Fate of potassium fertilisers applied to clay soils under rainfed grain cropping in south-east Queensland, Australia

Bell, Michael J.; Moody, P. W.; Harch, G. R.; Compton, BL; Want, Peter

doi:10.1071/sr08088

Cited by 20 publications

(18 citation statements)

References 12 publications

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“…Also in other geographical regions negative K balances in agricultural production systems have been reported urging for intensified research efforts on K management and dynamics in different soil types, climatic regions and cropping systems (e.g. Bedrossian and Singh 2004;Bell et al 2009). Greatly increased crop yields and nutrient off-take in harvested products have exacerbated this situation.…”

Section: Introductionmentioning

confidence: 99%

Quantifying uptake rate of potassium from soil in a long-term grass rotation experiment

2010

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Soil-plant potassium (K) dynamics were studied using a long-term field experiment in order to evaluate the plant performance and K delivering capacity of the soil parent material. Rye grass (Lolium perenne L.) based rotations on a loamy sand derived from granitic bedrock were studied over 30 years with two K-fertilisation regimes, nil (K0) and 65 kg K ha −1 yr −1 . Mineralogical and chemical methods were combined to identify and quantify soil K resources including the partitioning of K between minerals. Two or three cuts were taken annually and herbage yield and composition together with exchangeable soil K were analysed. Herbage yield declined with time and significantly reduced when the K concentrations approached 1%. The grass K concentration also declined over time and stabilized at around 0.5-0.7% (dw) in K0 in all cuts. Input-output mass balances showed an accumulated net K off-take (deficit) of 1,100 kg ha −1 , i.e. 35 kg ha −1 yr −1 . With an exchangeable K pool of 100 kg ha −1 (in the rooting zone 0-40 cm) this indicated a substantial release of K from mineral sources, most probably biotite and hydrobiotite. Assuming a similar net off-take was continued then this particular mineralogical K source would be depleted within two centuries. The study illustrates the strength of combining long-term field experimental data with state of the art quantitative mineralogical methods in order to assess site-specific resources which can form a basis to evaluate the sustainability of different management practices.

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Section: Introductionmentioning

confidence: 99%

Quantifying uptake rate of potassium from soil in a long-term grass rotation experiment

2010

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“…Bell et al . reported that soil solution K values varied by 6–7 fold in different soil types despite similar exchangeable K contents 19 , so it can be concluded that measures of K intensity and quantity differ greatly across soils with varying soil properties. In particular, soil clay content influence the K levels observed in different extraction methods.…”

Section: Introductionmentioning

confidence: 99%

Comparison of soil analytical methods for estimating wheat potassium fertilizer requirements in response to contrasting plant K demand in the glasshouse

Zhang

Nachimuthu

Mason

et al. 2017

Sci Rep

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The traditional soil potassium (K) testing methods fail to accurately predict K requirement by plants. The Diffusive Gradients in Thin-films (DGT) method is promising, but the relationship between the DGT-measured K pool and plant available K is not clear. Wheat (Triticum aestivum L., cv. Frame) was grown in 9 Australian broad acre agricultural soils in a glasshouse trial until the end of tillering growth stage (GS30) with different plant K demands generated by varying plant numbers and pot sizes. Different K concentrations in soils were varied by 4 rates of K fertilizer application. The relative dry matter and K uptake were plotted against the soil K test value (CaCl2, Colwell and NH4OAc and DGT K measurements). To obtain 90% of maximum relative dry matter at low root density (closest to field conditions), the critical value of the NH4OAc K method was 91 (R2 = 0.56) mg kg−1. The DGT K method was not able to accurately predict relative dry matter or K uptake due to a weak extraction force for K from soils with high CEC values. Further endeavor on increasing K extraction force of the DGT method is warranted to obtain accurate plant available K results.

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“…Conversely, in fertilized K treatments, the K-specific adsorption sites may become saturated with K, with subsequent K fertilization resulting in leaching of surplus K into subsoils. Bell et al (2009) support K determination in their soils at deeper depths than those usually considered to account for these aspects. In Alabama, USA, Cope (1981) summarized 50 years of K fertilization in four sandy low CEC (<5 cmol(+) kg -1 ) soils and one silt loam soil with CEC about 10 cmol(+) kg -1 .…”

Section: The Mass-balance Approachmentioning

confidence: 64%

“…Thus, the mass-balance approach appeared to be operating during the first 2 years, but not in the subsequent 4 years. What was not considered by the researchers, but has been observed in Australia (Bell et al 2009) is that K can be extracted by roots from deeper soil layers not measured in traditional soil testing approaches (e.g., the cultivated layer), especially when surface soil K availability is depleted (unfertilized treatments), or leached to deeper soil depths and retained at these depths when surplus K applications are made (Bell et al 2017a, b). In both instances, the surface layer soil K tests may remain relatively unchanged.…”

Section: The Mass-balance Approachmentioning

confidence: 99%

How Closely Is Potassium Mass Balance Related to Soil Test Changes?

Franzen

Goulding

Mallarino

et al. 2020

Improving Potassium Recommendations for Agricultural Crops

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The exchangeable fraction of soil potassium (K) has been viewed as the most important source of plant-available K, with other sources playing smaller roles that do not influence the predictive value of a soil test. Thus, as K mass balance changes, the soil test should change correspondingly to be associated with greater or reduced plant availability. However, soil test changes and the availability of K to plants are influenced by many other factors. This chapter reviews research on soil test K changes and the relation to crop uptake and yield. A mass-balance relationship is rarely achieved from the measurement of exchangeable K because of the potential for buffering of K removal from structural K in feldspars and from interlayer K in primary and secondary layer silicates. Similarly, surplus K additions can be fixed in interlayer positions in secondary layer silicates, or potentially sequestered in sparingly soluble neoformed secondary minerals, neither of which is measured as exchangeable K. In addition, soil moisture, temporal differences in exchangeable K with K uptake by crops, K leaching from residues, clay type, organic matter contribution to the soil CEC, and type of K amendment confound attempts to relate K additions and losses with an exchangeable K soil test. Research is needed to create regionally specific K soil test procedures that can predict crop response for a subset of clays and K-bearing minerals within specific cropping systems.

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Fate of potassium fertilisers applied to clay soils under rainfed grain cropping in south-east Queensland, Australia

Cited by 20 publications

References 12 publications

Quantifying uptake rate of potassium from soil in a long-term grass rotation experiment

Quantifying uptake rate of potassium from soil in a long-term grass rotation experiment

Comparison of soil analytical methods for estimating wheat potassium fertilizer requirements in response to contrasting plant K demand in the glasshouse

How Closely Is Potassium Mass Balance Related to Soil Test Changes?

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