REFERENCE AND CROP EVAPOTRANSPIRATION ESTIMATIONFOR MUSTARD AND CHICKPEA AT DIFFERENT LOCATIONS OF GUJARAT

Abstract

The accurate estimation of crop water requirement which depends on duration of crop, growth
stage, their growing season and location are essentially required for efficient irrigation water
management and water resource management in agriculture. The study was therefore carried
out to estimate crop evapotranspiration (ETc) for winter crops (mustard and chickpea) at
eighteen stations of Gujarat, India using crop coefficient (Kc) and reference
evapotranspiration (ETo). The reference evapotranspiration (ETo) was determined by
Penman-Monteith method. The Kc values for winter chickpea and mustard as given in FAO- 56 were corrected for climatic condition of stations. The results revealed that during winter
season (November to February) the mean daily reference evapotranspiration (ETo) varies from4.4 to 7.4 mm day-1
. However, the large variation in ETo across the locations (2.9 to 10.3 mmday-1
) was observed. The mean water requirement (ETc) of chickpea during its initial stage
was found to be almost constant (2.0 mm day-1
) and it increased continuously during
developmental stage from 2.0 to 4.5 mm day-1
, it further increased during the mid season and
reached to its peak value of 5.9 mm day-1 at the end of this stage and during the late-season
stage ETc decreased progressively from 5.6 to 2.5 mm day-1
. The mean water requirement
(ETc) of mustard during its initial stage was found to be almost constant (1.7mm day-1
) and it
increased continuously upto 4.5 mm day-1 during developmental stage, it further increased and
reached to its peak value of 5.9 mm day-1 during the mid and ETc decreased progressively
from 5.6 to 2.5 mm day-1 during the late-season stage. However total crop water requirement
of mustard (515.0 mm) was more than that of chickpea (470.2 mm). The results are useful for
planning the irrigation scheduling in winter season at different locations of Gujarat.