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 determine the limiting factors of varying pH levels. Manganese and boron in
 the fertilizer mix totaled 10 Ibs. MnO and 5.4 Ibs. B203 per acre.

 Table 6. Effects of pH adjustment and boron and manganese spray treatments on
 Utah 52-70 celery.

 pH at Lbs./plot Cracked Petioles/30 plants
 Harvest Check Boron spray Mn spray Check Boron spray Mn spray
 6.28 150 162 149 46 17 47
 5.99 146 154 149 25 22 26
 5.74 152 151 152 30 15 33
 5.41 155 145 156 20 11 19

 Table 7. Chemical data from outer Petiole tissue, all from check plots, dry
 weight basis, of Utah 52-70 celery grown on varying pH levels.

 pH P % Ca % M ppm Mn ppm
 6.28 .53 2.17 .27 7 42
 5.99 .57 2.02 .28 16 47
 5.74 .59 1.89 .26 23 44
 5.41 .61 1.87 .28 36 45

 Differences in phosphorus, calcium and manganese contents of petiole
 tissue were highly significant, and it was concluded that the significant
 yield response on the high pH level where boron was sprayed was due to a
 higher boron/calcium ratio. Manganese spray effects were significant in none
 of the experiments conducted. It was concluded boron sprays were of value on
 higher pH levels, but may actually reduce yields on pH levels below 5.5 with
 Utah 52-70. Neither pH levels, nor supplementary nutritional sprays signifi-
 cantly affected Summer Pascal.

 2. A further experiment was conducted with Summer Pascal, Utah 52-70, FFVA
 2-13 and Fla. 683. These data are given in more detail since several of the
 differences in the chemical data between the two selections, FFVA 2-13 and
 Fla. 683, both selections from Utah 52-70, were highly significant and of
 interest. Boron and manganese were applied in the broadcast fertilizer mix
 at 7.2 Ibs. B ,0 and 10.0 Ibs. MnO per acre, an increase in soil boron appli-
 cations over the former experiments.

 Table 8. Total weight in pounds per 20 feet of row of celery varieties and
 strains.

 pH at Summer Utah FFVA Fla.
 Harvest Pascal 52-70 2-13 683
 6.24 97 124 124 128
 5.53 95. 119 123 122
 5.20 98 114 117 119

 Summer Pascal growth as in the previous experiments seemed little
affected by pH adjustment, whereas Utah 52-70 and the Florida selections
significantly decreased with decreasing pH. Boron spray treatments did not
increase yields in this experiment.