Strip-seeding white clover (Trifolium repens L.) in tall fescue (Festuca arundinacea Schreb.) pastures at 8 lbs/acre (4X) on only 25% of the field improved clover stands during the first growing season in the planted area compared to solid-seeding clover at 2 lbs/acre (1X) over 100% of the field. Clover volunteered into unplanted areas between the strips during the second year thus increasing the total acreage of clover. The stand percentage also remained higher for the 4X rate than the 1X rate through the second growing season. Strip-planting provides good clover establishment and requires less calibration precision, time, and fuel than conventional solid-seeding.
Nitrogen fertilizer costs have sharply increased making it difficult for producers to sustain adequate pasture productivity. Establishing clover in cool-season grass pastures helps reduce toxic endophyte infected fescue effects on livestock and helps reduce the need for expensive N fertilizer. Clover seed is typically broadcast or no-till planted in dormant grass sod across the entire pasture. In theory, planting clover over 100% of the pasture should result in an even distribution of clover over the field, but in practice, uniform stands of clover are seldom achieved. When clover is planted into an existing grass pasture, the resulting clover stand is considered good at 25% of the total pasture sward and is often distributed in patches.
When planting white clover at 1-3 lbs/acre, calibrating broadcast seeders is difficult and the recommended settings of no-till drills are often inaccurate. Because it is difficult to calibrate planters for low seeding rates and because clover planted at low rates often becomes established in only 25% of the pasture, it may be more cost-effective to plant clover at a higher seeding rate only in the areas of the field best suited for clover and let both vegetative growth and dispersal of seed by grazing animals spread clover into other areas of the pasture. In theory, 100% of the recommended clover seed for a field could be planted on only 25% of the area (4X rate), thus increasing the likelihood of establishing the same amount of clover as for planting the entire field. This would reduce time and calibration requirements while reducing labor and planting costs.
Two additional experiments were conducted within this On-Farm research effort to improve understanding of interseeding clover into fescue sod. These experiments were 1) herbicide suppression (metsulfuron or glyphosate) of tall fescue on establishment of white clover and 2) comparison of N fertilizer vs. clover for fall forage production.
1) Herbicide suppression of tall fescue on white clover establishment: Tall fescue (Festuca arundinacea Schreb.) is avigorous forage that forms a dense sod which makes establishment of small-seeded legumes difficult without sod suppression or sod disturbance. Metsulfuron herbicide is often used for weed control in bermudagrass pastures and is known to suppress tall fescue. It has less effect on established clover than fescue, but the effect on germinating clover is not well known. Glyphosate herbicide has been used to suppress fescue sod for renovating toxic fescue pastures, but the effect of low rates for sod suppression is not well documented. If very low herbicide rates can be used to suppress, but not reduce, fescue sod then establishment of white clover (Trifolium repens L.) may be enhanced while retaining the grass vegetative sod cover.
2) Yield response of tall fescue/white clover mixtures with and without N fertilizer when managed for stockpiled winter pasture: Tall fescue (Festuca arundinacea Schreb.) is often stockpiled for fall and winter grazing as an effective practice for reducing winter feeding costs. In four years of Extension demonstrations in Arkansas, producers saved an average of $20 per animal unit by grazing stockpiled fescue compared to the cost of hay. For stockpiling fescue, a N fertilizer rate of 50-60 lbs/acre is recommended during early September. In 2008, N fertilizer cost hit record high prices making producers less likely to fertilize pastures. Addition of clover to fescue pastures reduces the need for N fertilizer because well-established clover stands can fix substantial amounts of N. However, this fixed N must be recycled (primarily by grazing) to be available for use by the companion grass. With increased interest in adding clover to fescue pastures, a common question is “Will N fixed from clover in a fescue/clover pasture be adequate to promote a desirable yield of stockpiled pasture in fall without N fertilizer?”
The objective of the overall study was: to compare two strategies for establishing white clover into tall fescue grass sod which are planting white clover at a rate of 2 lbs/acre (1X) over the entire pasture vs. planting clover is strips to equal 25% of the pasture at a rate of 8 lbs/acre.
Additional Experimental Objectives:
1)To determine if metsulfuron or glyphosate herbicides applied at low rates to fescue sod in late winter would improve establishment of white clover.
2)To determine the forage yield response of tall fescue/white clover mixtures managed for stockpiled fall/winter pasture with and without N fertilization.
