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However, it has been shown that, depending on species and the size of their aggregates (faeces), earthworms may either increase or decrease soil bulk density. [50] A lower bulk density by itself does not indicate suitability for plant growth due to the confounding influence of soil texture and structure. [51] A high bulk density is indicative ...
For the wet bulk density (total bulk density) this sample is weighed, giving the mass M t. For the dry bulk density, the sample is oven dried and weighed, giving the mass of soil solids, M s. The relationship between these two masses is M t = M s + M l, where M l is the mass of substances lost on oven drying (often, mostly water). The dry and ...
Organic material and therefore Histosols have very low bulk density. Many are acidic and very deficient in major plant nutrients, especially the raised bogs, which are saturated by rainwater and lack connection to nutrient-containing groundwater. Histosols are known by various other names in other countries, such as peat or muck.
The density of quartz is around 2.65 g/cm 3 but the dry bulk density of a soil can be less than half that value. Most soils have a dry bulk density between 1.0 and 1.6 g/cm 3 but organic soil and some porous clays may have a dry bulk density well below 1 g/cm 3 .
Effect of plant density on (a) total shoot mass and (b) seed mass per unit ground area. Schematised figure, inspired a.o. by experiments with maize by Li et al. (2015). Many of the processes related to plant density can well be studied in monocultures of even-aged individuals that are sown or planted at the same time. These can be referred to ...
Soil compaction, also known as soil structure degradation, is the increase of bulk density or decrease in porosity of soil due to externally or internally applied loads. [1] Compaction can adversely affect nearly all physical, chemical and biological properties and functions of soil . [ 2 ]
The primary materials needed for the process of humification are plant detritus and dead animals and microbes, excreta of all soil-dwelling organisms, and also black carbon resulting from past fires. [12] The composition of humus varies with that of primary (plant) materials and secondary microbial and animal products.
After the death of plants, animals, and microbes, microbes begin to feed on the residues through their production of extra-cellular soil enzymes, resulting finally in the formation of humus. [162] As the residues break down, only molecules made of aliphatic and aromatic hydrocarbons, assembled and stabilized by oxygen and hydrogen bonds, remain ...