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Full text of "Effects of Pinyon-Juniper conversion on watershed values in Utah"

BLM LIBRARY 




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Project Report 

EFFECTS OF PINYON-JUNIPER CONVERSION 
ON WATERSHED VALUES IN UTAH 



Prepared by 
Gerald F. Gifford 



Utah Agricultural Experiment Station 
in cooperation with 
Bureau of Land Management 

April l, 1963 



* 



O e^%.o.|° c o^ 



• 







^ 






# 



• 



Title of Study : "Effects of Pinyon-Juniper Conversion on Watershed Values 
in Utah" 



Objectives : 

A. To determine the water budget of natural stands of pinyon-juniper and 
adjacent areas which have been cleared and/or seeded. 

B. To determine the effects of vegetation conversion on soil physical 
properties and soil stability. 

C. To ecologically evaluate sites before and after as to phenology, 
composition, and production of vegetation. 

D. To evaluate the economics of conversion practices in terms of the 
watershed values and multiple use relations. 

E. To obtain data necessary for determination of hydrologic soil cover 
complexes on the study sites. 

Introductory Comment : This report is concerned with additional data analysis 
and compilation which has resulted since the project report dated January 1, 
1969. As before, the report will provide information to supplement previous 
reports as well as indicate progress to date. 

Infiltrometer Studies : Data from the second phase of the two-year study 
utilizing the Rocky Mountain infiltrometer on several treated (and nearby 
untreated) P-J sites in central and southern Utah are still being analyzed. 
However, some information is now available and is presented below. 

METHODS 

A Rocky Mountain infiltrometer (Dortignac, 1950 was utilized to simulate 
high intensity (three in./hr. or greater) rainfall on plots approximately two 
and one-half square feet in area. Fourteen treated and nearby untreated 




• 




pinyon-junfper sites near Blanding and Milford, Utah were sampled with 325 
infiltrometer plots during the summer of 1968. Tables 1 and 2 give a brief 
description of each site. 

The experimental procedures were identical to those already described 
by the authors (Williams, Gifford, and Coltharp, 1969) . 

Soils in the study sites were derived from colluvium, alluvium, residium, 
and eolian of mainly sedimentary and volcanic rocks (Milford area) and sand- 
stones and shales (Blanding area). 

Pinyon- juniper sites near Blanding Utah 

Table 3 shows mean infiltration rates (?n./hr.) during specified time 
intervals and Figure 1 denotes relative differences in sediment production from 
treated and nearby untreated conditions on six pinyon-juniper sites studied 
near Blanding, Utah. As noted from Table 1, age of treatment varied from 1 
to 6 years. 

U.S.U. (Utah State University) study site . No significant differences in 
infiltration rates are indicated between treated and untreated conditions 
during any time interval on the area double chained with debris in place 
(item 1, Table 3). However, on the area with debris windrowed, the untreated 
area showed significantly higher infiltration rates during the time interval 
8 to 18 minutes following start of simulated rainfall. There were no significant 
differences between treated and untreated areas with regard to sediment 
production. 

Area 1**9. Brush Basi n ,, Peters Point #1, and Peters Point #2 . No 
significant differences between treated and untreated conditions are indicated 
for either infiltration rates (Table 3) or sediment yields (Figure 1). 

Alkali Ridge . At the Alkali Ridge site, the following four exclosures 
were located within the treated area: (1) everything excluded, (2) rabbits 



i r t- 




• 







Table/ . Brief description of study sites near Blanding, Utah. 



Date 



Project 



Location Seeded— 



1/ 



1. Pelens Point 

Location #1— 

chained 
and debris in 
place 



Location #2 

' chained 
and debris in 
place 



T32S R23E 1964 
Sections Ik, 
15, 22, 23 



T32S R23E I960 
Sections 31, 
32 



Seed 

Type lbs/acre 



Crested 
Wheatgrass 



Crested 
Wheatgrass 



Average 
Production 
in 1965 
(lbs/acre 
dry weight) 



Unknown 



Unknown 



Elevation- 
(feet) 



2/ 



7,000 



7,000 



Annual- 
Precipitation 
(inches) 



lk 



Ik 



Grazing History- 



Negligible summer use 
before treatment. After 
treatment light summer 
use except heavy use 
around water. 

Same as #1 



2. Brush Basin 
Double chained 
and debris in 
place 

3. Alkali Ridge 
Double chained 
and debris in 
place 

k. Job #1^9 

chained 
and debris in 
place 



T35S R22E 1962 
Sections 20, 
29 



T36S R23E 1961 
Sections 25, 
26, 35, 36 



T37S R22E 1963 
Sections 5, 6, 
7, 8 



Crested 

Wheatgrass 



Unknown 



Crested 6 -Unknown 
Wheat grass 



Crested 6 
Wheatgrass 
(Four- wing saltbush Unknown Unknown 
and yellow sweet- 
clover) 



7,000 



6,000 



6,000 



16 Before treatment negligible 
use after treatment 
stocked at 5ac/AUM. 



11-12 



11-12 



Negligible use before 
treatment, after treat- 
ment stocked at ^ac/AUM. 



No grazing until 1969. 






Table / . Continued. 



Project 



Location 



Date , 
Seeded- 7 



5. Utah State University- 
Study plots 



Location #1 

chained 
and debris in 
place 

Location #2 

chained 
and windrowed 



Same 



Same 



1967 



1967 



Seed 
Type lbs/acre 



Crested 
Wheatgrass 



Same as #1 



Average 
Production 
in 1965 
(lbs/acre 
dry weight) 



2/ 

Elevation— 

(feet) 



New job 



New job 



6,500 



6,500 



3/ 
Annual- 
Precipitation 
(inches) 



11-12 



11-12 



Grazing History 



No grazing. 



No grazing 



- Seeded in fall unless otherwise indicated. 

2/ 

Elevations gxven on all sites were taken from United States Geological Survey quadrangles (15 minute series) 

- Annual precipitation values taken from the annual normal precipitation map for the State of Utah (1931-1960) 

V 

- Windrowed sites were drill seeded and non windrowed sites were broadcast seeded 






Table eR. . Brief description of study sites near Milford, Utah. 



Date 



Average 
Production 
in 1965 



Project 



Location Seeded— 



V 



Seed 



Type 



(lbs/acre Elevation-' 
lbs/acre wet weight) (feet) 



2/ 



l.o Indian Peaks 
L./ 
Location #1-' ; ' T30SR 17V/ . 1964 

chained Sections 9, 
and windrowed 10 



Pubescent 
Wheatgrass 



6 



2000 



6,500-7,000 



Location #2 

chained 
and windrowed 



Location #3 

chained 
and debris in 
place 

Location #4 

chained 
and windrowed 



2. New Arrowhead 
mine. 

chained and 
windrowed 



V 



T30S H17W I960 
Section 7 
T30S Kl8w 
Section 12 



T29S R18W 
Sec 23, 24, 
25,26 



Intermediate 6 
Wheatgrass 



3000 



6,500-7,000 



T30S R17W 
Section 27 



T31S R17W 
Sec 6, 7 
T31S Rl8w 
Sec 1, 12 



1961 



1962-64 



Pubescent 

Wheatgrass 



Intermediate 
Wheatgrass 



2000 



6,500-7,000 



6,400-6,800 



6 1,200-1,600 7,500-8,000 



Annual- 
Precipitation 
(inches) 



10 



11 



12 



11 



15 



Grazing History 



Grazed in spring, summer 
and fall before treatment 
grazed in mid and late 
summer in rotation 
system after treatment. 

Grazed in spring, summer 
and fall before treatment 
grazed in late spring and 
early summer in a rotation 
system after treatment. 



Same as #1 



Before the area was 
treated grazing use was in 
conjunction with private 
land to the west. Very 
little use because of the 
heavy trees and lack of 
feed. The seeding is now 
used from June 15 to August 
3f. In 1968 it was used 
until August in. 






Table ^^ . Continued. 



Project 



Location 



Date 1 / 
Seeded- 



3. Jockeys 

chained 
and windrowed 



T30S H15W 1958 
Sec 20, 21, 
28, 29 



4. 



Indian Creek T28S R?W 1959 
Conservation Area Sec 26, 27 

chained 
and windrowed 



5. 



