Want high yields from late-sown wheat? Master these planting techniques
Compensate for lateness with fertilizer
Compared with wheat sown at the proper time, late-sown wheat consumes relatively less fertilizer, but because late-sown wheat generally follows a previous crop that has consumed a lot of nutrients, the readily available nutrients in the soil are reduced, and moreover, with late sowing, the seedlings are small and weak in the early stage, so water and fertilizer management is not suitable. Therefore, applying sufficient base fertilizer and seed fertilizer, and increasing the application of quick-acting nitrogen and phosphorus fertilizers to promote early seedling growth, is especially important. Generally, apply more than 3 cubic meters of farmyard manure per mu, 30 kg of ammonium bicarbonate, 30 kg of superphosphate, and 5 kg of urea or diammonium phosphate as seed fertilizer. Organic fertilizer and ammonium bicarbonate should be plowed in as base fertilizer, phosphate fertilizer should be broadcast, and seed fertilizer urea or diammonium phosphate can be mixed with the seed and sown together, but it must be uniform and must not be excessive, so as to avoid burning roots and rotting sprouts and reducing the germination rate; it is best to apply the seed fertilizer first, then sow the seed. It should be particularly noted that seeds that have been soaked to promote germination should not be mixed-sown with seed fertilizer.
In addition, appropriately shallow sowing can also reduce the consumption of seed nutrients and ensure early emergence, early tillering, and more rooting; the sowing depth should preferably be 3-4 cm, but the soil preparation should be firm and the soil moisture sufficient.
Seize the time to make up for lateness
How to seek “early” within “late” is the key to increasing the yield of late-sown wheat. In production, on the premise of not affecting or only minimally affecting the yield and variety of the previous crop, the stubble should be cleared as early as possible, the soil prepared as early as possible, and sowing done as early as possible, adopting no-till and simplified soil preparation methods. Land that has been deep-plowed for consecutive years need not be deep-plowed again, and low-lying land with excessive moisture can be managed with no-till.
In order to promote early germination and early emergence of late-sown wheat, seed soaking to promote germination can be carried out. The method is: place the seeds in warm water at about 50°C, soak for 5-10 minutes, remove and pile them up, cover with wet gunny sacks or straw bags, and turn them over once after half a day, keeping the temperature at about 25°C; sprinkle cool water when hot and warm water when cool, and after one day and night the wheat seeds will split open and show white. If sowing cannot be finished that day, they must be spread out to dry to avoid the sprout roots of the wheat seeds elongating.
Compensate for lateness with density
Late-sown wheat has insufficient accumulated temperature before winter, fewer tillers per plant, and fewer tillers forming ears; therefore, the sowing rate should be appropriately increased, relying on the main stems to form ears and obtain a relatively high yield. The sowing rate per mu should preferably be 200,000-250,000 basic seedlings, and the maximum sowing rate should not exceed 300,000 basic seedlings.
Because wheat is sown late, its growth period is shortened; in production, weakly spring-type or spring-type varieties should be selected. Such varieties have a fast stage development process, a short vegetative growth period, and high grain-filling intensity, and easily achieve the goals of large ears, many grains, heavy grains, early maturity, and high yield. At present, the varieties suitable for late sowing in our province include Yumai 18-99, Yanzhan 4110, Zhengmai 9023, etc.
Compensate for lateness with management
Late-sown wheat consumes little fertilizer and water before winter and in early spring, and basically lacks neither water nor nutrients before returning green and jointing, so topdressing and watering are generally not suitable, lest the ground temperature be lowered and seedling development be affected. In February-March of spring, foliar spraying of urea or compound fertilizer can be used to promote seedling growth. For wheat fields with poor soil preparation quality, many clods in loose soil, easy loss of soil moisture, or relatively poor soil moisture, suppression can be carried out in winter and during the returning-green period in early spring, followed by shallow hoeing, so as to achieve the effects of lifting moisture, preserving moisture, and increasing temperature. In high-yield wheat fields, no topdressing and no watering should be done at the jointing stage, so as to control spring tillers and promote winter tillers to form ears; from mid-February to early March, shallow hoeing should be done to loosen the soil and let air in, increase temperature and preserve moisture, and promote early seedling growth and more rooting, but fertilizer and water should not be applied too early, otherwise it will not only affect root growth but also cause a large amount of spring tillering in the wheat seedlings, field shading and excessive growth, delayed polarization, and a postponed growth period. However, for medium- and low-yield wheat fields, small amounts of water and fertilizer management in spring can promote rooting and tillering and increase the population.
The standing-up and jointing stage is the key period for managing late-sown wheat; fertilizer and water can be applied together, with 7-10 kg of urea applied per mu, to prevent greening and late maturity and promote the growth of the flag leaf, the leaf below the flag leaf, and the stem nodes, which is very beneficial for increasing the thousand-grain weight.