Nitrification soils

Berg, P., Klemedtsson, L., and RoswaU, T. (1982). Inhibitory effects of low partial pressure of acetylene on nitrification. Soil Biology and Biochemistry 14, 301—303. 

For most crops, other than rice, urea in the soil must first undergo hydrolysis to ammonia and then nitrification to nitrate before it can be absorbed by plant roots. One problem is that in relatively cool climates these processes are slow thus plants may be slow to respond to urea fertilization. Another problem, more likely in warmer climates, is that ammonia formed in the soil hydrolysis step may be lost as vapor. This problem is particularly likely when surface appHcation is used, but can be avoided by incorporation of the urea under the soil surface. Another problem that has been encountered with urea is phytotoxicity, the poisoning of seed by contact with the ammonia released during urea hydrolysis in the soil. Placement of urea away from the seed is a solution to this problem. In view of the growing popularity of urea, it appears that its favorable characteristics outweigh the extra care requited in its use. 

The interest in gaseous losses of nitrogen from soil is now extensive and includes the well established community of soil scientists concerned with losses of fertilizer-applied nitrogen by nitrification and denitrification. More recently, interest in ammonia losses from plants and soil has been stimulated by the very large emissions from intensive cattle production in the Netherlands and their... 

In soil, microbial nitrification and denitrification are the predominant sources of NO and NjO and the emission fiiixes may be regarded as leakage during the transformation processes shown in Figure 6. Nitrifiers can produce NO and NjO during the oxidation of NH4 to NO3". Both gases are by-products of the nitrification pathway and the typical yield of NO in well-aerated soil is 1-4% of the NH4 oxidized and for NjO is less than... 

Figure 7 The production and emission of NO during denitrification in agricultural soil treated with NO3 fertilizer (KNO3) and the nitrification inhibitor Dyciandiamide (10%) under aerobic (air) and anerobic conditions (N,). Fluxes are means from three soil columns, error bars represent standard deviations from the mean. V = vertical flow through the column H = Horizontal flow over the soil surface.

Davidson, E., Hart, S.C., Shanks, C.A. and Firestone, M.K. 1991 Measuring gross nitrogen mineralization, immobilization, and nitrification by isotopic pool dilution in intact soil cores. Journal of Soil Science 42 335—349. 

Mariotti, A., Germon, J.C., Hubert, P., Kaiser, R, Letolle, R., Tardieux, A. and Tardieux, P. 1981 Experimental determination of nitrogen kinetic isotope fractionation some principles illustration for the denitrification and nitrification processes. Plant and Soil 62 413-430. 

When new pesticides are developed, their effects upon soil communities are tested. Typically these tests use functional parameters (e.g., generation of CO2 or nitrification) (Somerville and Greaves 1987). Many effects shown on soil communities are of short duration and are thought to lie within the range of normal fluctuations in soil processes. 

Because the nitrification and denitrification processes both form N2O as a by-product, control of anthropogenic N inputs to the soil in the form of synthetic fertilizers or manure would affect the amount of N2O produced... 

L. Landi, L. Badalucco, F. Pomare, and P. Nannipieri, Effectiveness of antibiotics to distinguish the contributions of fungi and bacteria to net nitrogen mineralization, nitrification and re.spiration. Soil Biol. Biocheiii. 25 1771 (1993). 

D. M. Crawford and P. M. Chalk, Mineralization and immobilization of soil and fertilizer nitrogen with nitrification inhibitors and solvents. Soil Biol. Biochem. 24 559 (1992). 

The low temperatures and low soil pH that usually prevail at higher altitudes and latitudes (e.g., heathlands) restrain nitrification and (to a lesser extent) ammonification (92). Studies of N relations in temperate and boreal ecosystems have dem-... 

While most authors have used the finite-difference method, the finite element method has also been used—e.g., a two-dimensional finite element model incorporating shrinkable subdomains was used to de.scribe interroot competition to simulate the uptake of N from the rhizosphere (36). It included a nitrification submodel and found good agreement between ob.served and predicted uptake by onion on a range of soil types. However, while a different method of solution was used, the assumptions and the equations solved were still based on the Barber-Cushman model. 

N20 production in order of effect size of treatment was wastewater sludge (H-SLUDGE) > vermicomposting > wastewater sludge (L-SLUDGE) > urea > unfertilized soil. Nitrifier nitrification and nitrifier denitrification were presumably the processes that contributed the most to the production of NzO under aerobic conditions. 

Liang C.A, Tabatabai M.A. Effect of trace elements on nitrification in soils. J Environ Qual 1978 7 291-293. 

Lipman CB, Burgess PS (1914) The effects of copper, zinc, iron and lead salts on ammonification and nitrification in soils. University of California Publications in Agricultural Science 1 127-139... 

Soils amended with arsenic-contaminated plant tissues were not measurably affected in C02 evolution and nitrification, suggesting that the effects of adding arsenic to soils does not influence the decomposition rate of plant tissues by soil microorganisms (Wang et al. 1984). The half-life of cacodylic acid is about 20 days in untreated soils and 31 days in arsenic-amended soils (Hood 1985). Estimates of the half-time of inorganic arsenicals in soils are much longer, ranging from 6.5 years for arsenic trioxide to 16 years for lead arsenate (NRCC 1978). 

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