Shandong Provincial Department of Agriculture Issues the 2017 Summer Corn Production Technical Guidelines

In order to optimize the corn planting structure, vigorously promote key corn production technologies, promote the integration of agricultural machinery and agronomy, improve production efficiency, achieve cost savings and efficiency gains, and ensure the stable and sustainable development of corn production, the Provincial Department of Agriculture organized relevant experts to research and formulate the "2017 Summer Corn Production Technical Guidelines", which are hereby issued to you. Please carefully organize and implement them in light of local conditions.

Shandong Provincial Department of Agriculture

May 23, 2017

2017 Summer Corn Production Technical Guidelines

In order to vigorously promote key practical yield-increasing technologies such as “one increase and four changes”, “precision sowing”, and “simultaneous sowing of seed and fertilizer”, promote the integration of agricultural machinery and agronomy, raise the level of mechanization, advocate green production models, achieve high yield and high efficiency, guide the adjustment and optimization of the planting structure, and promote the stable and sustainable development of corn production in our province, these guidelines are hereby formulated.

I. Adjust and optimize the planting structure to ensure sustainable development

In this year's corn production, all localities should, on the basis of consolidating corn planting in advantageous production areas, actively adjust and optimize the corn planting structure. According to market demand and the development of local livestock farming, moderately develop silage corn, fresh-eating corn, specialty corn, etc., keep grain corn production generally stable, and advocate crop rotation.

Specifically, first, in areas with poor production conditions, where corn production depends on the weather and yields are low and unstable, actively switch to drought-tolerant crops such as miscellaneous grains, miscellaneous beans, and root and tuber crops. Second, in areas with developed livestock farming, develop forage grass according to demand, give consideration to both grain and feed, and improve the planting structure. Third, moderately develop fresh-eating corn such as waxy corn and sweet corn, improve the dietary structure, and increase economic benefits. Fourth, advocate intercropping or rotation of corn with soybean and corn with peanut, which can both give play to the nitrogen-fixing and soil-nourishing role of leguminous crops and improve benefits.

Advantageous corn production areas should also continue to strengthen the construction of high-standard farmland, increase efforts to promote green planting models, tap yield potential, and ensure stable corn production. Actively introduce new varieties, new fertilizers, new pesticides, and new planting methods, demonstrate and promote them, and assemble them into comprehensive technical models suitable for local conditions. Do a good job in infrastructure construction and technical reserves, achieve "storing grain in technology and storing grain in land", ensure stable corn production, and achieve sustainable development.

II. Make good pre-sowing preparations and improve sowing quality

Before summer corn sowing, farmers should be guided to make preparations such as selecting improved varieties and handling the previous crop, and machinery operators should be guided to make good machinery selection and debugging, creating favorable conditions for sowing at the right time and improving sowing quality.

(1) Variety selection. Select varieties suitable for mechanized operations, tolerant to dense planting, resistant to lodging, highly adaptable, with suitable maturity periods, and stable and efficient yields. For grain corn, varieties such as Zhengdan 958, Denghai 605, Jinhai No. 5, Liaoyu No. 22, Ludan 818, Tiantai No. 33, Denghai 618, Yuyu 30, Jiyu 901, Qingnong 11, Nongxing 207, Hualiang 78, Huasheng 801, Dika 517, Ludan 9088, Liansheng 216, and Bangyu 339 may be used; for silage corn, varieties such as Shannong Siyu No. 1 may be used; for fresh-eating corn, varieties such as Qingnong 206, Shannong 207, Jinuo 33, Ludan 801, and Xixing Wucai Xiannuo may be used. For mechanical grain harvesting, varieties with a slightly shorter growth period, fast grain dehydration, moderate ear height, and lodging resistance should be selected.

(2) Select seeds carefully. Select high-quality seeds with high purity, high germination rate, strong vigor, and suitable for single-seed precision sowing. Seeds must be carefully selected to ensure full, uniform, and strong seedlings after precision sowing. Seed purity ≥98%, seed germination rate ≥95%, cleanliness ≥98%, moisture content ≤13%.

(3) Seed treatment. Use pesticide coating or seed dressing to prevent and control various diseases and insect pests, mainly maize rough dwarf disease, head smut, seedling blight, and underground pests. To prevent maize rough dwarf disease, use systemic insecticides for seed dressing or coating; 70% imidacloprid SE can be used at 0.6 of the seed weight for seed dressing or coating. 2% Raxil or 50% carbendazim can be used at 0.2% of the seed weight for seed dressing to prevent fungal diseases such as head smut and seedling blight. For underground pests, 40% isofenphos-methyl can be used at 0.2% of the seed weight for seed dressing, and it can also control pests such as the small brown planthopper and corn aphid. Adopting unified technology, concentrated contiguous areas, and whole-village advancement can improve the effectiveness of disease and pest control.

