ISSN:
1432-0789
Keywords:
Key words Nitrogen variability
;
Grazed grassland
;
Nitrogen losses
;
Leaching
;
Geostatistics
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Geosciences
,
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract The within-field variability of soil mineral nitrogen (Nmin) in a grazed grassland of 8000 m2 was examined. NO3 –-N concentrations were characterized by a high spatial variability. This can be explained by the uneven deposition of animal excreta. All NH4 +-N as well as NO3 –-N values were lognormally distributed, before and after the grazing season. At the end of the grazing season the largest part of the variability of NO3 –-N was found for NO3 –-N concentrations measured within a distance of a few metres. A high variability for NO3 –-N over very short distances was also indicated by a large nugget variance. During the grazing season, observed mean Nmin values increased from 22 to 132 kg N ha–1. Regions with clearly higher NO3 –-N concentrations could be identified. These zones matched with the drinking place and the entrance of the pasture, places which were more frequently visited than others. High residual N levels in autumn led to relatively high losses of N, mostly by leaching, during the subsequent drainage period. Knowing the variability of Nmin, the number of samples needed to estimate the average Nmin in a field could be calculated for different probabilities and various degrees of precision. From the spatial distribution of the Nmin concentrations and the restrictions imposed by the new European decree, adapted fertilizer strategies can be proposed at least for places where systematically higher Nmin concentrations can be expected.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003740000233
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