Utah State I 30S KL5W 
University study Sec 18, 19 
sites, chained and T30S KL6W 
one-half windrowed Sec 13 t 2h 
and one-half debris 
in place 



1967 



Seed 

Type lbs/acre 



Crested 
Wheatgrass 



Crested 
Wheatgrass 



Crested 
Wheatgrass 



Average 
Production 
in 1965 
(lbs/acre 
wet weight) 



Elevation— 
(feet) 



2000 



2000 



6,500-7,000 



6,000-6,500 



New 



7,000 



3/ 
Annual- 
Precipitation 
(inches) 



12+ 



12 



12 



Grazing History 



Grazed year around before 
treatment - grazed only 
in spring and early 
summer after treatment. 

Grazing spring and 
summer before treatment - 
after treatment it is 
grazed in rotation system 
with few numbers. Cattle 
are put in when grass is 
considered ready. 



— Seeded in fall unless otherwise indicated 
2/ 



3/ 

V 



Elevations given on all sites were taken from United States Geological Survey quadrangles (15 minute series) 
Annual precipitation values taken from the annual normal precipitation map for the state of Utah (1931-1960) 
Windrowed sites were drill seeded and non windrowed sites were broadcast seeded 



- -vi 






Table 3. Mean infiltration rates (in./hr.) during specified time intervals (minutes) on various pinyon- juniper sites near Blanding, Utah. 



Site y 



3-4 



4-5 



5-6 



6-7 



7-8 



8-13 13-18 



18-23 



23-28 



28-33 



33-38 



USU study site T 4.2 

(Debris in place) U 3.9 

USU study site T 4.2 

(Debris windrowed) U 3.9 



Area 149 



Brush Basin 



T 3.2 

U 3.8 

T 3.0 

U 2.7 



Alkali Ridge T 3.9 

(everything except U 3.0 
deer excluded) » 

Alkali Ridge T 3.6 

(everything U 3.0 
excluded) 

Alkali Ridge T 3.3 

(Including cattle) U 3.0 

Alkali Ridge T 3.4 

(excluding every- U 3.0 
thing except deer 
and rabbits) 



4.0 
3.7 


3.6 
3.9 


3.3 
3.9 


3.4 
3.8 


3.4 

3.4 


2.6 
3.2 


2.4 
2.7 


2.4 
2.6 


2.3 
2.6 


2.3 
2.6 


4.2 
3.7 


4.0 
3.9 


3.7 
3.9 


4.0 
3.8 


3.0 

3.4* 


2.6 

3.2* 


2.6 
2.7 


2.5 
2.6 


2.5 
2.6 


2.5 
2.6 


3.8 
3.9 


3.6 

3.8 


3.1 
3.5 


3.4 
3.4 


2.1 

2.7 


2.1 

2.3 


2.0 
2.2 


1.8 
2.2 


1.8 
2.2 


1.8 
2.2 


2.8 
2.3 


2.6 
2.6 


2.4 
2.3 


2.2 
2.1 


1.8 

1.8 


1.4 
1.5 


1.4 
1.6 


1.4 
1.5 


1.4 
1.5 


1.4 
1.5 


3.8 
2.9 


3.7 
2.9 


3.7* 

2.7 


3.3 
3.0 


2.9** 
1.7 


2.4** 
1.5 


2.3** 
1.4 


2.2** 

1.4 


2.2** 
1.4 


2.2** 
1.4 


3.6 
2.9 


3.4 
2.9 


3.4 
2.7 


3.5 
3.0 


2.7* 
1.7 


2.1* 
1.5 


1.9* 
1.4 


1.7 
1.4 


1.8 
1.4 


1.8 
1.4 


3.1 
2.9 


3.0 
2.9 


3.0 
2.7 


2.9 
3.0 


2.3* 
1.7 


2.0* 
1.5 


1.9* 
1.4 


1.9* 
1.4 


1.8* 
1.4 


1.8* 
1.4 


3.4 
2.9 


3.4 
2.9 


3.1 
2.7 


3.0 

3.0 


2.4 
1.7 


2.1 
1.5 


2.1* 
1.4 


2.0 
1.4 


2.0 
1.4 


1.9 
1.4 




Table 3. Continued. 





Site - 




3-4 


k-3 


5-6 


6-7 


7-8 


8-13 


13-18 


18-23 


23-28 


28-33 


33-38 


Alkali Ridge 


I 


3.7 


3.8 


3.6 


3.1 


2.8 


2.0 


1.6 


1.5 


1.5 


1.5 


1.5 


(excluding every- 


U 


3.0 


2.9 


2.9 


2.7 


3.0 


1.7 


1.5 


1.4 


1A 


1A 


lA 


thing except 


























rabbits) 


























Peters Point 


T 


k.o 


3.6 


2.6 


2.7 


2A 


1.5 


lA 


l.k 


1A 


1A 


lA 


#1 


U 


k.6 


3A 


3.0 


3.0 


2.7 


1.8 


1.6 


1.6 


1.5 


1.5 


1.5 


Peters Point 


T 


k.O 


3.6 


3.** 


2.8 


2.7 


1.9 


1.8 


1.7 


1.6 


1.6 


1.6 


#2 


U 


k.G 


3A 


3.0 


3.0 


2.7 


1.8 


1.5 


1.6 


1.5 


1.5 


1.5 



- See Table 1 for a brief description of sites. 

* Significantly larger at 5% than other value in pair. 

** Significantly larger at 1% than other value in pair. 




2.S-, 



1-5. 




.69 



Q.S. 

.35 
.27 I— I 



.28 



Treated 
' I Untreated 



n.s. 
1.09 



.96 



.65 



P < .05 
.65 



.15 



JSU Study Sited BSD Study ' Area 1^9 "Brush Basin "Alkali Ridge Alkali Ridge 

(D in place) Sites (Deer only) (Nothing) 

(D Windrowed) 

n.s. indicates no significant difference between treated and untreated. 




2.5, 



£ 2.0- 

! 



1.5- 



1.0. 



0.5. 



0.0 



.65 



.51 



P < .05 
.65 



.15 



.65 



.73 



.35 



^. 



Treated 
I ' Untreated 



.73 



Alkali Ridge 'Alkali Ridge 'Alkali Ridge "Peters Point "Peters Point 
(Cattle) (No Cattle) (Rabbits only) #1 « 

n.s. indicates no significant difference between treated and untreated. 




Fig. 1. Sediment yield from six P-J sites near Blanding, Utah. 






only, (3) deer only, and (h) deer and rabbits only. As noted in Table 3, 
infiltration rates were significantly greater after approximately 6 minutes 
of simulated rainfall in the deer only exclosure and on the treated area 
(outside exclosures) after 8 minutes. Similarly, in the exclosure excluding 
everything, a significantly higher infiltration rate was observed during the 
8 to 23 minutes time interval. A significantly higher infiltration rate is 
indicated for the deer and rabbit only exclosure during the time interval 
between 18 and 23 minutes. No significant differences were noted in infiltration 
rates between treated and untreated conditions pertaining to the rabbits only 
exclosure. 

As noted in Figure 1, sediment yields are significantly greater from 
untreated conditions than from the deer and rabbits only exclosure and the 
everything excluded exclosure. No significant differences are signified 
between any other treated or untreated conditions. 

Pinyon- juniper sites near Milford, Utah 

Table k shows mean infiltration rates during specified time intervals and 
Figure 2 denotes relative differences in sediment production from treated and 
untreated conditions on eight sites near Milford, Utah. 

Arrowhead Mine and Indian Peaks #1, 2, 3, and k . As noted in Table k the 
infiltration rate during the 3 to k minute time interval on Indian Peaks #1 
site was significantly greater on the untreated area. No significant differences 
in infiltration rates between treated and untreated conditions were demonstrated 
for any other time intervals on Indian Peaks numbers 1, 2, 3, and k, or Arrow- 
head Mine. Also, as noted in Figure 2, there were no significant differences 
between treated and untreated conditions with respect to sediment production 
on any of the above areas. 

