Spatial Inﬂuence of Topographical Factors on Yield
of Potato (Solanum tuberosum L.) in Central Sweden
ANDREAS PERSSON firstname.lastname@example.org
Swedish Institute of Agricultural Engineering (JTI), P.O. Box 7033, SE-750 07, Uppsala, Sweden
GIS-centre, Lund University, So
lvegatan 12, SE-223 62, Lund, Sweden
LARS EKLUNDH email@example.com
Department of Physical Geography and Ecosystems Analysis, Lund University, So
SE-223 62, Lund, Sweden
Abstract. This study has evaluated the sampling density for creation of high-resolution digital elevation
models (DEMs) for precision agriculture purposes. The relationships between yield and topographical
factors were investigated in a study area located in the central Sweden province of Dalarna. The DEM
data sampling was carried out with a RTK-GPS system. A dense sampling scheme was employed and data
was divided into two for both interpolation and validation. Kriging interpolation was used for DEM
generation. From the DEM, topographical parameters were extracted and topographical indices were
estimated. The indices were calculated with slope length and its vertical and horizontal components. The
drainage area for a point of interest and the relationship of this area to the total drainage area were also
estimated. The relationship of yield and the topographical parameters and indices was investigated using
both circular and spatial statistics. A spatial regression was used to calculate a model for the relationship.
Up to 20% of the yield could be explained in the ﬁnal model for one of the ﬁelds.
Keywords: Yield, Topographical indices, Potato, DEM, Drainage area, Spatial regression
Yield variation and its relation to topography
The aim of site-speciﬁc agriculture is to optimise the use of spatial and temporal
management strategies. Such optimisation can improve crop yield and quality and
reduce the risks for nutrient and pesticide leakage. During the past decade, several
projects have focused on quantifying and characterising variation in factors such as
crop yield, soil properties and precipitation and their interrelationships.
Generally, yield variation has been expected to be related to variation in properties
of the underlying soil. Research has focused on topsoil depth, soil organic matter
content, clay content, pH, phosphorus content, and, of course, soil nitrogen content.
For instance, a negative correlation between crop yield and phosphorus content was
reported by Webster (Lake et al., 1997). Electrical conductivity and topographic
attributes were used for management zone delineation in Missouri, USA. The
Precision Agriculture, 6, 341–357, 2005
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