MINERAL-COMPOSITION OF RED-CLOVER TREATED WITH GROWTH-REGULATORS IN EARLY SPRING

The effect of growth regulators on mineral composition of red clover ( Trifolium pratense L.) was assessed in two growing seasons. daminozide (butanedioic acid [mono(2,2-dimethylhydrazide)]} or mefluidide (2,4-d imethyl-5{[(trifluoromethyl)sulphonyl]amino} phenyl) acetamide]] was a pplied early (mid-May) or late (late May) at low rate [daminozide, 4 k g active ingredient (a.i.) ha-1; or mefluidide, 0.13 kg a.i. ha-1] or twice the low rate (high rate) to an early-flowering cultivar, Florex, and a late-flowering cultivar, Altaswede; the controls were the untre ated cultivars. Red clover was deficient in S, but all other minerals were present in sufficient amounts for productive cattle. The first cu tting showed increases in P and Zn contents after an early application of daminozide, Cu was increased when the high rate of daminozide was applied early, and Ca, Cu, K and Mg were increased when mefluidide was applied early or at the high rate. There were no interactions between daminozide and cultivar in terms of minerals, but mefluidide treatmen t increased Mg in Altaswede only. Altaswede showed a narrower N/S rati o in the first cutting, and contained more P, K and Mg in both cutting s than did Florex. This study indicated that growth regulator applicat ion, particularly the early application of daminozide at the high rate , improved the mineral profile in red clover.