Current situation and countermeasures in fertilization process and related machinery application in orchards

Abstract: Fruit is an important agricultural product. In 2017, China’s orchard area reached 1.11×107hm²,and the total fruit output reached 2.52×108t and both the orchard area and fruit output ranked first in the world. Orchard fertilization is an important part of orchard management and reasonable fertilization method and amount can effectively promote the growth of fruit trees and improve the yield of fruits.The production practice has proved that in the orchards where fertilizer and water are applied early in spring, the fruit trees show bud break early, blossoms open orderly, flowers are large and full, the leaves are large and thick, the leaves are green and bright, the fruit setting rate is high, and the young fruit de-velopment is fast. At present, the degree of orchard mechanization in China is relatively low compared with that in some foreign countries. The problem of excessive labor input in orchard management has increased the cost of fruit production and restricted the further development of orchard. There are great differences in the planting patterns and agronomic characteristics of orchards in different regions of Chi-na, so the fertilization methods and techniques in different regions and orchards are quite different. At present, there are four kinds of fertilization methods in orchards, including soil fertilization, water and fertilizer integration, foliar spraying and injection fertilization, among which soil fertilization and ferti-gation are the two and main fertilization methods. The fertigation is to dissolve the fertilizer in water, transport the solution through the water pipeline after pressurization, and transport the water and fertiliz-er together to the root system by means of spray irrigation or micro irrigation. It is a modern intelligent and precise fertilization method. However, long-term use of water and fertilizer integration will easily lead to soil hardening, soil secondary salinization and long-term soaking suffocation of fruit tree roots. There are three kinds of operation techniques of soil fertilization, such as broadcast application in the whole garden, furrow fertilization and hole application. The application of fertilizer in the whole garden is to spread the fertilizer on the surface of the orchard in an average amount, turn it over and then irri-gate the ground. The machine used is the fertilizer spreading machine. This operation method is suitable for orchards with roots covering the whole surface, and the fertilizer consumption is relatively large,which is easy to cause fertilizer waste and environmental pollution. Furrow fertilization is to open a ditch near the main trunk of fruit trees. Fertilizer is put into the ditch and then covered with soil and sup-pressed. According to different ditch shapes, it can be divided into annular furrow fertilization, strip fur-row fertilization and radial furrow fertilization. The operation machinery is a furrow fertilizing ma-chine, which has the advantages of good fertilizer absorption, fast fertilizer efficiency and fertilizer sav-ing. In addition, furrow fertilization can cut tree roots and promote them to grow new roots. Hole appli-cation is to dig holes for fertilization. During the operation, several holes with a depth of 30-60 cm are dug around the crown of fruit trees, and then the fertilizer is put into the holes according to the actual de-mand to make the fertilizer cover the root system. Then the furrow and hole after fertilization are cov-ered with soil. The machine used is the hole application machine. This fertilizer application method has the advantages of concentrated fertilization and fast fertilizer efficiency, but it is easy to cause fertilizer damage. The inter-row sod and fertilizer cover system in the orchard is a new type of water conserva-tion and green fertilization mode, which is planting green manure crops or natural grass between fruit tree rows. It has the advantages of drought resistance, soil moisture conservation, soil fertility iand struc-ture improvement, soil organic matter content rising, and environmental protection. The main operation links of grass and fertilizer mulching include crushing and rolling, and the operation machinery in- cludes grass crushing and rolling machinery. Foliar spraying is to sprinkle the fertilizer/water solution on the leaf surface of the fruit tree. It is characterized by less fertilizer and quick efficacy. It is mainly used for fertilizer supplement in the critical period of fruit tree growth, and can be carried out with the plant protection of fruit trees. Injection fertilization is to inject fertilizer (nutrient solution) from the base of the tree with a high-pressure syringe, which is generally used to correct the deficiency disorders of fruit trees. Due to the vast territory of our country, the unbalanced development of orchard mechani-zation has appeared in various fruit production areas, and some orchard farmers, orchard management and researchers do not know enough about the operation technology and related machinery, leading to some problems in the fertilization process in some orchards, such as unreasonable selection of fertiliza-tion technology and related machinery, and disconnection between agricultural machinery and agrono-my. In this paper, from the orchard fertilization mode and fertilization operation technology, the fertil-ization process and corresponding fertilization machinery are summarized under different fertilization methods, and the development trend of fertilization machinery is put forward according to the cur-rent situation of fertilization machinery in China, which can provide reference for the reasonable se-lection for orchard fertilization machinery and the integration between agricultural machinery and agronomy.