Strip-seeding vs. Solid-seeding: White clover (variety Patriot) was planted with a Haybuster 107 no-till drill in tall fescue pastures of approximately 40 acres each in Cleburne County, Arkansas on February 20, 2007 and in Van Buren County, Arkansas on February 20, 2008. Both fields were closely grazed before planting. Two planting strategies were used: 1) no-till plant white clover at the recommended seeding rate of 2 lbs/acre (1X) rate over the entire pasture area and 2) no-till plant white clover at a rate of 8 lbs/acre (4X rate) in three strips totaling 25% of the pasture area. The same total amount of clover seed was planted for each treatment. The strips were generally fifty to sixty feet wide and 500 to 600 feet long depending on paddock shape. Each treatment was replicated twice with paddocks of approximately 9-10 acres each. Each site was fertilized or limed according to soil test recommendations for overseeding clover. The Cleburne County site had adequate soil P and K, but was limed at 2 tons/acre in 2006 and the Van Buren County site only needed K and B which were applied in early spring of 2008. Paddocks were separated by electric fence and were grazed during March and April to reduce grass competition until the clover began emerging. When the clover began to emerge, cattle were divided into two herds with one herd assigned to each treatment. Each herd rotationally grazed the two replicates of the assigned treatment to prevent potential seed dispersal among treatments. Stocking rate was approximately one animal unit per acre. Cattle remained on the paddocks throughout the season and were removed only as necessary based on field conditions. Clover establishment was assessed at approximately monthly intervals along transects in each paddock using a 5×5 wire grid frame with 5”x5” squares. Fifteen counts were made along transects in each strip, in the unplanted areas between each strip, and along three transects in each solid seeded pasture. Presence of clover within the 25 grid squares was used to calculate percent stand.
Clover was also planted in Washington County in February, 2007, but an unexpected change in farm management occurred in the spring after planting making the project unuseable so it was abandoned with no data collected. A third project was successfully established on the Van Buren County site in February 2008 and is included in this report.
Clover was planted on the University of Arkansas Livestock and Forestry Branch Station near Batesville, AR in a larger project in 2006 to compare strip-seeding and solid-seeding of white clover as was outlined in the SARE proposal. Unfortunately, poor rainfall patterns caused stand failure due to drought conditions. Clover germinated but died by early summer due to extremely dry conditions. Therefore, no data were collected and no field day was held for that project.
Herbicide Suppression of Tall Fescue Materials and Methods:
Cleburne County: White clover was no-till planted in a closely grazed fescue sod at 2 lbs/acre on February 20, 2007. Immediately after planting, metsulfuron (Cimarron®) herbicide was applied at the rate of 0.33 oz/acre. Plot size was 7’ x 20’. Treated plots and the untreated check were replicated four times. Clover stand was assessed by counting the number of squares containing clover in a 5×5 wire frame. Counts were made in May, July, August, and September. Significance levels are reported at the P = 0.05 level of confidence.
Van Buren County: White clover was no-till planted in a closely grazed fescue sod at 2 lbs/acre on February 20, 2008. Three days after planting, glyphosate (Roundup®) herbicide was applied at the rate of 0, 4, 6, 8, 12, and 16 oz/acre. Treatments were replicated three times. Plot size was 10’ x 25’. Clover stand was assessed by counting the number of squares containing clover in a 5×5 wire frame. Counts were made in May, June, July, August, and September. Data are shown for the May, June, and September dates. Significance levels are reported at the P = 0.05 level of confidence.
Yield response of tall fescue/white clover mixtures with and without N fertilizer when managed for stockpiled winter pasture Materials and Methods: White clover (Trifolium repens L.) was planted by no-till drill in tall fescue pastures on two north-central Arkansas farms in February, 2007 (Cleburne County) and 2008 (Van Buren County). The fescue fields on each farm were approximately 40 acres in size and clover was planted in two treatments; 1) clover planted at a 4X rate (8 lbs/acre) in strips to equal 25% of the pasture area and 2) solid-seeded at a 1X rate (2 lbs/acre) across the entire pasture. Each treatment was replicated two times so that four equal-sized paddocks were established. Clover stand percentage was determined by counting the number of squares occupied by clover in a 5×5 wire frame over predetermined field transects. In early September 2008, cattle were removed from the pastures and half of each paddock received ammonium nitrate fertilizer applied at 50 lbs/acre of N and the other half was unfertilized. On October 13 (Wells farm), and October 20 (Swenson Farm), two 3’x20’ strips of forage were harvested in each paddock from within the 4X clover strips, from the unplanted area between the 4X strips, and from the 1X planted paddocks. Subsamples were dried for dry matter determination. Significance levels are reported at the P = 0.10 level of confidence.
