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Citrus fruits

 Crop contribution citrus fruits

In citriculture the foliar fertilization is a fixed component in the general complex of nutrition for years. The foliar fertilization is used in case of already visible deficiency symptoms (e.g. manganese, iron, magnesium etc.) but also with latent (not visible) lack. 
The foliar analysis has proved itself for detecting a latent nutrient lack.
 

Nutrient availabilty

Even if the soil is supplied optimally with nutrients, the need-based supply of the tree with major-, secondary- and trace elements is not always guaranteed. Many factors limit the availability and admission from the soil, e. g. high pH values with trace elements and low pH values with major- and secondary elements, aridity, cold, soil compressions, competitions by greenings, and antagonisms (reciprocal effects) between the elements.

Special nutrient demands

One of the most frequent lack symptoms on the leaves of citrus fruits are iron chloroses. Iron deficiency appears by yellowness of the youngest leaves with dark veins. Here the early and regular foliar fertilization with  Lebosol®-Eisen-Citrat GOLD put things right.

Fruit quality/improvement of storage stability

Concerning the fruit firmness care has to be taken on the K-/Ca-relation of the fruit: an oversupply with potassium restrains the admission of calcium and that leads to an undersupply with calcium.

Even a good availability of calcium in soil is, on the basis of the peculiarities of the calcium transportation in the plant, no guarantee for a sufficient supply of the fruits. So that repeated calcium sprayings with Lebosol®-Calcium Forte SC (calcium formiate as a particularly compatible calcium source) are necessary. Lebosol®-Calcium Forte SC ensures an additional care with manganese and zinc.

Coloration

Phosphorus and potassium have a positive effect on the coloration of the fruit, so that with several foliar fertilizations with Lebosol®-PK-Max after fruit setting the body color is promoted. At the same time phosphorus contributes to a better fruit firmness.

Leaf spots and premature leaf fall

Some sorts incline to nutritional-physiological conditional leaf necroses and premature leaf fall. The causes are, among other things, an undersupply with manganese and magnesium. The combination of Lebosol®-Magnesium 400 SC with Lebosol®-Mangan 500 SC alleviates the symptoms and reduces the premature leaf fall.

Molybdenum lack in citrus fruits  is known as “Yellow spot” (“Yellow blotches”). In spring glassy, roundish to oval spots appear between the vains which later will assume a golden yellow coloring on the leaf top. In case of a severe shortage the necrosis can spread out up to the leaf border which is curling up. Here an early and regular foliar fertilization with  Lebosol®-Molybdän prevents the formation of “Yellow spot”.

Flourish quality, fruit setting

Boron in combination with Calcium (in Lebosol®-Robustus SC), zinc (Lebosol®-Zink 700 SC) and amino acids (Aminosol®) have a positive influence on flourish, pollen tube growth and fruit setting. They can be brought out in this combination before the flourish or after the harvest to protect an optimal care. Moreover the application of boron and zinc promotes the calcium uptake.

Main recommendations

Aim/Problem Recommendation Time
Treated crops are avoided by furred game 2 l Aminosol® (Aminosol with 2 l water 2 - 3 days beforehand (quantity for 1 ha)) When required
Depositing of reserve substances, regeneration, winter hardiness, flower quality 0,5 l/ha Lebosol®-Zink 700 SC +
2 times 2 - 3 l/ha Aminosol®
After harvesting
Promotion of red top colour, fruit size, fruit firmness 2 - 4 times 6 - 8 l/ha Lebosol®-PK-Maxor2 - 4 times 5 l/ha Lebosol®-Kalium 450 Between the end of fruit drop and harvesting
Improvement in skin quality, calcium transport, flower bud quality 2 - 4 times 2 l/ha Lebosol®-Robustus SC +
2 - 4 times 0,25 l/ha Lebosol®-Zink 700 SC
Fruit set to harvesting
Prevention and alleviation of iron chlorosis, improvement in water transport, leaf quality 2 - 5 times 3 - 7 l/ha Lebosol®-Eisen-Citrat GOLD First leaves fully developed until harvesting (not during flowering)
To prevent premature leaf drop; increased vitality, leaf quality, photosynthesis rate 2 - 4 times 3 - 5 l/ha Lebosol®-Magnesium 400 SC End of flowering to harvesting
Increase in fruit firmness, storage stability and resilience 4 - 6 times 5 - 8 l/ha Lebosol®-Calcium-Forte SC End of flowering to harvesting
Increasing stress tolerance 2 - 3 l/ha Aminosol® End of flowering to harvesting, at stressed sites
Improvement in leaf quality, photosynthesis rate, N efficiency 2 - 4 times 1 l/ha Lebosol®-Mangan GOLD SC From the end of flowering to the end of fruit drop
Stärkung der Widerstandskraft gegen Krankheiten 2 - 4 times 2 - 4 l/ha Lebosol®-Kalium-Plus Green buds to the end of flowering
Boosting of the resistance of the flowers to frost, yield 5 l/ha Lebosol®-Kalium 450 +
1 l/ha Lebosol®-Robustus SC +
1 - 2 times 2 l/ha Aminosol®
From green buds before frost
Improvement in flowering quality, fruit set, calcium transport, fruit quality, colouration 2 times 2 l/ha Lebosol®-Robustus SC +
2 times 0,25 l/ha Lebosol®-Zink 700 SC
White buds to beginning of flowering
Promotion of fruit set, fruit size and colouration 2 times 5 - 7,5 l/ha Aminosol® Green and white buds
Improvement in effectiveness and tolerability of plant protection products 150 - 300 ml Aminosol® (in 100 l spraying water) With plant protection products