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1. Apple Fertilizer Recommendations
2. How Our Recommended Fertilizers Work on Apple
3. Trial Data For Our Recommended Fertilizers
Lono is Levity’s flagship nitrogen fertilizer which greatly improves fruit number and size, and promotes good root growth. Lono provides apple trees with ‘Stabilized Amine Nitrogen’ which focuses growth on fruit development rather than vegetative growth.
Albina is our highly efficient calcium fertilizer which improves fruit set, fruit firmness and reduces susceptibility to bitter pit, russeting and other physiological disorders. Conventional calcium fertilizers give erratic results because fruit are not always able to absorb calcium, making applications inefficient. Albina uses Levity’s special LoCal technology to make it easy for fruit to absorb.
Sulis is Levity’s fertilizer which helps apples to build maturity (colour and brix). Sulis maximizes the function of the enzymes responsible for maturity in the apple tree and results in better colour and brix, meaning that farmers can harvest earlier.
As the primary plant nutrient, apple farms need to supply nitrogen for growth of the crop. However conventional nitrogen fertilisers disproportionately favour vegetative growth, meaning farmers are faced with a difficult balancing act between supplying enough N to achieve a good crop, and pushing out too vigorous shoot growth which detracts from yield and can increase fruit drop.
It is nitrates that drive vegetative growth. Nitrates are processed in leaves, and as they accumulate apple trees increase synthesis of the growth hormone auxin. The more nitrates the tree takes up, the more auxins are produced and the more the tree pushes towards building vegetation rather than supporting fruit development.
Different forms of nitrogen like amine and ammonium do not produce this ‘auxin effect’ but despite this switching to conventional ammonium and urea nitrogen sources still tends to produce increasingly vegetative growth as supply increases. This is due to the inherent instability of nitrogen fertiliser in the environment.
Regardless of the form applied most N given to apple orchards does not get taken up by the crop, and the majority that does make it into the trees does so in the nitrate form. This is due to bacterial activity that alters nitrogen from the form applied to nitrates, with losses along the way through leaching and volatilisation.
Levity have developed LimiN, a technology that holds nitrogen in the amine form, preventing conversion to nitrates. Our product Lono supplies stabilised amine nitrogen, and this can be used by farmers to help apple trees better allocate growth via a process known as ‘growth partitioning’.
When trees are exposed to stabilised amine N via applications of Lono, they allocate growth differently. The crop becomes less ‘apical dominant’ developing more branching rather than shoot extension, better root development, and greater emphasis on flower and fruit development.
By regularly applying small doses of Lono alongside conventional N inputs, farmers can increase the number and size of apples produced by the tree, reduce fruit drop and improve quality.
Although fruit quality in apples is strongly linked with fruit calcium levels, it is rarely the case that the crop as a whole is calcium deficient. Even on crops with high levels of bitter pit there are frequently no signs of calcium deficiency in leaf analysis.
Indeed, when we consider the amount of fruit calcium needed to prevent bitter pit, we can see that far too much calcium is used for ‘prevention’ in terms of calcium required to solve an extremely small problem.
Depending on variety and location, fruit calcium levels need to be above 5 – 5.4 mg Ca/100g fresh weight (Terblanche et al, 1980). Most apples are close to this level without any correction, with the difference between calcium level in fruit with and without bitter pit being typically between 2 and 4 ppm.
If we look at a crop with 100% bitter pit and do some simple calculations, we can see just how little calcium is needed to make the difference.
If the crop is 30MT per Ha and every apple has bitter pit, only 2% of every apple is actually affected (the lesions), making a total 600kg of deficient tissue. If the difference in calcium content between the bitter pit affected tissue and the rest of the fruit is 4ppm then this makes the amount of calcium implicated in the problem 2.4g.
This means a 2.4g calcium deficiency created 30MT of crop loss. When we see how small the level of extra calcium needed to prevent bitter pit risk, it raises questions about why we apply so much calcium to prevent it.
To understand why we get these small areas of calcium deficiency, we need to understand more about how calcium is picked up, moved around and absorbed by plants.
Unlike most other nutrient’s calcium is not phloem mobile, instead plants move calcium in the xylem with water. This means calcium moves through the plant in the same direction as water flow, moving through the plant from roots to leaves via transpiration stream.
This makes calcium movement susceptible to water availability and weather conditions, hence bitter pit increases when water flow is restricted by growing conditions. It also makes getting applied calcium to fruit tricky, as fruit is low in transpiration so receives little throughput of calcium when compared to other parts of the plant like leaves.
Absorption of calcium is also linked to presence of the auxin hormone. Tissues high in auxin absorb calcium easily, but tissues low in auxin have difficulty absorbing calcium no matter how much is available. Given that mature apples are naturally low in auxin, this makes absorption of calcium rather than availability of calcium the main driver in bitter pit susceptibility in apple crops.
When we look at the physiology of the fruit, we can learn a little about best timings for reducing bitter pit incidence. Auxin levels are highest in fruits between flowering and when the fruit is 5mm in size, this is the main period of cell division (which is powered by auxins).
As the fruit gets bigger it is focused on increasing the size of cells rather than creating cells, and auxin levels drop making it progressively harder to get calcium into fruit as it increases in size.
To help improve calcium levels in apples Levity have developed LoCal, a chemistry that improves calcium absorption in the absence of auxins. This helps apple fruit (naturally low in auxins) to properly absorb calcium.
Albina uses LoCal chemistry to deliver calcium into apples, which allows farmers to use lower application rates and less frequent applications than with conventional calcium fertilisers. Albina (and other products using LoCal) have been demonstrated to reduce bitter pit on apples in field trials around the world.
