Pollution-free production technology of pomegranate

1. Garden selection

Environmental conditions: annual average temperature above 9℃; annual rainfall of 300~1000mm; fertile soil, organic matter content above 1%, soil layer above 60cm, groundwater level below 1m; soil pH value 6.5~7.5, total salt content below 0.3%; slope below 15 degrees.

Garden planning: flat land, beach land and gentle slope land below 6 degrees, planting north-south direction;6~15 degrees slope, planting line along the contour line extension. Provide necessary drainage facilities and buildings. Windbreaks should be built in wind-damaged areas.

II. Variety selection

The selection of varieties and rootstocks should be based on regionalization and improved varieties, according to pomegranate regionalization, combined with local natural conditions, select excellent varieties, and implement suitable planting. Selective development of Dahongpao, Taishanhong, Mengyanghong and other fine varieties.

III. Planting

Soil preparation: dig planting ditches 0.8~ 1m deep and wide according to row spacing, and fill the bottom of the ditches with crop straws about 30cm thick. The excavated topsoil is mixed evenly with sufficient organic fertilizer, phosphorus fertilizer and potassium fertilizer to backfill the ditch hole. After filling to 20cm below the ground, irrigate thoroughly to make the soil sink, and then cover a layer of topsoil to preserve moisture.

Planting method and density: flat land, beach land and gentle slope land below 6 degrees are rectangular planting, slope land of 6~15 degrees is contour planting. The planting density was 1143~1666 plants/hm2 on slope land (no irrigation), 833~1140 plants/hm2 on gentle slope land (no irrigation), 634~833 plants/hm2 on flat land or beach land (irrigation).

Selection and treatment of seedlings: 80~100cm high, 3~5 lateral roots, no laceration.

Planting time: pomegranate seedlings are generally planted in spring, the later the better. If autumn planting, the earlier the better. In rainy season, planting should be carried out in the rain on rainy days.

Planting technology: digging planting holes with depth and width of 30cm according to plant spacing in planting ditches, placing seedlings in the center of holes, lifting seedlings while filling, tamping, irrigating immediately after filling, covering plastic film to preserve moisture after watering. Spring seedlings should be stemmed immediately after planting; autumn seedlings should be stemmed before germination in spring of the following year. After drying, take appropriate measures to protect the cut.

IV. Soil, fertilizer and water management

Deep ploughing to improve soil, clean tillage: every autumn fruit harvest combined with autumn fertilizer base fertilizer. Soil backfill mixed with organic fertilizer, and then full irrigation, so that the root soil close contact. After rainfall or irrigation in orchard growing season, tilling and loosening shall be carried out in time, and the tilling depth shall be 5~10cm, so as to adjust temperature and preserve moisture.

Mulching: Mulching is carried out after fertilization and irrigation in spring. It can also be combined with deep turning of large ditches to bury grass to improve soil fertility and water storage capacity.

Fertilization: mainly organic fertilizer, chemical fertilizer as a supplement, the fertilizer should not have adverse effects on the orchard environment and fruit quality.

Types of fertilizers allowed: farm manure, commercial manure, other fertilizers.

Fertilizers prohibited to use: urban garbage that has not been treated without pollution or garbage containing heavy metals, rubber and harmful substances, nitrate-nitrogen fertilizer, chemical fertilizer containing chlorine element, undecomposed human excrement, fertilizer products that have not been approved for registration.

Fertilization method and quantity: apply base fertilizer, apply it from harvest to defoliation in autumn, mainly farm manure, mixed with a small amount of nitrogen fertilizer. Soil topdressing is carried out 3 times a year, the first time is from germination to early bud stage, the second time is in young fruit expansion stage, the third time is in fruit color transformation stage, and the last topdressing dosage is very small, which can be ignored; foliar fertilizer is sprayed 4~5 times a year, generally 2 times in early growth stage and 2~3 times in late growth stage, and trace elements required for fruit growth and development can be supplemented.