U.S.U. study site. No significant differences in infiltration rates are 






I 







Table 4. Mean infiltration rates (in./hr.) during specified time intervals (minutes) on various pinyon- juniper sites near Milford, Utah 



Site 



1/ 



3-4 



4-5 



5-6 



6-7 



7-8 



8-13 13-18 



18-23 



Indian Peaks 
#1 


T 
U 


3.1 
3.9* 


2.5 
3.2 


2.3 
2.7 


2.2 

2.2 


2.0 
2.2 


1.7 
1.8 


1.6 
1.7 


1.5 
1.6 


Indian Peaks 
#2 


T 
U 


3.6 
4.o 


2.6 
3.3 


2.2 
2.8 


1.9 
2.3 


2.0' 
1.2 


1.8 
1.8 


1.7 

1.8 


1.6 
1.7 


Indian Peaks 
#3 


T 
U 


4.2 
5.4 


3.9 
4.9 


4.8 
5.1 


4.4 
4.9 


4.3 
4.7 


3.9 

4.2 


3.8 
4.0 


3.7 
3.9 


Indian Peaks 
#4 


T 
U 


3.2 
4.0 


2.4 
3.4 


3.2 
3.1 


2.6 
2.6 


2.5 
2.7 


1.8 
2.5 


1.4 
2.3 


1.3 
2.1 


Jockeys 


T 
U 


4.1** 
2.0 


4.1** 
1.8 


3.0** 
1.7 


3.2** 
1.5 


3.0** 
1.6 


2.9** 
1.3 


2.8** 
1.0 


2.7** 
1.0 


USU study site 
(Debris in place) 


T 
U 


3.1 
3.5 


2.6 
3.0 


2.5 
2.9 


2.2 
2.7 


2.2 
2.7 


1.6 

2.2 


1.6 
2.1 


1.5 
2.1 


USU study site 
(Windrowed) 


T 
U 


2.6 
3.5 


2.4 
3.0 


2.4 
2.9 


2.3 
2.7 


2.2 
2.7 


1.8 
2.2 


1.4 
2.1* 


1.5 
2.0* 


Indian Creek 


T 
U 


3.8 
3.8 


3.1 
3.7 


2.6 
3.7* 


2.2 
3.0 


2.1 
3.0 


1.6 
2.6* 


1.3 
2.2* 


1.2 
2.0* 


Arrowhead Mine 


T 

U 


4.o 
3.6 


4.0 
3.6 


3.2 
3.5 


3.0 
3.1 


2.7 
3.7 


2.8 
2.7 


2.6 
2.6 


2.5 
2.3 



23-28 



28-33 



33-38 



1.5 
1.6 


1.5 
1.7 


1.5 
1.7 


1.6 
1.7 


1.6 
1.7 


1.6 
1.7 


3.9 
4.0 


3.9 

4.0 


3.9 
4.0 


1.3 
2.1 


1.3 
2.1 


1.3 
2.1 


2.8** 
1.0 


2.9** 
1.0 


2.9** 
1.0 


1.5 

2.0 


1.4 
2.0 


1.4 
2.0 


1.5 

2.0* 


1.5 
2.0 


1.5 

2.0 


1.3 
2.0* 


1.2 
2.0* 


1.2 
2.0* 


2.5 
2.4 


2.5 

2.3 


2.5 

2.3 



1/ 



See Table 2 for a brief description of sites. 
Significantly larger at 5% level than other value in pair. 
Significantly larger at 1% level than other value in pair. 




2.5-. 



9 



•■-.•t 



0.5- 



n.s 
.39 



n.s. 

.32 .33 



.26 



.16 



n.s. 
.35 



Indian Peak I Indian Peak ' Indian Pe 
#1 \Z #3 

1 



.28 



filsila Treated 
I I Untreated 




ak l Indian Peak * Jockeys I 



n.s, indicates no significant difference between treated and untreated. 



• 



2.5' 



1.5 



0.5' 



n.s. 
.28 



.15 



P < .01 

.38 

si .is 



UsUStudy 



icy t UJiO Slud) 




J Treated 
I I Untreated 



n.s. 
.12 .10 

n 



iy ( Indian Creeic * 'Arrowhead 1 
Sites Conservation Mine 

Area 



n.a. indicates no significant difference between treated and untreated. 



• 



Fig. 2. Sediment yield from eight P-J sites near Milford, Utah. 






shown (Table k) between the double chain with debris in place treatment and the 
untreated area. The area with debris windrowed shows a significantly lower 
infiltration rate during the time interval 13 to 28 minutes following start of 
simulated rainfall. No significant differences in sediment yields occurred on 
either area. 

Jockey ' s . The treated area shows significantly higher infiltration rates 
for all time intervals during simulated rainfall. Also, and somewhat 
unexpectedly, a significantly higher sediment yield is shown for the treated 
condition. 

Beaver . In contrast to the Jockey's area, the untreated area shows 
significantly higher infiltration rates during the 5 to 6 minute time interval 
and all time intervals after 8 minutes of simulated rainfall. No significant 
differences in sediment yields are apparent between treated and untreated 
conditions . 

SOME TENTATIV E CONCLUSIONS 

Infiltration and sediment data collected with a Rocky Mountain 
infi Urometer on ]k sites in southern Utah indicate that areas cleared of 
pinyon-juniper trees and seeded to grass show no consistent decrease or increase 
in sediment yields or infiltration rates at a given point. Of 14 sites studied, 
three indicated decreased infiltration rates on the treated portion and two 
sites indicated increased infiltration rates on the treated area. Nine sites 
showed no significant differences in infiltration rates between the treated and 
untreated conditions. As for sediment yields, one site had significantly less 
sediment yield from the treated area and two sites had significantly higher 
sediment yields from the treated areas. 

These findings are similar to the results recently reported from study of 






14 sites in central Utah by the authors. After study of 28 sites 
(approximately 550 inf i ltrometer plots) involving pinyon-juniper conversion 
practices and associated point changes in watershed values, it may be concluded 
that infiltration and erosion rates at a given point are not particularly 
affected as a result of treatment practices. If there is an effect, it may be 
either positive or negative. 

It is well known that many biotic, edaphic and climatic variables interact 
to determine infiltration and erosion rates at a point on given landscapes. 
All of the above data will be further analyzed to determine those factors 
important in determining or predicting infiltration rates and sediment yields 
on each inf i ltrometer plot. Such analyses should aid in future predictions of 
the effect that certain vegetation conversion practices have on watershed 
parameters . 

Future inf i ltrometer studies should concentrate on seasonal variations 
in infiltration and sediment production rates as well as the effect of 
anticedent moisture conditons, varied rainfall intensities, and grazing (and 
particularly trampling) on such values. 

Soil Studies . A copy of the manuscript entitled "Influence of Pinyon-Juniper 
Conversions and Water Quality on Permeability of Surface Soils'" is to be found 
in the Appendix B. The paper is scheduled for publication in the August 
issue of Water Resources Research . 

Runoff Plot S tudies, Blanding Area. Data from the storm of 7-28-68 (see Table 1, 
January 1, 1969 Project Report) was not included in the January 1 report. 
Table ^Dg'w/es runoff values for the chain and windrow treatment and control 
on a paired plot basis. Mean runoff from the chain and windrow treatment was 
0.07 area inches compared with 0.02 area inches from the control plots. The 



• 



able « 



Runoff data (area inches) from Blanding chain and windrow plots 
(0.11 acre) and control plots for storm of 7-28-68 (0.45 inches total 
precipitation) . 








Treatment 




Difference 
D - X l - X 2 


Deviation 
d ■ D - d 


Squared 


Plot 
No. 


Windrow 
X l 


Control 

x 2 


Deviation 

d 2 


1 




.02 


.01 




+.01 


-.04 




.0016 


2 




.16 


.05 




+ .11 


+.06 




.0036 


5 




.02 


.01 




+.01 


-.04 




.0016 


4 




.13 


.01 




+.12 


+.07 




.0049 


5 




.02 


.01 




+ .01 


-.04 




.0016 


Total 




.35 


.09 




.26 






.0133 


Mean 


.0133 
if 


.07 


.02 




a = .05 








K- 


- .0033 




S D 


= /.0033 = 


.057 






h- 


.057 
1724" 


= .025 




t 


.05 - 
" .025 


2.0 


(.20 


> p > .10) 






1.00 . 



in 

J! 



0.50 . 



0.25 . 



.09 



.03 



P< .05 



Blandinq Study Site 



.09 



p-C .01 



Storm of 7-30-68 
(0.h5 inches) 



.52 




p <:. io 



n 



p<.So 



Storm of 8-5-68 
(1 .^5 inches) 



~ o 




• 






difference is significant at the .20 level of probability. There was no 
measurable sediment. 

