
%0 Journal Article
%A Maier, NA 
%A Barth, G 
%A Bennell, M 
%T Effect of nitrogen, potassium and phosphorus on the yield, growth and nutrient status of ixodia daisy (<I>Ixodia achillaeioides</I> ssp. <I>alata</I>)
%J Australian Journal of Experimental Agriculture
%D 1994/09/01
%V 34
%N 5
%P 681-689
%K 
%R https://doi.org/10.1071/EA9940681
%U https://www.publish.csiro.au/paper/EA9940681 
%X The effect of annual applications of nitrogen (N), potassium (K) and phosphorus (P) on the yield, growth and nutrient status of Ixodia daisy (Ixodia achillaeioides ssp. alata) grown on a silty loam, was investigated in field experiments conducted during 1989-91 in the Mount Lofty Ranges, South Australia. The experimental design was a randomised block with 3 replications. The N and K treatments, at annual rates up to 200 kg N/ha and 150 kg K/ha, were applied as 2 equal side-dressings. The P treatments, at rates up to 200 kg/ha, were broadcast as 1 annual application. To assess plant nutrient status we sampled the fifth leaf below the growing terminal of 50 stems in October and whole stems at harvest. As rate of applied N increased, there was a significant (P<0.05) increase in total biomass harvested, number of 3040 and 41-50 cm stems, total number of marketable stems, plant height and width. Annual N application rates of 75-110 kg/ha were required for 95% of maximum biomass yield and number of marketable stems. The application of K did not significantly (P>0.05) affect yield or plant growth. First and second order interactions between N, K and year were not significant. Plant growth and yield responses to P applied as superphosphate were inconsistent and the interaction between P and year was not significant (P>0.05). Coefficients of determination (r2) for relationships between N, K and P concentrations in the fifth leaf samples v. total biomass yield and total stem number, were in the range 0.13-0.52 for the combined 1990 and 1991 data. Based on sensitivity, reproducibility and occurrence of the Piper-Steenbjerg effect, we concluded that N, K or P concentrations in the fifth leaf sampled in October, or in whole stems at harvest, were not reliable indicators of the nutrient status of Ixodia daisy. The application of N and P did not affect the concentration of minor or micronutrients in the fifth leaf. In contrast, the application of K increased calcium (Ca), magnesium (Mg) and sulfur (S) concentrations by 14.3, 33.3 and 12.2%, respectively. For a high density planting (13,000 plants) we estimated that for N, P and K, 69.4, 6.2 and 83.2 kg/ha, respectively, are removed in marketable stems. The application of P increased extractable-P concentrations in the surface (0-15 cm) soil from 22 to 73 mg/kg. We suggest that for surface (0-15 cm) soils, extractable-P and extractable-K concentrations in the ranges 15-95 and 210-260 mg/kg, respectively, are adequate and indicate that a yield response to the application of these nutrients in fertiliser may not occur. 
