|FAQ - Micronutrients for sugarcane|
- What is the role of micronutrients in sugarcane farming?
- What is the deficiency symptom of iron in sugarcane?
- How will you correct iron deficiency in sugarcane?
Micronutrients are those nutrient elements, which are required in very small quantities for plant growth and development. The micronutrients essential for green plants are iron, copper, manganese, zinc, boron, molybdenum and chloride. Most of the micronutrients are important constituents of enzymes or co-enzymes produced by an organism for performing various physiological processes. When the availability of these elements is very low, it produces characteristic deficiency symptoms and the plant growth is affected. On the other hand, excess availability and uptake of these elements may cause phytotoxic symptoms resulting in lower yields. Hence, it is always essential to maintain their availability at optimum levels and in correct proportions for realising the highest productivity. As in the case of other crops, sugarcane also requires all the micronutrients for optimum growth and yield. These elements are equally important to achieve quality canes. Sugarcane produces very high amount of biomass, which resulted in greater removal of the micronutrients. In addition, once planted this crop remains in the field for a period of three years and hence deficiency symptoms are manifested frequently.
General paling of leaves, followed by the formation of alternating green and chlorotic stripes extending to the full length of leaf blade referred as interveinal chlorosis. Later the leaf becomes yellow. The symptom first appears in young leaves as iron is immobile in plant system. It is severe in ratoon and young crops. Chlorosis results in stunted growth and sometimes even drying of the affected clumps.
The deficiency could be corrected by foliar application of 1.00 to 2.50% ferrous sulphate with 0.1% citric acid at weekly intervals until the symptom disappears. Under ideal soil conditions, soil application @ 25 - 50 kg of ferrous sulphate per ha is recommended. Ferrous sulphate enriched organic manure (125 kg FeSO4 in 2.5 t of organic manure per hectare) is more effective in correcting iron chlorosis. Addition of gypsum / sulphur and provision of drainage will improve the availability of iron in calcareous soils.
- Name a few sugarcane varieties tolerant to iron deficiency?
- What are the deficiency symptoms of manganese in sugarcane and how to rectify it?
- What is the deficiency symptom of zinc in sugarcane and how will you rectify it?
Sugarcane varieties tolerant to iron deficiency are Co 8021, Co 86032, Co 86249, Co 88025, Co 94005 and Co 94012.
Deficiency symptoms: Pale and yellowish green to white longitudinal stripes appear on the leaf blades. This interveinal chlorosis is confined to middle and tip of the leaves, but seldom extends to the full length as in the case of iron deficiency. Correction of manganese deficiency: This can be corrected by foliar spray of manganous sulphate (0.25-0.50%) at weekly intervals till chlorosis vanishes. Soil application of organic manure enriched with 25 kg MnSO4/ha may be recommended.
Deficiency symptoms: In the leaf blades, light yellow stripes along the veins are formed and the stripes are not interveinal as in the case of Fe or Mn, however, the interveinal region becomes progressively paler with increasing deficiency. In acute conditions, venial necrosis and cessation of growth of terminal takes place. Zinc deficient plants show a marked loss of auxin and therefore results in diminished growth and internode elongation. The internode length is reduced and clustering of leaves occurs. Removal of apical dominance results in the sprouting of lateral buds. Leaf blades are shortened with typical light yellow stripes along the vein. In severe cases, interveinal necrosis is seen. Correction of zinc deficiency: Repeated foliar spray of 0.25 to 0.50 % zinc sulphate at weekly intervals until the symptom vanishes. Soil application of 2.5 t of organic manure enriched with zinc sulphate 25 kg/ha is also recommended. Ameliorating the soil with gypsum to reduce excess carbonate and bicarbonate ions will improve the effect of soil application of zinc sulphate.