Miller, D.E., and W.C. Bunger. 1963. Moisture retention by soil with
 coarse layers in the profile. Soil Sci. Soc. Am. Proc. 27:586-589.

Montgomery, D.C. 1984. Design and analysis of experiments. 2nd ed. J.
 Wiley and Sons, New York.

Muller, J.P., and G. Bocquier. 1986. Dissolution of kaolinites and
 accumulation of iron oxides in lateritic-ferruginous nodules:
 Mineralogical and microstructural transformations. Geoderma
 37:113-163.

Nagpal, N.K. 1982. Comparison among and evaluation of ceramic porous cup
 soil water samplers for nutrient transport studies. Can. J. Soil
 Sci. 62:685-694.

Nair, P.S., T.J. Logan, A.N. Sharpley, L.E. Sommers, M.A. Tabatabai, and
 T.L. Yuan. 1984. Interlaboratory comparison of a standardized
 phosphorus adsorption procedure. J. Environ. Qual. 13:591-595.

Nelson, D.W., and L.E. Sommers. 1982. Total carbon, organic carbon, and
 organic matter. In A.L. Page (ed.) Methods of soil analysis. Part
 2. 2nd ed. Agronomy 9:539-580.

Neary, A.J., and F. Tomassini. 1985. Preparation of alundum/ceramic
 plate tension lysimeters for soil water collection. Can. J. Soil
 Sci. 65:169-177.

Nielsen, D.R., and J.W. Biggar. 1961. Miscible displacement in soil I.
 Experimental information. Soil Sci. Soc. Am. Proc. 25:1-5.

Nkedi-Kizza, P., J.W. Biggar, Th.M. van Genuchten, P.J. Wierenga, H.M.
 Selim, J.M. Davidson, and D.R. Nielsen. 1983. Modeling tritium and
 chloride 36 transport through an aggregated Oxisol. Water Resour.
 Res. 19:691-700.

Nkedi-Kizza, P., P.S.C. Rao, R.E. Jessup, and J.M. Davidson. 1982. Ion
 exchange and diffusive mass transfer during miscible displacement
 through an aggregated Oxisol. Soil Sci. Soc. Am. J. 46:471-476.

 Nye, P.H. 1955. Some soil-forming processes in the humid tropics: IV.
 The action of soil fauna. J. Soil Sci. 6:73-83.

 Ojanuga, A.G., and G.B. Lee. 1973. Characteristics, distribution, and
 genesis of nodules and concretions in soils of the southwestern
 upland of Nigeria. Soil Sci. 116:282-291.

 Ojanuga, A.G., and K. Wirth. 1977. Threefold stone lines in southwestern
 Nigeria: Evidence of cyclic soil and landscape development. Soil
 Sci. 123:249-257.

 Oilier, C.D. 1959. A two-cycle theory of tropical pedology. J. Soil Sci.
 10:137-167.