Wucheng District is the “Hometown of Chinese Pomegranates” and its area has grown to 130,000 mu. Pomegranate is drought-resistant, resistant to inferiority, simple in management and high in efficiency. It is the main tree species in the adjustment of fruit planting structure in our district. However, due to the lack of scientific management, especially in the fertilization period, the type of fertilization, the amount of fertilization, etc., the yield is low and the quality is poor.

First, the fertilization period

The key to scientific and rational fertilization period is to grasp the critical period of fertilizer demand in the process of growth and development of pomegranate trees. Pomegranate tree fertilization is divided into base fertilizer and top dressing. The base fertilizer is generally made of high-quality organic fertilizer, which can supply various nutrients of pomegranate trees in a balanced manner all the year round. The base fertilizer is best for autumn application, combined with deep soil application. At this time, it is the second growth peak of the pomegranate root system. The roots of the new roots are many, the growth rate is fast, the cut roots are easy to heal and regenerate, and the white absorption root energy occurs. Absorption of some nutrients is conducive to restoring tree potential and increasing reserve nutrients, and most of the organic matter is fully decomposed in the soil, which can be absorbed and utilized in the spring pomegranate flowering and germination stage.

The determination of the topdressing period is based on the progress of the phenological period and the need for growth and solidification. (1) Topdressing before germination and after flowering: It is mainly to supplement the lack of storage nutrition, improve the fruit setting rate and the growth of new shoots, mainly based on compound fertilizer. (2) Topdressing during the expansion period: promote the growth of new shoots and flower bud differentiation, apply appropriate amount of nitrogen fertilizer, apply more phosphorus and potassium fertilizer, mainly ternary compound fertilizer. (3) Pre-harvest topdressing: It is mainly based on quick-acting potash, which can promote fruit enlargement and improve fruit quality. It is generally applied 15 days before harvest . (4) Post-harvest topdressing: It is mainly for topdressing the varieties that consume more nutrients or trees with weak trees, which can enhance the tree potential and increase the stock of nutrients.

Second, a reasonable determination of the amount of fertilizer

　　 1. Organic fertilizer as a basic fertilizer for pollution-free pomegranate. Judging from the fertilization level of pomegranate production in our district, the amount of organic fertilizer used in the production of pollution-free pomegranate should be 4000-5000kg , while the amount of production per mu is only 600-800kg , and the application of organic fertilizer is seriously insufficient, thus increasing the application rate of chemical fertilizer. This is also one of the reasons for the decline in the quality of pomegranate. Organic fertilizer can improve soil, increase soil capacity, reduce environmental pollution, and significantly increase pomegranate yield and quality.

　　 2. Soil testing and formula fertilization. Soil testing and fertilization has a great effect on increasing fruit set rate and maintaining sustained and stable yield increase. The determination of soil fertilization amount should not only consider the factors such as the growth of fertilizer in the pomegranate garden, the fertilizer utilization rate and the growth of pomegranate, but also comprehensive analysis and increase or decrease as appropriate. According to the determination, yield 2300kg Megranate, more suitable nitrogen, phosphorus, potassium, and the amount of blending ratio: purity nitrogen 21.2kg / mu pure phosphorus 18.4kg / mu, pure potassium 9.6kg / acre, N: P2O5: K2O is 14 : 18 : 18 , and the appropriate formula ratio is related to pomegranate yield, soil N , P , K nutrient content. Therefore, the appropriate dosage of various fertilizers should be determined according to the yield and level of different pomegranates and the fertility of the soil.

Third, the fertilization method

According to the characteristics of pomegranate fertilizer and the characteristics of various chemical fertilizers, it is scientifically fertilized. The saplings are applied in the annular ditch and are located at the outer edge of the canopy. In the fruiting period, radial ditch is applied. According to the distribution of the root system, the ditch should be dug into the shallow and deep. The stem in the tree is about 10-20cm , and the head from the center is about 30-40cm . The clay soil is hard and the soil with strong fertility can be applied in depth to guide the root system to expand deep, and the sand nutrients are easy to be lost. The radiation ditch should be replaced every year to achieve the purpose of land reform.

Fourth, scientific application of micro-fertilizer

With the continuous increase in the production of pomegranate and the repeated use of the old pomegranate garden, a large amount of nutrients are taken away from the soil every year, resulting in the lack of some trace elements. At present, the quality and yield of pomegranate have been affected by the lack of trace elements such as zinc and boron in the pomegranate gardens. When the pomegranate is deficient, the spring germination is late, the fine leaves are clustered, the leaves are small, the flower buds are reduced, the fruit is not easy to be fruited, the fruit is small, the roots of the ill young trees are poorly developed, the roots of the old diseased trees are rotted, the canopy is sparse, cannot be expanded, and the yield is very high. low. Precautionary measures: (1) Soil application method: 0.1kg of zinc sulfate is applied in combination with the fertilization plant . This method has a long effective period. (2) Foliar application: Spray zinc sulphate solution 1-2 times 2-3 weeks before flowering . The preparation ratio of zinc sulphate solution is 36 %, namely 1 kg of zinc sulphate , 0.7 kg of quicklime and 200 kg of water . This method can not only reduce the production of small fruits, but also increase the fruit setting rate. When the pomegranate garden is deficient in boron, the initial tip appears irregular gangrene, the upper leaf is yellow, the top bud is dead when the medium is lacking, the growth stops, and the tip of the terminal is withered. Precautionary measures: 1220.2 % borax or 0.1 % boric acid can be sprayed 2-3 times before and after the initial flowering period ; 20g of borax can also be applied in combination with fertilization plants . Micro-fertilizer root application should generally be combined with spring fertilizer or autumn fertilizer application, and pay attention to the amount can not be too much, so as not to cause fat damage.