M. A. Hossain
Scientific Officer
IWM Division, BARI, Gazipur
M. A. Razzaque Akanda
Senior Scientific Officer
IWM Division, BARI, Gazipur
M. S. Islam
Principal Scientific Officer
IWM Division, BARI, Gazipur
M. S. Alam
Senior Scientific Officer
RARS, Jamalpur
The crop coefficient values of 0.42, 0.80, 1.30 and 0.93 were determined for initial, development, mid-season and late season stages of tomato (variety: BARI Begun-4). These locally determined values of brinjal were found to remain within the FAO recommended ranges of 0.4-0.5 for initial stage, 0.7-0.8 for development stage and 0.8-0.95 for late season stage. However, the value at mid season stage (1.30) was found to slightly exceed the FAO range, 1.05-125, by some margin. This might be due to the effect of local soil and temperature as well as crop variety on crop ET. However, locally determined values are always preferred to the generalized values for the estimation of crop ET.
Brinjal, crop coefficient, lysimeter, ET
Research field of IWM Division, BARI, Gazipur
This experiment was undertaken to find Kc values of brinjal (BARI Begun-4) by micro-lysimeter installed in BARI farm, Gazipur.
Tomato (variety: BARI Begun-4) was transplanted on 05 November 2004 in four lysimeter tanks each having 1.0m × 1.0m area. Also, to maintain a favorable atmospheric condition around the lysimetric tanks, the same crop was grown in the fields. The fruits were harvested six times starting from 24 February 2005 and ending at 28 March 2005. The soil was silty clay loam with field capacity and bulk density, 28% and 1.5 gm/cc, respectively. The selected treatments were;
T1= Irrigation at 5 days interval
T2= Irrigation at 10 days interval
T3= Irrigation at 15 days interval
T4= Irrigation at 20 days interval
Since, the micro-lysimeter contains 4 tanks, no replication of the treatments was possible. Climatic data such as, maximum and minimum temperatures, air humidity, sunshine hours and wind speed together with the location information like elevation, latitude and longitude were incorporated in the software, CROPWAT, to estimate the potential evapo-transpiration.
The crop was irrigated in accordance with the design of the treatments. Measured quantity of water was applied to the tanks to ensure drainage. Prior to irrigation, soil moisture was measured to determine the depleted soil water. The part of rainfall collected as drainage and the stored soil moisture during the period under consideration were subtracted from the applied water to obtain crop evapo-transpiration (ETc) i.e.,
ETct = Wa + Re– (Dw + Ss)
Where, ETct = crop evapo-transpiration in mm for time period, t
Wa = applied water, mm
Re = effective rainfall, mm, for time t
Dw = drainage water, mm, for time, t
Ss = stored soil moisture, mm, for time, t
Then from the potential evapo-transpiration (ETo) estimated for the specified period, the value of Kc for the period was determined from the ratio, ETc / ETo.
Annual Research Report 2004-2005, IWM, BARI
The crop coefficient values of brinjal at initial, development, mid season and late season stages were found 0.42, 0.80, 1.30 and 0.93, respectively, from the lysimeter study. As the lysimeter provides is a control environment, further study is not needed for conclusive remarks.
Report/Proceedings