Diseases and Management of Crops under Protected Cultivation

(Diseases and Management of Crops under Protected Cultivation)
Mmolawa and Or 2000; Neilsen et al. 2004) if proper care has not taken during fertigation.
Fertigation may favour NO 3 -N leaching, which requires a careful calculation of the fertilizer dose to
minimize the risk of groundwater contamination.
A well-designed fertigation system can reduce fertilizer application costs considerably and
supply nutrients in precise and uniform amounts to the wetted irrigation zone around the tree
where the active feeder roots are concentrated. Applying timely doses of small amounts of
nutrients to the trees throughout the growing season has significant advantages over conventional
fertilizer practices. Fertigation saves fertilizer as it permits applying fertilizer in small quantities at a
time matching with the plants nutrient need. Besides, it is considered eco-friendly as it avoids
leaching of fertilizers. Liquid fertilizers are best suited for fertigation. In India, inadequate
availability and high cost of liquid fertilizers restrict their uses. Fertigation using granular fertilizers
poses several problems namely, their different levels of solubility in water, compatibility among
different fertilizers and filtration of undissolved fertilizers and impurities. Different granular fertilizers
have different solubility in water. When the solutions of two or more fertilizers are mixed together,
one or more of them may tend to precipitate if the fertilizers are not compatible with each other.
Therefore, such fertilizers may be unsuitable for simultaneous application through fertigation and
would have to be used separately. This article reports on the various issues of fertigation i.e.
advantages and limitations, selection of water soluble fertilizers (granular and liquid), fertigation
scheduling in various crops and fertigation system for efficient fertigation programme and
response of plants to fertigation and its economic.
2. Why Chemigation
‣ No need to spread the agricultural chemicals (so coverage is more even, and a lot of work
is saved).
‣ Chemicals placement at right place and better uniformity.
‣ Chemical requirement in coordinate with crop development.
‣ Efficiency is high – saving of chemicals.
‣ Controlling the depth of application.
‣ Working with liquid fertilizers is very convenient.
‣ Prevent chemical leaching to the ground-water
‣ Reduces soil compaction caused by tractors & other tillage equipments
‣ Mechanical damage to the crop by sprayers is reduced by chemigation
‣ It reduces operator exposure to the chemical
‣ It may reduce environmental hazards associated with spray drift
‣ Chemigation of post emergence soil-acting herbicides may reduce phytotoxicity and
increase activity.
‣ Chemical application cost saved by 40% or more.
‣ Reduces energy consumption by 90%.
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