Cultivation Methods and Technical Points for Intercropping Onions with Corn

This model is suitable for promotion and planting in river-irrigated areas with good water and heat conditions. The usual yields are 7500 kg/hectare for corn and 57000 kg/hectare for onions, with an output value of 38000 yuan/hectare and a net income of 32250 yuan/hectare.

1. Planting arrangement

Onions are sown in drills in mid-to-late September at a row spacing of 20 cm. In mid-April of the following year, corn is interplanted between every other onion row at a row spacing of 40 cm and a plant spacing of 35-40 cm, with a stand of 61500-72000 plants/hectare.

2. Main techniques

2.1 Crop rotation selection and land preparation, with sufficient basal fertilizer. Choose previous crops such as wheat or potato. After the previous crop is harvested, plow deeply and sun the soil. Before sowing, shallow plow and harrow to eliminate clods and create soil conditions with fine, crumbly clods, a loose surface and firm subsoil, and a level surface, so as to store water, conserve moisture, and resist drought to ensure a full stand. In combination with pre-sowing shallow plowing, apply 45000 kg/hectare of farm manure, 225 kg/hectare of pure nitrogen, and 90 kg/hectare of pure phosphorus.

2.2 Select good varieties and sow at the right time. Choose varieties with good yield performance and strong stress resistance. For onions, generally choose varieties such as Xi'an Dahongpi and Yefu No. 1; for corn, choose Zhongdan No. 2 or Yedan No. 13. Sow onions in mid-to-late September. After sowing, firm and roll the soil, and spread a 1-2 cm thick layer of fine sand to increase temperature, conserve moisture, and prevent crusting. In mid-April of the following year, dibble corn between every other onion row.

2.3 Strengthen field management. Thin onions in late March and finalize the stand in early April at a plant spacing of 16 cm, with a stand of 300000 plants/hectare. After final thinning, apply 60 kg/hectare of pure nitrogen as a top dressing. At the same time, maintain soil moisture to promote seedling growth. In mid-June, hoe weeds and loosen the soil, control fertilizer and water, promote downward growth of corn roots, accelerate the transfer of onion nutrients to the bulbs, and promote bulb expansion. In early July, apply top dressing and irrigate, with a top-dressing amount of 75 kg/hectare. To promote bulb expansion, the soil should thereafter remain moist until the onion harvest in late July. After the onions are harvested, apply 120 kg/hectare of pure nitrogen to the corn, then hill up and form ridges before irrigating. After that, spray foliar applications of monopotassium phosphate and zinc fertilizer 2 times each every 10-15 days to ensure the nutrient needs of corn in the middle and late stages and achieve the goal of increasing yield and income. Irrigate during the grain-filling stage to promote grain filling and prevent premature senescence.

2.4 Do a good job in pest and disease control. While carrying out agricultural measures such as crop rotation and increased fertilizer application to prevent and control diseases, for onion downy mildew, at the early stage of the disease use 90% phosethyl-Al wettable powder at 400-500 times dilution, 75% chlorothalonil wettable powder at 600 times dilution, and other pesticides, spraying once every 7-10 days; generally 2-3 sprays can achieve good control. For onion gray mold, usually spray 50% procymidone wettable powder at 2000 times dilution for control. For corn borers and armyworms, use fenvalerate at 800-1000 times dilution to pour into the leaf whorl or spray for control.