Switchgrass recruitment from broadcast seed vs. seed fed to cattle.

Abstract

Fecal seeding by livestock may be an effective, low-cost means of rangeland restoration. We compared recruitment of switchgrass (Panicum virgatum L.) from seed fed to cattle and deposited in dung to that of broadcast-seeded plots receiving a comparable number of unfed seed. Although germinability of seed passed through livestock (52 to 62%) was reduced relative to that of broadcast seed (85 to 91%), recruitment of switchgrass from seed in cattle feces was equal to or superior to that of broadcast seed in terms of establishment (frequency of occurrence and density), plant growth and final plant size. The frequency of plot with emerging switchgrass plants ranged from 62 to 100% when seeds were delivered in feces, but only 2 to 40% when seeds were broadcast. After 1 year, the frequency of occurrence of switchgrass plant in fecal vs. broadcast-seeded plot was comparable for autumn trials. However, evaluations 1 year after the spring trials continue to result in higher frequency of plot with switchgrass plant from seed delivered in feces than of broadcast seedings (56 vs. 4% for May 1990, P < 0.05; and 90 vs. 51% for May 1991, P less than or equal to 0.01). Enhanced plant recruitment on fecal-seeded plots occurred even though broadcast-seeded plots received 1.5 to 1.7 times more pure live seed (PLS). Plants on fecal-seeded plots had a greater plant size score (based on visual ratings of height, culm density, and biomass) than plants on broadcast-seeded plots (P < 0.05 for May seedings; P < 0.05 for October 1990; P < 0.10 for October 1991). Results suggest significant advantages of fecal seeding over conventional broadcast seeding in terms of seedling emergence, establishment and growth.