Quality and Quantity of Organic Matter

FIGURE 5.40 Age of the organic matter is reflected by the changes in the relative fractions of lignin and cellulose content. (Adapted from DeBusk and Reddy, 1998.) 

FIGURE 5.41 Range of LCI (lignocellulose index) values during the different stages of organic matter decomposition. (Data from DeBusk, 1996.) 

The estimated LCI for soil organic matter and litter in various forest and agricultural soils was reported to be in the range of 0.45-0.8 (Melillo et al., 1989). The implication of this is that after 

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Sulfate reduction occurs mainly in sediments, with rates controlled by the quality and quantity of organic matter, S042- availability, bioturbation, abundance of dissolved O2 in overlying waters, rates of sulfide reoxidation, and availability of iron-sulfide minerals. 

The quality and quantity of organic matter inputs interact to drive soil metabolic activity (Zak et ai, 1994). Hence, annual soil... 

Crop rotation bears a close relationship to the title of this book since the crops grown, and the disposal made of them, affect the quality and quantity of organic matter in soils, and the extent of disease control. Nevertheless, the subject is in a sense a side issue and involves such a mass of research that no attempt will be made here to discuss it at length. Fortunately, Curl (1963), in a 67-page paper with 479 references has done an excellent job of assembling and analyzing the data. In addition, Kincaid (1960) has reviewed the information on the diseases of tobacco and states that some of those caused by nematodes, fungi, bacteria and viruses are amenable to control by crop rotation. 

The quantity of litter input provides the second critical link between NPP and decomposition because NPP governs the quantity of organic matter inputs to decomposers. When biomes are compared at steady state, heterotrophic respiration (i.e., the carbon released by processing of dead plant material by decomposer organisms and animals) is approximately equal to NPP. In other words, net ecosystem production (NEP), the rate of net carbon sequestration, is approximately zero at steady state, regardless of climate or ecosystem type. This indicates that the quantity and quality of organic matter inputs to soils, as determined by... 

The amount of biogenic methane is essentially controlled by both the availability and reactivity of organic matter in the upper hundreds of meters of the sedimentary sequence. Davie and Buffett (2001, 2003) demonstrated the critical need for quantitative models of biogenic methane production to describe the distribution of gas hydrate in the top few hundred meters of sediment. Key parameters are rates of sedimentation, quality and quantity of the organic matter and biological activity rates. They show that hydrate accumulation from in situ production in sediment with a TOC of 1.5%, will be less than 7% of the pore volume... 

The yield in organic matter swept along in the filtrate versus the total quantity of organic matter introduced in the system (figure 2) depends on two factors first, the quantity of NaOH available and second the quality of the dynamic filtration tap in the twin screw extruder. A low rate of NaOH (bran/soda = 7) with low straw concentration seems to be sufficient to extract... 

Table 1. Nature, significance and typical quantities of various measures of organic matter quality and the size and activity of the microbial biomass present in soils... 

V. Effects of Dissolved Organic Matter Quality and Quantity on the... 

V. EFFECTS OF DISSOLVED ORGANIC MATTER QUALITY AND QUANTITY ON THE ACTIVITY OF BIOFILM BACTERIA... 

Note that each state factor can influence soil carbon storage in two ways by influencing the quantity and quality of plant inputs and by influencing the residence time of organic matter in the soil. Figures 6.2-6.4 show the influence of three state factors on soil C storage. Many of the descriptions of state factors below touch upon the importance of controls on SOM stabilization, and these controls are discussed further in a following section. 

Schnitzer, M., McArthur, D. F. E., Schulten, FI.-R., Kozak, L. M., and Fluang, P. M. (2005). Long-term cultivation effects on the quantity and quality of organic matter in selected Canadian prairie soils. Geoderma 130,141-156. 

Not only the quantity but also the quality of organic matter has been shown to influence bioavailability (Karickhoff et al., 1979). Sediment organic carbon provides a primary food source for benthic organisms. DeWitt et al. (1992) found that sediment pore water partitioning and toxicity of fluoranthene to the amphipod, Rheopyxinius abronius, were affected by sediment organic matter quality. 

Actually some chemical activities as refineries are not so variable on the point of view of wastewater quality because of the large quantities of primary matter and products (Fig. 2). Near units, the UV spectrum shape often shows peaks due to the presence of additives used in the process, acting as revelatory of the organic pollution load [3], Without these compounds and considering that saturated organic compounds do not absorb, it would be difficult to use the UV signal for wastewater quality control. However, a nonparametric measurement (NPM) based on comparison of the UV absorption spectra can be used for the characterisation of wastewater quality variability [4], Obviously, as far as wastewater... 

These considerations lead to the conclusion that to a first approximation the quantity and quality (with respect to sulfate reducers) of organic matter at each of the three stations is nearly the same. The rate of supply of organic material also cannot differ much if it is assumed that a constant proportion of the flux of organics hitting the interface at each station must remain as refractory residue and therefore is reflected in the standing crop. Taken at face value, these data indicate that FOAM, which has the greatest buildup of decomposition products in the pore water, is not necessarily the most productive of the three stations. Additional evidence for relative reaction rates at the three stations comes from solid-phase properties as discussed subsequently. 

An improved understanding of the quantity and quality of more complex pyrolysis products of organic matter can be obtained by first examining the relatively simpler pyrolysis characteristics of the major types of biomacromolecules polysaccharides, lignin, nucleic acids, proteins, and lipids (Figure 8.2). 

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