Centre county Pennsylvania, USA |
Would the outcome be any different if we were to use USDA's reported national corn yield (for all states), expressed as a percent of national trend yield, as a national drought indicator instead of Palmer drought severity index?
Choosing the drought 'threshold' for percent of trend yield would still be subjective but most corn farmers in this area seem to think that corn yields below 90 percent of trend yield are caused by "drought years", and corn yields below 80% of trend yield are caused by "severe" drought years. That doesn't mean that Palmer drought severity index isn't useful for some folks (maybe soybean farmers?), but it probably adds more confusion (muddys the water, so to speak) for corn farmers that worry about droughts.
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The year following a drought.
