Soil type: Peaty muck six years under cultivation.

Soil test after fertilization: pH = 7.00; P = 10; K = 199 lbs/A.

Design: Randomized blocks with eight replications.

Herbicide: Lorox and mineral spirits.

Seeding date: December 9, 1968.

Alar treatment date: January 7, 1969.

Spray rate: Drip point.

Stage at Alar treatment: Length of tops 1"; length of roots 1"
and very slender (width of a pencil lead). Four leaves at timo of application.

Weather: 67 degree F; clear; soil moisture good.

Treatments Alar ppm: 1 = 0; 2 = 1000; 3 = 2000; 4 = 4000.

Harvest date: April 11, 1969.

Harvest plot: 10' x 45" = 37.5 sq. ft.

Results of experiments 582a and 582b: The effect of Alar was manifested
a few weeks after treatment. Again there was a reduction in top growth
proportional to the rates employed. This reduction was not noticeable at
harvest, as indicated in Table III.
 Effect of Alar on yield was dependent on the growth stage of the
plants, Tables II and III. In exp. 582a there was a significant yield
increase only when the 4000 ppm of Alar was compared to the check. In
experiment 582b, their was no yield increase. Yield increase appeared to
have no dependence on root length or diameter, but rather on greater
number of marketable roots in the Alar treated plots. It is possible
that most of the growth retardant spray fell on the heavy foliage of the
most vigorous plants resulting in stunted top growth of these plants.
Whereas the small plants underneath were protected from the spray by the
larger plants and continued to grow and produces roots of marketable size.
In exp._582b the application of Alar was made at very early stages of
growth. No treatment effect was found on root quality.
 These preliminary results seem to indicate that response of carrot
yields is to a large extent dependent on rates and time of application. It
appears that early application is of no benefit, whereas applications made
at later growth stages increase yields.
 It is possible that higher rates applied at later stages may further
increase yields.