Ministry of Agriculture Issues Technical Guidance on Wheat Autumn and Winter Planting for the 2014/2015 Season
Ministry of Agriculture Wheat Expert Steering Group
National Agricultural Technology Extension Service Center
This year winter wheat continued to increase production, with a substantial rise in yield per unit area, the highest increase in recent years. Building on this high starting point, to maintain the good momentum of steady winter wheat development next year, we need to start from autumn and winter planting and closely link every step of implementing key technical measures. According to forecasts by the meteorological department, affected by an El Nino event, precipitation in the northern winter wheat region will be below normal in autumn and winter, with temperatures generally on the high side, and some areas may experience continuous autumn-winter drought, which is unfavorable for timely sowing and safe overwintering of winter wheat. To effectively improve winter wheat sowing quality and consolidate the foundation for a bumper summer grain harvest next year, the Ministry of Agriculture Wheat Expert Steering Group, together with the National Agricultural Technology Extension Service Center, has studied and proposed by region the technical guidance on wheat autumn and winter planting for the 2014/2015 season.
I. Huang-Huai and Northern Winter Wheat Region
This region includes Hebei, Shandong, Henan, northern Jiangsu, northern Anhui, central and southern Shanxi, and the Guanzhong area of Shaanxi, and is the largest winter wheat producing region in China. The region has relatively good production conditions, abundant light and heat resources, annual precipitation of 400-900 mm, flat terrain and fertile soil. The cropping system is mainly a one-year two-crop rotation of wheat and maize, with wheat sown in early to mid-October and harvested from late May to early to mid-June. The main factors affecting wheat production are the shortage of water resources, frequent natural disasters such as drought, freezing injury and dry hot wind, and relatively severe damage from stripe rust, sheath blight, powdery mildew and fusarium head blight. The key aspects of autumn sowing and pre-winter management for wheat in this region include the following:
(1) Pre-sowing Preparation
1. Variety Selection. Select suitable varieties according to local climate, soil, soil fertility, cropping system, yield level and pests and diseases. First, select varieties according to weather. Choose winter or semi-winter varieties based on temperature conditions; cross-region planting and the use of unapproved varieties are strictly prohibited. In the northern winter wheat region, winter varieties should be strictly selected, while in the Huang-Huai winter wheat region, winter and semi-winter varieties should be selected. Second, select varieties according to soil. For high-yield fields with good water and fertilizer conditions, choose varieties with high yield potential, tolerance to fertilizer and resistance to lodging. For water-deficient areas, choose drought-tolerant, water-saving and stable-yielding varieties. For dry and poor land, choose drought-resistant and barren-tolerant varieties. For dry but fertile land with thicker soil layers and higher fertility, choose drought-resistant and fertilizer-tolerant varieties. Third, select varieties according to disasters. In areas with severe dry hot wind, choose varieties that are appropriately early-maturing and resistant to premature senescence and stalk wilt, so as to avoid or reduce the harm of dry hot wind. Fourth, select varieties according to disease. In areas with relatively severe rust infection, choose rust-resistant (tolerant) varieties; in areas with excessive precipitation and severe waterlogging, choose varieties tolerant to moisture, resistant (tolerant) to fusarium head blight, and with a long seed dormancy period. Fifth, select varieties according to quality. According to market demand, choose high-quality varieties with good nutritional quality, processing quality meeting finished product requirements, full grains and high test weight. Sixth, strictly manage variety introduction and replacement. Replace new varieties according to changes in production conditions and yield improvement, and prevent large-scale introduction, seed transfer and frequent replacement of improved varieties without testing; while planting main promoted varieties, actively introduce new varieties for trials and demonstrations, do a good job in seed propagation, determine “successor” varieties, and maintain the quality of seeds used in production.
2. Seed Treatment. Strengthen wheat seed treatment, effectively carry out seed coating or chemical seed dressing, reduce autumn seedling disease, lower overwintering inoculum sources, control underground pest damage at the seedling stage, and delay the onset time of wheat stripe rust, powdery mildew, sheath blight and other diseases. Reasonably select chemicals according to the disease resistance of wheat varieties, disease incidence, climate conditions and cultivation methods in each area. Strictly control the amount of chemical used for seed dressing, and prohibit excessive use; sow immediately after seed dressing, use immediately after mixing, and finish sowing the same day; appropriately increase the seeding rate after chemical seed dressing.