Sulis builds maturity (colour and brix) in apples. It works by supplying molybdenum and boron in a special formulation that helps the fruit maximise the function of the enzymes responsible for maturation, building better levels of colour and brix to allow earlier picking.
The processes of maturation require molybdenum and boron, but as molybdenum does not produce visible deficiency symptoms, the enzymes are often not adequately functioning, leading to a slow build of colour and sugars. The Blush technology that powers Sulis activates the plant’s natural process of maturity, whilst ensuring these key nutrients in the process are available.
The special formulation of Sulis helps fruit build better levels of colour and brix to allow earlier picking. It promotes the processes of maturation that are normally triggered by the hormone ABA. Importantly, Sulis does this without causing a spike in ethylene, which can retard shelf life and create quality problems.
Sulis also contains cell wall stabilisers, so that whilst colour and sugars build, the developing fruit can also maintain firmness. Normally, there is a trade-off between colour and sugar formation and softening, Sulis is designed to manage this process so that farmers can get the taste they need whilst still picking fruit that stays firm in storage.
Sulis is proven to improve colour and brix and to bring forwards harvest in multiple field trials on a wide range of varieties in both the UK and US.
Our apple fertilizers are independently trialed around the world to make sure that they excel above conventional fertilizers in all agronomic and weather conditions.
In this section explore some of the independent trials of our recommended fertilizers for apple by variety.
Studies were carried out in Poland Warsaw Agricultural university 2009. The trials looked at the comparison between Standard Calcium fertilizer and Levitys Albina Fertilizer with LoCal technology on apple variety Szampion. The standard Calcium was applied in greater volumes at 9 applications of 5 litres per hectare and Albina was applied at 3 applications of 1.5 litres per hectare.
The study showed that 3 x 1.5 L/ha Albina completley corrected Bitter Pit, whereas 9 x 5 L/ha of conventional calcium fertiliser did not. This is because Albina can be absorbed by the fruit.
Calcium content was much higher in the Albina treated apples when compared to the industry standard fertilizer. This is important for quality, shelf life and prevention of disease.
The Albina treated apples were also exhibited a higher average weight than those treated with industry standard fertilizer.
Independent studies were carried out in Kent, UK studying the effects of Sulis on Gala apples colour and brix, where Sulis was applied at 2 litres per hectare.
The studies showed that Sulis significantly increased the number of red apples and the increased the sugar content.
Independent studies were carried out in Washington state, USA studying the effects of Sulis on Gala apples colour, where Sulis was applied at 2 litres per hectare. The studies showed that Sulis worked better at improving colour than other treatments, significantly enhancing colour formation. The trial confirmed the performance seen in European trials.
Independent trials were conducted in Kent (2017) studying the effect of Sulis on apple variety braeburn. The trials studied the how well Sulis improved maturtiy (colour) in the braeburn apples, as well as sugar levels (brix). Sulis was applied at 2 litres per hectare and the results can be seen below.
These trials showed that sulis gave a significant improvement in both maturity and brix.
Honeycrisp is a variety that is highly susceptible to bitter pit and promoting better colour the fruit can have the undesirable side effect of increasing incidence of bitter pit.
This Independent trial in Washington State USA show two benefits from applications of Sulis. When compared with potassium used at higher rates Sulis still gave good improvements in colour compared to untreated control plots.
When measuring bitter pit incidence post-harvest, the K treatment showed a threefold increase in bitter pit, whilst Sulis actually gave a reduction in bitter pit greater than standard calcium treatments.
This trial demonstrates how well Sulis can improve maturity without compromising post-harvest fruit quality.
Independent trials on Honeycrisp in Oregon US, looked at the effect of Albina on bitter pit incidence and marketable yield. The trials showed that use of Albina significantly increased marketable yield, reduced the severity and incidence of bitter pit both pre and post-harvest.
This large scale replicated trial was carried out in Frittenden UK with 2400 trees treated with 1 2L application of Sulis and 5600 trees untreated. All other fertilization was standard across the trial.
The data here shows that ripeness, colour and sugar were all significantly improved in the Sulis treated trees. However, the main benefit was the reduced number of picks required in the treated blocks. The Sulis treated blocks were fully harvested in the first two picks, with the untreated blocks requiring 4 picks to fully harvest the fruit.
This trial demonstrated that Sulis not only improved colour, taste and brix on this variety, it also brought forwards harvest allowing large savings in labour costs on farm.
This trial looked at a range of commonly used calcium and potassium based foliar fertilizers and Levity’s Sulis on the variety Envy. Sulis gave the best results for colour significantly improving fruit maturity when compared to the control and all other treatments.
This independent replicated trial was conducted in Herefordshire UK in 2017. A single application of Sulis was applied at 2L/Ha and significant improvements were achieved in earliness, colour and brix.
This study on Cosmic Crisp looked at incidence of green spot, a physiological disorder sometimes associated with low levels of Ca in peel. Conventional foliar calcium and potassium treatments were tested alongside Sulis. Sulis gave good improvements in maturity, but also gave a significant decrease in green spot incidence. Conventional foliar calcium had no significant effect on green spot incidence, and conventional foliar potassium significantly increased green spot incidence.
This trial demonstrates the dual benefit of improved fruit maturity and reduced post-harvest problems achieved using Sulis.
This Independent UK trial conducted in Kent in 2011 compared Albina at 1L per Ha with Calcium chloride at 10L per Ha used at the same timings. Albina outperformed conventional calcium application with significantly better fruit firmness and brix even at 1/10th the application rate.
In this study conducted in Chile Albina applied at 1L/Ha was compared with 5L/Ha of calcium nitrate applied at the same timings. The Albina treatment had significantly higher levels of calcium in fruit and also improved the level of all other nutrients tested.