• To correct any nutrient deficiency in a standing crop• To maintain optimum level of a particular nutrient• To give a crop the nutritional boost at a critical juncture in life www.satyajitchemicals.com 16
What are the factors affecting Foliar Application ? www.satyajitchemicals.com 17
Right Source Foliar Application Right RightTiming Rate www.satyajitchemicals.com 18
How does Foliar Application work ? www.satyajitchemicals.com 19
Entry through STOMATA and CUTICLECuticle Water Water + Nutrient Stomata are minute pores present in large numbers on the leaves. Their main function is to control the absorption of gases (CO2), release of O2 and water vapour. Xylem The stomata thus also allow the passage of nutrient Phloem bearing solutions into the plant body. The cuticle is a waxy layer covering all the aerial parts of Stomatal Stomatal the plant. While the cuticle consists of basically fatty acids Cavity Pore and is mostly impermeable, there however exist intermolecular spaces or holes in it. Certain water-loving chemical radicals are also present in Leaf Transversal Section the cuticle www.satyajitchemicals.com 20
What are the advantages of Foliar over Soil Application ? www.satyajitchemicals.com 21
UTILIZATION OF APPLIED QUANTITYMore than 90% fertilizer is utilized by the plant whenapplied in Foliar form. When a similar amount of fertilizeris applied in the soil, the plant utilizes only 10% TRANS-LOCATION WITHIN THE PLANT 95% of the foliar fed nutrient solution can be found in the smallest root within 60 minutes if conditions are right FERTILIZER EFFICACY IN SANDY LOAM SOILS In sandy loam soils, foliar applied fertilizers are up to 20 times more effective when compared to soil applied fertilizers www.satyajitchemicals.com 22
How to identify Nutrient Deficiency in leaves ? www.satyajitchemicals.com 24
Nitrogen Uniform over leaf, small leaves Sulphur if symptoms also Chlorosis on young leaves Interveinal or Magnesium blotchyOld & mature leaves Tip or edge scorch, interveinal Phosphorous yellowing/browning Necrosis Interveinal or bloctchy, varying Magnesium shades of color www.satyajitchemicals.com 25
Sulphur, Uniform over leaf Iron Leaf edges purple, Chlorosis interveinal Sulphur yellowing, cupping Interveinal or Zinc, Manganese, blotchy Iron, CopperYoung leaves Interveinal blotches and leaf edge Calcium scorching Necrosis Yellow to brown interveinal areas, Boron red to purple, curled, torn leaves www.satyajitchemicals.com 26
Californian standard used in Australia came from work conducted by Cook (1966) and Chritensen etal. (1978), based on relative low yielding vines (3.5-4.5 tonnes / acre). The standard was thenmodified after survey work in South Australia by Robinson et al. (1985) from which they proposedsome working standards. Continued work by various researchers has lead to the today’s standards(Table 3). Element Deficient Marginal Adequate High Toxic or Excessive As a percentage of dry matter of leaf Nitrogen 0.8-1.1 Phosphorus Below 0.2 0.2-0.24 0.25-0.5 Above 0.5 Potassium Below 1.0 1.0-1.7 1.8-3.0 Calcium 1.2-2.5 Magnesium Below 0.3 0.3-0.3.9 Above 0.40 Sodium Above 0.5 Chloride Above 1.0 As mg/kg (parts per million) dry matter of leaf Nitrate - N03 Below 340 340-499 500-1200 Above 1200 Manganese Below 20 20-29 30-60 Above 500 Zinc Below 15 15-25 Above 26 Copper Below 3 3-5 6-11 Boron Below 25 26-34 35-70 71-100 Above 100 Iron Above 30 Table 3. Nutrient standards. Adapted from Reuter and Robinson (1997) www.satyajitchemicals.com 27 Page 44
A fertile soil is notnecessarily a productive soil www.satyajitchemicals.com 28
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