The effect of ionic strength variation and anion competition on the development of nitrate accumulations in variable charge subsoils
M. J. Donn A and N. W. Menzies A BA School of Land and Food Sciences, University of Queensland, St Lucia, Qld 4072, Australia.
B Corresponding author. Email: n.menzies@uq.edu.au
Australian Journal of Soil Research 43(1) 43-50 https://doi.org/10.1071/SR04036
Submitted: 16 March 2004 Accepted: 30 September 2004 Published: 14 February 2005
Abstract
The leaching of N fertilisers has led to the formation of nitrate (NO3) accumulations in deep subsoils (>5 m depth) of the Johnstone River catchment. This paper outlines the chemical mechanism by which these NO3 accumulations are formed and maintained. This was achieved via a series of column experiments designed to investigate NO3 leaching in relation to the soil charge chemistry and the competition of anions for exchange sites. The presence of variable charge minerals has led to the formation positive surface charge within these profiles. An increase in the soil solution ionic strength accompanying the fertiliser leaching front acts to increase the positive (and negative) charge density, thus providing adsorption sites for NO3. A decrease in the soil solution ionic strength occurs after the fertiliser pulse moves past a point in the profile, due to dilution with incoming rainwater. Nitrate is then released from the exchange back into the soil solution, thus buffering the decrease in the soil solution ionic strength. Since NO3 was adsorbed throughout the profile in this experiment it does not effectively explain the situation occurring in the field. Previous observations of the sulfate (SO4) profile distribution indicated that large SO4 accumulations in the upper profile may influence the NO3 distribution through competition for adsorption sites. A subsequent experiment investigating the effect of SO4 additions on NO3 leaching showed that NO3 adsorption was minimal in the upper profile. Adsorption of NO3 did occur, though only in the region of the profile where SO4 occupancy was low, i.e. in the lower profile. Therefore, the formation of the NO3 accumulations is dependent on the variable charge mineralogy, the variation of charge density with soil solution ionic strength, and the effects of SO4 competition for adsorption sites.
Anon., (1971).
Anon., (1995).
Anon., (1998).
Barber RG, Rowell DL
(1972) Charge distribution and the cation exchange capacity of an iron-rich kaolinitic soil. Journal of Soil Science 23, 135–146.
Black AS, Campbell AS
(1982) Ionic strength of soil solution and its effect on charge properties of some New Zealand soils. Journal of Soil Science 33, 249–262.
Black AS, Waring SA
(1976) Nitrate leaching and adsorption in a krasnozem from Redland Bay, Qld. iii. Effect of nitrate concentration on adsorption and movement in soil columns. Australian Journal of Soil Research 14, 189–195.
Black AS, Waring SA
(1979) Adsorption of nitrate, chloride and sulfate by some highly weathered soils from south-east Queensland. Australian Journal of Soil Research 17, 271–282.
Bolan NS,
Naidu R,
Syers JK, Tillman RW
(1999) Surface charge and solute interactions in soils. Advances in Agronomy 67, 87–140.
Bristow, KL ,
Thornburn, PJ ,
Sweeney, CA ,
and
Bohl, HP (1998).
Donn MJ, Menzies NW
(2005) Simulated rainwater effects on anion exchange capacity and nitrate retention in Ferrosols. Australian Journal of Soil Research 43, 33–42.
Donn MJ,
Menzies NW, Rasiah V
(2004) Chemical characterisation of deep profile ferrosols under sugarcane in wet tropical north Queensland. Australian Journal of Soil Research 42, 69–77.
| Crossref | GoogleScholarGoogle Scholar |
Gillman GP
(1981) Effects of ph and ionic strength on the cation exchange capacity of soils with variable charge. Australian Journal of Soil Research 19, 93–96.
Gillman GP
(1984) Using variable charge characteristics to understand the exchangeable cation status of oxic soils. Australian Journal of Soil Research 22, 71–80.
Gillman GP, Able DJ
(1987) A summary of surface charge characteristics of the major soils of the Tully–Innisfail area, north Queensland. CSIRO Australia, Division of Soils, Divisonal Report No. 85.
Isbell, RF (1996).
Isbell, RF ,
McDonald, WS ,
and
Ashton, LJ (1997).
Katou H,
Clothier BE, Green SR
(1996) Anion transport involving competitive adsorption during transient water flow in an andisol. Soil Science Society of America Journal 60, 1368–1375.
Kinjo T, Pratt PF
(1971) Nitrate adsorption: ii. In competition with chloride, sulfate, and phosphate. Soil Science Society of America Proceedings 35, 725–728.
Kinjo T,
Pratt PF, Page AL
(1971) Nitrate adsorption: iii. Desorption movement and distribution in andepts. Soil Science Society of America Proceedings 35, 728–732.
Menzies N, Guppy C
(2000)
In-situ soil solution extraction with polyacrylonitrile hollow-fibers. Communications in Soil Science and Plant Analysis 31, 1875–1886.
Moody PW, Reghenzani JR, Armour JD, Prove BG, McShane TJ
(1996) Nutrient balances and transport at farm scale—Johnstone River catchment. ‘Downstream effects of land use’. Developed from a National Conference on Downstream Effects of Land Use. Rockhampton, Queensland, Australia. (Eds HM Hunter, AG Eyles, GE Rayment)
pp. 347–351. (Department of Natural Resources: Brisbane, Qld)
Munns DN, Fox RL
(1977) Stabilization of calcium by surface charge variation in an oxisol. Soil Science Society of America Proceedings 41, 682–685.
Murtha GG
(1986) Soils of the Tully–Innisfail area north Queensland. CSIRO Australia, Division of Soils, Divisional Report No. 82.
Rasiah V, Armour JD
(2001) Nitrate accumulation under cropping in the ferrosols of far north queensland wet tropics. Australian Journal of Soil Research 39, 329–341.
| Crossref | GoogleScholarGoogle Scholar |
Rasiah V,
Armour JD,
Menzies NW,
Heiner DH,
Donn MJ, Mahendrarajah S
(2003) Nitrate retention under sugarcane in wet tropical queensland deep soil profiles. Australian Journal of Soil Research 41, 1145–1161.
Reuter, DJ ,
and
Robinson, JBD (1997).