SOIL TEST INFORMATION SHEET NO. C-170

Prepared by Extension Agronomist Walter C. Morrison

Soybeans

1.	Agricultural limestone should be applied when the soil pH value is below 5.5.  Limestone effectiveness is determined by the size of the particles and the Calcium Carbonate Equivalent (C.C.E).  The lime recommendation is based on a C.C.E of 100.  If the magnesium content of the soil is medium or lower, dolomitic limestone should be used.  Do not overlime.  Overliming can cause micronutrient deficiencies.

2.	On soils with a pH less than 6.2, plant seed treated with the micronutrient molybden.  One-fourth to one-half ounce of molybdenum per acre as a seed treatment should be used.  If Rhizobium  inoculant is to be used, apply the molybdenum to the soil separately from the Rhizobium  immediately in front of the inoculated seed.

3.	When soybeans are grown in rotation with rice, do not lime the soil higher than pH 5.8 because a zinc deficiency on the rice may result from over-liming.  Put out lime after the rice harvest to get the maximum benefit for soybeans.

4.	On soils low in phosphorous and low in pH, band placement of phosphorous usually results in higher efficiency than broadcast applications.  On soils testing medium, broadcast and band applications are generally equal.

5.	Although it may not always be necessary, yearly seed inoculation with a viable inoculum is recommended.  Seed should always be inoculated if soybeans have not been grown in 3 or more years.

6.	Solid or liquid sources of fertilizer are essentially equal in their effectiveness to produce soybeans when applied in the same way.

7.	Contact your county agent for additional information and help in your fertilization program.  The agent also receives a copy of this report for the parish office files.