There was no measurable sediment or runoff from the double chaining with 
debris in place treatment for the 7-28-68 storm. 

Runoff Plot Studies, Milford Area . Several runoff-producing storms occurred 
at the Milford site during the summer, but only those plots which were 
completed at the time of a storm provided runoff and sediment data. Runoff 
data has been analyzed for the storms of 7-30-68, 7-31-68 and 8-8-68 for the 
chain and windrow runoff plots only. Runoff plots in the double chaining with 
debris in place treatment were not completed until mid-August and therefore, 
runoff data from these plots are fragmentary. Respective controls were not yet 
installed either, so such data are omitted here. No runoff events occurred 
after 8-8-68. 

Precipitation records . Table J? given rainfall data through October 3 
when runoff recorders were shut down. 

Storm of 7-30-68 . Table _/_ gives runoff values for the chain and windrow 
treatment and control on a paired plot basis. Mean runoff was 1.27 area inches 
from the chain and windrow treatment plots compared with 0.77 area inches from 
the control plots. The difference is significant at the .10 level of probability, 

It may appear that runoff is unusually high from at least three of the 
runoff plots in the chain with windrow treatment. However, it should be noted 
that the storm was of fairly high intensity throughout the duration of most 
of the rainfall. In addition, surface soils were very moist due to cloudy 
conditions and rain which had fallen on each of the preceeding eight or nine 
days. Such conditions would promote high runoff rates. 

Sediment records were not good due to sampling problems. 



Table fe> . Precipitation data from Milford pinyon-juniper study site. 






Date 


Time Storm 
Began (MST) 






Total Rainfall 
(inches) 




Average Intensity 
(in/hr.) 


7-8-68 


Rainfall reco 


rds 


started 






7-21-68 


6:30 p.m. 






0.05 




.... 


7-22-68 


12:30 p.m. 






0.15 







7-23-68 


2:30 a.m. 






0.10 






7-23-68 


9:00 p.m. 






0.10 






7-23-68 


11:00 p.m. 






0.30 




0.30 


7-24-68 


10:30 a.m. 






0.05 







7-25-68 


10:30 a.m. 






0.55 




0.55 


7-27-68 


9:00 p.m. 






0.15 






7-28-68 


1 :30 a.m. 






0.05 






7-29-68 


10:30 a.m. 






0.05 




__„„ 


7-30-68 


3:30 p.m. 






1.65 

(based on 


f! 


2.40 
rst 1.50" of rainfall 


7-31-68 


12:15 P.m. 






0.60 

(based on 


fi 


0.80 
rst 0.40" of rainfall 


8-2-68 


9:00 a.m. 






0.10 




„«.„„ 


8-2-68 


4:00 p.m. 






0.10 






8-5-68 


1 :00 p.m. 






0.05 






8-8-68 


1:15 p.m. 






0.70 




0.15 


8-10-68 


5:30 p.m. 






0.10 




.... 


8-13-68 


12:30 p.m. 






0.20 






8-22-68 


4:00 a.m. 






0.15 







9-4-68 


1 :30 p.m. 






0.10 




—.-._ 


9-29-68 


2:30 a.m. 






0.15 






10-3-68 


Storage gage 


charged 


- recording gages s 


hut 


down 




*7 

Table f . Runoff data (area inches) from Milford chain and windrow plots 

(0.11 acre) and control plots for storm of 7-30-68 (1.65 inches 
total precipitation). 





Treatment 


Difference 
D = X ] - X 2 


Deviation 
d = D - d 


Squared 


Plot 
No. 


Windrow 
X l 


Control 
X 2 


Deviation 
d 2 


1 


1.51 


0.35 


+ 1.16 




+0.66 




.4356 


2 


1.53 


1.21 


+0.32 




-0.18 




.0324 


3 


1.45 


1.40 


+0.05 




-0.45 




.2025 


4 


0.72 


0.54 


+0.18 




-0.32 




.1024 


5 


1.15 


0.35 


+0.80 




+0.30 




.0900 


Total 


6.36 


3.85 


+2.51 








.8629 


Mean 


1.27 


0.77 


d = 0.50 












s 2 m J&29 = >2157 s d = /.2157 = .46 

s d = fW" - 205 * = -^fot -2 = 2M (.10> P >.05) 





Storm of 7-31-68 . Table K shows a mean runoff of 0.19 area inches from 
chain and windrow treatment compared with 0.12 area inches from control plots. 
The difference is significant at the .20 level of probability. 

Sediment records were not good due to sampling problems. 

Storm of 8-8-68 . Table J * shows a mean runoff of 0.07 area inches from 
chain and windrow plots as compared with 0.02 area inches from control plots. 
The difference is significant at the .20 level of probability. 

There were no measurable sediment yields. 

Additional Comments . Line intercept data concerning tree, shrub and ground 
cover of the Milford runoff plots are given in Table /O. Blanding runoff 
plot cover characteristics will be forthcoming in the next report. 






able 



{f . Runoff data (area inches) from Milford chain and windrow plots and 
control runoff plots for storm of 7-31-68 (0.60 inches total 
precipitation) . 



Plot 
No. 



Treatment 



Windrow 
X, 



Control 
X„ 



Difference 
C 2 



D^ - ) 



Deviation 


Deviation 


d = D - 


a 


d 2 


+0.14 




.0196 


+0.03 




.0009 


-0.02 




.0004 


+0.01 




.0001 


-0.03 




.0009 



• 



1 




.30 




.09 


2 




.39 




.29 


5 




.13 




.08 


k 




.05 




.11 


5 




.09 




.05 


Total 




0.96 




0.62 


Mean 




0.19 




0.12 


.2 

ID " 


.0219 
k 


Z2 


0055 





S d = 2T2? = * 033 



+ .21 
+ .10 
+ .05 
- .06 
+ ,0k 
+0.3^ 
3 = 0.07 



S D = ( A0055 = .07^ 



_ .07 - _ 2 , 2 

* .033 " 2 * 12 



.0219 



(.20 > p > .10) 





able 



Runoff data (area inches) from Milford chain and windrow plots 

(0.11 acres) and control plots for storm of 8-8-68 (0.70 inches total 

precipitation. 





Treatment 


D 

D 


ifference 
= X l " X 2 


Deviation 
d - D - d 


Squared 


Plot 

No. 


Windrow 
X l 


Control 
X 2 


Deviation 
d 2 


1 


0.15 


0.06 




+0 . 09 




-10.04 




.0C16 


2 


0.17 


0.05 




+0 . 1 2 




+0.07 




.0049 


3 


0.02 


0.01 




+0 c 1 




-0.04 




.0016 


j. 


0.02 


. GO 




+0.02 




-C.03 




.0009 


5 


0.00 


0.00 




0.00 




-0.05 




.0025 


Total 


0.36 


0.12 




. 24 








.0115 


Mean 


0.07 


0.02 


d 


= 0.05 












~-^ = .0029 



.054 

2.24 



,024 



s D = /.C029 = .054 



t = • G5 " f)f ° - 2.08 (.20 > p > .10) 




Table / . Tree shrub and ground cover (percent) on runoff plots at the Milford 
study site, September, 1968. 




Plot 



Transect. , 
Number — 



Percent Cover 



Tree 



Shrub 



Ground — 



Windrow 

# 1 



1 

19 ft. 



0.00 



0.00 



p 

Agcr 
L 

Phho 
R 
BG 



90.25 
2.28 
0.57 
0.19 
2.66 
4.05 



2 
33 ft, 



0.00 



0.00 



P 

Agcr 
L 

Phho 
B 
BG 



79.80 

0.57 
3.80 
0.19 
8.30 
7.34 



3 
7k ft. 



0.00 



0.00 



p 

Agcr 
L 
BG 



91.01 
0.57 
4.75 
3.67 




0.00 



0.00 



p 

Agcr 
L 

Phho 
R 
BG 



87.02- 
1.14- 
3.04- 
0.13 
3.65 

5.02- 



Windrow 
# 2 



1 
19 ft. 



0.00 



0.00 



P 

Agcr 

L 
Annuals 

R 
BG 
Lupine spp. 



3.00 
2.20 
5.00 
0.60 
0.20 
88.40 
0.60 



2 
33 ft. 



0.00 



0.00 



p 

Agcr 

L 
Annuals 

R 
BG 
Phho 
Misc. 



