Forage Yield and Nutrient Uptake of Warm-Season Annual Grasses in a Swine Effluent Spray Field

that ‘Coastal’ hybrid bermudagrass receiving 670 kg N ha 1 and 153 kg P ha 1 from swine effluent removed Five warm-season annual grasses were compared for dry matter an average of 382 kg N ha 1 yr 1 and 43 kg P ha 1 yr 1. (DM) yield and nutrient uptake alongside bermudagrass [Cynodon dactylon (L.) Pers.] on a Brooksville silty clay (fine, montmorillonitic, Adeli and Varco (2001) found that ‘Alicia’ bermudathermic Aquic Chromuderts) in a field that had swine (Sus scrofa) grass responded to increasing levels of effluent by ineffluent applied through a center pivot sprinkler system. Annuals creased DM yield and P uptake, up to a fertilizer N were browntop millet [Panicum ramosum (L.) Stapf in Prain], pearl equivalent of 448 kg ha 1, but the efficiency of nutrient millet [Pennisetum glaucum (L.) R. Br.], sudangrass [Sorghum birecovery in forage as a percentage of nutrient applied in color (L.) Moench], sorghum–sudan, [Sorghum bicolor (L.) Moench], effluent declined at greater rates of effluent fertilization. and crabgrass [Digitaria sanguinalis (L.) Scop.]. Grasses were tested This was consistent with a similar finding by Liu et al. in 3 yr (1999–2001), but results in 2000 were incomplete due to poor (1997) for ‘Russell’ bermudagrass. Macoon et al. (2002) growing conditions. In 1999 (establishment year for bermudagrass) also reported a threshold on forage growth, with relasorghum–sudan had the highest DM yield (18.9 Mg ha 1) and P uptake tively little effect from dairy manure N rates above 450 (50.3 kg ha 1). In 2001, sorghum–sudan DM yield (20.6 Mg ha 1) and P uptake (56.3 kg ha 1) were equivalent to established bermudagrass kg ha 1. (21.3 Mg ha 1 and 56.1 kg ha 1, respectively). In 2001 sudangrass and Higher plants require N and P in ratios between 6:1 pearl millet DM yields (17.4 and 15.7 Mg ha 1, respectively) were and 10:1, respectively (Sharpley and Halvorson, 1994). equal to and lower than sorghum–sudan, but P uptake of pearl millet Adeli and Varco (2001) found the N/P ratio of swine (49.5 kg ha 1) did not differ from sorghum–sudan, due to the high P lagoon effluent, collected from 1994 through 1996 (on concentration (3.2 g kg 1) in pearl millet. Browntop millet and crabthe same farm used in the present study), averaged grass DM yields and P uptake were less than those of sorghum–sudan 6.75:1. They also reported N/P ratios in harvested berin both years. Sorghum–sudan and pearl millet were higher in DM mudagrass from 6.8 without effluent to 11 with the highyield and P uptake than the other annuals in both years, equal to est level of effluent fertilization, and concluded that soil established bermudagrass, and therefore should be the most useful P accumulation would be expected for grass uptake in nutrient management hay systems in the southeastern USA. ratios 10. Nutrient uptake is not entirely a function of herbage yield but varies with cultivar, weather, soil, and manageS the 1980s, swine production in the USA has ment (Robinson, 1996). Brink et al. (2003) found that shifted away from large numbers of independent because of differences in nutrient concentration, P upgrowers toward fewer and larger farm operations and take per hectare by common bermudagrass was equal contract growers (Welsh and Hubbell, 1999). This industo or greater than that of several hybrids, despite lower trial shift resulted in concentrating larger numbers of annual DM yield. Annual forage grasses may be lower hogs per hectare and spreading their manure as fertilizer yielding and less responsive to applied nutrients, but over smaller areas. The value of swine effluent as fertilhave higher nutrient concentrations than perennial grasses izer is in its nutrient content, especially N. Even with (Robinson, 1996). Uptake of P by temperate species such good utilization of N, however, other manure nutrients, as ryegrass (Lolium multiflorum Lam.), grown as coolespecially P, can build up in manured soils. Accumulaseason annuals, may exceed that of bermudagrass betion of excess P to the point of runoff can pose an cause the typical N/P ratio in ryegrass may be lower than environmental risk. The need for better utilization of that in bermudagrass (6.2:1 vs. 10:1; Edwards, 1996). In N and P has focused research toward nutrient uptake a single spring harvest hay system, P, Cu, and Zn uptake by forages (Sims and Wolf, 1994). by annual ryegrass was greater than that by small grains In the lower South, perennial grasses receive more and annual legumes typically grown in the Southeast effluent than other forages. Burns et al. (1985) reported (Brink et al., 2001). The major limitation of cool-season (temperate) speUSDA-ARS, Crop Science Research Lab., Waste Management and cies, however, is that their growth occurs in late fall, Forage Research Unit, P.O. Box 5367, Mississippi State, MS 39762. winter, and early spring when weather and field condiMississippi Agric. and Forestry Exp. Stn. Journal Article no. J10284. tions often preclude hay harvest. The objective of this Mention of trade names or commercial products in this article is solely for the purpose of providing specific information and does not imply study was to determine and compare the DM yield and recommendation or endorsement by the USDA. This article was prenutrient uptake of five warm-season annual forage pared by USDA employees as part of their official duties, is not grasses and perennial common bermudagrass in the high copyright protected by U.S. copyright law and can be freely reproduced by the public. Received 26 Feb. 2003. *Corresponding author ([email protected]). Abbreviations: BMG, bermudagrass; BTM, browntop millet; CEC, cation exchange capacity; CRB, crabgrass; DM, dry matter; OM, orPublished in Agron. J. 96:1516–1522 (2004). © American Society of Agronomy ganic matter; PRL, pearl millet; SSH, sorghum–sudan hybrid; SUD, sudangrass. 677 S. Segoe Rd., Madison, WI 53711 USA