FERTILISER APPLICATOR
This is the process of applying fertilisers through the irrigation system. The soil is
negatively charged at high pH and PO4ˉ will be precipitated with Ca+ and absorbed with clay.
Availability of P is very low as time proceeds due to this precipitation. Fertigation is
problematic at high pH because the availability of micronutrients (Fe, Mn, etc.) is less due to the precipitation. Hence iron chelates (Sequestrene -138) are applied which prevents Fe from precipitation. Also zinc chelates are good to prevent Zn precipitation.
ADVANTAGES
1. Eliminates manual application
2. Quick and convenient
3. Uniformity in application
4. High efficiency and saving of fertiliser upto 30 – 40%
5. Less fel1ilizer leaching
6. Better penetration of P and K in the layers
7. Co-ordination of nutrition requirement with crop stage or development
8. Possibility of dosage control.
9. Others like herbicides, pesticides, acid, etc can also he applied
LIMITATIONS
1. Toxicity to field workers
2. Chance of backflow into water source, for that NRV and vacuum valve has to be installed
3. Insoluble fel1ilisers are not suitable (super phosphate)
4. Corrosive effect of fertiliser
5. Phosphate may get precipitated in the pipe line and dripper due to pH reaction
6. High cost
NITROGEN FERTILISATION
Nitrogen (N) being one of the major plant nutrients, is often supplied in order to
obtain optimum crop production. Nitrogen availability is usually limited in the soil compared with other plant nutrients because its various forms can be leached, volatilised, denitrified or fixed in the organic fraction of the soil.
PHOSPHORUS FERTILISATION
Generally, injection of phosphorus (P) fertiliser through a trickle irrigation system has
not been recommended. Most P fertilisers have created chemical or physical precipitation
problems and subsequent clogging of the trickle irrigation system. Further, the fixation rate of P by soils is high and subsequent movement from its point of placement is limited.
POTASSIUM FERTILIZATION
No adverse chemical reactions are expected with the COl1unon potassium (K)
fertilisers when they are added alone to water. However reduced solubility and/or fertiliser
incompatibility is possible when different fertiliser types are mixed. An example is a mixture of calcium nitrate and potassium sulphate, which will yield insoluble calcium sulphate.
