On-Farm
Research

Research Results

Potential for No-Till Interseeding & Banded Herbicide for Pasture Improvement

Central & Northern PA farms, 2003-06

Ron Hoover, On-Farm Research Coordinator

Abstract

Improvements in pasture forage productivity often can result in per-animal or per-acre increases in animal production. A pasture renovation study was initiated during 2003 on six private dairy or livestock farms in central and northern Pennsylvania to investigate the potential for improving pasture productivity by establishing new or improved forage species. Plots of grass or grass/legume mixtures were no-till drilled during August 2004 into pastures where broadcasted or banded applications of non-selective herbicide were applied from a spray boom that was mounted on the front of the drill. Banding herbicide was investigated for potential benefits that include the ability to renovate pasture without killing all existing plants, a more shorter downtime between planting and being able to graze livestock, and the reduction in the amount and cost of herbicide needed to get new seed established. One replication of twenty-one plots was drilled at each farm. Measures of performance included rate of establishment, stand density before and after several winters, and forage dry matter production. As a group, the ryegrasses and festuloliums established more rapidly and were more productive during early 2005 than orchardgrasses, fescues, meadow brome, and alfalfas. Extremely variable rainfall between the farms and inability to synchronize grazing events with farm owners prevented the collection of useful forage dry matter production during the latter half of 2005 and all of 2006. All entries overwintered well from 2004 through 2006; however, these first two winters were relatively mild and winterhardiness of the forages was relatively untested. The recent 2006/2007 winter was the most severe. Additional measurements of stand density will be taken during spring 2007 to determine how well entries are able to survive a more typical Northeastern winter.

Introduction

A large percentage of open land in the northern areas of Pennsylvania is not well suited for row crop production due to land use limitations that include moderate to excessive slopes, shallow soils, variable drainage, and excessive stoniness. Many dairy and livestock producers in the region have adopted some form of grazing to make use of those acres. Most are well aware of the need to maintain forage quality and yields through rotational grazing. However, few regularly introduce new plant materials via pasture rotation, reseeding, or interseeding for the purpose of further improving the pasture and animal production on their farms. Tillage as a part of pasture renovation on many of these sites can create soil erosion problems. Further, wholesale tillage that destroys all plants prior to renovation also results in a lengthy downtime until grazing can again occur. No-till drilling can minimize much of the soil loss problem; however, herbicide is often necessary to control some or all existing vegetation prior to successful no-till planting. Complete control of vegetation with herbicide likewise can result in long downtime until grazing commences. Of interest to the research team and farmers was the ability to enable satisfactory establishment of new seedlings through partial control of existing vegetation with band applications of herbicide.

Methods

Seven farmers in five central and northern Pennsylvania counties hosted this study. Soil tests of pastures were conducted during spring 2003 and lime was applied to adjust soil pH to 6.5 - 7.0. Phosphorus and potassium levels were adequate for forage establishment. The project was divided into two smaller studies at each farm. The first consisted of an evaluation of banding herbicide (glyphosate with 4.5 pounds per gallon acid equivalent, applied at 44 ounces per treated acre) with seven monocultures or binary mixtures. The other was a variety trial that contained eleven grasses that were drilled immediately after herbicide was broadcasted. A ten foot wide no-till drill with openers on 7.5 inch spacing was fitted with a 30-gallon spray tank, an electrically operate pump, and a spray boom mounted ahead of the no-till coulters. The boom was configured with one nozzle centered on each double-disk opener. Boom height was maintained so that 3.5 to 4 inch wide bands were sprayed when equipped with 40-degree even spray flat fan nozzles and an evenly broadcast pattern resulted when 110-degree flat fan nozzles were used. The drill was calibrated for the numerous entries to be interseeded. Seeding rates were according to local recommendations. Plots consisted of a single pass of a ten-foot no-till drill that ranged from 80 to 120 feet in length. Only one replicate of each treatment was planted at each farm. Nitrogen fertilizer as ammonium nitrate was applied periodically during the 2005 and 2006 growing seasons. Three separate applications of fifty pounds nitrogen per acre were made during a relatively dry 2005 growing season while four applications at the same rate were made during the wetter and more favorable cool-season grass growing season of 2006. Fertilizer was distributed via a shoulder-mounted spinner spreader. Visual observations were taken each fall and spring and plots were scored on a 1 to 10 scale for stand density with 10 being best. After the first or second grazing event, depending on the farm, a walk-behind power mower was used to clip refused forage on part of the plots to 2.5 inch high stubble. Prior to the second or third grazing, 0.5 square meter samples of forage were cut to a 2.5 inch height, collected, dried, and weighed. These estimates of dry matter were collected from the grass monoculture seedings planted behind broadcast applications of glyphosate. These data were subjected to analysis of variance and differences between means were determined by Duncan New Multiple Range test when appropriate.

Results

The moist conditions at the time of seeding and during the subsequent two months were ideal for germination and establishment of forages. While most plots at six farms looked good going into the winter, the plots at one farm did not establish well, probably due to poor seed placement. Plots at this farm were abandoned. Initial observations of the banded herbicide plots were very encouraging. While sprayed strips of existing vegetation were destroyed by the herbicide, the environmental conditions that were favorable for germination and establishment in September and October were also very favorable for recovery and spreading of the partially and non-treated plants. Large areas of many banded plots were had recovered remarkably well by spring 2005. Since the contribution to dry matter from existing plants was comparable or greater than that from the new seedlings in many plots, the banded herbicide plots were not sampled for dry matter production during 2005 or 2006. Visual observations of the plots during November 2004 revealed that the perennial ryegrasses (PRG) and festuloliums (FEST) established most rapidly, as measured by plant density in the row and fall growth vigor. The tall fescues (TF) were somewhat slower and these were followed closely by the orchardgrasses (OG). There was some alfalfa, but not nearly as much as was expected by that time. There was very little birdsfoot trefoil (BFT), meadow fescue, and meadow brome. The kura clover did not establish at any location. The winters of 2004/05 and 2005/06 were milder than average for the region. In 2005, dry early spring conditions resulted in soil moistures less than normal and the lack of rainfall through April and May resulted in slightly-to-greatly reduced dry matter production. Dry matter measurements from pastures prior to the second or third grazing (depending on host farmer’s initial spring turnout and grazing intensity) were very much reduced due to the lack of moisture (Table 1). Although yields for this one regrowth cycle ranged widely between the grass entries, the differences were not significant.

