Submitted to: Agronomy Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/9/2004
Publication Date: 1/1/2005
Citation: McLaughlin, M.R., Sistani, K.R., Fairbrother, T.E., Rowe, D.E. 2005. Overseeding common bermudagrass with cool-season annuals to increase yield and nitrogen and phosphorus uptake in a hay field fertilized with swine effluent. Agronomy Journal. 97:487-493. Interpretive Summary: Manure from concentrated swine feeding operations in the southeastern US is commonly flushed into lagoons and the effluent applied to farm fields. Repeated applications of effluent, however, can lead to soil buildup of excess phosphorus (P). To reduce soil P, farm managers often grow bermudagrass hay crops to take up P for removal from the field. Bermudagrass, however, only grows during warmer months (May to September) and is dormant the rest of the year. In the work presented here, during a 3-yr study conducted on a private hog farm in Mississippi, the nutrient uptake season in a common bermudagrass hay spray field was extended year round, hay yields and P uptake were increased, and pollution potential was decreased. This was accomplished by growing cool-season annual forage crops in the dormant bermudagrass. Planting cool-season annual forages in dormant bermudagrass, called overseeding, is often used in southern pastures to provide extra winter ground cover and earlier spring forage for grazing animals. In this study Common bermudagrass, grown for hay in a swine effluent spray field, was overseeded in the fall with cool-season annuals, including berseem clover, crimson clover, ryegrass and wheat. The annuals were harvested as hay the following spring, followed by summer harvests of Common. Growth of the cool-season crops did not reduce yield or P uptake of Common bermudagrass, but contributed extra forage in spring harvests, increased total annual hay yields by 6 to 16 percent and P uptake by 2 to 13 percent, and reduced soil P. Berseem clover provided the greatest benefit. Overseeding common bermudagrass with cool-season annual forages offers farm managers another way to boost hay yields and manage P in effluent spray fields.
Technical Abstract: Cool-season annual forages were overseeded in common bermudagrass [Cynodon dactylon (L.) Pers.] in a 3-yr study comparing DM yield and N and P uptake in a swine (Sus scrofa domesticus) effluent spray field. Berseem (Trifolium alexandrinum L.) and crimson (T. incarnatum L.) clovers, ryegrass (Lolium multiflorum L.), wheat (Triticum aestivum L.) and a standard practice (nonoverseeded) control were compared. Experimental plots were located in an existing stand of common bermudagrass on a Prentiss sandy loam soil (course-loamy, siliceous, thermic Glossic Fragiudults, Ultisols). The field received effluent for 6 years before the study and soil P was 232 mg kg-1in the top 2.5 cm at the start of the study. During the study, effluent equivalent to 1.3 Mg N and 229 kg P ha-1 was applied. Plots were overseeded each fall and annual species were harvested twice in spring for hay and bermudagrass and three times in summer. Spring harvests of ryegrass (3.8-5.3 Mg ha-1 yr-1) yielded more DM than crimson, wheat, and control treatments every year, but did not differ from berseem clover (3.1-4.6 Mg ha-1 yr-1) in 2 of 3 yr. Spring ryegrass and berseem consistently had P uptakes (11-16 kg ha-1 yr-1) that were higher than other treatments. The N uptake in spring harvests of berseem (71-128 kg ha-1 yr-1) was higher than other treatments in all 3 years. No treatment differences were observed in summer grass harvests throughout the study. At the end of the study soil test NO3 levels did not differ between overseeding treatments (mean, 0-5 cm = 35 mg kg-1), nor did Mehlich-3 P levels in the top 5 cm (mean = 83 mg kg-1). Overseeding treatments had no adverse affects on bermudagrass DM yield or nutrient uptake. Overseeding with berseem clover or ryegrass offers farm managers new choices in improving total hay yield and nutrient management of common bermudagrass in southern US spray fields.