Highly variable conditions and responses pose problem in product development

Abstract

Utilizing chemical leaching and electrolysis for the extraction of copper and molybdenum from ores, an iron and sulfur rich residue is created. This mining residue, when acidified with sulfuric acid, yields a product containing 16 to 20% Fe and 25% S, which is being used to prevent or treat lime induced chlorosis. This material, when soil applied, has sometimes given spectacular results, but has been ineffective at other times. We have, after five years research, identified many of the factors which suppress response. We have noted that variability in soil conditions in even a small area can substantially change responses. Effects of changes in placement, rate, or time of application were noticed. The highly acidic properties of the product are felt to contribute to its effectiveness. Broadcast applications on sorghum showed dramatic residual response, despite giving no response in the year of application. Placement effects were noted where small amounts placed with seeds or in drip zone of trees gave greater responses than did larger amounts placed further from seeds or from feeder root zone. Broadcast applications have shown to be highly effective in correcting chlorosis on turf, but not as effective as band applications when used on row crops at comparable rates.

Key words:

• Acidified mining residue
• Lime induced chlorosis
• Soil acidification
• Micro‐zone amending