Detailed Explanation of the Technique of Intercropping Corn with High Wheat Stubble Retained

The technique of retaining high stubble at wheat harvest and returning the wheat straw to the field. It is suitable for regions in North China and Northwest China where corn or other summer-sown crops are intercropped before wheat harvest, and where animal husbandry is relatively developed and corn stalks or other summer crop residues are mostly used as feed. The technique is mature and has already been promoted over large areas in Jiaodong, Shandong and the Yuncheng area of Shanxi.

1. Operating procedures

(1) 10 to 15 days before wheat harvest, intercrop corn or other summer-sown crops. At wheat harvest, the corn has emerged.

(2) At wheat harvest, raise the stubble height for mechanical or manual harvesting, generally to 20-25 cm. Evenly cover the wheat straw and wheat chaff between the corn rows.

(3) After wheat harvest, if there is no rain within 10 days, carry out inter-row cultivation to clear the stubble together with summer seedling management; if the rainy season comes early after wheat harvest, the stubble need not be cleared. For plots with irrigation available, irrigate once after wheat harvest to ensure full seedling emergence and accelerate the decomposition of the straw.

(4) If the following summer crop receives little rain during its growth period and the wheat stubble decomposes poorly, when plowing and turning the soil after the summer crop harvest, apply pure nitrogen at 1% of the amount of dry straw returned to the field.

(5) In plots with high stubble retained, pest infestation is more serious and should be controlled promptly.

(If instead of intercropping, the method of replanting summer corn is adopted, retain wheat stubble at a height of 20-46 cm, dibble corn seeds in the rows while the soil moisture is adequate, then rotary-till, so that the corn seeds enter the soil as the rotary blades turn, and the tall wheat stubble is also cut off by the blades and covers the ground surface; in this way the corn is sown and the tall wheat stubble is returned to the field at the same time).