0.00 
0.41 
19.98 
0.41 
0.41 

77.57 
0.61 
0.61 




— Line Transects across runoff plots at indicated distances measured from top 
of plot. 



2/ 

— P = pavement 

L = litter 



R = rock 
BG = bare ground 



• 



Table /O. 


Continued. 








r 


Transect , 
Number - 




Percent Cover 




Plot 


Tree 


Shrub 


Ground — 



3 

7k ft. 



o.oo 



0.00 



p 

Agcr 

L 
BG 
Annuals 

B 



0.00 
0.67 
14.69 
83.75 
0.22 
0.67 



0.00 



0.00 



p 

Agcr 

L 
BG 
Annuals 
Phho 

R 
Lupine spp. 
Misc. 



1.00 
1.09 
13.22 
83.48 
0.4i 
0.20 
0.20 
0.20 
0.20 



Windrow 
# 3 



1 
19 ft, 




0.00 



0.00 



p 

Agcr 
L 
BG 
Lupine spp. 



37.82 

1.53 

2.88 

56.81 

O.96 



2 
33 ft. 



0.00 



0.00 



p 

Agcr 

L 
BG 
Lupine spp. 

R 



13.05 
1.34 
4.60 

78.71 
2.11 
0.19 



3 
74 ft. 



0.00 



0.00 



p 

Agcr 

L 
BG 
Lupine spp. 

R 
Annuals 



0.00 
1.71 
0.95 
94.49 
2.4-7 
0.19 
0.19 



X 



0.00 



0.00 




p 

Agcr 

L 
BG 
Lupine spp. 

R 
Annuals 



16.96 
1.53 
2.81 

76.66 
1.85 
0.13 
0.06 




Table /O. 


Continued. 








» 


Transect.. / 
Number - 




Percent Cover 




Plot 


Tree 


Shrub 


Ground - 



Windrow 
# k 



1 
19 ft. 



0.00 



0.00 



p 

Agcr 
L 
BG 
Annuals 



95.21 
1.92 
2.68 
0.00 
0.19 



2 
33 ft. 



0.00 



0.00 



p 

Agcr 
L 
BG 



88.32 
0.76 
7.87 
3.03 



3 

7k ft. 



0.00 



0.00 



p 

Agcr 
L 
BG 
Ann C 
Penst, 
Rock 



spp. 



45.12 
1.97 
3.27 

48.69 
0.19 
0.38 
0.38 




0.00 



0.00 



P 
Agcr 

L 
BG 
Ann 
Penst. 
Rock 



spp. 



76.22 
1.55 
if. 61 

17.23 
0.13 
0.13 
0.13 



Windrow 
# 5 



1 
19 ft. 



0.00 



0.00 



P 

Agcr 
L 
BG 
Lupine spp. 

a 



0.00 

0.57 
2.68 
93.88 
0.38 
2.49 



2 
33 ft. 



0.00 



0.00 



P 

Agcr 

L 

BG 

R 



0.00 

1.15 
0.38 

96.55 
1.92 




3 

74 ft. 



0.00 



0.00 



p 

Agcr 

L 
BG 
Annuals 

R 



0.00 
1.53 
0.76 
92.15 
0.19 
5.37 




Table 



/o. 



Continued. 







Transect. / 
Number — 






Percent 


Cover 




Plot 


Tree 


Shrub 


Ground - 


X 






0.00 


0.00 


P 
Agcr 

L 
BG 
Annuals 

B 
Lupine spp. 


0.00 

1.08 

1.27 

94.20 

0.06 

3.26 

0.13 


Windrow 


1 


Juos 


29.38 


0.00 


P 


43.50 


Check # 1 


19 ft. 








L 
BG 
Lupine spp. 
Opuntia 
Phho 


50.19 
5.74 
0.19 
0.19 
0.19 




2 


Juos 


12.16 


0.00 


P 


62.16 




33 ft. 








L 
BG 
Annuals 


34.79 

2.86 
0.19 




3 




0.00 


0.00 


P 


83.58 




?4 ft. 








L 
BG 
Sihy 
Chvi 


13.20 

2.86 

0.18 
0.18 


X 




Juos 


13.85 


0.00 


P 

L 
BG 
Annuals 
Opuntia 
Phho 
Sihy 
Chvi 


63.08 

32.73 

3.89 

0.06 
0.06 
0.06 
0.06 
0.06 


Windrow 


1 


Pimo 


17.24 Artr 0.19 


P 


25.77 


Check # 2 


19 ft 


Juos 


4.26 




L 
BG 

R 


61.24 

0.19 

12.80 




2 


Pimo 


8.84 


0.00 


P 


25.73 




33 ft. 


Juos 


15.71 




L 

BG 

R 


67.19 
6.50 
O.58 



• 





Table /l/< C 


ontinued. 
















Transect. , 
Number - 








Percent 


Cover 




Plot 


Tree 




Shrub 




Ground - 




3 
74 ft. 


Pimo 
Juos 


1.16 
29.87 


Artr 


3.68 


P 
L 

BG 
R 


21.14 

50.82 

27.85 

0.19 


X 




Pimo 
Juos 


9.08 
16.61 


Artr 


1.29 


P 

L 

BG 

R 


24.21 

59.75 

11.51 

4.53 


Windrow 
Check # 3 


1 
19 ft. 


Juos 


40.28 


Artr 


0.95 


P 
L 
BG 
Phho 


3.80 
22.42 
72.64 

1.14 




2 
33 ft 


Juos 
Pimo 


6.65 
45.03 




0.00 


P 

L 

BG 


40.85 
43.89 
15.26 




3 

74 ft 


Juos 


47.31 




0.00 


P 

L 

BG 

R 

Chvi 


5.70 

34.77 

57.06 

0.38 

2.09 


X 




Juos 
Pimo 


31.41 
15.01 


Artr 


0.32 


P 

L 

BG 

R 

Phho 

Chvi 


16.78 

33.69 

48.33 

0.13 

0.38 

0.69 


Windrow 
Check # 4 


1 
19 ft. 


Pied 
Juos 


3.04 
7.03 


Artr 


3.80 


P 

L 

BG 

R 


55.29 

18.24 

26.09 

0.38 




2 

33 ft. 


Pimo 
Juos 


15.70 
7.98 


Artr 


1.33 


P 

L 

BG 


56.43 

35.72 

7.85 




3 

74 ft 


Juos 
Pied 


15.39 
37.62 


Artr 


5.32 


P 

L 

BG 


30.97 

60.61 

8.42 





• 



Table A'. 


Continued. 
















Transect.. / 
Number - 








Percent 


Cover 




Plot 




Tree 




Shrub 




Ground — 


X 




Pied 


18.79 


Artr 


3.48 


P 


47.56 






Juos 


10.13 






L 

BG 
E 


38.19 

14.12 

0.13 


Windrow 


1 


Pied 


34.77 




0.00 


P 


42.75 


Check # 5 


19 ft. 










L 
BG 
Opuntia 


45.60 

11.46 

0.19 




2 


Pied 


34.20 




0.00 


P 


48.64 




33 ft. 


Juos 


6.08 






L 
BG 
Opuntia 


49.97 
O.63 
0.76 




3 


Juos 


23.75 


Artr 


4.56 


P 


55.48 




74 ft. 










L 
BG 
Phho 


4l. 61 
2.15 
0.76 


X 




Pied 


22.99 


Artr 


1.52 


P 


48.96 






Juos 


9.94 






L 
BG 

Opuntia 
Phho 


45.73 
4.74 
0.32 
0.25 


Debris 


1 


Juos 


24.95 


Artr 


12.76 


P 


45.33 


Check # 1 


19 ft. 










L 
BG 
Sihi 
Phho 


49.52 
4.58 
0.19 
0.38 




2 


Juos 


14.67 


Artr 


4.77 


P 


42.94 




33 ft. 


Pimo 


22.52 


Arno 


8.40 


L 
BG 
Sihi 
Phho 
Annuals 


54.58 
0.00 

1.72 
0.38 

0.38 




3 


Pied 


45.64 


Artr 


8.16 


P 


30.61 


1 


74 ft. 






Arno 


3.52 


L 
BG 
Phho 
Sihi 
Annuals 


65.49 

3.15 
0.19 
0.37 
0.19 



• 



JTable /f . 


Continued. 

