Bell, R.W.

Limpinuntana, V.

Sitthaphanit, S.

English

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  2011 WA SOIL SCIENCE CONFERENCE   PROCEEDINGS     BUSSELTON, WESTERN AUSTRALIA 23‒24 SEPTEMBER 2011  38  Effect of clay amendment of sand on nitrogen, phosphorus and cations in soil solution and in leachate   SUPHASIT SITTIPHANIT1, RICHARD W. BELL2,VIRIYA LIMPINUNTANA3  1Faculty of Natural Resources and Agro-Industry, Kasetsart University Chalermphrakiat, Sakon Nakhon Province Campus, Sakon Nakhon, 47000. Thailand.  2School of Environmental Science, Murdoch University, Murdoch, Perth, 6150, Western Australia. 3Department of Plant Science and Agricultural Resources, Faculty of Agriculture, Khon Kaen University, Khon Kaen, 40002, Thailand.   Nutrient leaching in sands decreases fertiliser use efficiency and may depress plant production. Application of high cation exchange capacity (CEC) materials (e.g. high activity clay minerals) is hypothesised to reduce nutrient leaching and increase plant nutrient uptake in sands. A column experiment was established to determine nutrient (NH4+, NO3-, K, Na, Ca, Mg and P) concentrations in soil solution extracted by Rhizon samplers and in leachate from a Badgingarra sand (1.4 % clay) with three soil amendments (nil, clay-rich soil, bentonite clay) and three fertiliser rates (nil, 38 N 18 P 50 K kg ha-1 and 76 N 36 P 100 K kg ha-1). Soil amendments were applied at the rate of 50 Mg ha-1. The soil columns were leached with de-ionised water equivalent to 50 mm rainfall every 4 days. Leaching loss of soil solution NH4+ was decreased 38-43 % by bentonite addition but little of the soil solution N was in NO3- form and bentonite had no effect on leaching of this form of N. The application of bentonite was able to increase NH4+ in soil solution of top soil and delay leaching of NH4+ by 15 days after fertiliser application. The application of bentonite and clay decreased K leaching by 26-28 %. However, increased amounts of Na and Mg were leached from bentonite-amended sand. The soil solution indicated that there was a decrease and delay in leaching of NH4+, and K in clay-amended sand which can be attributed to its cation exchange capacity but may also involve decreases in macropore abundance. By contrast the decrease in P leaching with clay-rich soil addition  suggest that this amendment have significant P sorption that was lacking on bentonite. The clay amendments had different effects on nutrient leaching that were related to their mineralogy, effects on solution pH and probably on changes in surface area and pore size distribution. 

Effect of clay amendment of sand on nitrogen, phosphorus and cations in soil solution and in leachate

https://researchrepository.murdoch.edu.au/id/eprint/19945/1/clay_amendment_of_sand.pdf

Effect of clay amendment of sand on nitrogen, phosphorus and cations in soil solution and in leachate

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