WSP12137

• File Number: 8276.100
• Description: Grand Valley Unit-Colorado River Basin Salinity Control Project
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 11/1/1978
• Title: Report to the CWCB on Irrigation Demonstrations in Grand Valley
• Water Supply Pro - Doc Type: Report/Study

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zinc deficiency will cause a gap in the leaf growth on a
shoot. Zinc chelate sho~ld be applied about 5#/1000 trees

when iron and manganese are not being applied.

zinc and manganese should be above 20 PPM in the leaf

analysis. Iron should be 80 PPM + all during the season.

11. A most difficult problem is weed control. Lateral
lines will not allow for two way cultivation with a
disk unless the lines are taken up. Simazone is
dangerous in small trees. One of our demonstration
plots was almost wiped out because we used a wetting
agent to carry the iron and manganese, and it took
the herbicide directly to the root of the trees.
Caseron has been used in the Paonia areA with good
results. .A mixture of 24D and Amatrol T has been
effective. Paraquat is z contact herbicide which
is safe to use but difficult to handle, Whatever
the agent or method used, it should be used often
to keep the weeds in control.

12. The design of microtube systems has been made easier
by the use of a program which tests the pressure of
a lateral at each tree and calculates the proper
length of microtube to deliver the desired flow
through the tube.

Dr. Kincade of the Agr icul tural Research S,ervice has

assisted in the preparation of this program.

J
The following equations were used:

1. 85
= (q)
D4.8655-x

Pi+l = PL + ,433 x SL x Lt - .0426 (q -

hf

.0426 in psi Per 100'

EQN(l)

Q
6~ )

1. 85x L
t
100

EQN(2)

PL is initial pressure in P.si.
PL+l is the pressure differential caused by the ~ncreased

head and the loss in the line due to friction.

SL is the slope in feet/foot.
Lt is the distance between trees.
q is the initial flow at the head of the li.ne.

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