-4-

 DISCUSSION

 The determine ion of the electrical conductivities (soil soluble
 salts) of a trawberry field can be easily accomplished by one
 person. First, divide the field into areas of no more than 5
 acres. Be s re the fertilizer rate, source, and application
 method are th same within the 5 acres. In addition, the soil
 type, the surf ce and the internal drainage of the soil as well as
 the irrigation rate, timing and method should also be similar.
 Any arpa treat d differently should be sampled separately.

 The next step is to select at random 5 to 8 areas within the 5
 acres to be s mpled, and obtain a soil sample in each of these
 areas. When s mpling the bed, take a cross section of the bed (a
 one inch wide slice across the bed) to a depth of 6-8 inches.
 Place the 5 t 8 samples in one container and mix well. Remove
 one quart of t is soil for analysis. To determine the electrical
 conductivity, dd water to the soil while mixing it until the soil
 is saturated. The soil is saturated if a trace of water, after
 thorough mixin is present at the bottom of the container.
 Vacuum the w ter from the soil, and read the electrical
 conductivity o the water with an electrical conductivity meter.
 If a portable eter is used in the field it must be calibrated
 with a machine using the above procedure. If all slow-release or
 all soluble fe tilizer is applied to the bed, the values in the
 table may not b valid.

 Under normal circumstances and with a 50-50 mixture of
 slow-release (I DU, sulfur coated urea, osmocote, etc) and soluble
 fertilizer nitr gen sources, (NH NO3, urea, KNO (NH ) SO4, etc),
 an electrical c nductivity of a bed slice less than 0.75 indicates
 the soil will s on be unable to supply the strawberry plants with
 sufficient nut ients. If this occurs in the last month of
 harvest, it is f little concern. However; if this occurs prior
 to the last m nth of harvest, plants may require additional
 fertilizer for ptimum yields.

 CONCLUSIONS

Optimum electric l conductivities or soil soluble salt levels are
suggested for th strawberry plant bed during the fruiting season.

These suggested evels correlated well with the yield response and
are a starting oint for growers in evaluating the fertility of
plant beds during the fruiting season. Sampling of the bed must
follow the procedures described and the analysis of the soluble
salts must be p operly determined to obtain meaningful results.
In addition, the fertilizer sources must he as described.