EFFECT OF BASAL AND SIDE-DRESSED PHOSPHORUS ON THE ACHENE YIELD AND PYRETHRINS CONCENTRATION IN THE ACHENES OF PYRETHRUM (TANACETUM-CINERARIIFOLIUM) AND ON SOIL AND PLANT PHOSPHORUS
Aa. Salardini et al., EFFECT OF BASAL AND SIDE-DRESSED PHOSPHORUS ON THE ACHENE YIELD AND PYRETHRINS CONCENTRATION IN THE ACHENES OF PYRETHRUM (TANACETUM-CINERARIIFOLIUM) AND ON SOIL AND PLANT PHOSPHORUS, Australian Journal of Agricultural Research, 45(1), 1994, pp. 231-241
Field experiments were conducted for two years on a krasnozem at Devon
port and on an alluvial soil at Ouse in Tasmania to investigate the ef
fect of basal and side-dressed phosphorus (P) on the yield (achene yie
ld) and pyrethrins (Py) concentration in dry achenes, on tissue P conc
entrations of pyrethrum and on soil Colwell P (P-c). At both sites, 0,
50, 100, 200 and 300 kg P ha(-1) was band-placed at planting (basal P
) in May 1990. In September 1991, plots were subdivided and 0, 75, 150
and 200 kg P ha(-1) was side-dressed. Application of up to 100 kg bas
al P ha(-1) increased achene and Py yield by greater than or equal to
50% in the 1990 crop at both sites. Residual P from the 1990 applicati
on tended to reduce the 1991 achene yield, Py concentration and Py yie
ld at both sites (P = 0.09). Side-dressing of P in spring 1991 did not
influenced the achene and Py yield at either site. The maximum of com
bined 1990 and 1991 achene and Py yield was attained with 50 kg P ha(-
1) and no side-dressed P. Top-soil P-c in 1990 was highly correlated w
ith rates of both basal and side-dressed P, achene yield and P concent
ration in plant tissues. The concentration of P in shoots, apical tiss
ues and youngest fully expanded leaves of the 1990 crop was highly cor
related with the rate of basal P and achene yield. The apical tissues
were more suitable for diagnostic work because of the ease and speed o
f sampling.