1、Full article: Reducing nitrogen pollution while improving tomato production by controlled

Here, we conducted field experiments to identify the effects of a single application of controlled-release urea (CRU), conventional urea (CU), and chicken manure (CM) on N losses and yields improvement in a greenhouse tomato system in Beijing, China.

2、Cumulative release characteristics of controlled

Many studies have found that the application of controlled-release urea (CRU) and controlled-release potassium (CRK) greatly improved the yields and fertilizer use efficiencies of crops.

3、Combined application of polymer coated potassium chloride and urea improved fertilizer use efficiencies, yield and leaf photosynthesis of cotton on saline

The potassium recovery efficiency (KRE) and nitrogen recovery efficiency (NRE) of PCPC and PCU treatments were significantly raised by 24.34–33.77% and 19.68–36.25%, respectively, compared with potassium sulfate and urea treatments in 2014 and 2015.

Fate of labeled urea

Fate of labeled urea-15N as basal and topdressing applications in an irrigated wheat-maize rotation system in North China plain: II summer maize | Nutrient Cycling in Agroecosystems

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DeDatta and Gumez (1985) showed that the effect of nitrogen on grain yield significantly affected the response to potassium presence; when nitrogen fertilizers are not utilized, rice do not react to potassium fertilizer.

The fates of 15N

Appropriate fertilization practice is crucial to achieve maximum wheat grain yield with minimum nitrogen (N) loss.

Urea deep placement in combination with Azolla for reducing nitrogen loss and improving fertilizer nitrogen recovery in rice field

In conclusion, UDP combined with Azolla is a potential strategy to further reduce fertilizer N loss and improve total fertilizer N recovery while maximizing rice yield if it can be widely adopted by Chinese rice farmers.

Effects of topdressing with nitrogen fertilizer on wheat yield, and nitrogen uptake and utilization efficiency on the Loess Plateau

Studies from various countries show that topdressing with nitrogen fertilizer can effectively increase winter wheat grain yields. However, information on its effects on wheat yields on the Loess Plateau in China is scarce.

The Effect of Topdressing of Coated Urea Fertilizer at the Spikelet Formation Stage for Increasing Grain Protein Content of the Bread Wheat Cultivar

We examined whether it is possible to replace nitrogen topdressing, such as ammonium sulfate at the flowering stage, with the application of a coated urea fertilizer at the spikelet formation stage.

Responses of Agronomic Benefit and Soil Quality to Better Management of Nitrogen Fertilizer Application in Greenhouse Vegetable Land

As a result of intensive greenhouse vegetable production in northern China, the potential risk of nitrogen (N) fertilizer over-applied is increasingly apparent and is threatening ecosystem and the sustainability of food production.

Topdressing is a critical step in agricultural production, directly impacting crop growth and yield. Among the three major types of topdressing fertilizers—nitrogen (N), potassium (K), and phosphorus (P)—each plays a unique role and offers distinct advantages. Proper application can significantly enhance crop yield and quality. Below, we compare the characteristics of N, K, and P fertilizers and discuss how to select the most suitable type based on crop needs.

Nitrogen Fertilizer

Nitrogen fertilizer is the most demanded nutrient during plant growth. Nitrogen is essential for synthesizing proteins, nucleic acids, and other organic compounds, playing a vital role in crop development. Key functions of nitrogen fertilizer include:

1. Promoting Leaf Growth: Enhances leaf expansion, improves photosynthetic efficiency, and increases photosynthate production.
2. Accelerating Flowering and Fruiting: Appropriate nitrogen levels boost flower bud differentiation, increase flower quantity and quality, and raise fruiting rates.
3. Improving Quality: Strengthens disease resistance, enhances taste, and improves overall crop quality.

excessive nitrogen use leads to:**

1. Nutrient Imbalance: Rapid growth may cause premature aging or early senescence.
2. Environmental Pollution: Excess nitrogen can contaminate groundwater and soil.
3. Disease Risk: Overuse increases susceptibility to fungal diseases.

To mitigate risks, apply nitrogen in "small amounts and multiple applications" rather than large, single doses. Pair with phosphorus and potassium fertilizers for balanced nutrition.

Potassium Fertilizer

Potassium is the second most critical nutrient after nitrogen. It enhances stress resistance, disease defense, and crop quality. Key benefits of potassium fertilizer include:

1. Boosting Disease Resistance: Reduces infection risk.
2. Improving Stress Tolerance: Increases resilience to cold, drought, and flooding.
3. Supporting Root Development: Stimulates root growth and nutrient/water uptake.
4. Enhancing Quality: Improves taste, texture, and market value.

Challenges with potassium use:

1. Soil pH Changes: Excessive use may alter soil pH and disrupt microbial activity.
2. High Cost: Potassium fertilizers are pricier than others.
3. Salt Accumulation: Overapplication can lead to soil salinity issues.

Apply potassium in moderation, following a "small amounts and multiple applications" approach. Combine with other fertilizers to maintain nutrient balance.

Phosphorus Fertilizer

Phosphorus is crucial for root development, photosynthesis, and flowering. Its key roles include:

1. Root Growth: Strengthens root systems for better water/nutrient absorption.
2. Photosynthesis Efficiency: Enhances crop growth and yield potential.
3. Flower Formation: Promotes flower bud differentiation and increases bloom quality.
4. Quality Improvement: Elevates taste and nutritional value.

Issues with overuse:

1. Soil Acidification: Excess phosphorus can lower soil pH.
2. Water Eutrophication: Runoff may cause algal blooms in water bodies.
3. Environmental Impact: Risks of groundwater contamination.

Apply phosphorus judiciously, avoiding large doses. Pair with nitrogen and potassium for optimal results.

Nitrogen, potassium, and phosphorus fertilizers each offer unique benefits but require careful management. In practice, farmers should tailor fertilizer choices to crop requirements and soil conditions. Avoid overapplication to prevent environmental harm and economic waste. Scientific fertilization practices promote sustainable agriculture, improving yields while safeguarding ecosystems and farmer incomes.