Effect of N Rate on Cotton Yield and Biomass Accumulation

摘要

Two-year field trial has proved that cotton yield is positively related to N rate within the range of 0- 600 kg/ha in sandy and lower fertility field. How do cotton biomass accumulation, N absorption and distribution respond to N rate? A pot trial was carried out to determine how cotton (Gossypium hirsutum L.) dynamics of biomass accumulation, N uptake and partition was affected by N rate by using 15N labeled urea. The results, concerning cotton yield and biomass, showed that, both yield and biomass responded to N rate synchronously and positively within the same range. Cotton yield difference was derived from bolls per plant, while biomass difference was derived from both duration and accumulation rate during the fast accumulation period (FAP). It was suggested that more N be necessary in lower fertility and sandy soil to have a good cotton yield which might be resulted from higher biomass.