Moderate to high sensitivity to the deficiency of: Mg, B, Cu
Low to moderately sensitivity to the deficiency of: Ca, Mn
(the sensitivity to the deficiencies of these nutrients can vary in function of the variety)
Although copper is not directly know as the most important trace element for this crop, it is nevertheless very important because symptomless yield losses are often due to limited copper uptake or copper deficiency. This is confirmed by our own field experiences, where the programs which include copper often give better results even when crop development is optimal.
Above all on sandy and leached soils, and on soils with a high pH and/or high organic matter content, the risks of a copper deficiency are high.
Other trace elements that are important for carrots are, in order of importance: boron, magnesium, calcium and manganese.
Boron deficiency causes not only symptoms on the aerial parts of the plant (yellowing from the margins of the leaves, which turn reddish later on and spreads towards the base of the leave, and the necrosis of the growing point), it also provokes severe symptoms on the roots such as cracks in the body of the carrot, and hollows in the core of the root. The economic value of the harvest is thus strongly affected.
Calcium deficiency causes a lot of symptoms such as necrosis of the growing point, brown coloring of the core of the root and also “cavity spot” which are depressed lesions at the exterior of the root caused by the collapse of the epidermis. These spots might start to rot later on.
Magnesium and manganese
Magnesium and manganese have very similar deficiency symptoms: interval clorosis.
- With manganese the first symptoms appear on the completely developed leaves or the younger ones.
- In the case of magnesium deficiency, first the elder leaves are affected, and with a more severe deficiency they become necrotic (first at the border of the leave).
The general recommendation of BMS Micro-Nutrients consists on one hand of a copper application with Chelal Cu and on the other hand Fructol NF, which contains all the other nutrients but boron and magnesium in bigger quantities.