Strip-seeding vs. Solid-seeding clover: Growing conditions during 2007 for the Cleburne County farm in spring were good, followed by an extremely dry summer when no measureable rain occurred for 35 days with temperatures 90º to 100 º F, but with good growing conditions returning in fall. In 2008 at the Van Buren County farm, growing conditions were near ideal for clover growth with above normal rainfall and relatively mild temperatures.
Cleburne County: First and second year results from the Cleburne County site showed a significant difference in clover stand percentage between strip-seeded and solid-seeded treatments. In 2007 mean clover occupancy rate was 65% (SD ±17) for strip-seeded compared to 42% (SD ±24) for the solid-seeded treatment (Figure 1). Percent occupancy of white clover for the November, 2007 was 2.4 times greater for the strip-seeded treatment than for the solid-seeded treatment. Total percentage of the field covered by clover for each treatment was not different at the end of the first growing season and averaged 25.2% for the strip-seeded treatment compared to 26.6 % for the solid-seeded treatment (Table 1). Clover in both treatments covered approximately ¼ of the field even though ¼ of the area was planted in the strip-planted treatment compared to 100% of the field for the solid-seeded treatment. In 2008, mean clover occupancy rate was 84% (SD ±7) for strip-seeded compared to 61% (SD ±15) for the solid-seeded treatment (Figure 2). On many farms, new clover stands are quite variable with clover establishing in a patchwork pattern across the field. In this project stand variability was much higher for the solid-seeded treatment compared to the strip-seeded clover treatment. In early 2008, clover began volunteering into the unplanted area between the strips and spread significantly by October. In October, 2008 after two growing seasons, total percentage of the field covered by clover (Table 1) was significantly higher for the strip-seeded treatment (92.2%) than for the solid-seeded treatment (70.2%). The large increase in clover percentage in the unseeded portions of the strip-seeded treatment fields is attributed to seed dispersal by grazing cattle and by vegetative spread of the clover. In spring of 2009, clover stand percentage averaged >88% in planted areas for both treatments.
N Fixation by Volunteer Clover Plants: A concern with volunteer clover spread by livestock is that seed are not inoculated and thus would not actively fix N for the forage system. In spring of 2009, clover plants were excavated from the strip-seeded treatment from the strips and from volunteer clover between the strips to determine nodulation for volunteer clover. Clover plants in both the strips and between the strips were nodulated and the interior of the nodules for both areas were observed to have a pink/red pigment indicative of active N fixation. The source of inoculum for the volunteer clover plants is not known.
Van Buren County: Weather and planting conditions in 2008 were near ideal for clover establishment and growth, resulting in excellent clover stands for both the strip- and solid-seeded treatments in Van Buren County. Percent clover stand in May averaged 95% (SD ±3) for the strip-seeded treatment and 53% (SD ±9) for the solid-seeded treatment (Figure 3). But by October, clover percentage for both treatments averaged 99%. By October, 2008, excellent clover stands were established over the entire planted area for both treatments. The total percent of the field covered was 26% for the strip-planted treatment and 97% for the solid-seeded treatment (Table 2). In this location and year where conditions were near ideal, either planting method produced good stands. Volunteer clover was not noted between the strips during 2008, but was appearing in spring, 2009 resulting in an increase in total acreage of clover (Table 2). This result is similar to that observed at the Cleburne County site. Clover in both treatments averaged >95% in planted areas for both treatments in spring 2009 (Figure 3).
Herbicide Suppression of Tall Fescue Results and Discussion: Treatment with metsulfuron suppressed the tall fescue, but also reduced clover establishment (Table 3). Visual observation indicated an increase in orchardgrass (Dactylis glomerata L.) and Kentucky bluegrass (Poa pratensis L.) and a suppression of fescue in treated plots. The average percent clover stand for the metsulfuron treated plots was 3% and was 61% for the untreated control. Results clearly indicate that metsulfuron herbicide should not be applied when attempting to establish white clover in grass pastures.
