Article ID Journal Published Year Pages File Type
4394648 Journal of Arid Environments 2006 14 Pages PDF
Abstract
The objectives of our research were to describe the seasonal patterns in soil inorganic N and microbial biomass N and to assess the rates of net N mineralization and net nitrification in 29-year-old Mongolian pine (Pinus sylvestris var. mongolica) stands in the south-eastern area of Keerqin Sand Lands, China. The concentrations of soil ammonium-N (NH4+-N), nitrate-N (NO3−-N), and inorganic N as well as the rates of net N mineralization and net nitrification clearly showed seasonal patterns of a bell shape from April to October. However, the seasonal patterns were less obvious for microbial biomass N. Higher NO3−-N concentrations were found in the unfenced, grazed stand and higher NH4+-N concentrations were found in the fenced, ungrazed stand. The rate of cumulative net N mineralization was 55.4 kg ha−1 year−1 in the fenced stand and 33.0 kg ha−1 year−1 in the unfenced stand. Of the annual net N mineralization in the fenced stand, only 33.2% was nitrified to NO3−-N, whereas in the unfenced stand, 62.2% was nitrified. Apparently, N availability components in Mongolian pine stands were significantly affected by the two different management options. Our results suggest that a deficiency in N availability to these Mongolian pine plantations happens in the early part of the annual growing season.
Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth-Surface Processes
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