Grazing and Haying CRP Lands
By Paul Nyren, Bob Patton, Brian Kreft, Kevin Sedivec and Jeff Printz


Contents

Introduction
Procedure

-Models used
Results and Discussion


Introduction

The Conservation Reserve Program (CRP) was initiated in 1985 to remove fragile, marginal land from crop production. Producers who enrolled were required to convert marginal acreages to perennial vegetation for a specified period. In North Dakota about 2.9 million acres of cropland were retired. Nationwide, over 36 million acres were enrolled. The objectives of the program were to reduce soil erosion, decrease sedimentation, increase herbaceous cover, improve water quality and provide financial incentives for participants. Shortly after the program began, researchers and land management agencies across the nation developed research studies to examine the benefits of the program and to determine how well it fulfilled its objectives.

In 1992 the Central Grasslands Research Extension Center (CGREC) began researching the effects of grazing, and haying CRP acreages in south central North Dakota. The objectives of this study are to determine:

1. The floristic composition and structure of CRP lands and to note changes in species composition due to grazing and haying over a 10-year period.

2. The production and utilization of CRP land vegetation under a seasonlong and a 3-pasture rotation grazing system.

3. The production and quality of hay from CRP lands.

4. The economic returns from grazing and haying CRP lands.

In 1997, the original CRP project at CGREC was completed. The CRP task force which was set up to administer the original project decided that the cool season grasses seeded on most CRP contract lands were more suited to a complementary type of grazing system. A new CRP grazing project was developed which would use the original CRP grazing systems as the early season pastures in a complementary grazing system. The CRP grazing season was shortened by 50% and the number of animals increased to maintain a similar stocking rate to previous years. By shortening the grazing season, the cool season grasses on the CRP site are rested during late July and August. When the animals were removed from the CRP acreages in mid-July, they were placed on native mixed-grass prairie for the remainder of the grazing season.

This research indicates the productivity and economic potential of grazing and haying marginal, highly erodible land, whether it is enrolled in CRP or not, and is designed to resolve some of the issues concerning the use of marginal lands in general.

  Procedure

Three hundred and seventy acres of privately owned land located approximately 2 miles northwest of Streeter, North Dakota, were used for this study. Annual precipitation for this area averages 17.8 inches. Soils on the study area are a Barnes-Buse on 9% to 15% slopes. The site is classified as highly erodible land (HEL) by the Natural Resources Conservation Service. This land was seeded in 1985 to a mixture of tall wheatgrass, intermediate wheatgrass, sweetclover and alfalfa. In 1992, the land was subdivided into a 135-acre seasonlong treatment and a 235-acre twice-over rotation grazing treatment. In 1998, the twice-over rotation system was changed to a 3-pasture rotation system in that the pastures were grazed once rather than twice. Ninety acres of CRP land adjacent to the grazing systems are cut for the hay crop each year. These acres were also seeded in 1985 to the same species used in the grazing study. Exclosures are set up on silty sites and are neither grazed nor hayed. These unused areas serve as a control treatment to which the grazed and hayed treatments are compared.

Forage production and utilization are determined using exclosure cages and a paired plot clipping technique on each range site in each grazing treatment pasture. Pastures are sampled before and after each rotation on the rotation system and at the beginning, and end of the grazing season on the seasonlong system.

From 1992 to 1997, 32 cow-calf pairs grazed the seasonlong pasture and 55 cow-calf pairs grazed the twice-over rotational system. In 1998, 50 cow-calf pairs grazed the seasonlong pasture, an increase in stocking rate of 56.3% over the previous 6 years. The twice-over rotation system became a 3-pasture rotation system in 1998 with 85 cow-calf pairs, a stocking rate increase of 54.5%.The livestock are weighed at the beginning and end of the grazing season and the average daily gain and gain per acre are calculated for each grazing treatment.

Each year, floristic composition and changes in the plant community are monitored by sampling percent frequency of occurrence, density per square meter and percent basal cover of all plant species on each range site using 50 frames placed along permanent transects. The amount of basal cover, litter and bare ground are sampled by using a 10-point frame. Fifty 10-point frames are read along each permanent transect. These data will indicate any changes in the amount of actual soil surface occupied by plants or covered by litter from previous years' growth. This is important when predicting the impact that haying or grazing might have on the vegetation's soil holding capacity. The data were checked for errors in plant identification and data entry by comparing the change in the abundance of each species between years for each site with Cochran's Corrected Chi Square Test and Fishers Exact Test using Calcfreq, a computer program which operates on Lotus 1-2-3. Analysis of variance was performed to detect changes in species abundance. An arcsine transformation was used to normalize frequency, and basal cover data.

