Models in Irrigation andWater Management - Practices of Irrigation and On-farm Water Management - page 403

(Clarke, 1998 ) . The program uses a flexible menu system and file handling, and
extensive use of graphics. Graphs of the input data (climate, cropping pattern) and
results (crop water requirements, soil moisture deficit) can be drawn and printed
with ease. Complex cropping pattern can be designed with several crops with
staggered planting dates.
The input data manus are the following:

CLIMATE - to enter monthly climatic data to calculate ETo
ETO - to enter your own monthly ETo
RAINFALL - to enter monthly rainfall data
CROPS - to enter cropping pattern and crop coefficient data
SOIL - to enter data for your soil type

Once the data has been entered, it can be seen in a table with the Tables main menu
option or plotted in a graph with the Graphs main menu option. The Schedule menu
lets one to define how irrigations are calculated and to management groups of data
files (climate, rain, crop, soil). CROPWAT for Windows give the users a wide range
of methods to calculate an irrigation schedule. After the criterion of scheduling is
defined, the programwill calculate the irrigation dates and amounts. A useful feature
of CROPWAT is the ability to enter the user's own irrigation amounts and timing
with the User Defined irrigation options.

10.3.4.2 CropSyst

Overview of the Model

CropSyst (Cropping Systems Simulation Model) is a multi-year, multi-crop, daily
timestep crop growth simulation model (Stockle et al., 1994; Stockle and Nelson,
1994). The model simulates the soil water budget, soil-plant nitrogen budget, crop
phenology, crop canopy and root growth, bio-mass production, crop yield, residue
production and decomposition, soil erosion by water, and pesticide fate. The man-
agement options include cultivar selection, crop rotation (including fallow years),
irrigation, nitrogen fertilization, tillage operations, and residue management.
The water budget in the model includes rainfall, irrigation, runoff, interception,
water infiltration and redistribution in the soil profile, crop transpiration, and evap-
oration. The evapotranspiration model is the predominate component of CropSyst
crop growth model. Daily crop growth is expressed as bio-mass increase per unit
ground area. The model accounts for four limiting factors to crop growth: water,
nitrogen, light, and temperature.

Main Features of CropSyst

• Link of CropSyst simulations with GIS software is possible

• Optional runtime graphic display

• Report data graphics viewer