Introduction
Sulfur coated urea (SCU) is a fertilizer product that slowly releases nutrients over an extended period. The urea prills or granules are coated with a thin layer of elemental sulfur. This sulfur coating allows the urea to be released gradually as the coating breaks down, making SCU function as a controlled-release nitrogen fertilizer.

How SCU Works
SCU works through a process called dissolution retarding. The thin sulfur coating acts as a barrier, controlling how quickly the urea inside can dissolve and be taken up by plants. Water and soil microbes must first break down the sulfur layer before the enclosed urea becomes available for plant use. This breakdown occurs at a steady, controlled rate over 4-6 weeks depending on soil temperature and moisture conditions. In comparison, conventional uncoated urea dissolves and releases its nitrogen much more quickly, within just a few days or weeks.

Benefits of Using SCU
The slow-release properties of sulfur coated urea confer several agronomic and environmental benefits over conventional fertilizers:

Improved Nitrogen Use Efficiency
Because the nitrogen is released gradually over an extended period synchronized with plant uptake needs, SCU reduces the amount of nitrogen lost through leaching or volatilization. Studies show SCU can increase nitrogen recovery by crops by 10-30% compared to other sources. This improved efficiency lowers fertilizer costs for farmers.

Reduced Runoff Risk
The controlled release of nitrogen from SCU means there is less potential for excess nitrogen to be washed away by rain or irrigation. This lessens the risk of contaminated runoff polluting nearby water sources.

Higher Yields
Sulfur coated urea performs consistently well across diverse soil and weather conditions. By maintaining steady nitrogen levels in the soil, SCU supports continued plant growth and optimize yields compared to other fertilizers applied at the same rate.

Flexibility in Application Timing
SCU's slow release properties provide more flexibility in application timing. It can be surface applied at planting like other fertilizers, but retains effectiveness even if weather delays incorporate the fertilizer into soil. SCU also works well with split or late season applications.

Reduced Labor Needs
SCU requires fewer applications over the growing season since one application sustains the crop's needs. This lowers the time, equipment usages and costs associated with multiple fertilizer applications.

How to Properly Use SCU
To maximize the benefits of SCU, it is important farmers understand proper application practices:

- SCU works best when incorporated into moist soil within 1-2 days of application. Incorporation can be shallow, 2-3 inches deep is sufficient to allow urea granules to come into close contact with soil.

- Surface applied SCU may release more slowly than incorporated SCU, but watering or rainfall after application helps the sulfur coating break down.

- SCU can be knifed in or banded at planting when used for row crops. For broadcast applications a lighter discing or disc harrowing is recommended.

- Higher application rates of 150-200 lbs of N per acre are recommended since SCU's nitrogen is released gradually versus all at once like urea.

- Split applications of SCU at 50% of total N at planting and 50% 6-8 weeks later can maximize yields for certain crops.

- Soil temperatures above 50°F help accelerate the sulfur coating breakdown for more rapid N release to the crop.

Conclusion
Proper use of SCU delivers efficient nitrogen nutrition to maximize crop yields while reducing the nitrogen lost to the environment compared to conventional fertilizers. SCU's slow-release properties make it a valuable tool for farmers seeking to improve profitability through optimal fertilizer performance and reduced input costs over the long term. When application practices maximize contact with soil moisture and tillage, SCU reliably delivers consistent agronomic and environmental benefits season after season.