Treatment of the fescue sod with glyphosate caused slight suppression of tall fescue (data not shown), but did not significantly affect percent clover establishment (Table 4). Mean clover percent ranged from 79% to 88%. In July and August, crabgrass (Digitaria sanguinalis (L.) Scop.) invasion was more pronounced as glyphosate rate increased suggesting more fescue suppression. The lack of significant effect on clover percent may have been due to the near ideal growing conditions for clover that occurred in 2008. Results suggest no benefit to sod suppression with glyphosate on clover establishment under the conditions of this study.
Yield response of tall fescue/white clover mixtures with and without N fertilizer when managed for stockpiled winter pasture Results and Discussion: At the Cleburne County site (Figure 4) where clover had been established for two growing seasons, no significant differences in DM were measured between N fertilized and unfertilized areas within the clover strips planted at the 4X rate, in the areas between the clover strips that were not seeded in 2007, or in the area planted at the 1X clover seeding rate. This suggests that the N fixed by the clover at either seeding method was being adequately distributed by rotational grazing within the clover seeded areas and within the unseeded areas. Additionally, clover had spread into the unseeded areas between the 4X strips by the second growing season which further improved forage growth. Dry matter yield of the 4X strips and the 1X planted areas were lower than in the unplanted middle area probably due to the higher observed grazing pressure within the 1X and 4X areas having the highest clover stand. Clover stands in 2008 averaged 85% in the 4X strips and 62% in the 1X planted treatment.
At the Van Buren County site (Figure 5) where clover had been established for one growing season, DM yield of the N fertilized and unfertilized areas in the 4X clover strips was not different. Clover was the dominant forage within the 4X strips which resulted in no response to N fertilization. The solid-seeded clover areas and the middle area between the 4X strips did respond to N fertilizer but at the high N prices of 2008 ($45/acre) the response was not high enough to offset the high N fertilizer expense. At lower N fertilizer prices, the additional yield from N fertilization could be economical. Forage yield within the 1X clover seeded area was 487 lbs/acre higher than the unfertilized treatment. Although the clover stand was extremely good in the 1X seeded area, enough grass was present to respond to the N fertilization. Forage yield in the fertilized treatment in the unplanted area between the 4X clover strips had 737 lbs/acre greater DM yield than the unfertilized treatment. The area between the 4X strips did not contain volunteer clover since the clover had only been established for one growing season. Any forage yield response in the unfertilized treatment would have been due to the recycled N spread due to rotational grazing for one growing season. Clover stands in 2008 were very good and averaged 98% in the 4X strips and 82% in the 1X planted treatment.
At the high clover stand percentages obtained in this study, results suggest low or no DM yield response to N applied in fall to tall fescue/clover mixtures. Thus, fescue pastures with good clover stands can produce desirable stockpiled forage yields without N fertilizer.
Educational & Outreach Activities
Field Days: Field days were conducted in October, 2008 for both projects. A total of 100 producers from 17 counties attended the two field days. Topics presented included clover establishment results, planter setup and calibration, planting depth, clover management, effect of herbicide treatment on fescue suppression and clover establishment, and comparison of clover vs. N fertilizer for fall pasture yield.
Presentation at Regional/National Meetings: Five abstracts on results of this work were submitted to three regional/national meetings. Two posters and one talk were presented at the Southern Branch of the American Society of Agronomy meeting in Atlanta, GA in February, one presentation was given at the Southern Pasture and Forage Crop Improvement Conference in Lexington, KY, and one presentation was given at the American Forage and Grassland Council conference in Grand Rapids, MI. Results were also presented at the University of Arkansas Cooperative Extension Service State Faculty Conference in 2008, and at the Tri-State Forage Workers Conference (AR, OK, & TX) in Hope, AR in 2009.
J. A. Jennings*, K. J. Simon, D. J. Griffin, M. Mobley, J. Boyd, and M. S. Gadberry. 2009. An alternative planting strategy for establishing white clover in tall fescue pastures. In Agronomy Abstracts of the Southern Branch ASA. Madison, WI. Abstract ID# 51407
J. A. Jennings, K. J. Simon, D. J. Griffin*, M. Mobley, J. Boyd, and M. S. Gadberry. 2009. Yield response of tall fescue/white clover mixtures with and without N fertilizer when managed for stockpiled winter pasture. In Agronomy Abstracts of the Southern Branch ASA. Madison, WI. Abstract ID# 51419
J. A. Jennings, K. J. Simon, D. J. Griffin, M. Mobley*, J. Boyd, and M. S. Gadberry. 2009. Effect of herbicide suppression of tall fescue sod in winter with metsulfuron or glyphosate on white clover establishment. In Agronomy Abstracts of the Southern Branch ASA. Madison, WI. Abstract ID# 51421
J. A. Jennings*, K. J. Simon, D. J. Griffin, M. Mobley, J. Boyd, and M. S. Gadberry. 2009. Strip-seeding vs. solid-seeding for establishing white clover in fescue pastures. In proceedings of the Southern Pasture and Forage Crop Improvement Conference. Lexington, KY.
