1. Carrot Fertilizer Recommendations
2. How Our Recommended Fertilizers Work on Carrot
Lono is our flagship nitrogen fertilizer. Farmers use Lono to greatly improve their yield, establish better root growth and more uniform size distribution. Lono supplies Stabilized Amine Nitrogen to carrots which, unlike conventional fertilizers, focusses growth on the carrot vegetable rather than top leaf growth.
Albina is our innovative calcium fertilizer which improves quality, shelf life and firmness of carrots, and also protects against disease and physiological disorders. Conventional calcium fertilizers give erratic results as the carrot is only able to absorb calcium when it is small. Albina supplies calcium in a new way which makes it is easily absorbed by the carrot all season long.
Damu is our specialist boron fertilizer which improves and bulking and yield of carrots, while also safeguarding quality. Damu works by helping the carrot crop to use its energy to bulk up the vegetable rather than force late season leaf growth.
In this section we will look at how Lono can be used to focus growth on the carrot we harvest rather than leafy top growth we discard.
Carrots can take up Nitrogen in three forms: amine (NH2), ammonium (NH4) or nitrate (NO3). The amount of nitrogen taken up by the carrot dictates how quickly the whole crop grows, however, it is the ‘form’ of nitrogen which dictates where the crop allocates this growth.
Nitrate (NO3) makes the crop produce more of the growth hormone ‘auxin’, which are made in the top leaves. Increased auxin production stimulates the carrot to accelerate leaf top growth at the expense of the carrot root. While this does result in slightly higher yields, there is a large amount of growth energy wasted on excessive top growth which could be utilized to increase yield much further.
Conventional amine nitrogen seems like the ideal solution, if the carrot takes up this form of nitrogen, it will produce the growth hormone cytokinin, which favours carrot root growth rather than leafy top growth. However, this is not effective either. When amine nitrogen is used on carrot, small bacteria compete for, and use up the available amine nitrogen and convert it into nitrate. This all happens before the carrot is able to take up even a small amount and results in the crop taking up nitrate anyway. This, like before, results in excessive leafy top growth at the expense of carrot root growth, meaning the farmer does not reach the full potential yield for their crop.
To make the crop favour carrot root growth rather than leafy top growth, we need the crop to take up amine nitrogen. Unfortunately, this is not possible with conventional nitrogen fertilizers.
Levity have developed fertilizer Lono which uses ‘LimiN’ technology. Lono supplies carrot with ‘Stabilized Amine Nitrogen’. This is a unique form of amine nitrogen which is unrecognisable to the bacteria which would usually convert amine into nitrate. This means that nitrogen is taken up by the crop in amine form rather than in nitrate. By helping the carrot to take up amine nitrogen we help it to produce more of the growth hormone cytokinin which favours harvestable carrot root development rather than top leafy growth. This process (known as growth partitioning) helps us to minimise the amount of wasted energy and maximize farmers yields by helping the crop grow in the right place.
It is well established that calcium is needed for carrots to reduce susceptibility to diseases like cavity spot, and also keep quality high. However, farmers often get poor results from applying conventional calcium fertilizers in addressing these issues. In this section we will explore why conventional calcium fertilizers miss the mark in combatting these issues and how our fertilizer ‘Albina’ supplies calcium in a unique way, allowing for better and more consistent results on improved quality and reduction of physiological disorders like cavity spot.
Carrots don’t actually need a lot of calcium to be healthy. In the case of cavity spot, only 2% of the carrot is actually affected, and these are characterised by small, localised deficiencies (dark spots).
In fact, if a farmer lost and entire 50MT/ha crop of carrots due to cavity spot, the actual affected area is only 1MT (2%), and the difference in calcium levels between the affected and non-affected areas is only 4mg/kg (four parts per million). This means that the amount of calcium required to prevent the entire crop loss is only 4g per hectare.
So, why doesn’t simply ‘applying more calcium’ work in reducing susceptibility to cavity spot?
