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Potential Yield Response of Corn to Treatments that Conserve Fertilizer Nitrogen in Soils 1
Author(s) -
Blackmer A. M.
Publication year - 1986
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1986.00021962007800040003x
Subject(s) - fertilizer , agronomy , leaching (pedology) , soil water , yield (engineering) , crop , environmental science , crop rotation , nitrogen , crop yield , mathematics , chemistry , biology , soil science , organic chemistry , materials science , metallurgy
Recent 15 N‐tracer studies have provided evidence that a substantial portion of the fertilizer N applied for corn ( Zea mays L.) production in Iowa may be lost by leaching and (or) denitrification before plants have an opportunity to utilize this N. Because this finding seems contradictory to the results of studies showing that corn yields usually are not increased significantly by treatments known to reduce these losses, a study was conducted to assess the sensitivity of yield response measurements for evaluating the cost‐effectiveness of using treatments that prevent losses of N from soils. Models were developed from responses observed to N fertilizers in the long‐term crop rotation experiments conducted at various locations in Iowa. These models were used to identify combinations of conditions (rates of N application, percentages of fertilizer N saved by the treatment, and sufficiency levels of soil‐derived N) that could be expected to cause statistically significant yield increases from ideal treatments in studies having various levels of precision. Ideal treatments were considered to be 100% effective at preventing losses of fertilizer N and to have no effects other than increasing the availability of fertilizer N to plants. The results suggest that many experiments to evaluate the cost‐effectiveness of treatments that prevent losses of fertilizer N have been conducted under conditions where statistically significant yield responses could not have been expected, even if the treatments were cost‐effective for the crop producer. This finding indicates a need to reevaluate the methodology commonly used to evaluate the cost‐effectiveness of using treatments that reduce losses of fertilizer N from soils.