J. A. Jennings*, K. J. Simon, D. J. Griffin, M. Mobley, J. Boyd, and M. S. Gadberry. 2009. Comparing strip-seeding with solid-seeding for establishing white clover in tall fescue sod in Arkansas. In Proceedings of the American Forage and Grassland Council. Grand Rapids, MI.
Other Educational Efforts: The University of Arkansas Extension Animal Science Section started a statewide demonstration program in 2008 titled “300 days of Grazing”. The goal of the program is to demonstrate practices on farms that help producers achieve a 300 day grazing season to minimize feed and hay expenses. One of the eight program demonstrations is use of legumes in forage systems. The strip-seeding method developed through this SARE On-Farm Research Project is being used on Arkansas farms enrolling in the Legume demonstration of the 300 days Grazing Project.
Results from this project will also be presented at an in-service training for county agents titled “Managing Legumes in Grazing Systems” scheduled for February of 2010. A fact sheet titled “Interseeding Clover and Legumes in Grass Sod” is being developed including results of this project and will be distributed to county agents and producers.
In the Cleburne county site, clover stands were equivalent or better for strip seeding vs. solid seeding. In the Van Buren county site, strip seeding produced higher initial stands, but because of ideal conditions, the solid seeded treatment provided the highest amount of total clover by the end of the first year. For both locations, rotational grazing in the strip-seeded treatment provided the opportunity for cattle to spread ingested clover seed to unplanted areas between the clover strips as well as for vegetative spread of the clover to occur. This result makes it feasible to strip-seed clover and allow the rest of the pasture to “fill-in” under good management.
Results indicate that strip-seeding clover at a higher seeding rate into fescue pastures is a viable alternative to solid seeding at low recommended seeding rates. Additionally, this reduces the requirement for tedious calibration of imprecise planting equipment. Basically the producer can choose an approximate planter setting at a higher than recommended seeding rate and then plant strips of clover in areas where best establishment would be expected. This helps insure good establishment in the planted area. Rotational grazing and other management practices recommended for clover will promote clover growth and reseeding over time, thus increasing the percent stand over the entire field. If clover can be planted at the recommended rate per field in strips, instead of per acre as a solid seeding, and if producers can expect the same or better clover stands, it will be easier and faster to strip-plant clover at a higher rate. Increasing use of legumes in pastures will reduce N fertilizer need and will help maintain viability of livestock operations under pressure from increasing cost of fertilizer inputs.
Based on no-till drill rental ($10/acre) and fuel costs ($3/acre) for the period of this project, estimated savings for a 40 acre field were about $9.75 per acre for planting 25% of the field compared to planting 100% of the field. Savings in labor/time are not included in the estimate, but would increase the potential savings.
In the stockpiled fescue/clover experiment, N fertilization only increased forage yield on fescue/clover stands one year old, but not on the two-year old stand. Dry mater yield was acceptable even where no N was applied in the Van Buren County site suggesting that good stands of clover in fescue under similar management can produce acceptable stockpiled forage yields without N fertilization.
Field day surveys indicated that based on the field day information, 100% of attendees planned to use more clover on their farms and 78% planned to use the strip-planting method demonstrated in this project. Three producers who attended the field days strip-planted clover in fall of 2008. Five pastures were strip-seeded in February of 2009 as part of the Arkansas 300 day Grazing Demonstration Program.
Areas needing additional study
If this strip-seeding method could be used successfully to establish other legumes, both annual and perennial species, the impact would reach a wider range of producers. It is unknown if the hard seed characteristic and stoloniferous growth habit exhibited by white clover are required for other legumes to spread in a strip-seeded pasture. Other legumes may be better choices with fescue or bermudagrass or certain forage systems, but establishment of excellent stands in grass sod remains a challenge. Further study using this method with other legumes and in warm-season grasses is needed.