Stress-free growth during the growing season is very important for optimal carrot production, both quantitatively and qualitatively. A factor to avoid obstacles to growth is a timely and sufficient (not too large) supply of nutrients. Especially when it comes to nitrogen, carrots have a limited need.
Especially during germination, the crop is very sensitive to salts in the soil. All the more reason to keep the supply of minerals limited at the base. In order to have the right amount of nitrogen available at any time and for a longer period of time during the foliage development phase, it is necessary to OCI Exactote developed. This fertilizer combines 3 forms of nitrogen and with a controlled release ensures that nitrogen is continuously available for up to 3 months.
Carrots take up nitrogen, but not as much at all times. The uptake varies and depends on the growth stage of the crop; more than 50% of the nitrogen is taken up during the foliage growth phase. After that, the crop needs a gradual availability of nitrogen; in any case sufficient to keep the foliage green for as long as possible (ripening and harvest).
Different forms of nitrogen, which one do you choose?
As indicated earlier, carrots have a limited total nitrogen demand; the recommended fertilization for B carrot is only 100 kilos of nitrogen per hectare minus 'the N-min'. To meet that demand, there is a range of nitrogenous mineral fertilizers. In essence, they are different because of the form in which the nitrogen is present in the product: nitrate (NO3-), ammonium (NH4+) or amide (urea). This nitrogen form also makes it possible to control more based on the (expected) growing conditions.
Plants prefer to take up nitrogen in the form of nitrate. This is immediately and completely available as plant food after application. The nitrate contained in the soil moisture is also absorbed by the extraction of soil moisture by the roots of the plant. For sufficient absorption of nitrate, it is important that there is sufficient moisture in the soil. Nitrate promotes the absorption of nutrients such as calcium, magnesium and potassium.
Only a small part of the nitrogen from ammonium can be absorbed directly by the plant. Most of the ammonium has to be converted to nitrate by means of soil life. This is called nitrification. Due to the positive charge of ammonium (NH4+) it adheres to the bottom. The roots of the plant should grow towards ammonium nitrogen. As a result, only a small part of the ammonium is directly absorbed by the plant.
Amide nitrogen (urea) is not directly absorbed by the plant. Only a small part can be absorbed directly by the leaf. The uptake of nitrogen from urea consists of 2 parts. First of all, urea is converted into ammonium (NH4+) by the enzyme urease, which is in every soil. Subsequently, ammonium is largely converted into nitrite and then into nitrate (NO3-), which can be easily absorbed by the plant. As a result, the action of urea nitrogen is slower.
OCI Exacote: 3 forms of nitrogen combined
OCI Exactote is a nitrogen-sulfur blend in which all 3 nitrogenous forms are combined. The blend contains Nutramon KAS, Granular 3 Ammonium Sulfate and coated urea. When it comes to the nitrogenous forms, this corresponds to 20% nitrate, 45% ammonium and 35% amide.
This coating ensures a controlled release of nutrients, tailored to the growth curve and nutritional needs of the carrot. Norbert Huveneers, agronomist at OCI Agri advises for carrot to OCI Exactote 29+8 to bet. It contains 6% nitrate-N, 13% ammonium-N and 10% urea N. This fertilizer can be used fairly quickly in the growing season so that not too much, but still enough immediately absorbable nitrogen is available when the carrots are there. asks for. The ratio of ammonium-N and urea provides a customized amount of nitrogen for a long time during the foliage growth phase.
Research by Delphy (plant fertilizer B carrot, field trial 2018) shows that proportionally more foliage is also formed when OCI Exacote 29+8 is used. The practice in the cultivation of B carrots is that nitrogen fertilization is carried out in various small steps. With the efforts of OCI Exactote so some number of trips through the crop can be saved. The result may also be there, because OCI Exactote gave stress-free growth, minimal nitrogen loss, optimal yield, improved product quality and a 9% higher yield compared to standard (practice) fertilization.