What are the key technical points for fertilizer and water management of spring wheat?

    Water and fertilize well at the green-up and jointing stages. Applying nitrogen fertilizer at the green-up and jointing stages of wheat can significantly increase protein content and is also a key period for increasing wheat yield. Therefore, fertilizer and water at the green-up and jointing stages should be used well according to local conditions. Wheat grain yield and protein content largely depend on the nitrogen supply level during the development period. Within the range of applying 16 kg of pure nitrogen per mu, grain protein content increases as the nitrogen amount increases. In fertilization, adopt the method of "promoting early, controlling midway, and improving later," that is, 50% base fertilizer, 50% jointing and booting fertilizer, and grain-promoting fertilizer with emphasis on preventing premature senescence. When soil moisture is suitable, for plots with average soil fertility and suitable seedling conditions, the first spring watering should be delayed until the early jointing stage, so as to control excessive tillering of ineffective tillers in spring and elongation of the first and second internodes at the stem base, and about 30 kg of standard nitrogen fertilizer per mu should be applied together with watering; for plots with relatively high soil fertility and somewhat vigorous seedlings, this fertilizer and water application can be appropriately delayed until the late jointing stage; for plots with poor soil fertility and somewhat weak seedlings, the first spring fertilizer and water application can be advanced to the green-up stage.

    Apply supplemental fertilizer and water well in the middle and late stages. Applying a small amount of fertilizer after the booting stage of wheat not only has a certain effect on reducing floret degeneration and increasing the number of grains per spike, but can also increase grain protein content and improve gluten quantity and quality. In the middle and late growth stages of wheat, from the flag-leaf booting stage to the heading and flowering stage, 5 kg-7 kg of urea per mu should be applied together with watering, or at the flowering stage a 2%-3% urea solution plus a 0.3%-0.5% potassium dihydrogen phosphate solution can be sprayed on the leaves, spraying 50 kg-60 kg per 667 sq m. However, fertilizer and water at this stage must not be too late; soil fertilization should be no later than the flowering stage, and foliar spraying should generally be no later than the grain-filling stage.

    Reasonably control watering in the late stage. From the milk-ripe stage to the harvest stage of wheat, appropriately controlling watering can improve grain glossiness and vitreousness rate, significantly reduce the "black embryo" phenomenon, increase grain protein content, and prolong dough stability time. Therefore, considering the simultaneous optimization of yield and quality, the number of waterings should be appropriately controlled in the late growth stage of wheat.