Transect 
Number 










• 






1/ 






Percent 


Cover 




Plot 


Tree 




Shrub 




Ground = 


X 




Juos 


13.21 


Artr 


8.56 


P 


39.63 






Pimo 


7.51 


Arno 


3.97 


L 


56,53 






Pied 


15.21 






BG 
Phho 
Sihi 
Annuals 


2.57 
0.32 
0.76 
0.19 


Debris 
Check # 2 


1 
19 ft. 


Juos 


8.02 


Artr 
Arno 


1.68 
3.73 


P 
L 
BG 
Phho 
Sihi 


67.54 

22.76 

8.96 

0.37 

0.37 




2 


Juos 


32.65 


Artr 


5.97 


P 


46.27 




33 ft. 






Arno 


2.24 


L 
BG 
Phho 
Sihi 


40.86 
12.31 

0.56 


; 


3 
74 ft. 




0.00 


Artr 


2.24 


P 


76.70 








Arno 


15.11 


L 


13.21 














BG 


9.36 














Eri. spp. 


0.73 


X 




Juos 


13.56 


Artr 


3.30 


P 


63.50 










Arno 


7.03 


L 
BG 
Phho 
Sihi 
Eri. spp. 


25.61 

10.22 

0.12 

0.31 

0.24 


Debris 
Check # 3 


1 
19 ft. 




0.00 


Arno 


8.33 


P 

L 
BG 
Eri. spp. 
Phho 


76.55 

13.95 

8.34 

0.97 
0.19 




2 


Pied 


11.63 


Artr 


4.65 


P 


41.28 


) 


33 ft. 






Arno 


13.76 


L 
BG 
Eri. spp. 
Annuals 
Chvi 
Sihi 


52.71 
4.67 
0.38 
O.58 
0.19 
0.19 




Table 



JO. 



Continued. 



• 






Transect. / 
Number — 








Percent 


Cover 






Plot 




Tree 




Shrub 






2/ 
Ground — 




3 


Juos 


33.33 


Artr 


1.76 


P 




36.47 




74 ft. 










L 
BG 
Chvi 




38.82 

23.93 

0.39 














Annuals 


0.39 


X 




Juos 


11.11 


Artr 


2.15 


P 




51.43 






Pied 


3.88 


Arno 


7.36 


L 
BG 
Eri. 


spp. 


35.16 

12.52 

0.32 














Annuals 


0.32 














Chvi 




0.19 














Sihi 




0.06 


Debris 


1 


Juos 


34.78 


Artr 


6.13 


P 




37.94 


Check # 4 


19 ft. 






Arno 


9.88 


L 
BG 
Phho 
Sihi 




49.21 

11.86 

0.79 

0.20 




2 


Juos 


24.46 


Arno 


2.76 


P 




55.03 




33 ft. 










L 

BG 




40.43 
4.54 




3 


Pimo 


26.10 


Arno 


2.39 


P 




50.80 




7^ ft. 










L 
BG 
Sihi 

Eri. 


spp. 


47.01 
1.60 
0.20 
0.39 


X 




Pied 


8.70 


Artr 


2.04 


P 




47.92 






Juos 


19.75 


Arno 


5.01 


L 
BG 
Phho 
Sihy 

Eri. 


spp. 


45.55 
6.01 
0.26 
0.13 
0.13 


Debris 


1 


Juos 


3.67 


Arno 


2.32 


P 




55.21 


Check # 5 
i 


19 ft. 










L 
BG 
Sihi 
Phho 




27.99 

16.02 

0.39 

0.39 



('= ^Table/ft 



Continued. 



• 



Transect 1 , 
Plot Number - 








Percent 


Cover 






Tree 




Shrub 




2/ 

Ground — 


2 




0.00 




0.00 


P 


97.28 


33 ft. 










L 
BG 
Astrag. 
R 


1.16 

0.59 

spp. 0.19 

0.78 


3 


Juos 


16.15 




0.00 


P 


50.96 


74 ft. 


Pied 


14.62 






L 
BG 
Phho 


42.31 
6.34 

0.39 


X 


Juos 


6.61 


Arno 


0.77 


P 


67.82 




Pied 


4.87 






L 
BG 

B 
Astrag. 
Phho 


23.82 

7.78 

0.26 

spp. 0.06 

0.26 


^d.i.p. # i y i 




0.00 


Artr 


4.67 


P 


66.54 


19 ft. 










L 
BG 
Agcr 
Phho 
Annuals 
Misc. 
Eri. spj 


28.22 
1.51 
0.56 

2.24 

0.56 

>. 0.37 


2 




0.00 


Artr 


0.68 


P 


69.56 


33 ft. 






Arno 


0.68 


L 
BG 
Agcr 
Phho 
Annuals 


14.12 

13.77 

0.51 

1.19 

0.85 


3 




0.00 


Artr 


0.54 


P 


56.65 


74 ft. 










L 
BG 
Agcr 
Annuals 


36.33 
3.42 
0.90 
2.70 



• 



Chain with debris in place plots. 



m Kable /O. 



Continued. 




• 





Transect, , 
Number - 






Percent 


Cover 














o/ 


Plot 


Tree 




Shrub 


Ground —' 


5 




0.00 


Artr 


1.96 


P 


64.25 








Arno 


0.23 


L 
BG 
Phho 
Annuals 
Misc. 
Eri. spp. 


26.22 
6.23 
0.40 
1.93 
0.19 
0.12 


D.I. P. # 2 


1 
19 ft. 


0.00 


Artr 


0.40 


P 

L 
BG 
Eri. spp. 

R 
Agcr 


73.19 

20.77 

5.64 

0.20 
0.20 




2 


0.00 




0.00 


P 


59.26 


1 


33 ft. 








L 
BG 
Eri. spp. 
Lupine spp. 
Phho 


21.40 

12.35 

0.82 

5.97 

0.20 




3 


0.00 




0.00 


P 


56.49 




7*+ ft 








L 
BG 
Annuals 
Astrag. spp 
Agcr 


31.38 
9.09 
0.22 

. 2.60 
0.22 


5 




0.00 


Artr 


0.13 


P 

L 
BG 
Eri. spp. 
Lupine spp. 
Astrag. spp 
Phho 
Agcr 

R 


62.98 
24.52 
9.09 
0.27 
1.99 
. 0.87 
0.07 
0.14 
0.07 


D.I.P. # 3 

) 


1 
19 ft. 


0.00 


Artr 


0.96 


P 

L 
BG 
Agcr 
Annuals 
Eri. spp. 


58.62 
33.72 
6.13 
0.38 
O.96 
0.19 



m ^Table/^. 



Continued. 



Plot 




• 



Transect.. . 
Number — 



Percent Cover 



Tree 



Shrub 



2/ 
Ground - 







2 


Pied 


4.21 


Artr 


0.96 


P 


65.52 






33 ft. 






Arno 


2.11 


L 

BG 
Lupine spp, 
Sihi 

Agcr 
Misc. 


27.01 
4.59 
1.15 
0.77 
0.19 
0.77 




3 


Juos 


0.57 




0.00 


P 


79.35 






74 ft. 










L 
BG 
Eri. spp. 
Sihi 
Agcr 
Annuals 


13.96 
4.22 
0.57 
0.19 
1.14 

0.57 


X 




Juos 


0.19 


Artr 


0.65 


P 


67.83 


) 






Pied 


1.40 


Arno 


0.70 


L 
BG 
Agcr 
Annuals 
Eri. spp. 
Lupine spp. 
Sihi 
Misc. 

? 


24.90 
4.95 
0.57 
0.51 
0.25 
0.38 
0.32 
0.29 


D.I. P. 


# 4 


1 




0.00 




0.00 


26.97 






19 ft. 










L 
BG 
Eri. spp. 
Lupine spp. 


68.44 
2.76 
0.18 
1.65 




2 




0.00 




0.00 


P 


21.95 






33 ft. 










L 
BG 
Penst. spp. 
Misc. 


52.57 

22.12 

2.48 

0.88 




3 




0.00 




0.00 


P 


46.02 






74 ft. 










L 
BG 
Annuals 


44.55 
8.94 
0.49 




Table 



JO. 



Continued. 



Plot 



Transect.. , 
Number — 



Percent Cover 



Tree 



Shrub 




Ground - 



X 






0.00 




0.00 


P 

L 
BG 
Eri. spp. 
Lupine spp. 
Penst. spp. 
Annuals 
Misc. 


