| Abstract | Managing irrigation practices for rice and non-rice (upland) crops
need proper utilisation of available water in an economic way in order
to get increased crop production . To achieve this effective rainfall must
be used effectively and efficiently to meet part of irrigation
requirement. Other important consideration in this regard is the various
on-farm operations for achieving t he above objective.
The study was conducted basing on the various climatological and
hydrological data available from Mae Klang irrigation project for
(Thamaka sub project) in the Central Thailand. A model is presented in
this study for calculating the irrigation requirement for nine crops viz.
rice (wet and dry season), sugarcane, soyabean, peanut, sweet corn ,
potato, green onion, mungbean (pulses) .
The model requires crop data (crop coefficient, crop acreage , crop
growth duration, transplanting , pre-sowing irrigation , nursery bed
preparation etc.) , meteorological data ( maximum and minimum temperature ,
r elative humidity (maximum and minimum)), rainfall data, day time wind
run, sunshine hours, cloudiness, net evaporation on daily bas is. Using
the data , the model determines reference evapotranspiration, consumptive
use, chance-effective rainfall based on past 29 years of rainfall data,
net irrigation requirement, gross irrigation requirement for different
crops which ultimately gives an idea for proper water distribution and
allocation basing on the crop need and availability of water. The program
developed for calculation of various parameters in Fortran 77 is suitable
for Mainframe as well as microcomputers. |