(4) Machinery selection. Select multifunctional, high-precision corn sowing machinery. Farmers with a small production scale may use rotary spoon-type or finger-clip-type corn precision seeders; farmers or cooperatives with a larger production scale may choose air-suction or finger-clip-type corn precision seeders; in areas where wheat straw crushing quality is poor, a stubble-clearing (or stubble-killing) corn precision seeder may be chosen; in areas with hardened soil layers or a large amount of fertilizer applied, a deep-loosening multi-layer fertilizing corn precision seeder may be chosen; in areas with deep soil layers and evenly scattered straw, a “three-position” fertilizing corn precision seeder may be used.

(5) Rush stubble and direct sowing. The suitable sowing period is early to mid-June. After wheat harvest, sow corn as soon as possible according to conditions. During wheat harvest, use a combine harvester with straw chopping and scattering functions, and return the chopped straw to the field during harvest. The wheat straw chopping length should be ≤10 cm, the qualified rate of cutting length ≥95%, the uneven scattering rate ≤20%, and the missed cutting rate ≤1.5%. Leave a low stubble during wheat harvest, with the stubble height above the ground not exceeding 20 cm. After the wheat straw is returned to the field, immediately sow corn to achieve a “one-stop” operation of wheat mechanical harvest with straw chopping and return, corn mechanical precision sowing, and deep fertilizer application. Where conditions permit, a stubble-breaking, deep-loosening, no-till seeder may be used. In areas where maize rough dwarf disease occurs year after year, the sowing period of summer corn may be postponed to after June 10, and severely affected plots should be sown after the 15th.

(6) Sowing method and density. Use corn precision sowing machinery for no-till stubble-attached precision sowing, with a row spacing of 60 cm and a sowing depth of 3-5 cm. Ensure consistent sowing depth, consistent row spacing, consistent soil covering, and consistent compaction, and prevent missed sowing, repeated sowing, or slipping of the press wheels. The sowing density should be increased by about 10% compared with the intended harvest density. For density-tolerant corn, generally sow about 5,000 seeds per mu in ordinary fields, about 5,500 seeds per mu in demonstration fields, and 5,800-6,000 seeds per mu in research plots. For large-ear varieties, generally sow about 4,600 seeds per mu in ordinary fields and about 5,300 seeds per mu in high-yield fields.

(7) Soil moisture and fertilizer. The suitable relative soil water content at sowing is 70%-75%. If soil moisture is insufficient, sow first and then irrigate, to avoid affecting the seeding machinery's entry into the field after irrigation and delaying the sowing time. Appropriate shallow sowing combined with watering the “covering water” is conducive to cultivating strong seedlings. Base fertilizer or seed fertilizer should be applied with a seeder equipped with a fertilizing device. Give priority to deep-loosening multi-layer fertilizing and “three-position” fertilizing corn precision sowing machinery to apply sufficient base fertilizer. When applying base fertilizer, it should be applied deeply to the side, separated from the seeds by an appropriate distance, to prevent seed and seedling burning.

(8) Chemical weeding and pest control. Use a seeder equipped with a spraying device to spray soil-closed herbicides in one operation, or carry out closed weeding before emergence when soil moisture is suitable. Compound preparations should be mainly used, with single agents as supplements. The main varieties include: acetochlor · atrazine, alachlor · acetochlor · atrazine, propisochlor · atrazine, metolachlor · atrazine, atrazine, acetochlor, pendimethalin, etc. For chemical pest control before corn emergence, spray 10 g of 10% imidacloprid per mu for control; during the peak nymph stage of the small brown planthopper, 20 g of 25% buprofezin per mu may be used for control, and attention should also be paid to spraying at field edges and ditch edges for control.

III. Strengthen seedling-stage management and lay a solid foundation for high yield

The main tasks are to maintain suitable soil moisture needed for emergence, ensure safe emergence, control diseases, pests, and weeds, and ensure full, uniform, even, and strong seedlings.

(1) Water the “covering water”. When soil moisture is insufficient, water the “covering water” after sowing to ensure sufficient bottom moisture, early seed germination, and full seedlings from one sowing, and to ensure suitable planting density.

(2) Chemical weeding. For fields where soil-closed weeding was not carried out or failed, at the 3-5 leaf stage of corn and the 2-5 leaf stage of weeds, 48% butachlor · atrazine or 4% nicosulfuron, etc., may be mixed with water for post-emergence weeding. Do not spray repeatedly or miss spraying, ensure weeding quality, and pay attention to application safety.

(3) Prevent and control diseases and pests. At the 4-5 leaf stage of seedlings, use 25% triadimefon wettable powder at 1,500 times dilution or 50% carbendazim at 500-800 times dilution for foliar spraying to prevent and control brown spot. To control armyworms, diflubenzuron and fenvalerate emulsifiable concentrate, etc., may be sprayed; to control thrips, 10% imidacloprid may be sprayed. According to the occurrence of the small brown planthopper, beet armyworm, and cotton bollworm, insecticides such as emamectin benzoate and chlorantraniliprole may be selected for spray control. In plots where nicosulfuron herbicide is used, avoid using organophosphorus pesticides to prevent phytotoxicity.