3. Straw Return. For maize straw crushing and return to the field, the length is required to be ≤10 cm, and the straw should be evenly spread on the soil surface. Plow the crushed straw into the soil; if the subsoiling technique is used, rotary tillage must be carried out to cut the straw into the soil layer, with a rotary tillage depth of more than 15 cm. After straw return, irrigate to settle the soil; if soil moisture is suitable, harrow and press in time.
4. Deep Plowing (Subsoiling) and Harrowing-Pressing. Deep plow 23-25 cm and then harrow and press, or subsoil 30-35 cm and then rotary till and harrow-press, in order to break clods, settle the soil, facilitate root penetration, prevent air leakage and moisture loss, and protect seedlings for safe overwintering. The effect of deep plowing or subsoiling can last for 2 years; with 1 year of deep plowing or subsoiling, rotary tillage and land preparation are sufficient within 2-3 years. For dryland fallow wheat fields with one crop per year, deep plowing and subsoiling should be carried out in early July, which helps store rainwater and conserve moisture, combined with pre-sowing harrowing to conserve moisture.
5. Irrigation to Build Soil Moisture. Insist on sowing with sufficient soil moisture to ensure full seedling emergence after sowing. When the relative water content of the 0-40 cm soil layer is below 75%, irrigation should be carried out first to build moisture before sowing. For wheat fields that cannot be irrigated in time to build moisture and are irrigated after sowing, hoe in time to prevent soil cracks and reduce soil moisture loss.
6. Application of Base Fertilizer. Use soil testing and formula fertilization, combine nitrogen, phosphorus and potassium fertilizers, and supplement trace element fertilizers. For high-yield fields, adopt the technique of postponing nitrogen fertilizer, with 50% of nitrogen applied as base fertilizer and 50% as topdressing, while all other fertilizers are applied as base fertilizer. According to production experience, the reference suitable fertilization rates for different fertility levels are: for low-yield fields with a yield of 200-300 kg per mu, apply 6-10 kg of pure nitrogen (N), 3-5 kg of phosphorus (P2O5), and 2-4 kg of potassium (K2O) per mu, with all nitrogen, phosphorus and potassium applied as base fertilizer; for medium-yield fields with a yield of 300-400 kg per mu, apply 10-12 kg of pure nitrogen (N), 4-6 kg of phosphorus (P2O5), and 4-6 kg of potassium (K2O) per mu, with 70% of nitrogen applied as base fertilizer and 30% topdressed at the jointing stage, and all phosphorus and potassium applied as base fertilizer; for high-yield fields with a yield of 400-500 kg per mu, apply 12-14 kg of pure nitrogen (N), 6-7 kg of phosphorus (P2O5), and 5-6 kg of potassium (K2O) per mu, with 60% of nitrogen applied as base fertilizer and 40% topdressed at the jointing or stem elongation stage, and all phosphorus and potassium applied as base fertilizer; for super-high-yield fields with a yield of more than 500 kg per mu, apply 14-16 kg of pure nitrogen (N), 7-8 kg of phosphorus (P2O5), and 6-8 kg of potassium (K2O) per mu, with 50% of nitrogen applied as base fertilizer and 50% topdressed at the jointing stage, and all phosphorus and potassium applied as base fertilizer.
(2) Sowing
7. Suitable Sowing Date. Generally, the suitable sowing date for winter varieties is when the daily average temperature is 16-18 degrees C, and for semi-winter varieties 14-16 degrees C. To cultivate strong seedlings before winter, winter and semi-winter varieties must ensure an effective accumulated temperature of 550-600 degrees C before winter, while also considering weather conditions, fertility level, pests and diseases, and safe overwintering. Generally, the suitable sowing period is late September to early October in the northern winter wheat region, October 5-15 in the northern and central Huang-Huai winter wheat region, and October 10-20 in the southern Huang-Huai winter wheat region.
8. Reasonable Seeding Rate. A reasonable seeding rate and suitable number of basic seedlings are the starting point for establishing a high-quality population, and are also important measures for building a reasonable population structure and coordinating the relationship between population and individuals, and between wheat growth and development and environmental conditions. Principles to grasp: First, variety characteristics; for varieties with strong tillering ability and high spike-forming rate, appropriately reduce the seeding rate. Second, sowing time; for early sowing, appropriately reduce the seeding rate, and for late sowing, appropriately increase the seeding rate. Third, soil fertility level; where soil water and fertilizer conditions are relatively good, basic seedlings should be sparse and the seeding rate should be small. Generally, the basic seedlings per mu are 200,000-300,000 in the northern winter wheat region, 150,000-250,000 in the northern and central Huang-Huai winter wheat region, and 150,000-180,000 in the southern Huang-Huai region. When the daily average temperature at sowing is below 15 degrees C, for each day of delayed sowing, increase basic seedlings by about 10,000, but it should generally not exceed 350,000.