31.65 
55.19 
11.27 
0.06 
0.55 
0.83 
0.16 

0.29 


D.I.P. 


# 5 


1 
19 ft. 


0.00 




0.00 


P 

L 
BG 
Agcr 
Annuals 


30.68 

6^.20 

h.7k 

0.19 

0.19 




2 


0.00 


Artr 


1.67 


P 


70.37 


> 




33 ft. 








L 

BG 
Agcr 
Annuals 

? 


27. 0^+ 
0.36 
0.56 
1.67 




3 


0.00 


Arno 


2.35 


88.81 






7^ ft. 








L 

BG 
R 
Agcr 
Annuals 


1.99 
8.30 
0.36 
0.36 
0.18 


X 




0.00 


Artr 


0.56 


P 


63.29 










Arno 


0.78 


L 
BG 

R 
Agcr 
Annuals 


31.08 
kM 

0.12 
0.37 
0.68 



• 





Appendix A 

Copy of the manuscript entitled 

"Influence of Pinyon- Juniper Conversions and 
Water Quality on Permeability of Surface Soils" 






Influence of Piny on- Juniper Conversions and Water 
Quality on Permeability of Surface Soils 1/ 

by 
Gerald F. Gifford -and Ronald K. Tew & 



INTRODUCTION 

The influence that various eradication treatments for pinyon- juniper 
( pinus fdulis Fngelnu, Pinus monophylla Torr. and Frem. - Juniperus spp. ) have 
on water yield, runoff, sediment production, soil moisture patterns, etc., is 
of utmost concern to watershed managers in the western United States. The 
majority of published papers concerning the hydrology of pinyon- juniper sites 
deal with rainfall interception or water yields associated with plant removal. 

Pinyon- juniper is generally controlled by chaining (a large anchor chain 
is pulled between two tractors to fell the trees), and the debris either left 
where it falls or later windrowed. In conjunction with chaining, grass seed 
is usually broadcast or drilled, depending on how the debris is handled. 
During windrowing, the upper h inches of soil is thoroughly disturbed. Less 
disturbance occurs when the debris is left where it falls. It is conceivable, 
therefore, that the infiltration and percolation rates of surface soils might 
be affected by the debris-disposal treatments. 




This study conducted under cooperative agreement between U.S. Forest 
Service, Intermountain Forest and Range Experiment Station, and Utah State 
University in cooperation with the Bureau of Land Management (Contract 14-11- 
0008-2837) . 

2/ 

Assistant Professor, Range Watershed Science and Chairman, Watershed 
Science Unit, Utah State University, Logan, Utah 84321. 

3/ 

Presently Associate Professor, Plant Science Dept., Fresno State College, 
Fresno, California. Formerly Associate Plant Physiologist, U.S. Forest Service, 
Intermountain Forest & Range Experiment Station, Forestry Sciences Laboratory. 
Logan, Utah 84321, 





' . 



• 



L 






Infiltrometers have been widely used to study the influence of land 
management practices on infiltration and erosion. Depending on distance 
between sites, natural waters of various qualities may be used to provide 
simulated rainfall for infiltration measurements. Final infiltration rates 
(governed somewhat by percolation rates) could differ significantly at a given 
time and location depending upon source (and, therefore, quality) of water 
applied as rainfall. 

The objective of this study was to determine the influence that pinyon- 
juniper eradication treatments and water quality have on percolation rates of 
southern Utah rangeland surface soils disturbed less than one year ago. 

METHODS 

Two sites were studied, one in southeastern Utah near Blanding and the 
other in southwestern Utah near Milford. Pinyon and juniper were the dominant 
vegetation types present on both sites. Surface soils varied from a sandy 
loam (sandstone-siltstone parent material, 0.2 to 1.1$ rock > 2 mm diameter) 
at the Blanding site to a silt loam (basalt parent material, 18.^ to 31.6% 
rock > 2 mm diameter) at the Milford site. At each site were the following 
treatments: (1) pinyon- juniper chained and windrowed, (2) pinyon- juniper 
chained with debris left in place, and (3) undisturbed pinyon- juniper. 
Chaining treatments were applied during November, 1967 to a minimum of 30 
acres, crested wheatgrass was seeded, and the areas were fenced. 

Soil samples were collected during May, 1968 at the 0-2 and 2-k inch 
depth intervals at 30 grid points on each 30-acre plot. Samples from three 
points were then randomly selected and composited until 10 replications of 
composited samples were obtained for each depth interval. The samples were 
taken to the laboratory, passed through a 2 mm sieve, and stored until analyzed. 



• 



• 



• 



Soil texture was determined by hydrometer method (Bouyoucos, 1962) . 

Organic matter content was determined by a wet oxidation method 
(Schollenberger, 19^5) • Aggregation, particle density, porosity, and pH were 
determined by methods outlined by Richards (195*0. The procedure given by 
Reeve (1965) was used for permeability measurements. Only 6 of the 10 
replications of the soil samples collected were used for the permeability 
measurements. 

Three different qualities of water were used for permeability tests on 
each soil sample: (1) distilled water, (2) tap water obtained at Milford, and 
(3) tap water obtained at Blanding. The quality of the waters (see Table 1) 
including pH, conductivity and the content of calcium, magnesium, sodium, 
potassium, carbonate, bicarbonate, chloride and sulfate was determined by 
methods of analysis given by Richards (195*1-) • 

The soils were prepared for permeability studies by dumping each sample 
into a 3-ounce can which had a wire screen and a filter paper covering the 
bottom. Each can had a small hole punched in the bottom for drainage and a 
cylinder extension placed at the top. The soil was packed by dropping the 
container from a height of 2.5 cm 200 times on a wooden block. The cylinder 
extension was removed and the soil leveled to the top of the can. The same 
packing procedure was used to obtain bulk density values used in porosity 
calculations. After the soils were leveled in the cans, the cylinder extension 
was replaced and sealed to the can with rubber cement. The sample was then 
placed on a rack where water was admitted to the sample from a supply tank 
having a constant head. The quantity of water percolating through the soil 
was measured at 5-minute intervals for a total of k^> minutes. 

Soil permeability was calculated using the equation and symbols given by 
Reeve (1965) where: 

k = _N_ VL 

P g A & h a t 
w 



• 



Table 1. Quality of waters used for percolation study (excluding distilled 
water. 



Quality 
Measured 



Source of Water 

Bl an ding Mil ford 




ECX 


: lcr 


PH 




Ca 


(ppm) 


Mg 


(ppm) 


Na 


(ppm) 


K 


(ppm) 


C0 7 




HOC 


) (ppm) 


50 k 


(ppm) 


CI 


(ppm) 



18 
8.15 
25 

5 

h 

0.8 

none 
176.3 

11.0 
0.50 



^5 

8.36 
Ik 

k.8 
63 

3.2 

none 

10^.6 

37.^ 

35.5 



• 





# 



in which: 



• 



2 
k = intrinsic permeability with water, cm 

N = water viscosity, poises 

3 
P s water density, g/cm 

2 
g = acceleration of gravity, cm/sec 

V s volume of percolate in time t, cm 

L = length of soil column, cm 

.:\h a difference in hydraulic head between inflow and outflow, cm 

2 
A = cross sectional area of soil column, cm 

/\t = time interval involved, sec. 



RESULTS 

Analysis of variance of intrinsic permeabilities after k$ minutes and 
also volume of water percolated through the soil columns after each 5-minute 
interval revealed significant interactions among site x treatment, site x depth, 
and treatment x soil depth. Quality of water did not significantly affect 
percolation rates the first half hour, but was a significant factor thereafter. 

At the Milford site, treatment significantly influenced intrinsic 
permeability of the soil columns (Table 2). Pooled over both depths and three 

waters, mean intrinsic permeability of surface soils from the chain and windrow 

2 2 2 

treatment was 1.13 cm compared with 0.34 cm and 0.5^ cm for chaining with 

debris in place and control treatments, respectively. The trend was the same 

at the Blanding site but differences among treatments were not significant 

at the .05 level of probability. 

In addition, at the Milford site, intrinsic permeability values of soil 

samples from the 2-k inch depth were significantly greater than those from 

the 0-2 inch depth (Table 3). Pooled over three treatments and three waters, 





• 



k 




Table 2. Influence of pinyon- juniper treatment on intrinsic permeability 
(cm ) of soil columns after 45 minutes (two sites). 