Table 1. Spring 2005 dry matter yields from grasses seeded where glyphosate was broadcasted.
Species Variety Dry matter yield*
    --pounds per acre--
Orchardgrass Tekapo 655
Extend 778
Perennial ryegrass Grand Daddy 929
Mara 1148
Tivoli 1134
Festulolium Perun 985
Spring Run 1045
Tall fescue Bronson 924
Barolex 764
Meadow fescue Laura 794
Meadow brome Paddock 945

* differences between entries were not different as determined by analysis of variance (p<.05).

Additional dry matter yield data were not collected during the summer and fall of 2005 due to the persistent dry weather.  Overall, rainfall during 2006 was greater, however the distribution between participating farms was very uneven.  Grazing cycles were likewise very asynchronous between farms, preventing the acquisition of useful dry matter production data.

The plot conditions scores during November 2005 were very different between the entries (Table 2).  The plots of PRG and FEST entries, as a group, were in better condition after the first year than those of OG and TF.  The meadow fescue and meadow brome at most locations and for the overall average had the lowest score of the eleven grass entries in part B.  The one exception was inconsistent stands of Perun FEST across the six locations.

Table 2. Visual estimates of relative plot condition after the first year of grazing (November 2005).
Species Variety Condition score*
    (0 to 10 scale, 10 is best)
Orchardgrass Tekapo 6.6 c
Extend 7.2 a b c
Perennial ryegrass Grand daddy 8.3 a
Mara 8.2 a b
Tivoli 8.0 a b
Festulolium Perun 6.1 c d
Spring Green 6.9 b c
Tall fescue Bronson 6.4 c
Barolex 6.4 c
Meadow fescue Laura 4.8 d
Meadow brom Paddock 6.0 c d

* differences between means follwed by the same letter are not significantly different as determined by Duncan's new multiple range test (p<.05).

The plot condition scores during the early spring green-up of 2006 are listed in Table 3.  The relative rankings did not change very much.  There were a few exceptions.  Tekapo OG and Tivoli PRG did not look as good in the spring as they did during the previous fall.  Paddock meadow brome also had a slightly lower score in the spring compared to its previous fall rating.

Table 3. Visual estimates of relative plot condition during the spring of the second year of the study (April 2006).
Species Variety Condition score*
    (0 to 10 scale, 10 is best)
Orchardgrass Tekapo 5.2 c d
Extend 7.1 a b
Perennial ryegrass Grand Daddy 8.0 a
Mara 7.8 a
Tivoli 7.1 a b
Festulolium Perun 6.2 b c
Spring Glen 6.9 a b
Tall fescue Bronson 6.9 a b
Barolex 6.4 b
Meadow fescue Laura 4.8 d
Meadow brome Paddock 5.3 c d

* differences between means followed by the same letter are not significantly different as determined by Duncan’s new multiple range test (p<.05).

Plot condition scores during November 2006 were similar or slightly lower when compared to the spring scores for nearly all entries (see Table 4).  However, Tekapo OG and Barolex TF were found to have slightly improved scores from the beginning to the end of the 2006 growing season.

Table 4. Visual estimates of relative plot condition during the fall of the second year of the study (November 2006).

Species

Variety

Condition score*
     (0 to 10 scale, 10 is best)
Orchardgrass Tekapo 5.4 d e
Extend 6.6 a b c
Perennial ryegrass Grand Daddy 7.2 a b
Mara 7.4 a
Tivoli 6.9 a b c
Festulolium Perun 6.3 b c d
Spring Green 6.6 a b c
Tall fescue Bronson 6.0 c d
Barolex 6.8 a b c
Meadow fescue Laura 4.6 e
Meadow brome Paddock 4.8 e

* differences between means followed by the same letter are not significantly different as determined by Duncan’s new multiple range test (p<.05).

Conclusions

The anticipated benefits from band spraying herbicide during renovation instead of broadcasting it were threefold.  Leaving some vegetation between newly drilled rows should reduce soil erosion during establishment.  A second anticipated advantage was a reduction in the downtime between planting and the restart of grazing.  The third was that less herbicide would be needed to accomplish the task.  Neither of the first two ideas resulted in benefits to the system.  Leaving half the existing vegetation alive did not improve soil conserving properties of the sites; a dead sod during the first year after being killed serves as a very effective mulch and effectively holds soil in place.  While there was more vegetation on plots that were strip killed the previous fall, both strip and broadcast killed plots were ready to graze at about the same time in the spring.  Surprisingly, some of the older, well established bluegrasses, clovers, orchardgrasses, and fescues did not die.  They were able to recover from the broadcast applications of glyphosate.  The recovery was extensive enough that by the second season, the contribution from the volunteer and non-controlled plants was as great as or greater than that from drilled species.  The savings in cost of the herbicide was probably not worth the difficulty involved making a band application system to fit a drill.