What are the sowing methods for walnut cultivation?

  (1) Land preparation To make grafting operations convenient, the wide-narrow row method is commonly used when growing rootstock seedlings, with wide rows at 60 cm, narrow rows at 40 cm, and plant spacing of 15-2,0 cm. If only seedling trees are to be grown without grafting, they can be planted somewhat more densely, with plant and row spacing of 2,0 cm x 40 cm.

  (2) Irrigation Before sowing, water thoroughly once, or sow during rain. In arid and water-scarce areas, generally dig furrows first, pour water into the furrows, and sow after the water has seeped down.

  (3) Dibbling Walnut seeds are large, so the dibbling method is generally used. The seed suture line should be perpendicular to the ground, and the seed tip (from which the radicle and germinate) should be parallel to the ground; this favors seedling emergence and robust growth. With other placement methods, seedlings emerge late, the root crown curves in growth, and growth vigor is weak.

Pictured: walnut

  When sowing a large quantity at one time, a machine for sowing potatoes can also be used; when seed quality is high, it has almost no effect on germination.

  (4) Soil covering thickness Generally, the soil covering thickness for sowing is 3-5 times the seed diameter; for large seeds use 3 times, for small seeds use 5 times. Common walnut diameter is 3-4 cm, so a soil covering thickness of 8-12 cm is suitable. In arid areas it can be appropriately thicker to help preserve soil moisture; where plastic film is used for mulching it can be appropriately shallower, with 5-7 cm of soil covering favoring emergence.

  (5) Plastic film mulching After sowing, plastic film is generally used for mulching, which helps preserve water and soil moisture, raises soil temperature, and promotes seed germination and growth. After seedlings emerge, promptly use a small knife to cut openings for ventilation. You can also first cover with plastic film and then punch holes for dibbling; generally, an old flashlight or an empty almond drink can cut open and punched with holes can be used. Straw can also replace plastic film, but the moisture-preserving effect is poorer, soil temperature is lower, and germination is late.

  Sowing rate Generally, the seedling raising rate for walnuts is about 6,700 plants per mu, with a maximum of no more than 8,000 plants. Each mu requires 120 kg of large seeds (60 seeds/kg), or 70 kg of medium and small seeds (1,00 seeds/kg). Before sowing, calculate the required sowing rate based on the determined plant and row spacing, seed size, etc.; when preparing seeds, prepare 5%-10% more, so as to remove moldy and empty-shell seeds, or to replant when severe missing plants are found after emergence.