V. Water management

The concentration of elements and compounds in irrigation water of pollution-free pomegranate producing areas shall meet the following requirements: mercury ≤0.01mg/L, cadmium ≤0.05mg/L, arsenic, lead and chromium (hexavalent)≤0.01mg/L; fluoride ≤0.01mg/L, cyanide ≤0.01mg/L, petroleum ≤ 0.01mg/L.

Irrigation: irrigation period should be determined according to soil moisture, usually including germination period, after falling flowers, fruit rapid expansion period and soil freezing before 4 periods.

Drainage: When the orchard appears ponding, use ditches to drain water in time.

VI. Shaping and pruning

Suitable tree form: after planting, select suitable tree form according to planting density. Common tree types are: three main branches open, 800 trees/hm2, tree height 3.0~3.5m, no trunk, with three main branches with an azimuth of 120 degrees, each main branch and the ground horizontal angle of 40~45 degrees, each main branch is equipped with 3~4 branches. Natural open-heart shape, 1500 trees/hm2, tree height 2.5~3.0m, trunk height 0.5~0.7m, three main branches with azimuth angle of 120 degrees on the trunk, the extension angle between the main branch and the trunk is 50~65 degrees, and each main branch is respectively matched with 1~2 branches. The tree has two main branches, which are inclined at an angle of 80~100 degrees, and each main branch has 2~3 lateral branches.

Trim: At the young tree stage, according to the crown structure of the tree, select and cultivate good backbone branches and enlarge the crown; at the early fruit stage, cultivate all main branches and lateral branches, gradually cultivate various branch groups, thin out useless branches, excessive long branches and slender branches, cultivate fruiting branch groups dominated by medium and small branch groups, and slowly release vegetative branches with moderate growth and more secondary branches to promote flower fruiting; During the full fruiting period, the main pruning measures are to remove useless branches, excessive long branches, slender branches, dead branches of diseases and insect pests, etc., cultivate the group of strong fruiting branches mainly composed of medium and small ones, adjust the fruiting amount, and reasonably load. The pruning measures mainly include "control","promotion" and "protection" for strong and strong trees, weak trees and moderate healthy trees respectively, so as to make the trees stable and robust. The rejuvenation measures of "removing old branches, retaining new branches, removing weak branches, retaining strong branches, removing distant branches, retaining near branches, removing oblique and horizontal branches, retaining upright strong branches" were adopted for senescent trees.

VII. Flower and Fruit Management

Pollinating: using artificial pollinating, bee or wallbee pollinating methods to improve fruit setting rate and fruit uniformity.

Thinning flowers: pomegranate flower quantity is large, should be timely thinning flowers, the earlier the better, the third crop of complete flowers are generally thinning. Thinning once every 10 days from recognizable flowers.

Fruit thinning: fruit thinning adopts the method of keeping more flowers and fruits, selecting and keeping 2 fruits and thinning 3 fruits, so that pomegranate trees can be planted reasonably.

Ring cutting before flowering and removing flourishing shoots during flowering and fruiting period: ring cutting twice on the trunk or main branch and auxiliary branch of flourishing tree before flowering (early May) to improve fruit setting rate. In florescence and young fruit stage, the vigorous shoots on the back were removed many times to improve the fruit setting rate and reduce flower and fruit drop.

VIII. Pest control

According to the plant protection policy of "prevention first, integrated control", based on agricultural and physical control, biological control as the core, according to the occurrence law of pests and diseases, scientific use of chemical control technology, effective control of pests and diseases.

The main diseases of pomegranate are scab, dry rot and early leaf blight. The fungicides such as carbendazim, 80% M-45, dihydantoin, fuxing and bordeaux mixture can be used alternately to control effectively. The pests that harm pomegranate include aphids, scales, peach borers, leaf mites, etc., which are controlled by natural enemies or spraying insecticides such as imidacloprid, aphimicarb, mefenuron No. 3, abamectin, triflumuron, peach xiaoling, etc. The implementation of bags can also effectively prevent various pests.

9. Fruit harvesting

According to the fruit maturity, use and market demand to determine the harvest time. Varieties with inconsistent maturity should be harvested by stages.