A Fertility Program for Celery Production


in the cost per acre for growing the crop, but in many cases
in which both the formula and the rate per acre applied before
the plants were set were suitable, the chief benefits from the
side-dressing was only to add to the fertilizer reserve of the
soil, and considerable amounts of it were undoubtedly lost by
leaching during the summer months.
 The previous history of the soil is, therefore, a factor affect-
 ing the rate of fertilizer application. In virgin land it has
 been found that a fertilizer analyzing 3% nitrogen (half from
 nitrate of soda, half from sulfate of ammonia), 6% P25O, (from
 superphosphate or basic slag) and 6 to 12% KO (from muriate
 or sulfate of potash) should be applied at the rate of two tons
 to the acre, broadcast. With land previously cropped and fer-
 tilized for crops other than celery, a fertilizer having the formula
 3-6-12 should be applied at the same rate and in a similar man-
 ner. For succeeding years, experiments have shown that for
 the average year one ton per acre of the 3-6-12 should suffice
 for the entire growing period of the crop, when the previous
 crop has been stripped in the field and the strippings retained
 on the land. In the event that pink rot has shown up in the
 field it may not prove advisable to return the strippings to the
 soil, and there is experimental work under way at this time
 to determine the advisability of returning the strippings under
 these conditions. If the strippings are removed from the field
 for sanitary reasons it is advisable to continue the use of the
 3-6-12 fertilizer at a rate of approximately 3,000 pounds per
 acre per year. It has been found that with a crop yielding 500
 crates of marketable celery per acre, about 40% by weight of
 the plant is represented by strippings. With higher yielding
 crops, this percentage is somewhat lower, and with low yield-
 ing ones it is, of course, somewhat higher. On the average,
 however, it is estimated that 50% of the fertilizer taken up
 by the crop can be returned to the soil in the form of the strip-
 pings and roots, and under such conditions, one ton of 3-6-12
 should be sufficient additional fertilizer for the succeeding celery
 crop. Another factor which makes possible this lower applica-
 tion in succeeding years is the residue of potash and phosphate
 which is left in the soil despite summer leaching.
 As mentioned above, experimental evidence indicates that on
 these peat soils all of the fertilizer can be applied before the
plants are set (no side-dressing necessary), and it is recom-
mended that it be applied broadcast or by drill and disked and