Interaction of nutrients

Micronutrients or trace elements are required in small quantities, yet play pivotal role in plant growth. These invariably have synergistic or antagonistic effects with other nutrients.

• Silicon: Paddy and sugarcane are highly siliciferous plants. Roles of Si include rise in pH, improved P nutrition and water relation.
• Sulphur: Sulphur is associated with chlorosis formation.

• Fe-Mn interaction: Iron deficiency can not be seen in isolation since it mostly interacts with Mn. In a normal cane Fe: Mn ratio is 15: 1 or greater, whilst Fe deficiency/ Mn toxicity is associated with a ration of 1: 1 or even less. Iron deficient plant has an accumulation of Fe in the nodal region. In general Fe deficiency can be ameliorated by soil/foliar application of 25-30 kg/2 kg FeSO₄. Interveinal  chlorosis is a distinct symptom of Mn deficiency in sugarcane.

• Liming induces Zn deficiency and solubility decreases as pH increases.
• Antagonism of Zn and P is well documented.
• Besides P, high concentration of Fe, Mn and especially Cu causes severe Zn deficiency. This can, however, be overcome by soil application (20-25 kg ZnSO₄ ha^-1) or foliar spray (1-2% ZnSO₄). Foliar spray is superior to soil application.

Other micronutrients- Mo, Co, Cu, B

            The primary role of B is the transport of sugars across cell membranes as sugar-borate complexes. Boron deficiency resulted in marked reduction of sucrose in cane stalks.