9. Fine Sowing. Use wheat seeders that meet requirements and are of qualified quality, and determine the suitable sowing row spacing according to local actual conditions, so as to achieve consistent row spacing, accurate seeding rate and consistent depth, with a sowing depth of 3-5 cm, without missed sowing or repeated sowing.
10. Post-sowing Pressing. Seeders equipped with press wheels should press as they sow; seeders without press wheels should be pressed with a presser after sowing. Ensure sufficient pressing strength and pressing quality, so as to firm the soil, reduce field moisture loss, promote wheat seedling growth, cultivate strong seedlings before winter, and increase the proportion of strong seedlings.
(3) Pre-winter Management
11. Irrigation for Overwintering. For wheat fields lacking soil moisture and fields with straw return, rotary tillage sowing, and loose or unsettled soil, irrigate for overwintering at the appropriate time to protect seedlings for safe overwintering. Winter irrigation is generally carried out when the daily average temperature is stable at 3-4 degrees C, when it freezes at night and thaws during the day, and when water can infiltrate in time, and should be completed before heavy freezing. Advocate water-saving irrigation and prohibit flood irrigation. After irrigation, hoe in time, loosen the soil and conserve moisture, prevent surface cracking, and avoid root damage and seedling death caused by air leakage. For wheat fields with suitable soil moisture, high land preparation quality, sufficient base fertilizer, normal growth and suitable population, overwintering irrigation may be omitted before winter. For wheat fields without irrigation conditions, hoe in time after each rainfall to conserve moisture.
12. Chemical Weeding. In recent years, malignant grassy weeds have shown a gradual development trend and have a great impact on wheat yield. It is necessary to focus on autumn treatment of spring weeds and do a good job in autumn chemical weeding, generally from mid-November to early December, when wheat is at the 3-4 leaf stage and weeds are at the 2-leaf-1-heart to 3-leaf stage. To control grassy weeds such as wild oat, jointed goatgrass, Alopecurus aequalis and ryegrass, use 60-70 ml of 6.9% quizalofop-p-tefuryl emulsifiable concentrate per mu plus water for foliar spraying. To control jointed goatgrass and bromegrass, use 30 g of 3% mesosulfuron or 20 g of 3.6% mesosulfuron-iodosulfuron per mu, add water and spray. To control broadleaf weeds such as flixweed, shepherd's purse and cleavers, use 1.0-1.8 g of 75% tribenuron-methyl dry suspension concentrate per mu, or 10 g of 10% tribenuron-methyl wettable powder, or 50-60 ml of 20% fluroxypyr emulsifiable concentrate plus 30-40 kg of water, and spray evenly. To control Puccinellia distans and hard grass, after wheat emergence use 500-600 g of 25% isoproturon wettable powder per mu, add water and spray.
13. Pest and Disease Control. For wheat fields with relatively severe damage from underground pests such as white grubs and wireworms, use 500 ml of 40% isofenphos-methyl emulsifiable concentrate or 50% phoxim emulsifiable concentrate per mu plus 750 kg of water, and pour along the rows; or use 250-300 ml of 50% phoxim emulsifiable concentrate or 48% chlorpyrifos emulsifiable concentrate, dilute with 10 times water, mix with 40-50 kg of fine soil, and apply into the soil while hoeing. For wheat fields with severe infestation by the wheat leaf miner, use 80 ml of 40% omethoate per mu plus 30 ml of 4.5% beta-cypermethrin, add 40-50 kg of water and spray; or spray with 1% abamectin at 3000-4000 times dilution, which also controls wheat aphids and red spiders. To control wheat sheath blight, use 20-30 g of 12.5% diniconazole wettable powder per mu, or 100 g of 15% triadimefon wettable powder, mix with 50 kg of water and spray evenly. For fields with severe occurrence of wheat cyst nematode, use 3.7 kg of 5% nematode control granules per mu, broadcast along the rows at the seedling stage, and irrigate in time to improve control efficacy.
14. Strictly Prohibit Grazing on Green Seedlings. Strengthen the management and protection of wheat fields before winter, manage livestock and poultry well, eliminate grazing by livestock and poultry on green seedlings, and ensure normal growth and safe overwintering of wheat seedlings.