(4) Drain water promptly in case of waterlogging. If water accumulates in the field during the seedling stage, promptly dredge field ditches and other drainage systems for drainage, and ensure smooth drainage during the corn growth period. After drainage, loosen the soil promptly to break soil crusting and allow moisture to dissipate and air to penetrate.

IV. Do a good job in ear-stage management and build a good framework for high yield

The main task is to strengthen management, promote leaf growth and strong stalks, promote large ears, ensure a reasonable population and sturdy, robust individuals, coordinate vegetative growth and reproductive growth, and build a good framework for high yield.

(1) Remove small plants. Small, weak, and diseased plants appearing in the field should be removed promptly to reduce nutrient consumption and disease spread, improve the population structure, and create a good environment for normal plants.

(2) Apply ear fertilizer. The period from the small trumpet stage to the large trumpet stage is the key fertilization period for summer corn, and attention should be paid to applying ear-promoting fertilizer. Ear fertilizer should be mainly nitrogen fertilizer, with 10-15 kg of nitrogen fertilizer applied per mu, and phosphorus and potassium fertilizers may also be applied. Dig a furrow about 10 cm from the plant and apply deeply, at a depth of about 10 cm.

(3) Prevent drought and waterlogging. From the large trumpet stage to the tasseling stage is the critical water-demand period for corn, and it is especially sensitive to water. If drought occurs, irrigate promptly, especially to prevent “neck-choking drought”, which causes asynchronous development of male and female ears. Excessive soil moisture can also hinder development, increase the barren stalk rate, and cause lodging. Measures such as intertillage and hilling can be taken to promote aerial root development and improve plant lodging resistance.

(4) “One prevention and two reductions”. During the ear stage, diseases such as northern and southern leaf blight and sheath blight, and pests such as the Asian corn borer, armyworm, and aphids, are prone to occur. Spraying a compounded or mixed insecticidal and fungicidal agent once at the large trumpet stage of corn can prevent and control multiple diseases and pests in the middle and late stages, reduce the base number of late-stage ear pests, alleviate the degree of disease epidemics, protect normal plant growth, improve leaf photosynthetic efficiency, and achieve increased corn yield and efficiency.

(5) Chemical control to prevent lodging. For plots with high fertilizer and water, relatively high density, excessive growth, and a relatively high lodging risk, spray a chemical control agent at the 7-11 leaf unfolding stage of corn to prevent lodging. This can moderately control plant height, promote leaf photosynthetic capacity, enhance stress resistance and lodging resistance, and improve the population structure. Chemical control is not suitable for plots with reasonable density and normal growth, low-fertility medium- and low-yield fields, or plots replanted to fill gaps.

V. Attach importance to grain-stage management, prevent premature senescence and increase grain weight

The main goal is to improve the seed-setting rate, nourish roots and protect leaves, extend the functional period, maintain grain number, and increase grain weight.

(1) Artificial supplementary pollination. Closely monitor corn pollination and take timely countermeasures in case of special weather. High-yield research plots and demonstration fields may carry out artificial detasseling and supplementary pollination. If continuous rain or extreme high temperatures occur during the flowering and pollination period of field corn, remedial measures such as artificial supplementary pollination should also be taken to effectively improve the seed-setting rate and strive to increase the number of grains per ear. Where conditions permit, small drones may be used to fly low to assist pollen dispersal.

(2) Supplement with flower-grain fertilizer. Increase nitrogen fertilizer application at the flowering stage to improve leaf photosynthetic efficiency and extend the leaf functional period. Flower-grain fertilizer should be mainly urea, with the amount increased as appropriate in high-yield research plots. When applying, it may be combined with irrigation or applied before rainfall to improve fertilizer efficiency. Potassium dihydrogen phosphate and urea may also be sprayed as foliar fertilizer to extend the leaf functional period and increase the transformation of photosynthetic products.

(3) Pay attention to drought and waterlogging prevention. During the flowering and grain-filling period, irrigate field corn promptly in case of drought; in high-yield research plots, irrigate as soon as the soil surface dries. Later-stage waterlogging will also reduce root activity, cause leaves to turn yellow, and cause lodging, so drainage should be noted.

VI. Harvest mechanically at the appropriate time to ensure a bumper harvest

The main point is to harvest at the appropriate time, give play to the high-yield potential of the variety, reduce the loss rate of mechanical harvesting, and ensure a bumper harvest.

Harvest with a combine harvester when the milk line of summer corn grains disappears. Without delaying the sowing of the next wheat crop, appropriately delay harvest; it is recommended to harvest on October 1-5.

Harvesting at the appropriate time should be advanced in large contiguous areas, whole villages and whole towns, and jointly by agricultural machinery and agronomy, to dispel farmers' worries about theft and loss and improve the working efficiency of combine harvesters. After harvest, dry or dehydrate promptly to prevent mold.