High-yield Cultivation Techniques for Sichuan Pepper in Cold, High-altitude, Arid Mountain Areas
I. Overview of the Cultivation Area
Cold, high-altitude, arid mountain areasSichuan pepperThe cultivation area is located along the Datong River in Tianzhu County, Gansu Province, with an average altitude of 2300 m, an average annual temperature of 4 degrees C, an average annual rainfall of 500 mm, and an average annual evaporation of 1600 mm. Transportation is convenient and communications are unobstructed.
II. Planting Methods
Planting time: It can be divided into two planting seasons, spring and autumn, with spring planting being the most suitable. Digging holes for planting: The planting holes should be 50-60 cm square. Apply 3-5 kg of farmyard manure and 50 g of superphosphate per hole. The fertilizer must be mixed evenly with the soil, and 100 g of fresh lime should be added to prevent root rot. After planting and filling with soil and watering, cover the holes with fine soil.
Planting spacing: Pure stands generally use a spacing of 1.5 m × 2.5 m between plants and rows. For Sichuan pepper orchards intercropped with crops and trees, a spacing of 4 m × 5 m between plants and rows can be used. The principle is: where the slope is steep, the spacing is small; where the slope is gentle, the spacing is large. Where the soil is fertile and thick, the spacing is large; where the soil is thin and poor, the spacing is small.
III. Soil Management
Deep plowing to mature the soil: Dig shallowly beneath the canopy of the Sichuan pepper trees and plow deeply outside the canopy to avoid damaging the roots. The soil between rows is generally dug 33-66 cm deep. When deep plowing pits, combine this with the application of organic fertilizer as a base fertilizer. If the soil is heavy clay, mix sand in when deep plowing. Newly planted young trees should undergo rotating pit expansion. Intercropping Sichuan pepper with grain: Crops with a short growth period, small plant size, and a certain economic return should be selected for intercropping.
This is done in late autumn by mounding soil around the root system of the Sichuan pepper trees. It can increase soil temperature, reduce frost damage, and reduce water evaporation.
Weeding: After rain, carry out shallow tillage and weeding in the pepper orchard. This can cut off capillaries, reduce soil moisture evaporation, and remove weeds, thereby facilitating the growth and development of Sichuan pepper.
IV. Fertilization
Fertilization methods: Acidic soil should be given more alkaline fertilizer, and alkaline soil should be given more acidic fertilizer; sandy soil has poor fertilizer retention and should be fertilized frequently, while clay soil has good fertilizer retention and can be appropriately given heavier applications. Fertilization methods include hole application, ring trench application, radial trench application, and short strip trench application. Flatland pepper orchards mostly use ring trench application or radial trench application. Mountain and slope pepper orchards should use hole application or short strip trench application. Regardless of the fertilization method, the fertilization trenches or holes should be dug below the outer edge of the canopy. After fertilization, soil must be covered immediately to prevent nutrient volatilization.
Fertilization time and amount: For base fertilizer, the period from after picking the pepper until the Sichuan pepper sprouts in the following spring is all suitable for base fertilizer application, and applying it immediately after picking is best. Base fertilizer is mainly organic fertilizer, mixed with phosphate fertilizer. For a generally 6-7 year old Sichuan pepper tree bearing 1-2 kg of pepper, 5-10 kg of barnyard manure can be applied, mixed with 150-250 g of superphosphate. For topdressing, during the growing season, mainly use decomposed human and livestock manure or nitrogenous inorganic fertilizer, combined with potassium fertilizer. There must be no fewer than 2 applications in one growth cycle.
V. Winter Management
Whitewashing: Mix lime powder with water into a paste and brush it on the trunk to prevent cold damage. Straw wrapping: Before winter begins, wrap the trunks of the pepper trees with wheat straw or straw bags and tie them with rope to protect them from freezing damage.
Applying warming fertilizer: Before the coldest days of winter, apply hot-natured horse and sheep manure at the roots of the pepper trees. Scrape away the topsoil 15-25 cm around the trunk, apply 5-10 kg per tree according to tree size, and then cover with soil.
Watering: After applying the warming fertilizer, water the pepper trees for winter. Then spread a layer of sand. Water only individual trees, and never flood irrigate, strictly preventing excessive water from lowering soil temperature and causing the pepper trees to freeze.
Before winter begins, spraying the pepper trees 1-2 times with high-concentration wood ash liquid can also prevent the pepper trees from freezing and can sterilize and kill insects.
VI. Training and Pruning
Pruning period: Pruning can be done throughout the entire dormant period from leaf fall to before sprouting; in areas with freezing damage, early spring pruning after thawing and before sprouting can prevent the pruning cuts from suffering freeze damage.
Training young trees: When training, first consider light and ventilation conditions. Under the premise of ventilation and light penetration, gradually cultivate a strong framework with even distribution to form a tree structure with high and stable yield. The general tree forms are the multi-main-branch clump form and the natural open-center form.
Pruning methods: Generally divided into thinning and heading back. Thinning can promote flowering and fruiting, while heading back is beneficial for producing strong new shoots and enhancing growth. Generally, young and vigorous trees should be mainly thinned to rapidly expand the canopy structure, while appropriately retaining more small branches to become auxiliary branches and fruiting branches, so as to facilitate early fruiting and more fruiting; for strong branches, leave them unpruned; for weaker branches, head them back, generally cutting off 1/3 or 1/4 of the branch. During the full fruiting period, heading back should be the main method. Through heading back, continually renew the fruiting branch groups so that branches at all levels are continually rejuvenated, promoting growth and fruiting branches; in addition, avoid hollowness inside the canopy and prevent the fruiting area from moving outward. Pruning of trees in the full fruiting period is generally light for vigorous growth and heavier for weak growth and excessive fruiting. For pepper trees showing alternate bearing, in an on-year, heavily prune fruiting branches and retain more vegetative branches or promote vegetative branches; in an off-year, retain more fruiting branches and appropriately thin out some vegetative branches.
VII. Control of Sichuan Pepper Root Rot
Symptoms: After seedlings are infected, growth stops, and they appear as old, weak seedlings. Leaves lose green color, leaf veins turn red, until the leaves fall off and the whole seedling dies. The underground roots are yellow-brown, water-soaked, and edematous, and the root bark easily falls off and has a foul odor. After adult Sichuan pepper trees are infected, the diseased plants grow weakly, and the leaves are small and yellow. If the soil is dug open, root rot and discoloration can be clearly seen, with an abnormal odor.
Control methods: During the seedling stage, apply more phosphorus and potassium fertilizer and wood ash. When planting Sichuan pepper, add 100 g of fresh lime powder to each planting hole. Do a good job of drainage and try to keep the pepper orchard from accumulating water.
VIII. Harvesting Sichuan Pepper
After timely harvesting, Sichuan pepper must be dried and stored. There are two methods for drying Sichuan pepper: one is air-drying in the sun; the other is drying over a fire pit. Air-drying in the sun is generally used. For storage, Sichuan pepper mainly uses the “low-temperature, low-humidity, sealed storage method.”