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Soil phosphorus–crop response calibration relationships and criteria for winter cereal crops grown in Australia


Bell, R and Reuter, D and Scott, B and Sparrow, L and Strong, W and Chen, W, Soil phosphorus-crop response calibration relationships and criteria for winter cereal crops grown in Australia, Crop & Pasture Science, 64, (5) pp. 480-498. ISSN 1836-0947 (2013) [Refereed Article]

Copyright Statement

Copyright 2013 CSIRO Publishing

DOI: doi:10.1071/CP13016


Soil testing is the most widely used tool to predict the need for fertiliser phosphorus (P) application to crops. This study examined factors affecting critical soil P concentrations and confidence intervals for wheat and barley grown in Australian soils by interrogating validated data from 1777 wheat and 150 barley field treatment series now held in the BFDC National Database. To narrow confidence intervals associated with estimated critical P concentrations, filters for yield, crop stress, or low pH were applied. Once treatment series with low yield (<1 t/ha), severe crop stress, or pHCaCl2 <4.3 were screened out, critical concentrations were relatively insensitive to wheat yield (>1 t/ha). There was a clear increase in critical P concentration from early trials when full tillage was common compared with those conducted in 1995–2011, which corresponds to a period of rapid shift towards adoption of minimum tillage. For wheat, critical Colwell-P concentrations associated with 90 or 95% of maximum yield varied among Australian Soil Classification (ASC) Orders and Sub-orders: Calcarosol, Chromosol, Kandosol, Sodosol, Tenosol and Vertosol. Soil type, based on ASC Orders and Sub-orders, produced critical Colwell-P concentrations at 90% of maximum relative yield from 15 mg/kg (Grey Vertosol) to 47 mg/kg (Supracalcic Calcarosols), with other soils having values in the range 19–27 mg/kg. Distinctive differences in critical P concentrations were evident among Sub-orders of Calcarosols, Chromosols, Sodosols, Tenosols, and Vertosols, possibly due to differences in soil properties related to P sorption. However, insufficient data were available to develop a relationship between P buffering index (PBI) and critical P concentration. In general, there was no evidence that critical concentrations for barley would be different from those for wheat on the same soils. Significant knowledge gaps to fill to improve the relevance and reliability of soil P testing for winter cereals were: lack of data for oats; the paucity of treatment series reflecting current cropping practices, especially minimum tillage; and inadequate metadata on soil texture, pH, growing season rainfall, gravel content, and PBI. The critical concentrations determined illustrate the importance of recent experimental data and of soil type, but also provide examples of interrogation pathways into the BFDC National Database to extract locally relevant critical P concentrations for guiding P fertiliser decision-making in wheat and barley.

Item Details

Item Type:Refereed Article
Keywords:Better Fertiliser Decisions for Crops (BFDC), critical concentration, confidence interval, Australian Soil Classification, soil acidity
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Crop and pasture production
Research Field:Crop and pasture nutrition
Objective Division:Plant Production and Plant Primary Products
Objective Group:Grains and seeds
Objective Field:Grains and seeds not elsewhere classified
UTAS Author:Sparrow, L (Dr Leigh Sparrow)
ID Code:86331
Year Published:2013
Web of Science® Times Cited:35
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2013-09-05
Last Modified:2017-11-03

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