Date of Award

12-2017

Degree Type

Thesis

Degree Name

Master of Science

Major

Plant Sciences

Major Professor

Renata Nave Oakes

Committee Members

Gary E. Bates, David M. Butler, Shawn A. Hawkins

Abstract

Alternatives to conventional nitrogen (N) fertilization on tall fescue [Schedonorus arundinaceus (Schreb.) Dumort., nom. cons. cv. Kentucky-31] and Bermudagrass [Cynadon dactylon (L.) Pers. cv. Vaughns # 1] were studied at the University of Tennessee Plateau Research and Education Center in Crossville, TN. Experimental period occurred from April-September 2016 and 2017, and the experimental design for each experiment was a completely randomized block design with six treatments and four replications per treatment (n = 24). For both experiments treatments were as followed: 1) control (CN) without N fertilization; 2) grass and white clover (WC) [Trifolium repens (L.) cv. Ladino-Will] at a rate of 2.2 kg ha-1; 3) grass and red clover (RC) [Trifolium pretense (L.) cv. Cinnamon Plus] at a rate of 4.5 kg ha-1; 4) grass and cowpea (CW) [Vigna unguiculata (L.) cv. 'Iron & Clay'] at a rate of 56 kg ha-1 5) fertilization with broiler litter (BL) at a rate of 4,500 kg ha-1; and 6) fertilization with ammonium nitrate (AN) at a rate of 67.2 kg ha-1. Differences between least squares means by treatments for botanical composition variables of legume and grass were tested for each species. For each analysis, the dependent variable was herbage mass (HM), crude protein (CP), acid detergent fiber (ADF) and neutral detergent fiber (NDF). There were significant year x treatment interactions for each species for all dependent variables. Red clover treatments resulted in highest for total HM for 2017, which was 1986 kg ha-1 more than other treatments in tall fescue. Red Clover treatments resulted in highest for HM for 2016, 4526 kg ha-1 more than other treatments and 2017, 4289 kg ha-1 more than other treatments in bermudagrass. Treatments containing BL and AN showed no differences for total HM and CP for 2016 and 2017 in both experiments. Treatments containing CW presented over-all lower results compared to other treatments. Utilizing these results in combination with cost associated with each source could assist producers in choosing a more sustainable source of N or a method of reducing their amount and annual-overall cost associated with conventional N.

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