Summary
An account is given of the interactions which occur when urea or ammonium sulphate is banded in a clay soil. The spatial distributions of ammonium, nitrate, and nitrite around the band are given as functions of time and are discussed in relation to results from a series of incubations of homogeneous mixtures of various nitrogen compounds and soil. The diffusion of the banded fertilizers and their products through the soil presents the nitrifying organisms with a wide range of environments. The patterns of nitrification are therefore complicated. Nevertheless, they are explicable in terms of the main results of the incubations which were that (a) nitrification was completely inhibited if the osmotic suction of the soil solution was higher than 10 bars, if the ammonium-N concentration in the soil solution was above 3000 ppm, or if the pH was greater than 8, (b) nitrite accumulated if the pH was between 7 and 8, (c) nitrate accumulated if the pH was less than 7, and (d) above a minimum concentration of fertilizer the rate of nitrate formation was independent of the concentration unless the latter was so high that either pH, osmotic suction or ammonium concentration became inhibitory.
An agronomic implication of the work is that if a given amount of fertilizer is applied to a given area of soil, the rate of nitrate formation per unit area may be controlled by banding the fertilizer and varying the band spacing.
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References
Alum, M. I. H. and Alexander, M., Nutrition and physiology ofNitrobacter agilis. Applied Microbiol.8, 80–84 (1960).
Bremner, J. M. and Edwards, A. P., Determination and isotope ratio analysis of different forms of nitrogen in soils: I. Apparatus and procedure for distillation and and determination of ammonium. Soil Sci. Soc. Am. Proc.29, 504–507 (1965).
Broadbent, F. E., Tyler, K. B., and Hill, G. N., Nitrification of ammoniacal fertilizers in some California soils. Hilgardia27, 247–267 (1957).
Chapman, H. D. and Liebig, G. F., Field and laboratory studies of nitrite accumulation in soils. Soil Sci. Soc. Am. Proc.16, 276–282 (1952).
Duisberg, P. C. and Buehrer, T. F., Effect of ammonia and its oxidation products on rate of nitrification and plant growth. Soil Sci.78, 37–49 (1954).
Duncan, W. G. and Ohlrogge, A. J., Principles of nutrient uptake from fertilizer bands II. Root development in the band. Agron J.50, 605–608 (1958).
Freney, J. R. and Wetselaar, R., The determination of mineral nitrogen in soil with particular reference to nitrate. CSIRO, Australia, Div. of Plant Industry, Tech. Pap. No.23 (1967).
Harada, T. and Kai, H., Studies on the environmental conditions controlling nitrification in soil I. Effects of ammonium and total salts in media on the rate of nitrification. Soil Sci. Plant Nutrit.14, 20–26 (1968).
Hauck, R. D. and Stephenson, H. F., Nitrification of nitrogen fertilizers. Effect of nitrogen source, size and pH of the granule, and concentration. J. Agr. Food Chem.13, 486–492 (1965).
Ishizuka, Y., Hayashi, M., and Harada, I., [Effects of relative position of fertilizers on the development of dry field crops. Relation between patterns of root development and concentration of various fertilizers.] J. Sci. Soil Tokyo35, 159–164 (1964).
Ishizuka, Y., Hayashi, M., and Hishizaki, N., [Effect of relative position of fertilizers on the development of dry field crops. Summary of the studies on the relation between concentrations and fertilizing methods of various fertilizers and root development.] J. Sci. Soil Tokyo38, 374–378 (1967).
Ishizuka, Y., Hayashi, M., Ogata, A., and Harada, I., [Studies on the fertilizer position in the crop field. The effect of diffusion of nitrogenous fertilizers in soil on the growth of crop roots.] J. Sci. Soil Tokyo36, 289–296 (1965).
Ishizuka, Y., Tanaka, A., and Hayashi, M., [Effect of relative position of fertilizers on the development of dry field crops. Relation between position and concentration of fertilizers and mode of root development.] J. Sci. Soil Tokyo34, 43–48 (1963).
Johnson, D. D. and Guenzi, W. D., Influence of salts on ammonium oxidation and carbon dioxide evolution from soil. Soil Sci. Soc. Am. Proc.27, 663–666 (1963).
Kelly, W. F., Nitrification in semi-arid soils. J. Agr. Research7, 417–437 (1916).
Martin, W. P., Buehrer, T. F., and Carter, A. B., Threshold pH value for the nitrification of ammonia in desert soils. Soil Sci. Soc. Am. Proc.7, 223–228 (1942).
Morrill, L. G. and Dawson, J. E., Growth rates of nitrifying chemoautotrophs in soils. J. Bacteriol.83, 205–206 (1962).
Morrill, L. G. and Dawson, J. E., Patterns observed for the oxidation of ammonium to nitrate by soil organisms. Soil Sci. Soc. Am. Proc.31, 757–760 (1967).
Peech, M., Hydrogen-ion activity. Methods of soil analysis. Agron. No. 9, Part 2, 914–926 (1965), Ed. C. A. Blacket al.
Porter, L. K., Enzymes. Methods of soil analysis. Agron. No. 9, Part 2, 1536–1549 (1965), Edit. C. A. Blacket al.
Wetselaar, R., Nitrate distribution in tropical soils. II. Extent of capilary movement during a long dry period. Plant and Soil15, 121–133 (1961).
Wiersum, L. K., Density of root branching as affected by substrate and separate ions. Acta Botan. Neerlandica7, 174–190 (1958).