Key Technical Points for Summer Corn Planting and Field Management
Most summer corn has already entered the jointing stage to the large trumpet stage. Therefore, doing a good job in chemical growth regulation to prevent lodging at the jointing stage, applying ear fertilizer, and controlling diseases and pests is crucial to achieving high corn yields.
1. Scientific chemical regulation. Because the wheat growing period was delayed, corn sowing dates were generally late, and the jointing stage coincided with the rainy season, creating hidden risks of lodging in corn. Chemical regulation not only makes corn stalks tougher, the root system well developed, and lodging resistance stronger, but also deepens leaf color, thickens leaves, increases chlorophyll content, and enhances photosynthesis. It can generally reduce plant height by 10-15 cm and ear height by 10-12 cm, and can also shorten internodes, shaping an ideal high-yield plant form with good ventilation and light penetration. It plays a role in drought resistance, disease resistance, lodging resistance, and promoting reproductive growth, helping produce large ears, many kernels, heavy kernels, and a low bald-tip rate. It increases density by 200-400 plants per mu, with yield increases generally ranging from 15%-30%, truly achieving “seeking high yield through dense planting”. The time for chemical regulation is generally best when corn has 6-13 expanded leaves, and the effect is best especially at 8-13 expanded leaves. Before the 6-leaf stage of corn, the leaves are slender and the leaf surface is smooth. When corn reaches the 7-expanded-leaf stage, the leaves become wide and thick, and fine soft white hairs appear on the leaf surface, which can be easily felt with the back of the hand. This is the best period for spraying chemical regulation agents. For the spray agent, the first choice is Dinongbao, the latest research achievement of the Chinese Academy of Agricultural Sciences.
2. Topdressing ear fertilizer. During the ear stage, the absorption of mineral nutrients is greatest and the absorption intensity is highest. This is the period of fastest nutrient uptake by corn and also the most important fertilization period in its entire life. Topdressing nitrogen fertilizer at the large trumpet stage can effectively promote the differentiation of female ear florets and achieve large ears with many kernels. Generally, 20-25 kg of urea or nitrogen-potassium compound fertilizer can be topdressed per mu. The topdressing method can be digging furrows at the side of the rows or digging holes beside the plants for deep application. It is best combined with irrigation or applied during effective rainfall. Never broadcast it on the soil surface to prevent fertilizer loss.
3. Strengthen disease and pest control. For diseases and pests at the ear stage of summer corn, focus should be placed on controlling brown spot and corn borer. Brown spot can be controlled by foliar spraying with 12.5% Hexaconazole or 12.5% Triadimefon; corn borer can be controlled at the large trumpet stage by pouring phoxim granules into the whorl, or by spraying the heart leaves with 4.5% beta-cypermethrin emulsifiable concentrate or 50% phoxim emulsifiable oil.