilizer should be determined from the variety, age, growth and fruit, and the previous year’s fertilization and site conditions and other comprehensive factors.
B、Young prune tree fertilization
Young prune trees, the need to promote growth, the rapid formation of productive crown. Therefore, in addition to the planting of sufficient fertilizer, in the growing season from March to August, we need to fertilize several times, and fast-acting nitrogen fertilizer. Such as urea, or compound fertilizer with appropriate amount of nitrogen, phosphorus and potassium. At present, the compound fertilizer that is more used in the market is the one produced by Nagric. Newly planted young trees in time after the survival of the application of fast-acting thin fertilizer. As the resistance of young trees is weak, the fertilizer should be applied before and after the rainfall, or mixed with water.
After 3 years of age, each plant increases the amount of fertilizer, with the appropriate amount of phosphorus and potassium fertilizer. For example, 0.3~0.5kg of urea plus 2~3kg of grass ash, 5~10kg of coke ash or 0.1~0.2kg of potassium sulfate should be applied to the plant throughout the year. When fertilizing after fruiting, pay attention to less nitrogen and more potassium. This can control growth and promote fruiting. Fertilizer application method mostly adopts ring and disk application. This can promote the root system to extend outward and expand the crown.
C、Fertilization of fruit-bearing trees
The fruiting trees target high yield, stable yield, high quality and high efficiency. The principle of fertilization is to increase potassium, less nitrogen and control phosphorus. General fertilization 2 to 3 times a year. Fertilize 3 times a year. The first time is February to March before budding, with potassium fertilizer, with nitrogen fertilizer. This can meet the nutrient needs of the spring growth, flowering and fruit growth and development of prune. The second fruit fertilizer, applied in mid-May, is based on fast-acting potassium fertilizer. This can supplement the nutrient needs of fruit growth and development and improve fruit quality. The third time for June to July after fruit harvesting, mainly organic fertilizer, supplemented by fast-acting nitrogen fertilizer. This can timely supplement the nutrients of the prune tree.
The three fertilization amounts accounted for about 30%, 30% and 40% of the whole year, respectively. The first fertilizer is applied twice a year before the first budding, and the amount of fertilizer applied accounts for about 40% of the year. The second time after the fruit harvest, about 60% of the year.
D、Fertilization of large and small fruit-bearing trees
Fertilization should be different for large and small fruit-bearing trees. Generally, the older trees have more flowers and more fruits and consume more nutrients. The occurrence of spring and summer tips decreased and the trees were weaker after harvesting. We need to apply good budding fertilizer and appropriate additional nitrogen fertilizer. This can promote the growth of spring tips. At the same time, we need to apply fruit picking fertilizer early. This will replenish nutrients in time to promote summer tip growth and flower bud differentiation.
In addition, in May to chase the strong fruit fertilizer and foliar fertilizer. Small year trees have fewer flowers and fewer fruits, and the tree is lightly burdened. We need to avoid too much and too vigorous spring tresses, which leads to flower and fruit drop and affects the yield of the year. The amount of fertilizer applied can be less or no budding fertilizer compared to the older trees. Post-harvest fertilizer mainly depends on the strength of the prune tree.
E、Outside the root chasing fertilizer
Outside the root fertilizer, in recent years the application of more common on the plum. Mainly in the fruit growth period application. Such as flowering spray 0.2% borax liquid, fruit growth period spray urea plus potassium dihydrogen phosphate or efficient rare earth liquid fertilizer. This can promote leaf growth, improve photosynthesis, improve fruit quality. Generally apply 1 to 2 times. If too many times, will lead to excessive nutritional growth, affecting fruit quality.
F、Deficiency and its correction
On the one hand, because the plum planted in the hillside, the soil is relatively infertile and susceptible to rain. On the other hand, the management is sloppy and does not pay attention to fertilization. The phenomenon of vegetation deficiency exists in all prune production areas.
Nitrogen deficiency of poppy prune shows yellowing and small leaves, poor growth of branches and tips, and weakness of the tree, resulting in yield reduction or small and large annual results.
Phosphorus deficiency shows reduced growth of new tips and roots, smaller leaves and lack of luster. In severe cases, it causes early defoliation, poor flower bud differentiation, affecting yield and quality.
When potassium deficiency, the fruit is small, poor coloring, poor quality and low yield.
Prune boron deficiency, the tree growth weakened, branch clusters of small leaves, new tips withered tips, poor flower bud differentiation, flower and fruit drop serious. Especially the prune is sensitive to the lack of boron. When the effective boron content in the soil is 0.09ppm, it shows boron deficiency symptoms. Leaf boron content in 20ppm ~ 80ppm are normal.
General nitrogen, phosphorus, potassium deficiency for correction by soil fertilization, but also in combination with the use of foliar spray cloth. In case of boron deficiency in poplar, we can spray borax plus urea plus potassium dihydrogen phosphate 1 to 2 times from the early bud sprouting to the flowering stage. Or in winter soil application, each plant sprinkled with borax about 50g.