A method for designing efficient sampling schemes for reconnaissance surveys of contaminated bed sediments in water courses is presented. The method can be used in networks of water courses, for instance to estimate the total volume of bed sediment of a defined quality class. The water courses must be digitised as arcs in a Geographical Information System.

The method comprises six steps: (1) stratifying the water courses; (2) choosing a variogram; (3) calculating the parameters of the variance model; (4) choosing a compositing scheme; (5) choosing the values for the cost-model parameters; and (6) optimising the sampling scheme. The method is demonstrated with a survey of the main water courses in the reclaimed areas of Oostelijk Flevoland and Zuidelijk Flevoland.

Land suitability analysis is very important to assess and propose the most suitable land-use options. The reliability of land suitability evaluation is controlled by choosing the most limiting land characteristics and their ratings for the proposed land utilization types (LUTs). This study aims at examining the possibility of using current land use and farmers' knowledge as a starting point to suggest and/or modify land evaluation criteria, and to improve the land suitability evaluation process. The potential suitability of land for five LUTs (open range, improved range, rainfed barley, drip-irrigated vegetables and drip-irrigated trees) was evaluated near Al-Mafraq in Jordan using the maximum limitation method. The results indicated variable agreement levels between potential land suitability and current land use for different LUTs. Sixteen farms were selected to represent different cases of disagreement between potential suitability and current land use and were visited to explore the farmers' improved management practices adopted to overcome land-use limitations. Using proposed criteria, only 1% of the study area was highly suitable for drip irrigation, whereas most of the area was moderately or marginally suitable for other uses. This represents the conventional land evaluation procedures, which, in most cases, overlook the farmers' knowledge and practices that are adopted in a particular area to overcome biophysical limitations. The ratings for different land characteristics were modified based on comparisons with current land use, and by referring to farmers’ adopted management practices. Using modified criteria, the highly suitable area for drip-irrigated vegetables increased by 18% and the highly suitable area for drip-irrigated trees increased by 25%. The results emphasized that the consideration of the farmer's indigenous knowledge and current land use improve the land evaluation process, which leads to better utilization of limited land resources in fragile environments.

Soil from 403 hedgerow, roadside verge, woodland, heathland or field sites was assessed for presence of entomopathogenic rhabditid nematodes with aGalleria larva baiting technique. Steinernematids were recovered from 48 % of the sites but only one site yielded Heterorhabditis sp. The species recovered most frequently was Steinernema bibionis (Bovien). Another unidentified Steinernema sp. was also isolated. Prevalence of steinernematids in the different types of habitat formed continuum so that roadside verges harboured them most often while heathland sites yielded them least often. Mean soil temperatures at 5 cm were about 15 °C in fields and verges, 13 °C in hedgerows and heathland and 12 °C in woodland. Prevalence of the nematodes varied in different parts of Britain and was influenced by soil type. They were associated with calcareous soils, especially those with a calcareous subsoil horizon. Soils which are periodically or seasonally water-logged were suitable. Soils enriched by humus and hence high in organic matter frequently harboured the nematodes and some suitable soils had significant clay contents or subsoils high in clay. It appears that the two steinernematids are relatively unspecialized species, occurring in diverse habitats and soil types and are adapted to cooler temperatures.