Effect of N fertilizer on the productivity and nutritive values of perennial grass mixtures in the alpine region of Qinghai-Tibetan Plateau, China

Abstract

. 2005 Effect of N fertilizer on the productivity and nutritive values of perennial grass mixtures in the alpine region of Qinghai-Tibetan Plateau, China. Can. J. Plant Sci. 85: 361-368. A study was conducted on grass mixtures that included smooth bromegrass (SB) + drooping wild ryegrass (DW), smooth bromegrass + Siberian wild ryegrass (SW) + crested wheatgrass (CW) and smooth bromegrass + Siberian wild ryegrass + drooping wild ryegrass + crested wheatgrass in the alpine region of Qinghai-Tibetan Plateau. The study was conducted from 1998 to 2000 to investigate the effects of N application rates and growing year on herbage dry matter (DM) yield and nutritive values. Herbage DM production increased linearly with N application rates. The effect of N application on DM yields was greater (P < 0.05) in the 2nd and 3rd production years than in the establishment year. Dry matter yields of SB + SW + CW and SB + SW + DW + CW can reach as high as 15 000 kg ha -1 at 345 kg ha -1 N rate in the 3rd growing year. With increased N application rates, crude protein (CP) contents and 48 h in sacco DM degradability of grasses increased (P < 0.05). No effect (P > 0.05) of N application was detected on organic matter (OM) and acid detergent fibre (ADF) concentration. It can be concluded that for increased biomass production in the alpine region of the Qinghai-Tibetan Plateau, a minimum of 345 kg N ha -1 should be applied to grass stands in three split application of 115 kg N ha -1 , in early June, early July and late July.

Botanical Composition and In Situ Dry Matter Degradability of Legume- Grass Mixture Pasture Fertilized with Different Amounts of Nitrogen

“…Linear and quadratic regression indicated a significant relationship between N fertilizer rate and forage DM yield for clovergrass mixture. Similar findings results were reported by Dong et al (2005) for perennial grass mixture. Besides, Malhi et al (1986) reported that annual fertilizer N applications sustained more dry matter production than single N applications for bromegrass.…”

“…Similar findings were stated by Reid et al (1966) for Orchardgrass, Van Vuuren et al (1991) for perennial rye grass, Messman et al (1992) for brome grass, Dong et al (2005) for perenniel grass mixtures. In contrast, Calder and Mcleod (1968) reported that nitrogen applying in amounts of 52 and 103 kg/ha to permanent pasture resulted in a decrease of digestibility by 2.15 and 2.23%, respectively.…”

“…Recently, researchers have shown that nitrogen fertilizer application is beneficial to production in terms of DM digestibility. Little information on fertilizer management of native legume-grass mixtures is available (Dong et al, 2005).…”

The effects of weed competition, clipping and fertilization treatments on the productivity of cultivated meadows on the Qinghai-Tibetan Plateau

“…It is characterized by low temperatures and high altitude, and its high temporal variability in temperature and precipitation directly affects plant productivity (Dong et al 2005a;Xue et al 2005;Gu et al 2009). This rangeland supports nearly 41 million Tibetan sheep and 13 million yaks, and extends over 130 million ha (Long et al 1999).…”