Open AccessComparison of soil analytical methods for estimating wheat potassium fertilizer requirements in response to contrasting plant K demand in the glasshouse
Author(s) -
Yulin Zhang,
Gunasekhar Nachimuthu,
Sean Mason,
Michael J. McLaughlin,
Ann McNeill,
Michael J. Bell
Publication year - 2017
Publication title -
scientific reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.24
H-Index - 213
ISSN - 2045-2322
DOI - 10.1038/s41598-017-11681-4
Subject(s) - fertilizer , soil water , potassium , potash , dry matter , greenhouse , agronomy , environmental science , extraction (chemistry) , soil science , chemistry , biology , organic chemistry , chromatography
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 (CaCl 2 , Colwell and NH 4 OAc 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 NH 4 OAc K method was 91 (R 2 = 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.