Agriculture Reference
In-Depth Information
a decade old. India has now emerged as one of the leading countries in
using microirrigation technology. Among the crops, maximum adoption
of drip system has been in coconut, followed by banana, grape, papaya,
pomegranate, mango, and sapota. There is growing awareness for use of
drip irrigation even for closely spaced crops especially tomato, capsicum,
chilies and potato. Microirrigation not only saves the water but also is
helpful in maintaining the hydration of root zone and efficient utilization
of the water. The research in this area is focused for predicting the tempo-
ral and spatial variation of soil moisture, the minimal and optimal fraction
of the soil volume to be wetted, and management system in different hor-
ticultural crops under varying weather and soil conditions, application of
nutrients, critical stages of growth and development.
Fertigation means supplying both water and fertilizer to growing crop
through drip irrigation. Through fertigation, many macro and micronutri-
ents like nitrogen, phosphorus and potash as well as micronutrients, for
example, Cu, Fe, Mg, Mn, Mo, Zn can be supplied directly to the ac-
tive root zone. This system helps in improving productivity and quality of
the produce and minimizes the losses of expensive nutrients. Fertigation
though tested on a large number of horticultural crops is ideally suited
for hi-tech horticulture production systems. Besides ensuring efficient
delivery of two important inputs, it also exploits the synergism of their
simultaneous availability to plants. When the drip system is adopted, the
root system proliferates only in the moist zone below the emitter making
this as a nutrient adsorption zone. One of the reasons for nonadoption of
fertigation widely even where drip system has been installed is the non-
availability of soluble fertilizers at affordable cost. Other reasons include
lack of scientific information on the frequency and time interval besides
nonavailability of Govt. policies to promote fertigation. Some problems
associated with this technology are that bad quality irrigation water rich in
calcium and magnesium results in precipitation of phosphorus and adds to
clogging of pores of the emitters. Because of the pH, carbonate, calcium
and magnesium, the micronutrients have to be supplied in chelated form,
which is costly. Clogging of emitters is another problem discouraging fer-
tigation. The form of N is also important. Excessive use of NO
3
-N results
in iron deficiency. The fertilizers are also supplied as NPK complexes and
freedom to choose required ratios is very limited. The grape, pomegran-
ate, and banana growers in Maharashtra have also adopted fertigation to
some extent. To exploit this technology fully, there is a need to remove the
