1) Combined application of organic fertilizer and inorganic fertilizer
　　 Organic fertilizer is rich in organic matter, complete in nutrients, long in fertilizer efficiency, and can significantly improve soil traits, while inorganic fertilizers are quick in fertilizer, but nutrients are simple. Therefore, the pomelo garden should pay attention to the application of organic fertilizer, usually accounting for more than half of the annual nitrogen fertilizer, and with inorganic fertilizer. Practice has proved that the implementation of the fertilization route combined with organic fertilizer and inorganic fertilizer can promote the improvement and ripening of the soil in the garden, and is conducive to the growth of the plant. It is also an important technical measure to correct the granulation of red meat and pomelo juice.
　　 (2) Rational fertilization and balanced application of elements
　　 At present, there are two tendencies in the amount of fertilization in China's pomelo-producing areas. One is that the amount of fertilizer is insufficient, resulting in low yield and poor quality. The other is indiscriminate application of fertilizer, especially the application of individual fertilizers, resulting in abnormal growth results and wasted fertilizer. ,polluted environment. Therefore, reasonable fertilizer application should be based on soil conditions and tree conditions. It is worth pointing out that the fertilization in the pomelo gardens still has different problems of nutrient supply imbalance, and the grapefruit tree has malnutrition, and the juice granulation is intensified. Therefore, attention should be paid to the reasonable proportion of various elements to maintain the balance of nutrients in the tree.
　　 (3) Fertilizing according to soil characteristics and fertilizer properties
　　 The soil types and traits of China's pomelo production areas vary greatly. It is necessary to apply suitable fertilizer types according to soil characteristics, and to grasp the reasonable application amount, period and method. Sandy soil has poor fertility, and should be applied in small portions; sticky soil has strong fertility, and the amount of application can be slightly more. Alkaline chloride, potassium chloride or sodium nitrate should not be used for saline-alkali soil. Calcium-magnesium-phosphorus or phosphate rock powder should be used for acid-based soil phosphate fertilizer. Acidic fertilizers such as superphosphate and ammonium sulfate should be selected for lime soil.
　　 The nature of various fertilizers varies widely. Generally, organic fertilizer is widely used as a base fertilizer. Inorganic fertilizers have alkaline and acidic fertilizers, and also have strong volatility or poor mobility in soil. They should be applied reasonably according to their characteristics. For example, nitrate nitrogen fertilizer and urea are highly mobile in soil, and can be applied in the new shoot and young fruit stages of the grapefruit tree, and should not be flooded after application; the acid soil containing high manganese should control the physiological acid fertilizer. ( such as ammonium sulfate, ammonium bicarbonate, etc. ) , otherwise it will easily aggravate soil acidification, leading to manganese poisoning; alkaline soil should avoid the application of alkaline fertilizer to prevent the increase of iron deficiency in pomelo; phosphate fertilizer is easy to be fixed in soil, Combined with organic fertilizer application.
　　 (4) Properly adjust the pH of the pomelo garden soil
　　 Zhuang Yimei et al. (1994) showed that there is a certain degree of difference between the soil pH of the orchard and the effective content of soil elements, and the soil reaction has a significant effect on the elemental efficiency. According to extensive survey and analysis, from the perspective of soil nutrient availability, the suitable pH range of honey pomelo garden soil is 5.5 ~ 6.5 . Therefore, the acid red soil grapefruit garden should pay attention to gradually reduce the acidity of the soil, especially the appropriate amount of lime to neutralize its acidity; for the salt-alkaline soil pomelo garden, sulfur, gypsum, physiological acid fertilizer and organic fertilizer can be applied.
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