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Determining the critical plant test potassium concentration for annual and Italian ryegrass on dairy pastures in south‐western Australia.
- Source :
-
Grass & Forage Science . Mar2018, Vol. 73 Issue 1, p112-122. 11p. - Publication Year :
- 2018
-
Abstract
- Abstract: Potassium fertilization in intensive grassland systems is particularly important on sandy soils with limited K storage capacity. A 3‐year plot experiment was conducted in south‐western Australia to determine the critical K concentration in herbage dry matter (DM) of annual and Italian ryegrass required to achieve 0.95 of the maximum yield, under best‐practice grassland management. A factorial design was employed with eight fertilizer K rates (range 0–360 kg ha−1 year−1) and two ryegrass species replicated four times, on a sandy soil site managed over 7 years to deplete mean soil Colwell K concentration to 42 mg/kg. Herbage was defoliated six times per year at the 3‐leaf stage of regrowth. Herbage DM yield, macronutrient and micronutrient concentrations were measured at each defoliation. Dry‐matter yield increased significantly (<italic>p </italic>< .001) with increasing levels of K fertilizer in all 3 years and the effect was curvilinear, while 0.95 of the maximum herbage DM yield was achieved at an annual K fertilizer application rate of 96, 96 and 79 kg/ha respectively. At these K fertilizer application levels, the mean K concentration of herbage DM over the 3 years was derived to be 11.4, 12.7 and 11.2 g/kg respectively. Sodium, magnesium and calcium concentrations of herbage DM all declined significantly (<italic>p </italic><<italic> </italic>.001) as the K concentration increased. Grassland producers on sandy soils should target a K concentration in herbage DM of 16 g/kg for annual ryegrass and Italian ryegrass‐dominant swards to ensure K availability is not limiting herbage production. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 01425242
- Volume :
- 73
- Issue :
- 1
- Database :
- Academic Search Index
- Journal :
- Grass & Forage Science
- Publication Type :
- Academic Journal
- Accession number :
- 127968792
- Full Text :
- https://doi.org/10.1111/gfs.12286