Another way to collect a stool sample is to loosely place plastic wrap across the rim of the toilet, under the seat. Then place the stool sample in a clean, sealable container before taking to the laboratory. Plastic wrap can also be used to line the diaper of an infant or toddler who is not yet using the toilet. The stool should be collected into clean, dry plastic jars with screw-cap lids.
The potential variations in the properties of agricul-. tural soils are less well known. Diaz et al. (1994) have. reported that under a climate change scenario the soil. organic matter content and erosion rate would de-. crease with regard to current values in the Arrecifes. River basin.
The loss of this top soil results in lower yields and higher production costs. When top soil is gone, erosion can cause rills and gullies that make the cultivation of paddocks impossible. The impacts of erosion on cropping lands include: 1  reduced ability of the soil to store water and nutrients. 2  exposure of subsoil, which often has poor physical and chemical properties. 3  higher rates of runoff, shedding water and nutrients otherwise used for crop growth. 4  loss of newly planted crops.