Nitrous oxide field trials and scorch tests
05 Aug 2022

Nitrous oxide field trials and scorch tests

In our newsletter from april, we wrote about nitrous oxide (N2O), and the problems it presents as a strong climate gas, formed during the transformation of ammonium to nitrate (nitrification) and particularly nitrate to free nitrogen (denitrification). See reaction scheme:

We also showed you some interesting lab-results, pointing towards foliar fertilizers being less prone to forming nitrous oxide, and teased a little about wanting to do field trials too. So that we have done 🙂

In the first field trials, there was no measureable N2O from the fertilizer applications at all. This was probably because the weather situation was quite dry, and the reaction forming N2O is mainly denitrification, which happens during wet/anoxic conditions. So a lot of work with no measureable results. Bummer.

BUT. The last trial was done around a period with rain. And then we started seeing something 🙂

It was done at a farmer named LaCour in spring barley fields near Tommerup in Denmark. The test was done so that we applied what was quivalent to 30 kg N/ha to each plot, one as a foliar and two as soil-applied fertilizers (and one control with no extra N applied). During the following week, we measured N2O release from the field 4 times.

The results you can see here:

Now, as explained, we did have some rain. And actually it rained the evening of the application day, so the worry was, that some of the foliar N may have rained off. And when we compare to the lab-trials, that does in fact seem to be the case. Therefore the foliar-treatment is not as low as we had hoped. And the variation of the measurements was quite high, so we can not conclude anything for certain yet. But it does point in the right direction 🙂

Over all the experiment does look promising, pointing in the direction of foliar N giving rise til less N2O formation. Just like the lab tests.

We are now trying to arrange more tests, probably in collaboration with Copenhagen University, to do even more extensive and precise measurements.

We don’t know when these will start, but hopefully in the fall after winter wheat sowing.

If you have questions about how to measure N2O or how to start using foliar fertilizers more – the benefits go far beyond N2O and climate – do not hesitate to contact us.



Scorch tests in Winter Wheat

When farmers test our foliar products, they typically notice, that they scorch much less than “normal” foliar products. But we haven’t actually had any independent testing done on the matter, really pushing the limits. Until now.

The Danish advisory group, VKST, set out to test our foliar products Flex Foliar NS 18-2 (recipe 113) and Flex Foliar NPS 18-1-2 (recipe 129) as yield/protein boosters (more on that later), and as part of the trial they really pushed the amounts applied to the max, and did a scorch evaluation comparing it to their normal alternative a NS 30-2 liquid fertilizer, based on UAN and thiosulfate.

To get the products to stick properly, they added the adjuvant Contact at a 0,1% level. Not doing so, means most of the foliar product will “bounce off” the leaf and in essence be turned into a soil-based fertilizer. The result of leaving out the adjuvant is therefore less scorch risk, but also that most of the fertilizer will not be taken up by the leaf. And to simulate overlaps, the high application rate of 22 kg N/ha was doubled to 44 kg – so more than we would normally recommend. So keep that in mind when you evaluate the results here:

VKST tested two amounts of fertilizer applied – both quite high: 22 kg N/ha, and 44 kg N/ha. As you can see, the differences are quite clear, Flex Foliars giving the lowest scores (=less tip-burn/scorch).

Do also keep in mind, that the crop itself, had scorched tips in most plants, regardless of foliar application, as a result of fungicide sprays presumably (see pictures to the right).

Looking at the fields, it is actually difficult to see the tip-burn from a distance, except in field site 1 with the 44 kg N/ha applikation of NS30-2. Here the scorch was really evident and we expect it to cause yield loss. The yield results will be along later, as the fields have not been harvested yet. So you will have to wait for those – maybe in the next news-letter.

At the evaluation in early July, it was quite evident, that in the plots where no foliar fertilizer had been applied, the crop was maturing faster. Or said in another way: applying foliar N seemed to prolong the growth period, hence giving the crop more time to build larger kernels 🙂 Just like we have observed in practice so many times.



Why do foliar N scorch:
When using urea or UAN as a foliar fertilizer, the N is taken up by the leaf quite rapidly. Any scorch is normally seen as a tip-burn, that happens from within – not as a result of the contact between fertilizer and leaf. Then you would see spots on the large leaf surfaces. And that is not common.
The reason why the tip-burn happens, is that the urea/ammonium/nitrate is transported with the sap-flow to the tip of the leaf, and particularly if the weather is cold, up concentrated in this area. This is what causes a toxic level of N to arise in the tip of the leaf, causing the scorch/tip-burn.

Ways to avoid scorch:
– lower the amount of N (particularly in dry or cold weather, as this increases the risk). Normal amounts you can apply safely in most crops is 5-10 kg N/ha per application.
– use “true foliars” that are formulated to capture the ammonia in the plant as it is being formed. I.e. do not use straight UAN-types, but use Flex Foliar types that complex the nutrients to get this effect. Using Flex Foliars, you can typically double the amount of N applied with less risk of scorch issues. At the same time, you apply other essential nutrients, that can boost yields further.

If you mix with e.g. fungicides, PGRs or herbicides, you lower tolerance of the plant, as these pesticides stress the plants even more. So if mixing, consider lowering the amounts further. Particularly, if you are selling your product on its appearance, always test any new treatments on a small area first.

If you have more questions about how to start using foliar fertilizers safely and effectively – do not hesitate to contact us.

Potato Europe fair in Germany

Flex Fertilizer System along with BJ-Agro will be attending the Potato Europe fair in Germany September 7th and 8th near Hannover (Rittergut Bockerode).

Will we see you there for a talk about effective fertilization, bespoke formulations and the advantages of foliar fertilizers?