Nitrogen accumulation

Amino nitrogen accumulates during protein degradation. In contrast to carbon, amino nitrogen is not suitable for oxidative energy production. If they are not being reused for biosynthesis, the amino groups of amino acids are therefore incorporated into urea (see p. 182) and excreted in this form. 

Adams, W.A. and Jan, M.T. 1999. Utilization of nitrogen accumulated by a clover containing ley following cultivation. Soil Use and Management 15 247-253. 

Slopes, C., Millington, S. and Woodward, L. 1996. Dry matter and nitrogen accumulation by three leguminous green manure species and the yield of a following wheat crop in an organic production system. Agriculture, Ecosystems and Environment 57 189-196. 

It was found that the majority of the bromine was concentrated in the carbon residue and while majority of the nitrogen accumulates in the liquid products irrespective of degradation conditions (134). Besides a large amount of styrene and benzene derivatives the pyrolysis oils contained around 1000 ppm of nitrogen, 1000-4000 ppm bromine, 5000-5200 ppm chlorine and 800-1300 ppm oxygen (135). 

Rice, D.L., and Hanson, R.B. (1984) A kinetic model for detritus nitrogen role of the associated bacteria in nitrogen accumulation. Bull. Mar. Sci. 35, 326-340. 

Many of the effects that occur as a result of these fumigations can probably be attributed to a destruction of chlorophyll. Chlorophyll loss attributed to fumigation with ozone or ozonated hexenes has been described (37, 39, 40, 41) and can be used as a quantitative measure of injury to cultured plants by certain pollutants. However, in the case of N02, growth suppression of tomato and bean occur after exposure to 0.5 ppm N02 for 10-12 days with a concomitant greening of the leaves, indicating the possibility of nitrogen accumulation and no chlorophyll destruction by the pollutant. 

Mycelial nitrogen accumulation and distribution in the forest floor... 

Considering the part of accumulated nitrogen that can be leached to the ground-water, we can estimate that in some case these values are of 22 to 66% of total nitrogen accumulated in ecosystems (Table 10). 

In order to estimate the fate of nitrogen accumulated in agroecosystems, we assessed the annual N accumulation in municipal waste for the urban area of the country (Table 16). 

TABLE 4 Estimated Rates of Organic Carbon and Total Nitrogen Accumulation in Soils (0- to 20-cm Depth) Developing Beneath Woody Plants Establishing on a Former Grassland... 

FIGURE 2 Biomass and nitrogen accumulation (means SE) in Erio-plioruin vaginatum grown in NO3, NH4, and amino acids (AA) during 24 days. Treatment responses with the same superscript letter above the bars are not significantly different at p s 0.05. (Redrawn from Chapin et al, 1993, with kind permission from Nature). 

In summary, there appears to be evidence for both mechanisms of NH3/NH4 transport in bacterial cells. Passive difiFusion of NH3 would not generally lead to net accumulation by cells with an alkaline interior pH relative to the medium pH. Passive diffusion would be rate-limited by the low level of NH3 available at physiological pH and by the solubility properties of the cell membrane. NH4 active transport would be required for net ammonium uptake. However, net nitrogen accumulation could be accomplished by rapid assimilation of internal ammonia into amino acids. Net accumulation might be limited by the balance of the two processes uptake by active transport vs. loss by passive diffusion. 

Organic matter accumulation, starting with a humus-free soil, is a function of time. Stevenson (1965) has presented an excellent discussion of the subject and pointed out some of the factors of major importance in the process. He states that in general the rate of nitrogen accumulation, and hence of organic matter accumulation, is rapid during the first few years, then slowly diminishes, and reaches equilibrium after 110—1500 years. 

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