TY - JOUR

T1 - Prediction of wheat response to an application of phosphorus under field conditions using diffusive gradients in thin-films (DGT) and extraction methods

AU - Mason, Sean

AU - McNeill, Ann

AU - McLaughlin, Mike J.

AU - Zhang, Hao

PY - 2010/12

Y1 - 2010/12

N2 - The ability of the Diffusive Gradients in Thin Films (DGT) technique and two other established testing methods (Colwell, resin) to predict wheat responsiveness to applied P from 35 field trials across southern Australia was investigated. Regression analysis of relative early dry matter production and grain yield responses demonstrated that the DGT method predicted plant responsiveness to applied P more accurately than Colwell P and resin P at sites where maximum yields were reached with P rates used (20 out of 35). The measured concentration in soils at the DGT surface, C-DGT, explained 74% of the variation in response for both early dry matter and grain, compared to 7% for early dry matter and 35% for grain using the resin P method. No significant relationships could be obtained for Colwell P although modifying the Colwell test data using Phosphorus Buffering Index resulted in a correct response prediction for 11 of the 20 field sites compared to 18 for DGT and 14 for resin P. These observations suggest that the DGT technique can assess plant available P in soils with significantly greater accuracy than traditional soil P testing methods. The critical P threshold, expressed as C-DGT, was 255 mu g L-1 for early dry matter and 66 mu g L-1 for grain.

AB - The ability of the Diffusive Gradients in Thin Films (DGT) technique and two other established testing methods (Colwell, resin) to predict wheat responsiveness to applied P from 35 field trials across southern Australia was investigated. Regression analysis of relative early dry matter production and grain yield responses demonstrated that the DGT method predicted plant responsiveness to applied P more accurately than Colwell P and resin P at sites where maximum yields were reached with P rates used (20 out of 35). The measured concentration in soils at the DGT surface, C-DGT, explained 74% of the variation in response for both early dry matter and grain, compared to 7% for early dry matter and 35% for grain using the resin P method. No significant relationships could be obtained for Colwell P although modifying the Colwell test data using Phosphorus Buffering Index resulted in a correct response prediction for 11 of the 20 field sites compared to 18 for DGT and 14 for resin P. These observations suggest that the DGT technique can assess plant available P in soils with significantly greater accuracy than traditional soil P testing methods. The critical P threshold, expressed as C-DGT, was 255 mu g L-1 for early dry matter and 66 mu g L-1 for grain.

KW - Nutrient availability

KW - Phosphorus deficiency

KW - Soil testing

KW - Soil fertility

UR - http://www.scopus.com/inward/record.url?scp=78449250242&partnerID=8YFLogxK

U2 - 10.1007/s11104-010-0521-0

DO - 10.1007/s11104-010-0521-0

M3 - Journal article

VL - 337

SP - 243

EP - 258

JO - Plant and Soil

JF - Plant and Soil

SN - 0032-079X

IS - 1-2

ER -