(1) Clear tillage method (fallow method after tillage)
Generally, the removal method is to dig deep into the orchard in autumn and intertillage for many times in spring and summer to remove weeds, which makes the soil loose and breathable, is beneficial to microbial reproduction, accelerates the decomposition of organic matter, improves soil nutrients and water content, and is beneficial to the growth of jujube trees. However, organic fertilizer must be applied in combination, otherwise the content of soil organic matter will decrease year by year, the soil structure will be destroyed, and soil erosion will affect the growth of jujube trees.
(2) Grass planting method
Where there are watering conditions, the grass planting method can be implemented. Planting grass can reduce intertillage weeding, save labor, reduce soil water loss, increase soil organic matter, improve soil physical and chemical properties, maintain good aggregate structure, and be beneficial to water storage and soil conservation. In rainy season, grasses can absorb excessive water in the soil, make the soil water content moderate, prevent jujube trees from growing white, promote fruit maturity and improve fruit quality. The grass species suitable for orchard planting are clover, sweet clover, soybean, mung bean and ryegrass. Perennial grass can be mowed several times a year to cover orchard plants and rows. Annual grass can be ploughed in situ when the grass yield and organic matter content are the highest. In order to increase forage yield and give full play to the role of forage growth, nitrogen, phosphorus, potassium and other fertilizers should be topdressing before germination and in the fast-growing period of young grass, and irrigation should be carried out in time to solve the contradiction between trees and grass competing for fertilizer and water. If we can combine raw grass with cattle and sheep breeding, and return it to the field after abdomen reduction or biogas digester fermentation, we can better improve the comprehensive benefits of the orchard.
(3) Methods of cleaning and cultivating pasture
In orchards lacking irrigation conditions, in order to avoid the competition between grass and trees for water and fertilizer, clear tillage can be carried out in the spring drought season, and green manure crops such as mung beans and sesbania can be sown before the rainy season, so as to make full use of the light, heat and water resources in the rainy season and turn over and press the ground when the green manure crops bloom. This method combines the advantages of clearing tillage and planting grass, solves the contradiction between planting grass and fruit trees competing for water in spring, and can be advocated.
(4) Covering method
In orchards with difficult irrigation, weeds and straws can be covered between trees and rows with a thickness of 15 ~ 20cm. After the grass is covered, you can also cover it with a layer of soil to prevent fire. Don't cover the grass within 20 cm from the trunk to prevent the roots from rotting. When the grass is rotten, lay new grass. Mulching with grass can inhibit the growth of weeds, reduce soil evaporation, maintain soil and water, increase soil fertility, inhibit soil alkali return, reduce the seasonal and daily variation of ground temperature, and be beneficial to root growth. According to Yao's research in shandong institute of pomology, covering the orchard with grass can significantly improve the enzyme activity. In May, the invertase activity in 0 ~ 5 cm soil layer increased by 72.29%, and that in 5 ~ 20 cm soil layer increased by 46.03%. The increase of soil enzyme activity accelerated the transformation of nutrients, and the contents of soil organic matter and nitrogen, phosphorus, potassium, calcium and magnesium all increased. After covering with grass for 3 years, the soil water content in orchard was 48. 13% higher than that in control, and the variation range of ground temperature decreased. The temperature difference between day and night is 7 ~ 8℃ when there is no grass mulching, and the temperature change between day and night is less than 2℃ when there is grass mulching, which creates a stable environment for root growth. Mulching with grass can increase soil porosity and aeration, which is beneficial to root growth. The disadvantage is that it will cause the root system of fruit trees to float. If we can cooperate with deep ploughing and fertilization in autumn, the root system will grow deeply, and the effect will be better.
(5) Jujube-grain intercropping
Jujube-grain intercropping is an efficient three-dimensional planting mode created by working people in China, which combines agriculture with forestry and makes full use of land, light, heat, water and gas resources. It is one of the pollution-free and efficient cultivation modes of jujube. The author saw that in the jujube orchard intercropped with wheat, the scarab did little harm in spring. After wheat harvest, the number of ladybugs on jujube trees increased sharply, which can control the spread of pests. Intercropping forms are as follows:
Jujube-grain intercropping: intercropping wheat in the early stage and intercropping beans after wheat harvest. This form of double harvest of jujube and grain is a good way to solve the problem that farmers spend money to eat grain. Jujube-grain intercropping is not suitable for intercropping tall crops such as corn and sorghum, so as not to affect the illumination of jujube trees.
Jujube-vegetable intercropping: Intercropping vegetables enriches people's food baskets, and the current benefit is higher than growing grain. However, it should be noted that autumn vegetables such as radish, Chinese cabbage, carrot and leek are not suitable for planting, so as to avoid the harm of floating dust to jujube trees in the later period.
Jujube-melon intercropping: Intercropping melon is more beneficial than intercropping grain, which is conducive to the improvement of soil fertility.
Jujube-medicine intercropping: Intercropping Chinese herbal medicines, especially shade-tolerant varieties, can not only receive higher economic benefits, but also inhibit the occurrence of diseases and pests of some varieties.