Spring Management Technical Recommendations for Wheat Fields in Central and Southern Hebei

Recently, the author conducted a survey on the overwintering conditions of wheat in Longyao County and surrounding areas. Overall, due to the influence of a warm winter, except for individual weak seedling fields that suffered frost damage, the seedling conditions in most wheat fields were normal. Although many wheat fields were not irrigated with winter water, the several rainfall events in early winter, combined with many foggy and hazy days and few windy days, resulted in relatively sufficient soil moisture. Therefore, the following recommendations are proposed for spring management of wheat fields:

I. Wheat fields sown relatively late with a relatively high sowing rate (exceeding 20 kg/mu)

Because the wheat seedlings had 3-4 leaves before overwintering, growing in dense clusters, with thin and weak individuals, weak or no tillering, low nutrient accumulation in the plant, and reduced cold resistance, and encountered the first snowfall of early winter in the earlier period, some had already suffered frost damage, with most fields showing dry tips and yellow leaves. The following points should be addressed in spring management.

1. Wheat fields with relatively many dead seedlings after overwintering. After green-up, promptly harrow and rake, remove dead leaves, and when the temperature reaches above 5°C, irrigation can be carried out. A small amount of water is appropriate for irrigation; combined with irrigation, apply 10 kg of urea per mu as topdressing. After irrigation, when soil moisture is suitable, promptly hoe and cultivate to conserve moisture.

2. Wheat fields with no dead seedlings or relatively few dead seedlings after overwintering. After green-up, promptly carry out harrowing and hoeing. For fields at risk of lodging, rolling or deep intertillage can be carried out before stem elongation (before the Rain Water solar term). If there is still a tendency toward excessive growth after rolling and hoeing, spray 15% paclobutrazol.

II. Wheat fields with appropriate sowing rate and relatively early sowing

Generally, these have more than 3.5 tillers per plant, with over 900,000 stems per mu, sometimes reaching 1.2 million. In many fields, the wheat seedlings have already completely covered the ground. This spring, such wheat fields account for the largest proportion. This is typical excessive growth. The goal of spring management is to transform excessive growth into vigorous growth, prevent cold damage and lodging, and prevent "late spring cold" in advance. Specific measures are as follows:

1. Compacting. Suppress excessively rapid aboveground growth, avoid premature stem elongation, and control excessive growth to achieve vigorous growth. Compacting should be done when the temperature is above 3°C, after green-up, from noon to before 5 PM. Self-made steel pipes and cement pipes can be used as tools, generally pressed along the rows, not too fast, covering 60-100 mu per day. Note: do not compact frozen wheat fields, saline-alkali land, small weak seedlings, or dry sandy land. Do not compact when the ground is wet; compact when the ground is dry. Do not compact on cloudy days; compact on sunny days. Do not compact in the morning; compact at noon.

2. Harrowing and hoeing. This not only raises and conserves soil moisture but also controls growth and promotes vigorous development. Promptly harrow and rake fields with many dead leaves and large populations, which can clear the rows, control growth, and promote vigorous seedling transformation. For small plots, hoeing can be done; note to hoe shallowly and finely. Generally, from green-up to stem elongation, hoe 2-3 times in total. Wheat fields at risk of lodging must undergo one deep intertillage before and after stem elongation.

3. Application of growth regulators. For fields that still show a tendency toward excessive growth after compacting and hoeing, use 30 g of 15% paclobutrazol per mu, diluted with 25-30 kg of water for foliar spraying. Note: do not miss any area and do not spray twice. For fields where growth weakens after compacting and hoeing, at the stem elongation stage, spray foliar fertilizers such as monopotassium phosphate, Tianfengsu, or Shuofeng 481 and other plant growth regulators per mu to promote robust plant growth and improve stress resistance. Foliar fertilization can be combined with disease and pest control.

4. Prevention of late spring cold. After entering April, carefully listen to weather forecasts to prevent late spring cold. Before a cold wave arrives, fields with irrigation conditions should be irrigated, and quick-acting nitrogen fertilizer should be applied as topdressing along with irrigation. Fields without irrigation conditions should receive foliar fertilization (water). After damage occurs, for mild cases with green leaves, immediately carry out foliar fertilization; for severe cases without green leaves, after new green leaves emerge, spray foliar fertilizers such as monopotassium phosphate, Tianfengsu, or Shuofeng 481 and other plant growth regulators.

III. Vigorously growing normal wheat fields

These refer to first-class seedlings with 700,000-900,000 stems per mu and more than 3.5 tillers per plant, and second-class seedlings with 600,000-700,000 stems per mu and 2.4 tillers per plant. Adhere to "normal management," combining promotion and control, to ensure normal individual development and appropriate population size, reaching 1-1.2 million stems per mu at stem elongation, achieving many ears, robust plants, large ears, and many grains. The following measures can be taken:

1. For first-class seedlings. After green-up, harrowing and hoeing can be carried out to raise and conserve soil moisture, thereby delaying the green-up irrigation. Generally, the first spring irrigation is postponed to the wheat stem elongation stage, that is, late March to early April. Apply appropriate fertilizer along with irrigation.

2. For second-class seedlings. Similar to first-class seedlings, if soil moisture in spring can satisfy wheat green-up growth, generally do not irrigate at green-up; only hoe and cultivate to conserve moisture. Postpone the first spring irrigation until the temperature is higher. Along with irrigation, supplement an appropriate amount of quick-acting nitrogen and phosphorus fertilizer at 10-15 kg.

IV. Wheat fields in sandy soil areas and nutrient-deficient wheat fields

Compacting for moisture conservation can be done in advance. After wheat green-up, promptly carry out irrigation, and at the same time apply 5-10 kg of urea per mu by burial to supplement nutrients, increase spring tillering, and improve the rate of tillers forming ears.

For abnormal seedlings such as "stubborn seedlings," "small old seedlings," and "yellow seedlings," the causes should be analyzed. They are generally caused by poor straw return quality, poor land preparation quality, insufficient soil moisture, or soil compaction, poor aeration, thin soil layer, poor fertility, or phosphorus and potassium deficiency. Targeted measures can be taken: loosen the surface soil, break up compaction, and when the temperature is higher, along with irrigation, open furrows to supplement phosphorus and potassium fertilizer. For yellow seedlings caused by moisture deficiency or fertilizer shortage, fertilizer and water should also be supplemented. Because they have few tillers and few secondary roots, combined with low temperatures and weak root activity, the wheat's ability to absorb soil nutrients is weakened. To promote seedling transformation, a mixture of 1% urea solution + 0.3% monopotassium phosphate solution can be sprayed.

Huang Yongshan, Longyao County Vocational Education Center