Carbon to-nitrogen ratio

Although these studies utilizing Incorporated debris are valuable because they show the potential for allelochemlcals to be released from plant litter, they suffer from a disadvantage. The amount of debris added and Its carbon to nitrogen ratio might lead to alterations In nutrient contents In the soil as the result of proliferation or shifts In populations of micro-organisms. Thus, a control In which a material of similar C/N ratio but lacking allelochemlcals needs to be Included for such studies to be conclusive. The above studies did not Include such controls and thus are not definitive. 

Several researchers emphasized that compost is also an excellent material to use to prevent the acidification and the deterioration of soil productivity [8, 51-54]. Several factors including moisture content, temperature, aeration rate, and carbon to nitrogen ratio have direct influence on composting process, which has been reviewed in detail in the past. 

C N ratio, carbon to nitrogen ratio (weight to weight basis) minimum weed-free period (MWFP), defined as the... 

A buried corpse surrounded by plant material (e.g., straw, pine branches) can display a more rapid rate of decomposition than a cadaver buried without these materials (Mant 1950). Mant (1950) believed that these plant materials introduced additional bacteria into the burial environment while providing a layer of air between the cadaver and the soil. Also, an increase in the rate of cadaver decomposition following the addition of plant material is due to the widening of the carbon to nitrogen ratio, which promotes microbial activity. In fact, this is the premise behind the composting of dead animals (Elwell, Moller, and Keener 1998). 

Table 9.1 Approximate carbon-to-nitrogen ratios in some terrestrial and marine producers.3...

Complete and balance an equation for the reaction in which cyanate ion (CNO ) is oxidized to CO2 and N03 by Mn04, in which two elements in the same chemical species are oxidized. (Hint The carbon to nitrogen ratio is set by the formula of CNO. )... 

Composting, the preferred method of stabilizing manure, is a controlled process in which nitrogen-containing materials are mixed with a carbon-containing source to produce a substance preferably in a carbon-to-nitrogen ratio (C N) of 30 to 1. Compost temperatures must reach 131-170Tforl5days, and be turned a minimum of 5 times to aerate the pile. 

Only occasionally has the N content of solid phase extracts been reported. At a site in the Atlantic Ocean the carbon to nitrogen ratio (C N) of XAD 8 and XAD 2 extracts fell in the range of 40-57 (57 0.9 and 41.1 3.3, respectively DrufFel et ai, 1992). In contrast, at the same site XAD 4, when used as the second resin in series with XAD 8 or XAD 2, extracted compounds with lower C N ratios - 19—24 (21.0 2.4). These values are only slighdy higher than ratios reported for total DOM (see below). McKnight and Aiken (1998) reported a C N value of 37 for DOM extracted by XAD 8 at one site in the Pacific Ocean at other sites in the N. Pacific Ocean XAD 2 was found to extract DOM with a C N ratio between 32 and 46.5 (Druffel et al, 1992 Meyers-Schulte and Hedges, 1986). Bronk (2002, Table III) compiled various literature values and arrived at an average C N ratio of 32.8 19.5 for total humic substances isolated from a variety of aqueous environments (see McCarthy and Bronk, this volume). 

Media used for ARA-rich SCO production vary depending on the process/strain used however, they tend to be relatively simple complex media composed of a base of yeast extract and glucose (51), although the ion composition is known to be crucial for optimal productivity as well as the carbon to nitrogen ratio in the medium (48, 52, 53). 

Estimate the role of carbon-to-nitrogen ratios in enhancement of greenhouse effects. How will the increase of nitrogen airborne deposition affect the greenhouse phenomenon ... 

Azide is often used to introduce nitrogen by nucleophilic displacement on a halide or sulfonate. Care must be exercised when producing or handling azides, since they can be quite explosive. In fact, azides are rarely used on an industrial scale. Special facilities are required to work with most azides on scale. The safety factor improves as the carbon-to-nitrogen ratio in the substrate increases. Beyond being a source of nitrogen, they are most commonly used to protect the amine during carbohydrate synthesis. 

Figure 5.5. Carbon to nitrogen ratios (C N) in the forest floor in relation to nitrogen deposition estimates in hardwood (R =0.19, P<0.001) and conifer (R =0.27, P<0.001) forests, showing different trends for hardwood and conifer stands (hardwood stands, R =0.19, P<0.001 conifer stands). From Aber et al. (2003), reprinted with permission, copyright American Institute of Biological Sciences...

FIGURE 8.24 Relationship between carbon-to-nitrogen ratio of plant litter and mineralization of organic nitrogen (Ponnamperuma, 1981). 

The carbon-to-nitrogen ratio, enzyme activity, and potentially mineralizable nitrogen (PMP) are useful indicators that can be used to determine the soil s capacity to release ammonium N. 

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