Nitrogen management for corn (Zea mays L.) grown on soils amended with oily food waste.

摘要

This thesis reports research on fertilizer N management for corn ( Zea mays L.) production on soils amended with oily food waste (FOG = fat + oil + greases). The objectives of the research were: (i) to determine the effect of rate and timing of FOG application on corn grain yields; (ii) to develop N fertilizer management guidelines for fields amended with FOG and cropped to corn; (iii) to determine the benefits of FOG application to soil; (iv) to determine the site-specific N requirements for corn grown on fields amended with FOG, and (v) to evaluate potential soil and plant indexes for making N fertilizer recommendations for corn production in soils amended with FOG.;Corn crop yields on soils amended with FOG waste in spring at 10 Mg ha-1 prior to planting were maintained relative to an unamended control providing supplemental fertilizer N was applied to meet the requirements for FOG decomposition and crop growth. In addition to the crop N requirement, an average of 6.1 kg N Mg-1 FOG was required for decomposition of the FOG.;Application of FOG resulted in an increase of 18, 19 and 27% over control of soil organic carbon. Essentially all of the FOG applied was degraded as less than 1% of the applied FOG was detected at the end of the growing season.;Nitrogen fertilizer management on a site-specific basis in soils amended with FOG reduced total N fertilizer inputs compared to applications of N fertilizer on a field-scale basis. In this study where upper, mid and lower slope areas were equally distributed, site-specific N management resulted in 66 kg N ha -1 less fertilizer N being applied.;Measurements of soil NO3- at pre-side dress (PSNT) sampling time and chlorophyll meter readings (CMR) at 5-6 leaf stage were highly correlated with the most economic rate of nitrogen and were used to make N fertilizer recommendations for corn grown on fields receiving FOG. Soil NO3- at PSNT sampling time and the CMR approach should be used for making N fertilizer recommendations for corn production in conjunction with FOG management. (Abstract shortened by UMI.)