Post harvest Management of Horticultural Crops (2+1)

Mineral Application

Mineral Application
Deficiencies of certain minerals result in physiological disorders, loss of storage life or quality. Calcium is the nutrient most commonly associated with post harvest disorders and can be overcome by external application of fruits after harvest by spraying or dipping, vacuum infiltration and pressure infiltration.
Advantages of minerals application

• Reduce physiological disorder - internal break down/ pitter pit, storage scald etc
• Calcium chloride (4-6%) dips or sprays for bitter pit in apples.
• Reduced chilling injury
• Increase diseases résistance
• Delaying ripeness - tomatoes, avocados, pear and mango
• Reduces chilling injury and increase disease resistance in stored fruits
• Low concentrations of 2.4-D to waxes assists in keeping citrus peduncles green

Disadvantages

• Skin discoloration (at higher concentration )
• Rotting (at higher concentration )
The pre-harvest spray problem can be overcome by dipping the apple fruit in solution containing calcium salts. Uptake can be enhanced by pressure infiltration to force calcium solution into apple flesh. The best results are obtained with apples that have a closed calyx so that the calcium solution is forced through lenticels and thus spread around the peripheral tissue where the disorder occurs. With open –calyx fruit, the uptake of solution is difficult to control as it readily enter the fruit via the calyx and excess solution accumulates in the core area, often lading to injury or rotting.



Vacuum infiltration (250mmHg) of calcium chloride at concentration of 1- 4% is beneficial.

Guava - Fruit dipped in 1% solution of calcium nitrate reduces weight loss, respiration, disease occurrence and increased the shelf life for more than 6 days as compared to 3 days in the control at room temperature.