Crop leaf symptoms and nutrient deficiency

Yellowing between the veins while the veins stay green is called interveinal chlorosis. It commonly points to a shortage of iron, manganese, zinc or magnesium, but general fertilizer often does not supply these, and high soil pH can lock them up even when they are present. Confirm with a soil and leaf test.

Where the yellowing starts is a useful first clue. On the newest leaves it more often points to iron, manganese or zinc; on older leaves, more often to magnesium. It is only a clue. A soil test and a leaf (tissue) test, read together by an agronomist, are the way to tell which nutrient is actually short, and whether the cause is a shortage in the soil or a problem with uptake.

Taskon makes sources of each of these nutrients, including Ferrous Sulphate Heptahydrate, EDTA Fe (Iron), Manganese Sulphate Monohydrate, Zinc Sulphate Monohydrate and Magnesium Sulphate Heptahydrate.

Zinc deficiency is commonly corrected with a zinc source applied to the soil, sprayed on the leaves, or both, chosen by crop, soil and stage. The right product, method and rate depend on your soil test and crop, so decide them with an agronomist or your state agriculture department.

The two common forms are zinc sulphate, supplied as the monohydrate at 33% Zn or the heptahydrate at 21% Zn, and EDTA chelated zinc. Taskon makes Zinc Sulphate Monohydrate, Zinc Sulphate Heptahydrate and EDTA Zn (Zinc). How the forms differ is set out in EDTA chelated micronutrients vs sulphate salts and zinc sulphate 33 vs 21.

Purple or reddish leaf tips in rice can be associated with phosphorus shortage, but cold weather, waterlogging, root damage and some varieties can cause similar colouring. A leaf and soil test is the reliable way to confirm whether phosphorus is actually the cause.

If a test confirms low phosphorus, the common sources include phosphate fertilizers. Taskon makes Mono Ammonium Phosphate and Di Ammonium Phosphate among others in its phosphates range. Which one, and how much, is a decision for your agronomist.

Yellow patches on new citrus leaves are often linked to zinc, manganese or iron shortage. A copper spray is usually used against fungal disease, so it would not be expected to correct a nutrient deficiency. A leaf test will show which nutrient, if any, is low.

Disease, root problems and soil pH can also cause similar patterns, which is why the leaf test comes first. Taskon makes sources of zinc, manganese and iron, including Zinc Sulphate Monohydrate, Manganese Sulphate Monohydrate and EDTA Fe (Iron).

Pale striping between veins can come from several nutrient shortages, including iron, zinc and magnesium, not only manganese, and a soil application may not reach the plant if soil pH or root health limits uptake. A leaf test taken now will show what the plant actually lacks.

A soil test and a leaf (tissue) test, read together by an agronomist, are the way to tell which nutrient is actually short, and whether the cause is a shortage in the soil or a problem with uptake. Taskon makes sources of these nutrients across its sulphates and EDTA chelated micronutrients ranges.

Leaf symptoms that have already formed often stay visible even after the plant receives magnesium, because damaged tissue does not recover; new growth is the better guide. High soil potassium or low pH can also limit magnesium uptake. A leaf test on new growth will show whether it is working.

Epsom salt is magnesium sulphate heptahydrate. Taskon makes it in three grades, published at 9.8%, 16% and 20% Mg: Magnesium Sulphate Heptahydrate, Magnesium Sulphate Monohydrate and Magnesium Sulphate Anhydrous. The differences are set out in magnesium sulphate grades compared.

In high pH soils, several micronutrients, especially iron, manganese and zinc, become less available to roots even when the soil contains them. Adding more of the same fertilizer often does not help. Correcting it depends on the soil, the crop and the nutrient, so start with a soil test.

Growers in alkaline soils often use chelated micronutrients or foliar sprays. Not every chelate holds up equally at high pH, and for iron in particular the choice of chelate matters, so this is a question for an agronomist rather than a general answer. Taskon's chelates are listed on the EDTA chelated micronutrients page.

Sandy soils hold water and nutrients poorly, so nutrients can wash below the root zone before the crop uses them. Growers in sandy soil often split feeding into smaller, more frequent doses or feed through drip irrigation. A soil test and an agronomist can set the right programme.

Water-soluble fertilizers are commonly used for feeding through drip. Taskon makes NPK 100% Water Soluble Fertilizer and water-soluble salts such as Mono Potassium Phosphate, Potassium Nitrate and Calcium Nitrate.

Brown leaf tips can come from salt build-up in soil or water, high chloride, potassium shortage, uneven watering or root damage. Because the causes are so different, test both the irrigation water and the soil, and have a leaf sample checked, before changing the feeding.

If the water or soil test points to chloride, a buyer may look at chloride-free potassium sources. Taskon makes Potassium Sulphate and Potassium Nitrate, which carry no chloride, alongside Potassium Chloride.

Blossom end rot is linked to calcium not reaching the developing fruit, and that is very often caused by uneven watering rather than too little calcium in the soil. Keeping soil moisture steady is usually the first thing to check, alongside a soil and leaf test.

Calcium moves to fruit with water, so irregular irrigation, root damage or high salinity can cause blossom end rot even in calcium-rich soil. Calcium sources Taskon makes include Calcium Nitrate and EDTA Ca (Calcium).