Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: November 4, 2007
Publication Date: November 8, 2007
Citation: Read, J.J., Brink, G.E., Adeli, A. 2007. Effect of swine effluent rate and timing on nitrogen utilization and residual soil nitrogen in common bermudagrass [abstract]. Agronomy Abstracts. Paper 327-6, CD-ROM. Technical Abstract: Frequent summer precipitation may delay the application of swine effluent to bermudagrass [Cynodon dactylon (L.) Pers.] until late summer or early fall. Because this period is marked by declining growth of this warm-season grass, late-season applications of effluent increase the potential for excessive N accumulations in soil and nitrate leaching. Field studies were conducted in 2000 and 2001 to determine the effects of irrigation rate and timing on crop N utilization and residual soil nitrate. Effluent was applied at 10 and 20 cm/ha in four treatment periods. Soil was sampled in fall and spring to estimate the amount of N not recovered by forage. Application of 20 cm effluent in April-May, June-July, and April-Sept treatments resulted in the greatest annual forage yield of about 11.5 Mg/ha in 2000 and 18.1 Mg/ha in 2001; the corresponding values for N uptake were 306 and 335 kg/ha. Averaged across effluent rates, the Aug-Sept treatment had the lowest N utilization efficiencies of 55% in 2000 and 34% in 2001. Application of 20 cm effluent in Aug-Sept treatment increased residual soil nitrate, particularly in fall 2000 and spring 2001. Nitrogen in swine effluent applied in fall is less likely to be utilized by common bermudagrass due to either dry summer conditions or declining growth rate.