Details
| Original language | English |
|---|---|
| Pages (from-to) | 585-590 |
| Number of pages | 6 |
| Journal | Journal of Plant Nutrition and Soil Science |
| Volume | 164 |
| Issue number | 5 |
| Publication status | Published - Oct 2001 |
Abstract
In Germany, field-average soil NO3- measurements are used to identify agricultural risks of groundwater pollution and to evaluate the compliance of land users with environmental regulations. In the present study, it was tested at three typical agricultural sites if common practices of soil NO3- sampling were appropriate to obtain reliable estimates of the mean field NO3- content in fall. Three sites of 1 ha area were extensively sampled for NO3-. Ordinary statisticial analyses were conducted on the NO3- data in order to calculate how many samples per ha were required to predict the mean field NO3- with a given accuracy. Variograms were derived to assess applicability and relevance of ordinary statistical methods for heterogeneous fields. Results from statistical analysis suggest that at two sites common practices of soil NO3- sampling would have been adequate to obtain estimates of the actual mean field NO3- content with a sampling error less than 10kg NO3--N ha-1 at a 95% probability level. At the other site, common practices obviously would have failed because NO3- contents varied much more spatially. It remains a problem of soil sampling for NO3- analysis that information on field heterogeneity is frequently not available a priori.
Keywords
- Indicator, Nitrate, Soil sampling, Spatial variability
ASJC Scopus subject areas
- Agricultural and Biological Sciences(all)
- Soil Science
- Agricultural and Biological Sciences(all)
- Plant Science
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In: Journal of Plant Nutrition and Soil Science, Vol. 164, No. 5, 10.2001, p. 585-590.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - How many soil samples are neccessary to obtain a reliable estimate of mean nitrate concentrations in an agricultural field?
AU - Ilsemann, Jan
AU - Goeb, Simone
AU - Bachmann, Joerg
N1 - Copyright: Copyright 2005 Elsevier Science B.V., Amsterdam. All rights reserved.
PY - 2001/10
Y1 - 2001/10
N2 - In Germany, field-average soil NO3- measurements are used to identify agricultural risks of groundwater pollution and to evaluate the compliance of land users with environmental regulations. In the present study, it was tested at three typical agricultural sites if common practices of soil NO3- sampling were appropriate to obtain reliable estimates of the mean field NO3- content in fall. Three sites of 1 ha area were extensively sampled for NO3-. Ordinary statisticial analyses were conducted on the NO3- data in order to calculate how many samples per ha were required to predict the mean field NO3- with a given accuracy. Variograms were derived to assess applicability and relevance of ordinary statistical methods for heterogeneous fields. Results from statistical analysis suggest that at two sites common practices of soil NO3- sampling would have been adequate to obtain estimates of the actual mean field NO3- content with a sampling error less than 10kg NO3--N ha-1 at a 95% probability level. At the other site, common practices obviously would have failed because NO3- contents varied much more spatially. It remains a problem of soil sampling for NO3- analysis that information on field heterogeneity is frequently not available a priori.
AB - In Germany, field-average soil NO3- measurements are used to identify agricultural risks of groundwater pollution and to evaluate the compliance of land users with environmental regulations. In the present study, it was tested at three typical agricultural sites if common practices of soil NO3- sampling were appropriate to obtain reliable estimates of the mean field NO3- content in fall. Three sites of 1 ha area were extensively sampled for NO3-. Ordinary statisticial analyses were conducted on the NO3- data in order to calculate how many samples per ha were required to predict the mean field NO3- with a given accuracy. Variograms were derived to assess applicability and relevance of ordinary statistical methods for heterogeneous fields. Results from statistical analysis suggest that at two sites common practices of soil NO3- sampling would have been adequate to obtain estimates of the actual mean field NO3- content with a sampling error less than 10kg NO3--N ha-1 at a 95% probability level. At the other site, common practices obviously would have failed because NO3- contents varied much more spatially. It remains a problem of soil sampling for NO3- analysis that information on field heterogeneity is frequently not available a priori.
KW - Indicator
KW - Nitrate
KW - Soil sampling
KW - Spatial variability
UR - http://www.scopus.com/inward/record.url?scp=0042904598&partnerID=8YFLogxK
U2 - 10.1002/1522-2624(200110)164:5<585::AID-JPLN585>3.0.CO;2-M
DO - 10.1002/1522-2624(200110)164:5<585::AID-JPLN585>3.0.CO;2-M
M3 - Article
AN - SCOPUS:0042904598
VL - 164
SP - 585
EP - 590
JO - Journal of Plant Nutrition and Soil Science
JF - Journal of Plant Nutrition and Soil Science
SN - 1436-8730
IS - 5
ER -