ReducingEragrostis lehmannianapopulations by preparing seedbeds with unconventional tillage implements and seeding in a semiarid grassland

Abstract

AbstractThe invasion of Lehmann lovegrass (Eragrostis lehmannianaNees) in rangelands of Chihuahua, Mexico, has resulted in a need for revegetation to recover lost forage productivity. Thus, new knowledge on generating alternatives to improve these invaded grasslands is of great importance. This study evaluated seedbeds prepared with unconventional tillage implements and seeded with a grass mixture to reduce the plant density ofE. lehmannianawhile increasing the productivity of an invaded semiarid grassland of Chihuahua. The unconventional tillage implements were: a Rangeland Harrow, which was used to prepare the Striped Harrowing and Full Harrowing seedbeds; Rangeland Rehabilitator, which was used to prepare the Deep-Stingray Subsoiler seedbed; and a Tandem-type Aerator Roller, which was used to prepare the Double-Digging Aeration seedbed. An area without tillage was left as a control. The seed mixture was composed of blue grama [Bouteloua gracilis(Willd. ex Kunth) Lag. ex Griffiths var. Hachita] (25%); sideoats grama [Bouteloua curtipendula(Michx.) Torr. ‘6107 Kansas’] (25%); green sprangletop [Leptochloa dubia(Kunth) Nees var. Van Horn] (5%); weeping lovegrass [Eragrostis curvula(Schrad.) Nees var. Ermelo] (40%), and Columbus grass [Sorghum almumParodi] (5%). The experiment was conducted across 4 yr, and the evaluation started at the second year. Plant density and dry matter (DM) production were evaluated per species. In the control plot, the plant density ofE. lehmannianaincreased approximately 180% from the 2nd to the 4th year (18 to 50 plants m−2). The use of unconventional tillage implements for seedbed preparation and the inclusion ofE. curvulain the seed mixture decreasedE. lehmannianadensity in more than 50% of plots and increased DM production in around 100% of plots. Considering the whole experimental period, in all the prepared seedbed treatments,E. curvulahad the highest establishment and DM production of all the seeded species. The native speciesB. gracilis,B. curtipendula, andL. dubiahad poor establishment in all the prepared seedbeds.