For the apple tree to apply the base fertilizer in autumn, this fruit farmers have paid more and more attention in recent years. Professor Jiang Yuanmao still has a move in his hand. If this move is done, the spring fertilizer will be saved in the coming year. Professor Jiang Yuanmao's coup is to spray 3 times of urea water every 7 days before the leaves. For example, according to experience, this area is about November 20th, so the first time urea water is sprayed at the beginning of November.

Take the orchard of Li Qingquan, a fruit grower in Luochuan County, Yan'an City, Shaanxi Province. He sprayed the apple trees several times a year, but all of them were sprayed before the harvest, while Jiang Yuanmao said that the spraying of urea on the foliar surface is After picking the fruit, it will start to spray in the winter and 15 days before the leaves, and the spraying method is a bit "strange".

In the first pass, spray 0.5% to 1% of urea water, that is, 50 kg of water plus 0.25 to 0.5 kg of urea.

The second time, after 7 days of the first pass, the concentration was a little higher to 2% to 3%.

The third time, after another 7 days, the concentration continues to increase, which can reach 5%~6%.

Each time the urea water is sprayed, 0.3% to 0.5% zinc sulfate and 0.5% to 2% borax may be added. The spraying time is selected before 10 am or after 4 pm, and the suitable temperature range is 10 ° C ~ 25 ° C. The spraying method is first, then, and evenly, and the spray is applied mainly to the young leaves, and the back of the blade is mainly sprayed.

Li Qingquan did not understand very well about this weight loss coup that Mr. Jiang said. He asked: "Mr. Jiang said that the concentration of urea water sprayed 3 times is getting higher and higher, but the absorption capacity of the tree body is definitely weak when the leaves are finally fallen. Why don't you just start spraying more?" Actually, this is sprayed. 3 times of urea water, each time is different. In the first pass, the urea water concentration is lower because the leaf absorption function is stronger at this time. In the second pass, the concentration of urea water increased, mainly considering that the leaves began to age in this period, and the absorption capacity became weak. In the third time, the concentration increased to 5%~6%. The effect of this time is not to supplement the nutrients, but mainly to give the leaves a signal, telling it that you should fall leaves at this time, actually two or three days after the third time of spraying. The leaves fall off on their own.

Why do you want to help the apple trees fall? In the late autumn, under normal circumstances, the sunshine is shortened and the temperature is slowly reduced. These signals will stimulate the natural leaves of the apples. About 80% of the nutrients in the leaves will be stored in the trees. However, in the event of a sudden cold, the leaves freeze directly on the branches, and only about 30% of the nutrients can flow back to the trunk. Therefore, the third time 5% ~ 6% urea water, just like the apple tree feels the signal of shortening sunshine and slow temperature, it stimulates it to open the physiological process of defoliation, which leads to the return of nutrients in the leaves.

In 2015, Professor Jiang Yuanmao's experiment in Zhang Xianlin Orchard, Yuxin Village, Yaodian Town, Luanchuan County, Gansu Province, was extremely convincing. At the beginning of May of that year, there was a low temperature of minus 5 °C in the village, and the orchard was seriously damaged. However, in the 8 rows of trees in the old Zhang Orchard, the results of the 4 rows of the experiment were not serious. On average, each tree had 165 fruits, while the comparison group had 4 rows with serious results, with an average of only 50 fruits per tree. The reason is that the four rows of trees tested were sprayed with urea water three times before the autumn fall of 2014. After sampling tests, the nutrient levels of the four rows of trees were significantly higher than those of the unsprayed, so the high nutrient level enhanced the tree body. Resistance.

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(Source: 191 agricultural capital)

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