
TY  - JOUR
A1  - Elliott, D. E. 
A1  - Reuter, D. J. 
A1  - Reddy, G. D. 
A1  - Abbott, R. J. 
T1  - Phosphorus nutrition of spring wheat (<emph type="2">Triticum aestivum</emph> L.). 3.<footnote> <p>Part 2, Aust. J. Agric. Res., 1997, 48, 869-81.</p></footnote>. Effects of plant nitrogen status and genotype on the calibration of plant tests for diagnosing phosphorus d
JF  - Australian Journal of Agricultural Research
JO  - Aust. J.  Agric. Res.
Y1  - 1997
VL  - 48
IS  - 6
SP  - 883
EP  - 898
KW  - plant analysis, total phosphorus, labile phosphorus, nutrient efficiency, nutrient interaction.
UR  - https://doi.org/10.1071/A96161 
N2  - The influence of plant nitrogen (N) status and plant genotype on plant test criteria for diagnosing phosphorus (P) deficiency in wheat was examined in 2 glasshouse experiments. Criteria for both total and labile P in leaf blades of standard physiological age are, to only a minor extent, affected by variations in N supply and by genotypic diversity Interactions between N and P supply had marked and complex effects on shoot and root yield, P and N uptake in shoots and concentrations in leaf blades, and on the distribution of P and P fractions within wheat shoots. Thus, whilst the external P requirement (i.e. P level required for 90% maximum shoot yield) more than doubled as N supply was raised, variations in N supply had only minor effects on internalP requirement (i.e. the tissue P concentration required for 90% maximum shoot yield). On the other hand, the external P requirement for root yield varied markedly with plant age and N supply. N deficiency increased total P concentrations in leaf blades at all P levels, primarily by increasing the concentration of the labile P fraction. Also, N concentrations increased to adequate levels in the shoots of P-deficient plants but only at the 2 lower levels of applied N. Plant N status also affected the shape of diagnostic relationships between relative shoot yield and P concentrations in young and mature leaf blades by constricting P concentration in the adequate-luxury zone and increasing the slope of the relationship in the zone of deficiency. Whilst the asymptotic grain yield and external requirement for P for the tall cultivar (Halberd) was substantially less than for the semi-dwarf cultivars (Condor and Durati), consistent P cultivar interactions on shoot yield and P uptake during vegetative growth, were largely absent. For leaf blade classes examined, the shape of the diagnostic relationship for total and labile P was essentially similar for each cultivar. As a result, differences in estimated critical P concentrations for total and labile P between the cultivars for leaf blades during vegetative growth, or criteria for grain, glumes, and straw at maturity, were relatively small. 
ER  -

