Manganese Deficiency in Cucurbits
· Cucumber · Pumpkin · Zucchini · Melon
Symptoms are less dramatic than other nutrient deficiencies. The veins of middle and upper leaves of manganese-deficient plants remain green while the rest of the leaf blade becomes mottled with pale green to yellow areas. Later, small necrotic lesions develop on the chlorotic tissues, particularly near the margins and tip (tip burn). Reduced leave size, deformation and crimping of leaf margins are other possible symptoms.
Highly acidic soils increase the availability of this nutrient. By contrast, alkaline soils can lead to manganese deficiencies. Excessive or unbalanced use of fertilizers may also result in some micronutrients competing with each other to become available to the plant. As iron, copper and zinc, manganese is used as enzyme catalyst in the plant cells. It is needed for plant basic metabolic reactions such as photosynthesis, respiration, nitrate assimilation and the production of the plant hormone auxin. Like iron, boron and calcium, manganese is immobile within the plant, accumulating mostly in the lower leaves. This explains why the symptoms develop first on mature leaves. Visual diagnosis is a simple tool, but it has some limitations. Soil and foliar analysis can be helpful to complement and confirm visual symptoms.
Use manure, organic mulches or compost to balance the nutrient content in the soil. These contain organic matter and many nutrients.
Use a balanced fertilizer program appropriate to the soil and to the crop in question. Plants absorb manganese as an ion through their foliage as well as their roots. That means that either foliage sprays or soil applications can be used. The most common fertilizer is manganese sulfate. Manganese application is often required with zinc application. Take care of the specified amounts and right utilization.