In conventional agricultural production systems, soil management is generally carried out without considering the spatial variability of its properties. This situation generates not only soil degradation but also an increase in production costs associated with the management of this factor. The objective of this research was to evaluate, through ge...
Naar aanleiding van de artikelen over numerieke verdroging verscheen onlangs in Stromingen een reactie over het gebruik van de drainage- en voedingsweerstand. In dat artikel geeft Kees Maas expliciet aan het niet eens te zijn met het door ondergetekenden gehanteerde voorbeeld dat een weerstandsbiedende laag in het bodemprofiel bij een freatische wi...
Onderzocht is of de kwaliteit van regionale, met een ruimtelijk model, gemaakte kaarten van de Gemiddeld Hoogste Grondwaterstand en Gemiddeld Laagste Grondwaterstand kan worden verbeterd door middel van aanvullend veldwerk. Hiervoor is de kwaliteit onderzocht van de modelmatig gemaakte kaart van het waterschap Rijn en IJssel en van de in het veld o...
The accuracy of design-based sampling strategies can be increased by using regression models at the estimation stage. The usual regression estimator requires that the means of the auxiliary variables are known. If these means are unknown, then it sometimes pays to estimate these from a large preliminary sample that is subsampled in the second phase...
A sample spacing up to 22 cm over a distance of several metres is just sufficient to collect information about preferential flow paths in a water-repellent sandy soil. When larger sample spacings were used, the water content distributions became more horizontally stratified. Increasing the sample size by pooling pairs of adjacently taken 100 cm3 so...
This research project addresses the Quantification of the risks due to contaminant (solute) concentrations in field-scale soils as contaminants migrate under various pollution loadings at the soil surface (boundary conditions), starting with initial contaminant plumes existing within the soil medium prior to the beginning of loadings (initial condi...
This research project addresses the Quantification of the risks due to contaminant (solute) concentrations in field-scale soils as contaminants migrate under various pollution loadings at the soil surface (boundary conditions), starting with initial contaminant plumes existing within the soil medium prior to the beginning of loadings (initial condi...
