orange fruits on green leaves

How To Identify And Treat Deficiencies In Citrus

Nutrient deficiencies can have a devastating effect on overall crop health and yields, if they are not dealt with quickly and effectively. But, with proper testing at the correct time, and appropriate interventions, their effects can be reversed. 

Testing nutrient levels

Before making any decisions about changes to fertilisation schedules and the like, it’s important to know where you stand with respect to your crops’ nutrient levels. What nutrients your crops are getting out of the soil will be reflected in their leaves, making a leaf analysis extremely useful.

A leaf analysis can not only identify nutrient deficiencies but also help you determine the effectiveness of your fertilisation regime. 

It’s important to take samples at the correct time, and from the right part of the crop. Select fully expanded young leaves and petiole on non-fruiting terminals. Generally the third leaf down from a new growth tip. This is important because, if you don’t select the correct leaves, you will not get an accurate result.

Macronutrient deficiencies

Like all plants, citrus crops need ready access to all three macronutrients: nitrogen, phosphorus, and potassium. Deficiencies in the macronutrients are all typically found first in older leaves. Low levels of nitrogen and potassium both result in yellowing of the foliage, while a lack of phosphorus causes stunted leaf growth with purple or bronze discolouration.

Fruits are also affected, with smaller than usual fruits resulting from a lack of potassium, and phosphorus deficiency causing fruits to drop earlier with hollow cores. Without enough nitrogen, fruit develops a pale and smooth peel.

Correcting macronutrient deficiencies

Roots, Shoots and Fruits’,Synergizer product provides a good balance of macronutrients to help, particularly with nitrogen and phosphorus problems. And can be applied as a foliar application for when your crop needs urgent correction. For issues with poor potassium levels, our K-Forte solution is ideal for your crops’ needs.

Micronutrient deficiencies

Citrus crops often face shortages of micronutrients, particularly zinc, manganese and magnesium. A lack of zinc stunts the growth of leaves, and causes a mottled yellow pattern to appear on new growth. Manganese deficiency similarly shows up on young leaves as dark green veins over a lighter green background. Magnesium, by contrast, affects mature leaves, and causes a distinctive v-shaped green pattern surrounded by yellowing.

Magnesium and zinc deficiencies often result in lower yields. Magnesium is notable for having a particularly strong impact on seeded fruits over unseeded varieties. Low manganese can cause smaller fruits that develop softer.

Correcting micronutrient deficiencies

For specific correction of these micronutrients, you can use our Biomin products for zinc, magnesium and manganese. As with our macronutrient fertilisers, these provide an excellent solution to deficiencies in a fast acting manner. Our Biomin Booster V fertiliser also offers a well balanced mix of trace minerals to protect your produce,  and is effective even on those crops with waxy leaf and fruit.

Amending the soil

Treating nutrient deficiencies through targeted fertilisation is important, but the ongoing health of your crops can be maintained by ensuring the soil is able to retain the necessary minerals. Using Roots, Shoots and Fruits’ Humax and Rootella products can do wonders for the stability and water retention properties of the soil, as well as increasing nutrient bioavailability.  

Contact us to arrange leaf analysis to diagnose deficiencies.

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