Lab 4


The water balance model can be used for any crop , native and irrigated vegetation. The objective of the lab is to create a new spreadsheet  for saltceder from a alfalfa spreadsheet water balance model and then run the model for  different locations. Assume that the soil type is a sandy loam and that the root system goes to the water table at 5 ft. Assume that the river floods the land in April 10 for 3 weeks and then that the plants can get water from the ground water when the root zone has as MAD level fluxuating between  50 and  70%. Adjust the irrigation amount so this occurs. Also calculate if saltceder is cut down it will be replaced with grass. Determine the water savings by saltceder irridacation. 



1. Using the  Penman alfalfa spreadsheet create a spreadsheet for saltceder for Las Cruces NM Use the 1985 climate year. Run the model for the condition above. Create a grass spreadsheet and run it for 99% depleation which means that the grass will survive only on rainfall after the initial flood. 

2. Run the model for the same year using the climate data from Los Lunas.

3. Run the model for the same year using the data from Alcalde.

4. Plot the yearly Et for the three locations and explain any differences in the values. and any difference in saving by saltceder eradication..

5. Show how much water is taken from the ground water.



Las Cruces  


location saltceder seasonal Et non stress not limited by water table depth


warm seas grass Et stressed inches only get water from initial filling of root zone by initial river rise Difference  inches
Las Cruces 53 11 42
Las Lunas 48 16 32