Models Used

The model Abundance = year + treatment + (year x treatment) was used to test for interactions between years and treatments. The model Abundance = year was used to test for differences in abundance of species between years. A third model (Abundance year 2 - abundance year 1) = treatment was used to test for differences in abundance of species due to treatments. Fisher's least significant difference test was used to compare means. All tests were performed at a significance level of p=0.05.

 Results and Discussion

Table 1 shows the total annual forage production including the production of legumes, other forbs, and grasses, the seven-year average production, and the total percent utilization. With the exception of grass production in 1994, legume, other forbs, grass production, and total production for each year of the study were not significantly different (p 0.05) between treatments. Analysis of the 7-year average production showed differences between treatments for legume and other forb production. The 7-year average yields for grass and total production were similar between treatments.


Table 1. Total forage production and percent use on the Stutsman County site 1992-1998.
Treatment Legume
Yield

(lbs/Ac)
Forb
Yield

(lbs/Ac)
Grass
Yield

(lbs/Ac)
Total
Yield

(lbs/Ac)
%
Use

1992

Non-grazed
Seasonlong
3-Pasture rotation
245
152
526
0
77
14
1831
2030
1797
2076
2259
2337

40
40
1993
Non-grazed
Seasonlong
3-Pasture rotation
537
298
802
42
40
18
1369
2066
2126
1948
2404
2946

40
57
1994
Non-grazed
Seasonlong
3-Pasture rotation
588
747
1393
18
71
74
2052 b1
2572 a
1583 b
2658
3389
3050

39
55
1995
Non-grazed
Seasonlong
3-Pasture rotation
1130
529
1088
41
75
38
3608
2898
3104
4778
3503
4230

39
42
1996
Non-grazed
Seasonlong
3-Pasture rotation
399
264
471
17
64
17
3057
2153
2406
3472
2480
2893

43
54
1997
Non-grazed
Seasonlong
3-Pasture rotation
803
339
641
3
221
20
2708
1685
2425
3513
2244
3087

56
59
1998
Non-grazed
Seasonlong
3-Pasture rotation
557
367
697
39
51
6
2769
2066
2468
3366
2485
3170

50
49
7-Year Average
Non-grazed
Seasonlong
3-Pasture rotation
608
385
803
23
85
27
2485
2210
2272
3116
2681
3102

44
51
1Means followed by the same letter, or no letter, are not significantly different (p0.05).

Table 2 shows the type of grazing system, grazing season length, average daily gains, and the average gains per acre for all years of the study. In 1998, calf average daily gains were significantly different between treatments, with calves on the seasonlong pasture averaging 3.05 lbs/head/day while calves on the rotation system averaged 2.88 lbs/head/day. The 7-year average daily gain for calves was similar at 2.87 and 2.93 lbs/head on the rotation and seasonlong systems, respectively Cows grazing the seasonlong pasture in 1998 gained 2.00 lbs/head/day while cows on the rotation pastures had similar gains of 1.62 lbs/head/day. Long term average daily gains for cows grazing the rotation and seasonlong systems, were also similar at 1.43 and 1.58 lb/head, respectively. Seven-year average gains per acre were not significantly different between treatments for the cows. Long term calf gains/acre were also similar between treatments (Table 2).

Table 2. Livestock Production on the Stutsman Co. CRP Site in Southcentral North Dakota 1992-1998
 



Treatment



Year

Grazing
Season
Dates


Season Length

Cow-
Calf
Pairs
--------Cows------- -------Calves-------
Gains/A
(lb)
ADG
(lb)
Gains/A
(lb)
ADG
(lb)
              
Seasonlong 1992 5/15-9/18 126 32 1.46 43.61 2.87 85.72
Rotation 1992 5/15-9/18 126 55 1.43 42.17 2.69 79.33
 
Seasonlong 1993 5/14-9/17 126 32 2.46 a1 73.47 2.94 85.06
Rotation 1993 5/14-9/17 126 55 2.10 b 61.93 2.95 86.99
 
Seasonlong 1994 5/19-9/23 127 32 1.22 a 36.73 3.11 93.62
Rotation 1994 5/19-9/23 127 55 1.08 b 32.10 3.02 89.76
 
Seasonlong 1995 5/17-9/14 120 32 1.83 52.05 3.24 92.16
Rotation 1995 5/17-9/14 120 55 1.53 42.97 3.18 89.31
 
Seasonlong 1996 5/17-9/23 129 32 1.29 39.45 2.44 74.61
Rotation 1996 5/17-9/23 129 55 1.47 44.38 2.43 73.37
 
Seasonlong 1997 5/16-9/25 132 32 0.82 25.66 2.86 89.60
Rotation 1997 5/16-9/25 132 55 0.77 23.79 2.94 90.83
 
Seasonlong 1998 5/18-7/21 64 50 2.00 47.48 3.05 a 72.39
Rotation 1998 5/18-7/21 64 85 1.62 37.57 2.88 b 65.89
 
7-Yr Average Seasonlong 118   1.58 45.49 2.93 84.74
7-Yr Average Rotation 118   1.43 40.70 2.87 82.21
1Means followed by the same letter, or no letter, are not significantly different (P 0.05).