Cavity spot in carrot is rarely due to a lack of calcium applied/available. There are two different limiting factors which dictate how effective carrot is at taking up and using the calcium we apply to it:
Unlike many other minerals, Calcium is not phloem mobile and can only be transported by the xylem. Calcium enters the carrot with water and is transported upwards with transpiration, where is it either absorbed, stored or precipitated from the leaves as excess.
This means that Calcium can only move upwards through the crop. Using foliar applications of calcium to target calcium uptake in a root crop like carrot will be ineffective as it is physiologically impossible for the carrot to move the calcium from the leaves down towards the root.
Calcium must be applied directly to the roots to help ensure good calcium levels in carrot.
“But we still get calcium deficiency problems when calcium is applied to the soil, why?”
Calcium moves into cells via ‘polar auxin transport’, this means that calcium is only able to move into the cell when auxin is moved out. Parts of a plant that are low in auxin, can’t absorb calcium effectively, regardless of how much is available.
High auxin producing areas include new shoots, new flowers, and new leaves. Low auxin producing areas include fruits, roots and tubers.
This is why applying calcium to correct physiological disorders can be so ineffective. It doesn’t matter how much calcium is applied, parts of the plant with low auxin levels such as carrot roots can’t absorb it properly.
Auxins are used by plants to induce cell division in newly growing tissue. In carrots the root grows from the tip, so the new cells in the tip are high in auxin and pretty effective at absorbing calcium, as the cells age they are no longer dividing and auxin levels decrease so capacity to absorb calcium drops off.
When plants are stressed calcium metabolism goes up, and carrot roots are not good at replacing it. This is why stressful growing conditions can lead to higher disease likelihood. Simply having calcium near the roots won’t help, to get it into the carrot absorption must be improved.
Levity have developed Albina (with LoCal Technology). Albina Granule is a fertilizer which can be placed in the root zone and helps carrot roots to absorb calcium even when they’re more developed and lower in auxin. This means calcium can be effectively absorbed by the carrot root all season long.
Albina contains Levity’s LoCal chemistry which is has been widely used and extremely effective on crops like tomato, strawberry and lettuce. Albina’s new granule form allows it to be applied in the root zone at planting, for slow release throughout the season. It is the first product ever available that supplies slow-release granular calcium with chemistry that allows active uptake by roots.
“Wet year or dry year, you never know when it [cavity spot] is going to make an appearance. Rotation plays a role, certainly, but then so too does a field’s weed profile, with some weeds – species that Pythium also favours – acting as a host or reservoir of infection.”
“We apply Albina at sowing, using a mounted applicator. As calcium is such an important nutrient in its own right, the application has merit beyond cavity spot control anyway, but since we’ve been using it we’ve not had a problem with the disease.”
“Alongside other methods of cultural control, such as the rotation and selection of more tolerant varieties, Albina is a valuable tool to be able to deploy.”
Carrots are a crop in which farmers must carefully balance top growth with carrot root growth.
Carrots deficient in boron make high levels of auxin and low levels of Cytokinin. Auxin synthesis can quickly get out of control resulting in an increased ‘nitrate affect’ and top growth accelerates at the expense of roots. On the other hand, carrot with high levels of boron make lower levels of auxin and high levels of cytokinin. This results in less top growth and better root bulking.
Boron can be used to regulate auxin synthesis and slow down periods of fast top growth. Quantity and timing are paramount in this balancing act because there is fine line between deficiency and toxicity with Boron.
Levity have developed Damu, a high efficiency product that allows lower rates of boron to be more effective, using stimulants to increase speed of uptake and metabolism. Damu can be used during periods of excess vegetative growth to reduce auxin production and refocus the crop on root growth.
In order to produce carrots, the plant must move sucrose from the leaves down to the roots, and because boron plays a part in this movement, it has a large impact of root growth.
During bulking, carrots translocate sucrose from leaves to roots using bis-sucrose-borate, a phloem mobile complex formed between boron and sucrose.
Damu works by improving the translocation of sucrose between leaves and roots for higher carrot starch formations. Damu applied during bulking supplies the boron needed to fuel carbohydrate translocation alongside Levity’s proprietary stimulant ‘Catalyst’ which stimulates the speed and intensity of the process.