| Abstract/Contents: | "Haying removes soil nutrients in manured fields. Grass hays were compared for nutrient removal in an effluent spray field. Eastern gamagrass (Tripsacum dactyloides L.), indiangrass [Sorghastrum nutans (L.) Nash], johnsongrass [Sorghum halepense (L.) Pers.], switchgrass (Panicum virgatum L.), and common and Coastal bermudagrass [Cynodon dactylon (L.) Pers.] were grown on a Brooksville silty clay (fine, montmorillonitic, thermic Aquic Chromuderts) in Mississippi. The field produced johnsongrass hay and received swine (Sus scrofa domesticus) effluent (estimated 371, 61, and 629 kg ha-1 yr-1 of N, P, and K, respectively) for 8 yr before the study. In the 3-yr study, common bermudagrass produced 4.6 to 15.0 Mg dry matter (DM) ha-1 yr-1 and was not different from Coastal bermudagrass (5.2 to 13.7 Mg ha-1 yr-1). Highest annual DM yields of johnsongrass, eastern gamagrass, switchgrass, and indiangrass were 9.7, 9.5, 9.1, and 5.5 Mg ha-1 yr-1, respectively. Highest annual uptakes of N by common and Coastal bermudagrass, johnsongrass, eastern gamagrass, switchgrass, and indiangrass were 314, 280, 188, 181, 167, and 106 kg ha-1, respectively. Respective highest annual uptakes of P were 44, 35, 23, 21, 19, and 14 kg ha-1. Uptakes of Ca, K, Mg, Cu, Fe, Mn, and Zn were as high or higher in common bermudagrass as in the other grasses. Dry matter yield of common bermudagrass was correlated (r = 0.99, P = 0.0001) with uptakes of N, P, and K. Replacing johnsongrass with bermudagrass would increase annual DM yield in the field 155 to 249% and P uptake 194 to 259%." |
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