Relationship of Ammonium Nitrogen Distribution to Mineralogy in a Hapludalf Soil

Abstract

Distribution of fixed and exchangeable ammonium were examined in three soil profiles of the Shrouts series from the Knobs region of eastern Kentucky. Shrouts soils (fine, mixed, mesic, Typic Hapludalfs) have high base status; exhibit strong, prismatic structure; and are derived from calcareous, high magnesium, soft (weakly cemented) clay shale. Soil pH ranges from 6.3 in the Ap horizon to 7.9 in the C. Analyses, using the Silva and Bremncr procedure, showed considerable fixed NH 4 *-N in all horizons of each profile. Mean fixed NH t +-N in the profiles was 365 ppm for the Ap, 463 ppm for the B21t, 433 ppm for the B22t, 469 ppm for the C, and 543 ppm for the Cr horizons. Exchangeable NH 4 +-N also increased with depth, with values being about 1.2 to 1.5% of the fixed NH t *-N values. X^ray diffraction analyses of the clays and silts revealed predominantly mica in the 2-0.2 and <0.2 /an fractions, with some vermiculite present, and large quantities of mica in the silt fractions. High correlation (r = 0.92) was found between fixed NH 4 +-N and exchangeable NH/-N. A correlation exists between fixed NH 4 +-N and mica + vermiculite content with an r value of 0.68. The fixed NH 4 +-N in the lower horizons is presumed to be indigeous, since no NH 4 +-N has been added recently to the soil.

Fixation and defixation of ammonium in soils: a review

“…In summary, the NH 4 non-exchangeable NH 4 -N (Doram and Evans 1983). The content in soils in Kentucky (USA) was as high as 365 mg kg −1 (Sparks et al 1979). Investigations on top soils from Antarctic also showed that NH 4 + f -N occurs in amounts (0 to 322 mg kg −1 ) similar to elsewhere in the world (Greenfield 1991).…”

“…Yaalon and Feigin (1970) found that illite contains approximately 600 mg N kg −1 illite, whereas montmorillonite contains small and kaolinite clays only negligible amounts. In mixed soil clays, the NH 4 + f -N level is determined by the quantity of illite (Feigin and Yaalon 1974) and illite plus vermiculite (Sparks et al 1979;Doram and Evans 1983), respectively. In contrast to the above results, Bajwa (1985) in a comparative study on fixation of NH 4 + and K + in wetland rice soils found that in five soil clays, montmorillonitic clay fixed the maximum of the added NH 4 + (98%) followed by vermiculite (88%) and least (34%) in clay containing hydrous mica, chlorite, and halloysite.…”

“…The content of NH 4 + f and the capacity of soils to fix NH 4 + is related to parent material (Table 1), texture (Baethgen and Alley 1987), clay content (Opuwaribo and Odu 1974;Sowden et al 1978;Moyano and Gallardo 1988;Juang 1990), clay mineral composition (Feigin and Yaalon 1974;Sparks et al 1979;Doram and Evans 1983;Niederbudde 1983), the K concentration in soil solution, the degree of K saturation of the exchange complex of the soil colloids and . In some cases, the plough layer was thicker or shallower than 30 cm b Modified according to Scherer and Mengel (1979) c Modified according to Marzadori et al (1994) d Fraction <1…”

Native Fixed Ammonium and Fixation of Added Ammonium in Relation to Clay Mineralogy in Some Ontario Soils

“…Soil Sci. 63: [631][632][633][634][635][636][637][638][639] (Aug. 1983) 63r incorporated into minerals during hydrolysis of the magma (Goldschmidt 1954), regional metamorphism of organic rich sediments (Martin et al 1970 (Stevenson 1959(Stevenson , 1962Schachtschabel 1961;Barker 1964;Vedder 1965 Sowden et al 1978), illite content (Feigin and Yaalon l9'74) and illite plus vermiculite content (Sparks et al 1979). Native fixed NH+* as generally measured in soils will also include NHo* that has been incorporated or fixed into minerals by pedological processes or by fertilizer application.…”

Measurement and simulation of soluble, exchangeable, and non-exchangeable ammonium in three soils

“…The amount of fixed ammonium and the fixation capacity of a soil depend on many factors: parent material, clay content (Opuwaribo and Odu, 1974;Moyano and Gallardo, 1988), type of clay minerals (Feigin and Yaalon, 1974;Sparks et al, 1979), concentration of potassium in the soil solution, saturation of potassium on exchange sites, saturation of 2:1 clay minerals (Hinman, 1966;Doram and Evans, 1983), and soil water content (Black and Waring, 1972). The myriad factors involved and their importance in clay soils mostly, make it rare to find models that simulate ammonium fixation and release in soils.…”