Production on the hayed treatment yielded 1.4 tons per acre in 1998. Table 3 shows the yield and nutrient content of the hay for the 7 years. A major concern for range managers and livestock producers planning to graze or hay CRP lands is how these stands will respond to grazing and haying pressures. In other words, will the species composition remain desirable?


Table 3. Summary results of CRP hay at the Stutsman Co. site, 1992-1998



Year


Yield
(Tons/Ac)


% Crude
Protein (CP)

% Acid
Detergent

Fiber (ADF)

% Total
Digestible
Nutrients (TDN)
1992 2.5 8.04 51.40 43.9
1993 1.7 8.31 47.39 48.5
1994 1.6 11.26 46.75 49.3
1995 2.2 10.63 50.57 44.9
1996 1.7 6.60 42.90 53.6
1997 1.2 9.04 46.81 49.2
1998 1.4 9.44 44.56 51.7
7-Yr. Avg. 1.8 9.05 47.20 48.7
TDN was determined using the Net Energy for lactation (NEL) formula for grass/legume forages: NEL = 1.0876-(0.0127 x %ADF); TDN=4.898 + (89.796 x NEL)

Table 4 shows the species composition changes that have occurred since 1992 as determined by sampling frequency, density and basal cover each year. While the table indicates changes in the seeded species, this may be due to natural succession.Total forage production and species composition changes to date are acceptable and suggest that these CRP tracts can be grazed successfully. Most land managers would prefer to see these highly erodible land (HEL) acreages remain in grass to protect them from soil erosion and to improve the overall quality of the soil. Gebhart et al. (1994) suggests that the perennial grass cover established under the CRP within the Great Plains has resulted in significant increases in soil organic carbon.

This 7-year study suggests that carefully managed highly erodible, marginal land is a source of economic potential for producers while preserving the resource.

Table 4. Changes in species composition (p 0.05) on Stutsman Co. CRP sites since 1992

  Silty Sites Overflow Sites
Species seeded in 1987 alfalfa
intermediate wheatgrass
smooth brome
tall wheatgrass
yellow sweetclover
alfalfa
intermediate wheatgrass
smooth brome
tall wheatgrass
yellow sweetclover
Decreased since 1992 alfalfa
annual foxtails
slender wheatgrass
tall wheatgrass
total plant basal cover
annual foxtails
Japanese brome
prickly lettuce
tall wheatgrass
total plant basal cover
Increased since 1992 Kentucky bluegrass
smooth brome
bare ground
Kentucky bluegrass
smooth brome
Fluctuated charlock mustard
Japanese brome
narrow-leaved goosefoot
horse-weed
intermediate wheatgrass and quackgrass
litter
yellow sweetclover
wild buckwheat
Russian thistle
field sowthistle
common dandelion
charlock mustard
common dandelion
field sowthistle
intermediate wheatgrass and quackgrass
narrow-leaved goosefoot
Russian thistle
wild buckwheat
yellow sweetclover
yellow wood sorrel
Increased on non-grazed blue lettuce
smooth brome
--
Increased on hayed bare ground
wild buckwheat


alfalfa
charlock mustard
horse-weed
western rock jasmine
wild buckwheat
Increased on seasonlong bare ground
common dandelion
scarlet gaura
western ragweed
yellow sweetclover
blue lettuce
common dandelion
Flodman's thistle
Kentucky bluegrass
tall wheatgrass
thyme-leaved spurge
yellow sweetclover
yellow wood sorrel
Increased on 3-pasture rotation common dandelion
total plant basal cover
yellow sweetclover
common dandelion
smooth brome
Decreased on non-grazed intermediate wheatgrass and
quackgrass
wild buckwheat
yellow sweetclover
--
Decreased on hayed intermediate wheatgrass and
quackgrass
tall wheatgrass
Decreased on seasonlong total plant basal cover
intermediate wheatgrass and
quackgrass
alfalfa
charlock mustard
wild buckwheat
Decreased on 3-pasture rotation wild buckwheat
wormwood
horse-weed
wild buckwheat

Paul E. Nyren, Director
North Dakota State University
Central Grasslands Research Center
4824 48th Ave. SE
Streeter, ND 58483
Phone: 701-424-3606
E-mail: grasland@ndsuext.nodak.edu


NDSU Central Grasslands Research Extension Center

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