Detailed Explanation of Key Technical Points for Soil Management in Apple Orchards

I. Ridge raising and mulching

1. Dig fertilization pits (this can be done together with the application of base fertilizer). On the inner side, 30-40 cm vertically below the extended branches on the outer periphery of the tree canopy, dig 2-4 fertilization pits each 40 cm long and 40 cm wide and 50 cm deep (the depth for topdressing is 20 cm).

2. Dig trenches and raise ridges. Outside the fertilization holes, along the row direction or the irrigation direction, make irrigation trenches (which also serve as drainage trenches) 30-40 cm wide and 30-40 cm deep, closely against the outer edge of the fertilization pits. The soil from the trenches is covered within the rows to a height of 15-20 cm, and no soil is buried within 3-5 cm around the tree trunk, ultimately achieving a shape that is low between rows and high within rows.

3. Cover with black plastic film. Lay black plastic film over the ridges and fertilization holes. The width varies depending on tree age and plant-row spacing, with 1-2 m on each side.

II. Artificial grass growing between rows

Through experimental research and large-scale surveys of orchard grass growing in our county and surrounding counties (cities, districts), we believe that grass species such as white clover, flat-stemmed milkvetch, bird's-foot trefoil, and hairy vetch are currently suitable and excellent grasses for apple orchards.

White clover, flat-stemmed milkvetch, and bird's-foot trefoil can be sown in spring or autumn, with autumn being the best. The spring and autumn sowing periods are from late March to April and from mid-August to mid-September. Before sowing, clear weeds from the orchard, plow to a depth of 20-25 cm, and level the ground before sowing. Both drilling and broadcasting can be used. For drilling, the row spacing is about 30 cm, with a depth of 1-2 cm, and the seeding rate is 1-2 jin per mu. The sowing method is, on the basis of loose soil, to scatter the grass seeds on the ground and rake back and forth several times with a vegetable rake so that the seeds enter the soil, or to open shallow furrows with a hoe, that is, raise the rear hand to open the furrow, sow the seeds by hand (to prevent the seeds from dropping too quickly, an appropriate amount of sand can be mixed in and stirred evenly before sowing), and then tread level with the feet. If the soil moisture is insufficient, irrigate to supplement moisture. When white clover grows to more than 30 cm, mow it in time, and it is appropriate to leave a stubble of about 10 cm, covering the mowed grass within the tree basin. The effective utilization period of white clover sown once is at least 5 years.

Hairy vetch should be sown in autumn at a depth of 2-3 cm. Because it is an annual grass, it does not need to be mowed. It dies in late June of the following year, and it does not need to be sown again in autumn; the seeds that fall on the ground can be used to grow new seedlings again.

III. Grass mulching method

Cover under the canopy of apple trees or across the whole orchard, with a mulching thickness of 15-20 cm (press some soil on the grass surface), without plowing and turning, and add new grass cover each year.

IV. Increase the application of farmyard manure, raise the soil organic matter content, and improve soil structure.