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.