Spring‐Applied Nitrogen and Productivity of Cool‐Season Grass Seed Crops

Abstract

Understanding effects of spring N rates and application timing on seed yield and yield components of cool‐season grass seed crops will help improve N fertilization management. We tested effects of 90, 120, 150, 180, and 210 kg N ha−1, applied at the double‐ridge (DR) stage of development on seed yield and yield components of Chewing's fescue [Festuca rubra L.subsp. fallax (Thuill.) Nyman; syn. F. rubra var. commutata Gaudin], tall fescue (F. arundinacea Schreb.), and orchardgrass (Dactylis glomerata L.) in 1985 and 1986. In a second study, effects of 120 kg N ha−1, applied either at DR, at spikelet initiation (SI), or equally split between the two stages, were tested. Soil type for both experiments was fine‐silty, mixed, mesic Aquultic Argixerolls. Chewing's fescue seed yield was not affected by N rates in 1985 and was the greatest at 90 kg N ha−1 in 1986. Averaged across years, orchardgrass seed yield was the greatest at 120 kg N ha−1. Nitrogen rates did not affect seed yield of tall fescue. Seed yield of all species was most closely correlated with the number of seeds produced per unit area. Seed number per unit area was primarily correlated with the number of seeds produced per panicle in all species; in orchardgrass, the number of panicles per unit area also contributed to total number of seeds produced. Seed yields of all three species were the greatest when N was applied at DR. Split application was not better than application of all N at DR or SI. We concluded that in western Oregon spring application of 90 kg N ha−1 for Chewing's fescue and tall fescue and 120 kg N ha−1 for orchardgrass should be adequate for seed production. For all species, spring N should be applied in one application at DR.

Planting Density and Irrigation Timing Affects Cleistogenes songorica Seed Yield Sustainability

“…The SEM indicated that the number of fertile tillers m −2 contributed most to seed yield. The present findings differ from previous reports indicating that seed number spike −1 and seed weight were the most important yield components for seed yields of perennial ryegrass and orchardgrass (Hebblethwaite and Ivins, 1977; Young et al, 1996, 1999). However, the results of the current study are similar to those of several studies showing that spike number unit area −1 was the most important yield component for seed yield in red fescues ( Festuca rubra L.) (Meints et al, 2001), smooth brome ( Bromus inermis L.) (Wang et al, 2004), and perennial ryegrass (Deleuran and Boelt, 2009).…”

North American Bristlegrass Seed Yield Response to Nitrogen Fertilizer and Environment

“…This phenomenon was also observed by Young et al (1999), who reported that N addition had a positive eff ect on orchardgrasss (Dactylis glomerata L.) seed yield and total dry weight of harvested reproductive structures (registered before threshing); however, tall fescue (Festuca arundinacea Schreb.) By contrast, seed production had a negative (−69%) relationship with the proportion of fi lled seed at Beeville in November 2005.…”

“…However, this variable was not related to seed yield at Beeville in May and October 2006. This phenomenon was also observed by Young et al (1999), who reported that N addition had a positive eff ect on orchardgrasss (Dactylis glomerata L.) seed yield and total dry weight of harvested reproductive structures (registered before threshing); however, tall fescue (Festuca arundinacea Schreb.) seed production was unaff ected while increasing total dry weight of those structures, indicating that seed yield is not necessarily related to the total dry weight of the harvested material and that other seed yield components may be responsible for seed yield changes.…”

Impacts of Fall Nitrogen Application on Seed Production in Leymus chinensis, a Rhizomatous Perennial Grass

“…As one of the most important nutrients affecting seed yield in grasses (Rolston et al, 1985), N application has a substantial effect on seed number per inflorescence and seed weight (Hebblethwaite and Ivins, 1977; Young et al, 1996, 1999; Cookson et al, 2001; Wang et al, 2010) but no influence on inflorescence number (Hampton and Hebblethwaite, 1983; Young et al, 1996). In the present study, the timing and rate of fall N applications not only had a significant effect on seed number per inflorescence and 1000‐seed weight but also on inflorescence number (Table 1).…”