Effects of fertilizer on plant biomass distribution and net accumulation rate in an alpine meadow in Central Himalaya, India

Abstract

The objective of this study was to observe the effect of nitrogen application on the plant biomass and rate of net aboveground accumulation in an alpine grassland of Central Himalaya, dominated by the grass Danthonia cachemyriana, Jaub. and Spach. Nitrogen was applied in the form of urea at the rate of 250 kg ha⁻¹ in late May 1984 and late April 1985. Aboveground and belowground biomass from both fertilized and control plots were measured from a day before fertilization and at 30-day intervals throughout the growing season in 1984 and 1985. The aboveground net accumulation (ANC) in 1984 was 409 g m⁻² for the control and 450 g m⁻² for treated plots, and in 1985 it was 382 g m⁻² in the control and 458 g m⁻² in the treated plots. The differences in ANC between control and fertilized plots were significant at P0.05 for 1984 and P0.01 in 1985. The belowground net accumulation (BNA) in 1984 was slightly greater in the treated plots (314 g m⁻²) compared to the control (207 g m⁻²), but in 1985 the BNA was significantly (P0.05) higher (328 g m⁻²) for the control plots compared to treated plot (222 g m⁻²). Results indicate that this alpine meadow is less nitrogen limited than the grasslands studied elsewhere. Nitrogen fertilization had more effects on the pattern of biomass allocation than on total production.