1, build a standard orchard
Citrus is a perennial fruit tree with tall plants, deep roots and high yield, and its age can reach 100 years. Mountain orchards should be selected according to the characteristics of warm and moist roots, tolerance to shade and aerobic, with soil depth greater than 1m, loose and fertile soil, organic matter content greater than 1.5% and PH value of 5.5 ~ 6.5. In mountainous areas or fields below 600 meters above sea level, orange orchards should be built on the south slope, east slope or southeast slope.
Terraces with the same height should be built, and the distance between terraces should be more than 3m. Embankment is built in front of terraced fields, and drainage ditch is dug behind terraced fields. Terraces are slightly inclined inward, and drainage ditches should be set at the top of terraces. In order to facilitate transportation and management, roads must be built. The main road runs through the whole park and connects with expressway. They can be used by trucks, and the road surface is 4 ~ 5 meters. The branch road in the citrus orchard can connect tractors and spraying machinery, and the road surface is 2.5 ~ 3 meters. There should be a pedestrian farming passage in the orchard.
2. Reasonable colonization
Reasonable planting can make full use of land and space. According to the mountainous characteristics of the county, 50 ~ 60 permanent citrus trees are planted in the citrus orchard, and the rootstock is rich orange or bitter orange. It is planned to densely plant a temporary tree between permanent trees, with one plant per mu 100 ~ 1 10.
Mountain citrus is mostly red soil, dry, sour, hard and thin. It is necessary to improve the soil to meet the needs of citrus growth and fruiting. Before planting, dig the planting hole with the depth, width and length of 1m respectively, air-dry 5- 10kg of green manure or straw, 2-3kg of lime 1-2kg of cake fertilizer and 2-3 kg of phosphate fertilizer 1-2kg of phosphate fertilizer on the upper layer, then mix with the soil, return to the hole and fill it. Citrus seedlings should be cultivated with improved varieties and strong seedlings, and it is best to follow them before planting.
3. Soil management
Citrus is a mycorrhizal plant. Generally, fibrous roots have no root hair, but there are mycorrhiza at the top of fibrous roots. Mycorrhiza plays an important role in root absorption of citrus. Mycorrhizal activities need rich soil organic matter, more oxygen and slightly acidic soil in order to create favorable environmental conditions for mycorrhizal growth in production. Young citrus trees should be dug in the first 1 ~ 3 years after planting to improve the soil year by year, with the depth of 0.6 ~ 0.8m, and the pressure per plant should be 10 ~ 15kg of dry green manure, straw, weeds or miscellaneous fertilizer, 1 ~ 2kg of lime, and 2 ~ 3kg of cake fertilizer should be applied to the upper layer.
After long-term cultivation in adult citrus orchards, local deep tillage should be used to improve the soil, with a depth of 0.3 ~ 0.4 meters and sufficient base fertilizer should be applied. It is difficult to improve the soil in the citrus orchard after the citrus enters the abundant period, and the soil can also be improved by blasting, which saves labor and reduces root damage.
4. Promote planting grass.
It is one of the important measures to improve the ecological conditions of orchards and popularize grass planting. Planting grass can increase soil organic fertilizer, reduce soil temperature in summer and reduce soil erosion; Provide breeding, survival and habitat conditions for natural enemies and protect natural enemies; Save weeding labor, etc. Key points and precautions of grass cultivation technology: 1. Dig out malignant weeds, select, retain and improve benign grass seeds. Second, the grass should not be left too high, so as not to affect the photosynthesis of fruit trees. Young trees are about 1 ~ 1.5 meters around the plant, and there is no grass in the tree tray or on other tables. Adult trees should be fully mowed, mowed with lawn mower or manual mowing in the growing season of weeds, mowed 2 ~ 3 times a year, and covered with tree trays. Third, appropriate application of quick-acting fertilizer in spring and summer.
5. Increase the application amount of organic fertilizer
1 ~ 2-year-old young trees should be fertilized once a month in the growing season from March to August every year, or once before and after the new shoots in spring, summer and autumn, with nitrogen fertilizer as the main fertilizer, and the amount of fertilization should be increased from less to more. Generally, 0.2kg ammonium bicarbonate or 0. 1kg urea is applied to each plant, and 40 ~ 50kg organic fertilizer is applied to each plant in winter to improve the soil.
Mountain citrus orchards generally have poor soil fertility and low organic matter content, so it is necessary to apply more organic fertilizer. Citrus enters its peak period and can be fertilized three times a year. First, after the fruit is picked, apply sufficient base fertilizer. During this period, apply organic fertilizer and chemical fertilizer, which account for 20% of the whole year, to promote the balance between reproductive growth and nutritional growth, and increase the vegetative branches of spring shoots as the mother branches of the next year; Second, 50% chemical fertilizer should be applied in the middle and late July after the physiological fruit drop is over and fruit setting is stable, so as to promote fruit growth and autumn shoot growth. This time, the amount of nitrogen fertilizer should be controlled according to the tree potential and the amount of fruit hanging, so as not to induce a large number of autumn shoots and affect the growth and quality improvement of fruits. 3. For trees with many flowers and fruits, appropriate topdressing should be applied before flowering and fruit picking, and the amount of chemical fertilizer applied should account for 30%.
Nutrition diagnosis and formula fertilization were carried out on soil and trees in orchard. According to the diagnosis results of soil nutrition in mountain citrus orchards in this county, the formula fertilization of citrus is 10: 4: 6, and the application amount of phosphate fertilizer should be appropriately reduced and the proportion of fertilizer should be adjusted. At the same time, pay attention to increase the application of calcium and magnesium fertilizer, supplement zinc and boron fertilizer, and change the single soil application into the combination of soil application and topdressing outside the roots.
6. Cultivate high-yield crown
In order to make citrus early-maturing, high-yield and stable-yield, it is necessary to cultivate a dwarf, open, natural, happy and high-yield crown by means of shaping, dewatering and coring. In the year of planting, the stem is fixed at 40 ~ 50 cm, and 3 ~ 4 main branches are cultivated. According to the growth characteristics of each secondary branch, the branches are scientifically controlled. For 1 ~ 2-year-old young trees, thinning should be carried out when the spring shoots are 5 ~ 6 cm long, and 2 ~ 3 strong shoots should be left on each basic branch, and the rest should be thinned. Remove sporadic summer buds, put them uniformly, and pick the core when the buds grow to 20 ~ 25 cm to promote the rapid formation of the crown. Autumn shoots should be released in early and middle August, generally not picked, only properly thinned.
7, timely harvest
Stored fruits can be harvested from June 1 1 to early February when the whole fruit is orange yellow or orange red, and the quality of fresh fruit is the best when the whole fruit is orange red. When harvesting, it should be carried out after the dew is dry on a sunny day, and it should be handled with care to avoid bumping. After the fruit is harvested, it should be moved into the shade and piled up in time. High-yield trees can be harvested in batches to reduce the serious defoliation caused by water loss after harvesting and ensure the quality of citrus to meet the green food standards.