Glen Harris
Growers should continue to make wise decisions when reducing input costs in the area of fertilization and liming.
Pegging zone calcium is the most important input to focus on. Dry weather in 1997 caused a great number of calcium problems in the form of pod rot and "pops." Under dryland conditions, even with adequate calcium present or applied, problems still occurred. This clearly demonstrated the need for both an available calcium source and water on a timely basis.
If a soil pH adjustment is needed as indicated by soil testing, lime can be used to adjust pH and supply calcium to the pegging zone (thus "killing two birds with one stone"). This practice should only be used when soil pH needs to be raised. In addition, the lime needs to be applied after deep turning but before planting. Fine lime or regular ground aglime can be used in this manner, although fine lime is preferred since it will react faster than regular ground lime.
If lime is not used to provide calcium to the pegging zone, the best way to determine if additional calcium is needed on runner peanuts is by taking a pegging zone test. Soil samples taken from near the row to a depth of 3 inches soon after emergence should contain at least 500 lb Ca/a and have a Ca:K ratio of at least 3:1. If either of these criteria are not met, additional calcium in the form of calcium sulfate (gypsum or landplaster) should be applied at bloom. Fine limes such as "LimePlaster" and "LimeMaster" should not be applied at bloom time, since they are ten times less soluble than calcium sulfate. As always, large seeded and seed peanuts should automatically receive bloom gypsum regardless of lime usage or pegging zone test results. New, thicker-hulled varieties may also have a greater need for bloom gypsum.
There is currently no research data to suggest that peanuts grown under conservation-tillage need to be fertilized any differently than those under conventional-tillage. Starter fertilizers and banding bloom gypsum have been suggested but not proven necessary at this time.
"Should I increase fertilization on Georgia Greens?" Again, there is no current research data to suggest that this more upright growth habit and higher-yielding variety needs increased fertilization. Some problems with "lapping" last year were more likely due to lack of water rather than inadequate fertility.