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.
Soil fertility depends on three major interacting components: biological, chemical and physical fertility. Soil organisms improve soil fertility by performing a number of functions that are beneficial for plants. This article examines six of these functions. Some management practices may help improve and maintain the biological fertility of soil. Releasing nutrients from organic matter