Calculate the impact of different fertilizer choices

Quickly estimate the emission reduction potential from low-emission fertilizer technologies with Proba’s intervention calculator for coffee, wheat, barley, and potatoes. 

How does it work?

First choose your relevant crop. Next, choose the fertilizer (inorganic or organic) you currently use for that crop, then pick the improvement you want to test, such as controlled-release fertilizer (CRF), a combination with nitrogen stabilizers, or a low-emission fertilizer variant, and you will get an estimated impact. 

Matching fertilizers to crops:

• Potatoes: CAN 27 and slurry are commonly used fertilizers for potato plantations, and are considered the most effective options. Slurry improves soil structure and microbial activity, while CAN 27 supplies readily available nitrogen for growth. Together, they provide balanced nutrition and boost crop yields.
  
  
• Coffee: Urea is a commonly used fertilizer option, providing a steady nitrogen supply to support strong growth and flowering.
  
  
• Wheat: Fertilizers such as CAN27, CAN24S, and slurry are commonly used. Wheat requires a high amount of nitrogen and sulfur for growth.
  
  
• Barley: With lower total nitrogen requirements to reach desired protein levels, fertilizers such as slurry and CAN24S are commonly used options.

Why more N isn’t always better

Nitrogen is essential for plant growth. However, when nitrogen is applied in excess, it promotes rapid vegetative growth, producing more leaves and stems, rather than grain filling. Excess nitrogen that plants do not absorb is prone to loss through leaching, volatilization, and denitrification, leading to air and water pollution.

Choosing the right fertilizer intervention

The interventions depend on the fertilizer you choose; certain options only fit certain fertilizer types.

Fertilizer composition

• Slurry (organic N content fertilizer)
• CAN24S (24% N, 7%S)
• CAN27 (27%N)
• Urea (26% N)

Slurry

Slurry is prone to leaking nitrogen: ammonia escapes, nitrate leaches, and microbes turn N into gas before plants can use it. 

If nitrogen stabilizers are applied in combination with slurry the conversion of ammonium to nitrate is slowed down, reducing ammonia volatilization, nitrate leaching and ultimately direct and indirect N₂O emissions.

CAN24S 

CAN24S is a synthetic nitrogen fertilizer, the production stage of CAN24S is emission heavy due to the reliance of fossil fuels. Similar to slurry, CAN24S is prone to nitrogen leakage. 

Depending on whether your aim is to promote crop growth and reduce nitrogen related emissions or to focus on the production emissions of the fertilizer, you can use CAN24S with nitrogen stabilizers, low carbon CAN24S or a combination of both.

CAN27 

Both wheat and potatoes use CAN 27.  Low-carbon CAN 27 is better suited to wheat because it has a moderate nitrogen demand and a shorter growing season. In contrast, potatoes benefit more from CRF that supply nitrogen steadily over a longer period.

Urea 

Urea is an inorganic fertilizer that  contains high levels of nitrogen, which is prone to leaching. Urea is often combined with nitrogen stabilizers to reduce nitrogen loss. Also, urea is highly soluble, when urea is coated, as in CRF, it releases nitrogen more slowly into the soil, improving efficiency and minimizing nitrogen losses to the environment.