The spatial variability of mineral nitrogen content in topsoil and subsoil
Haberle, J.(Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic))E-mail:[email protected] | Kroulik, M.(Ceska Zemedelska Univ., Prague (Czech Republic)) | Svoboda, P.(Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic)) | Lipavsky, J.(Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic)) | Krejcova, J.(Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic)) | Cerhanova, D.(Vyzkumny Ustav Rostlinne Vyroby, Prague (Czech Republic))
Spatial variability of soil mineral nitrogen Nmin (N-NH4+, N-NO3-) in a soil profile down to 60 cm was determined in a 19-ha experimental field in Prague. Winter wheat was grown in the years 2000 and 2001, oats in 2002 and mustard in 2003. Root length distribution and depth were determined at four locations representing different soil conditions within the experimental field. The coefficient of variation as the measure of the variability of nitrate N in topsoil and subsoil (0-30 and 30-60 cm, respectively) ranged between 18-39 and 20-37%, respectively. The variability of ammonium N in topsoil and subsoil ranged between 4-58 and 11-27%, respectively. There was a positive relation between nitrate concentration in topsoil and subsoil. Spatial dependencies were evaluated on the basis of model variogram parameters. The nugget value expressed as a percentage value of the total variogram's sill was used for the class of spatial dependence determination. When a spatial dependence of the observed factor was found, it was usually within a range of medium-strong dependence. Only in two cases a strong spatial dependence was found. A considerable variability of the variogram's range was found (between 61 and 396 m).
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