Total soil

Soil is a multi-phase system consisting of solids, liquids, and gases. In a typical soil, solids, liquids and gases compose about 50%, 20-30% and 20-30% respectively of the total soil volume (Brady and Weil, 1999). The solid phase can be broken down into two components inorganic and organic matter, with organic matter ranging from 1 to 5% of the soil. 

Total soil weight per given depth per hectare assumes a bulk density of 1500 kg soil m. Calculations are based on a nominal application rate of 0.168kga.i.ha . Soil core sectioning techniques are discussed in Section 3. 

This has led to research into identification of labile pools of organic matter (which make up a relatively small proportion of the total pool) that are more sensitive to changes in soil management or environmental conditions than total soil organic matter content. Examples of such pools include C and N held in the microbial biomass and in particulate organic matter and in water-soluble, easily-extractable and potentially mineralizable fractions (Haynes 2005). 

Total Soil Organic Matter 2.1 Nature of the Pool... 

Dilute acid (0.5 M- 2.5 M H2S04) - extractable C or carbohydrate - C have also been used as indicators of soil organic matter status (Angers and Mehuys 1989 Chan and Heenan 1999 Shepherd et al. 2001). The acid hydrolysable fraction generally accounts for about 20-40% of total organic C (Rovira and Vallejo 2002) and 65-85% of the total soil carbohydrate pool (Puget et al. 1999). 

A fraction of organic C oxidizable with 333 mM KMn04 is another measure of labile organic matter (Blair et al. 1995). This fraction encompasses all those organic components that can be readily oxidized by KMnCL including labile humic material and polysaccharides (Conteh et al. 1999). It commonly accounts for 15-20% of total soil organic C (Blair et al. 1998 Conteh et al. 1998). 

As noted earlier, total soil organic matter content can be considered as a coarse indicator of soil quality. However, changes in the content of organic C and total N occur only slowly and do not provide an adequate indicator... 

Sakamoto K, Oba Y (1994) Effect of fungal to bacterial biomass ratio on the relationship between C02 evolution and total soil microbial biomass. Biol Fertil Soils 17 39-44... 

Total soil As concentrations Depressed crop yields at 25-85 mg/kg 1... 

Fig. 6.2 (a) Niche dimension of a habitat that is co-limited by nitrogen (N), phosphorus (P), and potassium (K), and (b) niche dimension of the same habitat after N addition. The different shapes indicate soil areas that are limited by N, P, or K. If one nutrient is added, e.g., N by N deposition, the total soil area with limiting amounts of one or more nutrients for plant growth becomes smaller. The habitat becomes more uniform and may offer less niches for plants to coexist... 

Safarik IVO, Santruckova H (1992) Direct determination of total soil carbohydrate content. Plant... 

Thus the total soil pollution was connected with a respiratory system and a digestive tract. Both systems were also sensitive to such urban pollutants as heavy metals and PAH. For radionuclides the correlation with the given nosologies was not revealed. The asthma morbidity was mostly connected with soil pollution rates. This circumstance, apparently, can be related to nonspecific action of pollutants on a human organism, because the etiology of asthma is connected with the human immune defense system and allergy state (Roite, 1991). The last was shown for pesticides (Nikolaev et al., 1988) and heavy metals (Drouet et al., 1990). The sensitized immune system is, apparently, responsible for chronic toxic effects of other pollutants at low doses (Sidorenko et al., 1991 Novak and Magnussen, 1993). 

In the Mixed Forest ecosystems a soil fraction less than 1 pm contains most of the elements previously confined in the forest litter and gradually involved in the biogeochemical cycle. In this fraction Cu and Mo forms account for 60-70% of the total soil content. The metals, poorly absorbable by plants, for example, Cr and V, occur in finely dispersed soil fraction in smaller amounts, about 20-30%. 

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