Lately, I’ve been getting frequent calls from farmers asking: “Teacher Jia, is it still okay to apply a topdressing fertilizer to wheat now? When should we do it, and how many times? Some so‑called ‘experts’ say the fertilization must be completed before the New Year—is that right? And is it better to broadcast the fertilizer or use a fertilizer spreader?” Faced with this barrage of questions, many of you may feel confused and at a loss. Don’t worry—let me explain it all step by step.
When farmers proactively raise questions, it shows that their thinking is evolving. They no longer engage in farming blindly as they once did; instead, they base their practices on the nutrient requirements of crops and rely on scientific principles—what we now commonly refer to as “scientific farming.”
As the grain crop with the largest planted area, wheat yield has long been a major concern. How to produce high‑yielding, high‑quality wheat seeds remains a central research topic for scientists. In addition to selecting superior varieties, routine field management is equally critical for achieving both high yields and excellent grain quality; neglecting scientifically sound practices such as irrigation, fertilization, pest and disease control, and weed management amounts to farming without proper guidance.
As the earth revives and spring fills the air, the arrival of the Beginning of Spring heralds the season’s onset. “The whole year’s plan lies in spring; the whole day’s plan lies in the morning.” With the recent arrival of Lichun, the weather is gradually warming, and the wheat in the fields is beginning to stir, stretching its stems and leaves—ready to burst into growth. Next, I’ll take a closer look at how to cultivate wheat in a scientifically sound way.
The North China Plain is China’s major wheat-producing region, and winter wheat is the predominant variety. Below, we’ll use winter wheat as an example to explain the process. Wheat fertilization is divided into two stages: base fertilizer and topdressing. As we’ve often emphasized, wheat’s nutrient‑requirement pattern shows that before the green-up stage, it absorbs only about 20% of its total nutrients for the entire growing season; after green-up, this figure rises to roughly 80%. From this pattern, it’s clear that the jointing–booting stage is the period of most vigorous growth, with exceptionally high nutrient demands. Insufficient fertilization at this time can lead to premature senescence, while excessive application may result in overly vigorous vegetative growth, hindering proper spike differentiation and development. Therefore, topdressing after green-up is critical. So how should wheat be topdressed? When is the right timing? What is the appropriate rate? And which type of fertilizer works best? Don’t worry—China Agricultural University will guide you through these key questions.
01 Topdressing for wheat—timing is key.
The timing of topdressing for wheat depends on the condition of the crop. By “crop condition,” we mean assessing the overall stand—specifically, the number of tillers per mu, which should ideally range from 600,000 to 800,000. Taking into account the growth stage, the optimal period for applying jointing fertilizer is generally from late February to mid-March. At this stage, topdressing promotes the development of strong tillers into productive spikes, thereby increasing the spike‑setting rate; it also encourages the differentiation of spikelets and florets, helping to produce larger spikes with more grains, while simultaneously supporting the growth of the three uppermost leaves. Applying topdressing too early or too late can hinder yield formation. If the wheat stand is dense and individual plants are vigorous, the timing of topdressing should be delayed. The ideal moment is when the second‑from‑top leaf has unfolded—roughly when spike differentiation has reached the tetrad stage. For late‑sown, weak stands, topdressing is typically applied in early March, when the first internode of the main stem has already reached its final length and the second internode is beginning to elongate. This approach prevents excessively long internodes and enhances the plant’s lodging resistance.
02 Topdressing for Wheat—Master the Technique
The methods and techniques for topdressing wheat vary depending on local conditions, and primarily encompass the following aspects:
Topdressing timing: Choose a clear day and apply the fertilizer at noon. If cloudy or rainy weather is frequent during the topdressing period, spread the fertilizer directly into the wheat field before the rain.
Fertilization methods: In fields with irrigation, fertilizer may be broadcast and immediately followed by irrigation, or applied through the irrigation water. In fields without irrigation, deep placement using a furrower is essential; the application depth should be at least 5–8 cm, and the soil should be promptly covered afterward to minimize volatilization and enhance fertilizer use efficiency.
Topdressing application rates depend on the specific fertilizer product. If using a liquid fertilizer, apply it through irrigation; refer to the product label for the recommended dosage. For high‑nitrogen compound fertilizers, the typical rate is 20–30 kg per mu, with adjustments made according to the wheat’s growth condition: in fields where leaf color has faded and turned yellow, apply earlier and increase the dose slightly; in fields with dark green leaves and vigorous growth, delay application and reduce the amount accordingly. In addition, supplement with foliar feeding to enhance wheat quality—spray foliar fertilizer 2–3 times during the jointing and booting stages to promote full grain filling, boost yield, and improve grain quality.
03 Wheat topdressing—fertilizer selection for…
What kind of product should you choose for topdressing wheat? Here, we’d like to introduce two Nongda products: Nongda Yibajia (urea‑ammonium nitrogen fertilizer) and our foliar fertilizer—mineral-source humic acid potassium dihydrogen phosphate. Used together, they promise a bountiful harvest. So what makes this product combination so effective?
Agricultural University’s all‑in‑one product serves as a urea substitute. Compared with urea, urea‑ammonium nitrogen fertilizer slows down or inhibits the conversion of “urea molecules → ammonium nitrogen → nitrate nitrogen,” thereby reducing nitrate leaching and denitrification losses, and minimizing ammonia volatilization. It exhibits excellent slow‑release properties and prolonged fertilizer efficacy, with a seasonal nitrogen use efficiency that can reach as high as 77%, far exceeding the 30%–40% utilization rate of nitrogen in conventional urea. This fertilizer increases the number of effective tillers in wheat, promotes robust stems, well‑developed root systems, and dark green leaves, extends the functional period of roots and leaves, provides a sustained supply of nutrients, boosts 1,000‑grain weight, and delivers significant yield gains.
Nongda foliar fertilizer—mineral-source humic acid potassium dihydrogen phosphate—features a unique addition of mineral-source humic acid, setting it apart from conventional potassium dihydrogen phosphate. It is fully water-soluble, leaves no residue, and is easily absorbed. Particularly during the jointing and booting stages of wheat, foliar application helps produce fuller grains, enhances maturity, and delivers outstanding improvements in grain quality.
