Seeding Indian ricegrass in an arid environment in the Great Basin.

Abstract

Indian ricegrass [Oryzopsis hymenoides (R. & S.) Rickerl is a valuable forage species adapted to arid rangelands in temperate deserts. The purpose of this study was to test the influence of seeding date, depth, and rate on Indian ricegrass emergence and seedling establishment of acid scarified and intact caryopses (seeds). The seeding experiments were conducted on a wind eroding sand sheet of Lahontan age in western Nevada. During the initial year of planting, seeds of the cultivars Nezpar and Paloma Indian ricegrass were successfully established without pretreatment by acid scarification. Acid scarified seeds did not result in the established seedling stands in the field. Initial seedings were done in a season with prolonged moisture events with total precipitation about twice the average. Seedling stands of crested wheatgrass [Agropyron desertorum (Fisch.) ex Link Schult] as well as other exotic and native herbaceous and woody species were established during the first year. During the next 4 years crested wheatgrass seedlings were never again established. Indian ricegrass seedlings were established in 3 of the 4 subsequent years of seeding trials using a seeding rate of 0.8 seeds/cm of row and a seeding depth of 1 cm. Indian ricegrass seedling emergence was increased by either increasing the planting depth to 5 cm or by reducing the seeding rate to 0.03 seeds/cm of row. The ultra-low seeding rate resulted in a significant saving in seed cost.