Five Year‐Round Forage Systems in a Dairy Effluent Sprayfield

Abstract

In northern Florida, forages are grown in dairy effluent sprayfields to recover excess P. Our purpose was to evaluate five year-round forage systems for their capacity to remove P from a dairy sprayfield. The soil is a Kershaw sand (thermic, uncoated Typic Quartzipsamment). Systems included bermudagrass (Cynodon spp.)-rye (Secale cereale L.) (BR), perennial peanut (Arachis glabrata Benth.)-rye (PR), corn (Zea mays L.)-forage sorghum [Sorghum bicolor (L.) Moench]-rye (CSR), corn-bermudagrass-rye (CBR), and corn-perennial peanut-rye (CPR). Forages were grown for five 12-mo cycles. Effluent P rates were 80, 120, and 165 kg ha-1 cycle-1. The 5-cycle P removal was 67 kg ha-1 cycle-1 for BR, 54 kg ha-1 for CBR, 52 kg for CSR, 45 kg for PR, and 43 for CPR. Removal of P by winter rye was low. There were differences in system rankings among cycles primarily due to changes in the performance of perennial forages. In the first two cycles, BR had the greatest P removal (91 kg ha-1 cycle-1) due to high bermudagrass yield and P concentration. In the first cycle, P removal was lowest for PR (36 kg ha-1) because perennial peanut was slow to establish. In later cycles, P removal for BR declined because bermudagrass yield and P concentration declined. It increased for PR because peanut yield increased. The yield of corn in CBR, CPR, and CSR was consistently high but P concentration was modest (avg. 2.2 g kg-1). Sorghum produced moderate but stable yield and had low P levels (avg. 1.8 g kg-1). Effluent rate marginally affected the performance of most grasses. For P recovery in dairy sprayfields in northern Florida, the best warm-season forage would likely be a high yielding, persistent bermudagrass.

Use of Warm‐Season Grasses Managed as Bioenergy Crops for Phytoremediation of Excess Soil Phosphorus

“…During the establishment year (2007), elephantgrass yields were 95 and 32% greater than stargrass and switchgrass, respectively. Elephantgrass, stargrass, and switchgrass DM yields were consistent with previous reports under similar environmental conditions (Woodard and Prine, 1993; Mislevy, 2006; Newman et al, 2009a, 2009b; Woodard et al, 2007). Despite its high yield potential in other regions in the United States (Hall et al, 1982; Muir et al, 2001), switchgrass demonstrated poor adaptability to the soil and environmental conditions and only persisted during the first 2 yr of the study (2007 and 2008).…”

Phosphorus and Other Soil Components in a Dairy Effluent Sprayfield within the Central Florida Ridge

“…A detailed description of the pivot design and site layout has been reported by Woodard et al (2007) In their study, forages of five year‐round systems were grown in a dairy effluent sprayfield and irrigated with three effluent loading rates (low, medium, and high) over five consecutive 12‐mo cycles (1996–2001). The current study involves soil and soil water data collected over the last three 12‐mo cycles (1998–2001).…”

“…Results were inconclusive and will not be addressed. We think that the relatively small differences in soil P removed among systems (Woodard et al, 2007) were obscured by the large, variable amount of P present in the topsoil at the start of the project. Therefore, the effects of effluent rate, soil depth, and period (time) were analyzed across forage systems.…”

The Effect of Drought on Lignin Content and Digestibility of Tifton-85 and Coastal Bermudagrass (<i>Cynodon dactylon</i> L.) Hays Produced in Georgia

“…Notably, Tifton-85 offers hay production and heavy grazing potential in the year of establishment, whereas most other cultivars do not produce high yields until the 2nd year. In research trials, Tifton 85 has produced among the highest dry matter (DM) yields with greater quality when compared to other grasses under diverse management and environmental conditions [3,5,6,7,8], making it an ideal forage for dairy and beef in the southern US [2,7]. Since its release in 1993, Tifton 85 has been increasing in popularity among hay and cattle producers in the southern US, Central and South America, and Southern Africa.…”