Charles Wortmann from the University of Nebraska at Lincoln details how last year's drought may have impacted carryover for NPK this year. Nitrogen uptake in fields whose yields were less than normal last year was probably limited, leaving some N in the soil. Less leaching and denitrification, and increased organic N mineralization during the warm autumn also may contribute to carryover N this spring. Breakdown of manure applied in 2011 and 2012 was also inhibited by the dry conditions and is another potential source of carryover N in the spring.
The report suggests the drought may also have left a significant amount of P&K in the soil. Soil sampling is recommended before making any final decisions. Wortmann points out that, given the dry conditions, it may not be a good year for grid soil sampling. "The unusual soil nutrient status of water-limited fields indicates that the spring of 2013 is not a good time for grid soil sampling. Grid soil sampling is a significant investment intended to be useful for eight or more years. In a very atypical year grid sampling provides a poor basis for nutrient management over future years," said Wortmann.
The impacts of drought can be severe, but potential carryover NPK in the dry soil may give growers a little breathing room on production costs this spring. (Click here for more.)
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