Bermudagrass and Weeping Lovegrass - Mixtures for Forage
| Tables: Table 1 Table 2 Table 3 Table 4 |
The study area was on the Noble Foundation Headquarters Farm one mile east of Ardmore, Oklahoma. Established rhizomatous bermudagrass of unknown variety was used. The soil was a shallow Durant loam with a pH of 6.4 and was typical of southern Oklahoma's upland soils. Phosphate and potassium levels were high because of past fertilization practices. Typical farm field equipment was used for seedbed preparation and planting.
The following primary seedbed treatments (T) in bermudagrass were used on 30-foot-square plots replicated three times in a randomized block design:- T 1 — moldboard plowed 6 to 8 inches deep during fall and moldboard plowed similarly the following spring
T 2 — moldboard plowed during fall, as was the first treatment, and tandem disked 2 to 3 inches deep the following spring
T 3 — no fall tillage and moldboard plowed during spring, as was the first treatment
T 4 — no fall tillage and offset disked 4 to 6 inches deep the following spring
Seedbed preparation was begun September 27 and completed April 7 the following spring.
Herbage residue was burned before primary tillage and all seedbeds were finalized by tandem disking 2 to 3 inches deep three times and firming three times with a rolling cultipacker. Each tillage treatment during a given season was completed in one day. Fall tillage treatments lay fallow from winter to spring. Spring tillage was done in two consecutive days and weeping lovegrass was planted the day of completion, April 7, 1970.
We used more tillage trips to complete the seedbed than normal in a usual farming operation because long-term weathering and rain were not part of the preparation. A usual farming sequence could reduce tillage trips about 50 percent.
"Common" weeping lovegrass was planted in 7-inch rows at 4 pounds of pure live seed per acre by using a drill equipped with a small-seed seedbox, but without press wheels. Ammoniated phosphate (N-P2O5-K2O) at 23-58-0 pounds per acre was banded with the seed on the freshly completed seedbed surface. Subsequent rains lightly covered and firmed the seed-fertilizer row. The objective of the first season was to establish the grass, and no additional fertilizer was applied to optimize production during the first season. Actual nitrogen at 43 pounds per acre was applied to all areas early the second season. Yield samples were harvested at the end of each season and bermudagrass and weeping lovegrass yields were separated the second season. Production did not warrant more sampling.
Both bermudagrass and weeping lovegrass can respond well to 50 to 100 pounds of actual nitrogen in areas with rainfall equivalent to that in the study/applied use area. Maximum split application rate of nitrogen may go as high as 150 to 200 pounds per acre, but there are few graziers who want to undertake that level of production and management. Excessive nitrogen levels tend to thin weeping lovegrass and increase bermudagrass stands. This response is especially evident during severe drought.
If upper-level forage yields had been part of the objective of this research, about 75 more pounds of nitrogen could have been applied during the first year and 60 more the second. Split applications totaling up to about 200 pounds of nitrogen per acre are appropriate on good soils. During a normal season in zones with 35 to 36 inches or more of rainfall, these nitrogen rates could more realistically optimize yields.
Conversion of nitrogen to pounds of forage was excellent. The first year, moldboard-plowed treatments produced 71 to 101 pounds of forage per pound of nitrogen; the second year, 67 to 87 pounds. The data were calculated without a check-plot deduction. The forage was not analyzed chemically but would have been rated medium to low quality because of its age at harvest, physiological maturity, and nitrogen conversion results.
Results and DiscussionWeeping lovegrass establishment and production in bermudagrass was best in any treatment involving moldboard plowing (table 1). There was little difference the first season because dry soil restricted production when weeping lovegrass represented 40 to 70 percent of the yield. Yields from moldboard-plowed seedbeds contained over 80 percent weeping lovegrass the second season, which was over three times that in the disked seedbed, and the grass was darker green and more vigorous. Moldboard plowing reduced bermudagrass's vigor and competitiveness even more to favor weeping lovegrass establishment and production. In other applied trials, heavy disking two to three times during winter produced effects similar to those with moldboard plowing in these trials.
There was not a statistical difference in yields during year one (table 1). During year two, bermudagrass yields in all moldboard-plowed treatments were statistically different at the 95 percent level of probability compared with yields in the disked treatments. Weeping lovegrass yields of the first two treatments were statistically different at the 90 percent level of probability compared with those of the disked treatment. Coefficient of variation percentage was 21, 35, 60, and 43 for the first to fourth data columns, respectively.
Other establishment observations illustrated that attempts to establish weeping lovegrass in bermudagrass without reducing the latter's vigor or preparing a seedbed have failed consistently. Early spring plantings made with hoe or disk drills emerged, but unrestricted bermudagrass competition soon killed the weeping lovegrass seedlings. The best weeping lovegrass stand achieved in undisturbed bermudagrass was from a late-summer broadcast planting. It was extremely thin and ineffective as a forage mixture. Similar stands were obtained by winter-feeding cattle weeping lovegrass hay, harvested in the seed stage, on grazed bermudagrass pastures. Late-summer plowing and seedbed preparation on bermudagrass followed by late summer weeping lovegrass planting also failed because of poor weeping lovegrass emergence and growth before winter. This method still offers the possibility of establishing weeping lovegrass in bermudagrass if it is done early enough to allow weeping lovegrass seedlings to become well tillered before winter.
 Figure 1. Typical response of weeping lovegrass to absence of starter fertilizer (left) and banded nitrogen-phosphate fertilizer (right). |
Weeping lovegrass planted in pure stands has a good response to nitrogen-phosphate fertilizer banded at planting. Starter fertilizer studies were initiated to evaluate the response from usual pasture rates when weeping lovegrass was planted in bermudagrass.
Study Area and MethodsTwo studies were conducted. The first was on the Noble Foundation Pasture Demonstration Farm located five miles northwest of Ardmore, Oklahoma. The soil is a shallow, low-phosphate Durant loam with a 6.5 pH. The second study was conducted on the Noble Foundation Red River Demonstration and Research Farm near Burneyville, Oklahoma, where the soil is a deep Eufaula fine sandy loam with high levels of phosphate and potassium and a 6.4 pH. The planting and fertilizer application methods were the same as those listed in the "Forage Yields of Bermudagrass – Weeping Lovegrass Mixtures" section of this publication.
Results and DiscussionAmmoniated phosphate starter fertilizer at 23-60-0 (N-P2O5-K2O) pounds per acre consistently gave positive results when on a prepared seedbed in a bermudagrass pasture. In a study on Durant soil, starter fertilizer plus 59 pounds of nitrogen per acre as a topdressing applied soon after emergence resulted in 1,414 pounds of first-season forage per acre, with 90 percent of the yield being weeping lovegrass. There was much more vigorous stand the second season (figure 1). Yield was 727 pounds per acre, with 67 percent of it weeping lovegrass, when only the postemergence nitrogen was applied and was 51 percent of the yield from the treatment with 23-60-0 pounds of N-P2O5-K2O per acre. Production was 687 pounds more per acre with starter fertilizer plus nitrogen, or 94 percent more than that with the nitrogen alone. Because of higher production, forage from starter-plus-nitrogen areas averaged 38.7 percent dry matter, which was 3.9 percent higher than that of the other treatment. These data were collected during a dry summer season.
| < Previous: Preface | Next: Forage Yields of Bermudagrass - Weeping Lovegrass Mixtures > |