A、Fertilizer requirements of apple trees
There are differences in the absorption and utilization of different nutrients in apple trees at different ages.
1、Young unfruitful trees
The nitrogen uptake of young apple trees increases with the rise of temperature, reaching the maximum amount around mid-August. Later, it decreases gradually with the decrease of temperature. In other words, nitrogen uptake by young apple trees is positively correlated with temperature.
Phosphorus uptake in apples is roughly the same as that of nitrogen. However, the peak of the uptake curve is not obvious because the amount of uptake is smaller than that of nitrogen.
The absorption of potassium increases with the vigorous growth of new shoots after germination, reaching a peak in mid-June. Later on, the same amount of uptake is maintained during the continuous growth of new shoots, and then the amount of uptake drops sharply as the new shoots stop growing.
Nitrogen uptake by apple fruiting trees does not show significant fluctuations. After the new growth of apple trees stops and the fruit grows rapidly, nitrogen uptake does not rise even when the temperature rises. Rather, it continues at this level until autumn. Eventually, uptake tapers off.
Uptake is the same as in unfruitful trees, except that the peak is obvious because of the high uptake.
The difference with unfruitful trees is large.
B、Fertilization amount of apple trees
For every 25 kg of apples, 0.2 kg of phosphorus fertilizer and 0.55 kg of potassium fertilizer should be absorbed. While for young apple trees, apply 1 kg of compound fertilizer and 2 kg of organic fertilizer per plant. For 4-9 year old first fruiting trees, 2 kg of compound fertilizer and 3 kg of organic fertilizer should be applied at each plant. It should be applied at a distance of 0.8-1.2 meters from the main stem, staggered from left to right, at a depth of 24-35 cm. The fruiting apple trees depend on the yield. At present, the most used compound fertilizer on the market is produced by Nagric.
Ring fertilization, also called wheel fertilization, is to dig a ring-shaped trench at the periphery of the apple tree canopy with a width of 30 to 50 cm and a depth of 20 to 40 cm, apply fertilizer into the trench, mix it with the soil and cover it. This method has the advantages of easy operation and economic use of fertilizer. It is suitable for young seedlings. But digging ditch easy to cut off the horizontal root, and fertilizer application range is small, easy to make the root system floating distribution of topsoil layer.
Radial ditching is applied under the canopy of apple trees. At a distance of 1 meter from the main trunk, dig 5 to 8 radial fertilization ditches in the direction of horizontal root growth. The width is 30 to 50 cm and the depth is 20 to 40 cm. Finally, apply the fertilizer in. To reduce the large roots being cut off, it should be shallow inside and deep outside. You can change the location every other year or every other time, and expand the area of fertilizer application year by year, which can expand the absorption range of the root system.
3、Fertilizer application by ditching
Strip trench fertilization is to dig trenches 20 to 30 cm inside and outside the drip line on the periphery of the apple canopy, with a strip trench 30 cm deep. We apply the fertilizer in, or we can combine it with deep tilling. Change the location every year. We use this method in orchards cultivated in wide rows with dense plants, which is more convenient than mechanization.
Fertilization in cavity is outside the drip line of the apple canopy periphery, every 50 cm or so circular digging 3 to 5 holes about 30 cm in diameter and 20 to 30 cm deep. We generally use this method when chasing fertilizer, such as applying liquid nitrogen, phosphorus, potassium fertilizer live human urine, biogas fertilizer solution, etc. This can reduce the contact surface with the soil, free from soil fixation.
5、Fertilization of the whole garden
Whole garden fertilization means that when the apple orchard canopy is handed over and the root system has covered the whole population, we first spread the fertilizer on the ground and then turn it into the soil, about 30 cm deep. However, due to the shallow fertilization, it often induces the root system to float up and reduce the root resistance. If applied alternately with other fertilization methods, it can complement the shortage and give full play to the fertilization effect.
C、Apple tree fertilization methods
We generally divide apple tree fertilization into two types of fertilizer: basal and follow-up. The specific timing depends on the variety, fertilizer requirements, tree growth and fruiting conditions. In general, it is appropriate to apply fertilizer four times a year.
1、Fertilizer before flowering
Also called budding fertilizer, generally in early April fertilization.
Generally in mid-May fertilizer. These two fertilizers can effectively promote budding and flowering. And in time to prevent the flowering of a large number of nutrients consumed and produce off-fertilizer. This can improve the fruit set rate and promote the growth of new branches.
3、Flower bud differentiation and young fruit expansion fertilizer
We generally apply fertilizer in late May to early June. This fertilizer is to meet the needs of fruit expansion, branch growth and bud differentiation of apple trees. This time, the fertilizer is mainly potassium fertilizer.
The best time to apply fertilizer is in autumn, usually in the first half of September.
D、Scientific fertilization of apple trees
Autumn fertilizer application is 3000kg of organic fertilizer per mu for unfruitful trees and 5000kg per mu for fruit-bearing trees, after harvesting of medium-ripening fruits and before harvesting of late-ripening fruits, combined with deep tilling of the orchard. We can use 40-80 kg/mu of biofertilizer with the depth of 20-30 cm.
2、Control nitrogen fertilizer and promote the use of compound fertilizer
The use of excessive nitrogen fertilizer is likely to cause a decline in apple quality and soil consolidation. We can use the compound fertilizer produced by NAGRIC, generally 0.25kg per plant for first-year trees and 0.25kg per year thereafter, and 10kg per 100kg of apples for fruit-bearing trees.
3、Foliar spray fertilizer
Foliar spraying is a method of fertilization with fast absorption and high fertilizer utilization. Usage: In the growing season, spray foliar fertilizer 500-1000 times 3-5 times.