Failure to take such precautionary measures may result in exposure of unproductive soil layers that require costly and difficult corrective action to permit acceptable crop production. Recent research by the University of Arkansas has shown that repeated yearly applications of 1,000 to 2,000 pounds of poultry manure, fresh or composted, may help to restore some rice-producing sodic soils to an acceptable productive state. Data are also being collected for soybeans and cotton but are not conclusive at this writing. Research by Dr. Darrell Widick, soybean breeder with the University of Arkansas Agricultural Experiment Station and Arkansas State University, has identified major differences in chloride tolerance among soybean varieties. Rice has been shown to be very sensitive to chloride and nitrate salts in the seedling stage.
Rice is more sensitive to total soluble salts than soybeans.
Seedling plants are more sensitive to elevated soluble salts than older plants. Seedling rice is very sensitive to soluble salts. At most sites where chloride salts have been recognized as causing significant problems for soybeans, salty irrigation water has been the major culprit. Long-term use of this water may harm certain soybean varieties. Select chloride-excluding varieties.