How farmers can cut greenhouse gas and ammonia emissions

Use of protected urea nitrogen fertiliser is the largest single avenue currently open to Irish agriculture to meet the  commitments to reduce GHG and ammonia emissions.

Protected urea is urea treated with an active ingredient called a urease inhibitor. The urease inhibitor can be coated onto the outside of the fertiliser granule or incorporated into the urea granule during manufacture.

No, because the conversion of protected urea to ammonium begins as soon as the fertiliser granule starts to melt.

The result is that the conversion occurs over a few days rather than a few hours, as would be the case with conventional urea.

Remember, when fertiliser N is applied to soil, its aim is to supply the grass or crop with N over a period of days to weeks, rather than hours.

Yes, the following products are recognised as acting effectively as urease inhibitors: NBPT, 2-NPT, NBPT+NPPT.

Teagasc has conducted research with all three inhibitor options, most extensively with NBPT and NBPT+NPPT.

Yes, you can spread protected urea across the growing season when you would otherwise spread calcium ammonium nitrate (CAN) or unprotected urea.

This may potentially simplify fertiliser spreading on the farm, and setting up a fertiliser spreader for only one straight-N product each year.

No, published Teagasc trials have shown protected urea consistently yields as well as CAN in Irish grasslands, with no difference in annual production.

Analysis of costs in March 2019 showed protected urea to be less costly than CAN, while performing just as well in terms of yield and N recovery efficiency.

Bear in mind that fertiliser costs fluctuate, but always make cost comparisons on the basis of cost per kg of N for straight N-products.

Yes, published Teagasc trials have shown protected urea has 71% lower nitrous oxide emissions than CAN.

Yes, based on published Teagasc research, protected urea has comparable ammonia loss to CAN, and ammonia loss is reduced by 79% compared to urea.

Protected urea does not deliver N directly as nitrate to the soil, therefore reducing the risk of nitrate losses occurring with rainfall after fertiliser application.

Reduced ammonia loss compared to urea will also reduce the risk of ammonia N being deposited from the atmosphere onto sensitive habitats or into sensitive water bodies.

While no definitive list has been approved by the Department of Agriculture, Food and the Marine (DAFM), the accompanying table shows a list of products that have shown efficacy to reduce emissions.

Urea protected with the active ingredients NBPT, 2-NPT, and NBPT+NPPT have been shown to be effective in protecting urea in Irish and/ or international research.

If the inhibitor can be protected from exposure to the acidity which often comes along with P blending, then possibly yes. Ask your supplier to show you evidence that P blending has not affected the protection.

However, protected urea treated and used within six to 12 months should still have very high efficacy.

Even where degradation decreases NBPT below the current regulatory minimum inclusion level, the urea will still be protected.

Yes, Irish trial results show no significant yield or N recovery difference between CAN and urea protected with NBPT. However, if conditions are dry and remain so, response to any N fertiliser will be limited. So if you are hesitant to spread CAN, you should also be hesitant to spread protected urea. Consider waiting for rain and growth conditions to return.

It is more hygroscopic than other fertilisers, which causes it to draw moisture, if the spreader is not washed out.

Post time: Oct-28-2019
WhatsApp Online Chat !