Site 



Bl an ding 
Mil ford 



Treatment — 



Chain , windrow 



1.00 c 



1.13 



Chain, debris 
in place 



o.8o a 

0.84 a 



Control 



0.76 s 

0.54 £ 



1/ 




Any two means in same row with same letter are not significantly different 
at .05 level of probability (Duncan's multiple range test). Means 
represent two depths, three waters, and six replications. 





Table 3. Influence of depth from which soil sample was collected on 
intrinsic permeability (cm 2 ) after k5 minutes (two sites). 



Soil depth (inches) — 



Site 0-2 2-4 



Blanding 0.71 a 1.00 & 

Milford 0.^0 a 1.28 b 




- Any two means in same row with same letter are not significantly 

different at .05 level of probability (Duncan's multiple range test). 
Means represent three treatments, three waters, and six replications, 




mean intrinsic permeability was 3.2 times greater in soil from the 2-4 inch 
depth than in soil from the 0-2 inch depth. For soil from the Blanding site, 
mean intrinsic permeability was 1.4 times greater at the 2-4 inch depth than 
at the 0-2 inch depth. Differences at the Blanding site were not significant. 

The chain and windrow treatment significantly influenced intrinsic 
permeability at the 2-4 inch depth (Table 4) . There were no significant 
differences between control and chaining with debris in place at the 2-4 inch 
depth, nor were there significant differences among any treatments with respect 
to intrinsic permeability of soil from the 0-2 inch depth. The trend, however, 
was toward increased permeability with the chain and windrow treatment. 

As mentioned above, water quality influenced volume of percolate only 
after 30 minutes. Since intrinsic permeabilities were calculated after 45 
minutes, water quality was a significant factor. Pooled over two sites, three 

treatments, and two soil depths, mean intrinsic permeability for distilled 

2 2 

water was O.78 cm , for Milford water 0.88 cm , and for Blanding water 0.87 

2 
cm . Intrinsic permeabilities for Milford and Blanding waters were not 

significantly different at the .05 level of probability. 
Factors Influencing Permeabilities 

Parameters associated with each soil column were measured to determine 
their influence on percolation rates and intrinsic permeabilities for each of 
the three waters. The parameters included soil texture (sand, silt, clay, 
silt plus clay, % rock > 2 mm diameter originally in sample), % aggregation, 
% organic matter, pH, bulk density, particle density, and % total porosity. 
Soil factors important for predicting percolated volumes after each 5-minute 
interval did not change significantly with time, so only factors important in 
predicting intrinsic permeabilities after 45 minutes are considered here. 

Three multiple regression equations were derived for predicting intrinsic 




Table k. Influence of pinyon- juniper treatment on intrinsic permeability 
(cm ) after V? minutes (two soil depths). 

Treatment - 

Depth Chain, debris 

(inches) Chain, windrow in place Control 

0-2 0.72 9 " 0.50 a 0.^ a 

2-4 l.^l 13 l.l^ a 0.87 a 



• 



1/ 

- Any two means in same row with same letter are not signifxcantly 

different at .05 level of probability (Duncan's multiple range test). 

Means represent two sites, three waters, and six replications. 



• 



i 



• 



p 

permeabilities (k , cm ) after 45 minutes at either the 0-2 or 2-4 inch soil 
w 

depth at either site, one equation for each of the three waters: 
Distilled water 

Y = -2.65^ - .087 (.% organic matter) + .090 (% total porosity) 

- .011 {% silt plus clay) R 2 = O.56 (R = .75) 

Mil ford water 

Y - -15.362 + 3.796 (bulk density, g/cc) + .026 (% sand) + 

.195 (% total porosity) + .04l (% clay) R 2 = 0.65 (R ■ .81) 
Blanding water 

Y = -8.527 + 4.986 (particle density, g/cc) + .027 (% sand) 

-3.893 (bulk density, g/cc) + .037 (% clay) R 2 = 0.64 (R = .80) 
It is obvious that the optimum equation for each water contains factors which 
differ from the other two. Percent total porosity explained 45 and 58% of the 
variation associated with intrinsic permeabilities measured with distilled 
and Milford waters, respectively. The remaining variables explained from one 
to six percent of the variation. With Blanding water, bulk density explained 
45% of the variation associated with intrinsic permeabilities while the 
remaining variables explained from 1 to 12% of the variation. 



DISCUSSION 

Permeability of surface soils on pinyon- juniper sites is an important 
hydrologic variable. This factor is particularly important on sites where 
soil surface protective cover (canopy cover, litter, erosion pavement) is 
sufficient to allow potentially high infiltration rates. Vegetative 
manipulation treatments which enhance surface soil permeability, and at the 
same time maintain or increase protective soil cover, should be encouraged 
where economically (or otherwise) feasible. 




• 



Results of this study indicate that chaining of pinyon- juniper does 
increase permeability of the 0-2 and 2-4 inch surface soil depths during the 
first year following treatment. The chaining with windrowing treatment was 
particularly effective in this respect. Mechanical soil disturbance 
associated with this treatment probably increases noncapillary porosity 
through decreased bulk densities and incorporation of litter into the surface 
soils. Such relationships are shown in Figure 1 for the Milford (Basin and 
Range Province) site. 

Permeability of soil from the 0-2 inch depth was less than that from the 
2-k inch depth, regardless of treatment. A greater aggregation percentage in 
the 2-h inch depth, especially at the Milford site, may partially account for 
the observed differences. 

Percolation rates were not influenced by the qualities of water in this 
study during the first 30 minutes of each percolation trial. Therefore, to 
the extent that percolation governs infiltration, no bias resulting from water 
quality should arise if infiltrometer runs on these sites are held to 30 minutes 
or less. 

Effect of percolation on infiltration rates at these sites should increase 
as seeded species become established. During the time when chained and 
windrowed pinyon- juniper sites lack soil protective cover, surface conditions 
such as raindrop compaction and aggregate breakdown plus clogging of soil pores 
will result in increased overland flow and greater sediment production than 
control (or undisturbed) areas which still support some protective vegetative 
canopy (Gifford, unpublished data). In other words, increased soil permeability 
is no asset if water is unable to enter the soil surface. 

Regression equations for predicting intrinsic permeability of soil columns 
varied according to the quality of water. This type of variation may influence 
regression equations used for predicting infiltration rates on semiarid range- 
land sites, especially if various qualities of water are used during infiltration 
measurements. 




20' 


,A 


ft 

u 


^ 


fc 




u 
3 




0- 










"""""v^ 


10 


. 


u 

s 






2-4 0-2 

SOIL DEPTH , INCHES 



• 



Figure 1. Characteristics of soils under three pinyon-juniper eradication 
treatments at the Milford, Utah site. Dotted line represents 
untreated; broken line represents chaining with debris in place; 
solid line represents chain and windrow treatment. 




REFERENCES 

Bouyoucos, G. J., Hydrometer method for making particle size analysis 
of soils, Agron. J., 3k, k&k-k65, 1962. 

Reeve, R. C, Air-to-water permeability ratio, In Methods of soil analysis, 
I., Amer. Soc. Agron., Madison, Wisconsin, 19 65. 

Richards, L. A., Diagnosis and improvement of saline and alkali soils, 
U. S. Dept. Agr. Handbook No. 60, Washington, D. C, 195^. 

Schollenberger, C. J., Determination of soil organic matter, Soil Sci., 
59, 53-56, 19^5- 




* 



• 




# 



^r 



• 






Abstract. Permeability of surface soils from the 0-2 and 2-k inch 
depths at each of two sites in the pinyon- juniper type of southeastern and 
southwestern Utah were studied using disturbed soil samples. Three recent 
vegetation manipulation practices (chaining and windrowing, double chaining 
with debris left in place, and undisturbed) and three qualities of water 
^ dre studied in this respect. The chaining with windrowing treatment 

significantly increased permeability of surface soils from southwestern Utah. 
Significant differences in permeability were lacking between soils from 
double chaining with debris in place and undisturbed treatments. Permeability 
of surface soils from southeastern Utah provided a similar trend, though 
significant differences among treatments were not evident. 

Water quality influenced percolation only after approximately 30 
minutes. Multiple regression equations developed for predicting intrinsic 
permeabilities varied according to quality of water. 



# 







j 






<mmf 






£>. 



<F 






• 



# 



._:!