Submitted to: Geospatial Information in Agriculture and Forestry International Conference
Publication Type: Proceedings
Publication Acceptance Date: November 7, 2001
Publication Date: November 7, 2001
Citation: HATFIELD, J.L., PRUEGER, J.H. INTERACTIONS OF WATER AND NITROGEN ACROSS SPACE AND TIME IN CORN PRODUCTION. GEOSPATIAL INFORMATION IN AGRICULTURE AND FORESTRY INTERNATIONAL CONFERENCE. CD-ROM. ANN ARBOR, MI. ALTARUM AGRICULTURE CONFERENCES. Technical Abstract: Variation of corn yields across production fields is quite large and attempts to add production inputs has not always reduced the amount of variation. We designed a study to evaluate the interactions of water and nitrogen across a range of soil types within a production field in central Iowa. The goal of the study was to improve N use efficiency by understanding these interactions. In 1997-1999 nitrogen rates were designed to provide a range of N to crop that ranged from 50 to 200 kg ha-**1. In each year we measured the daily crop water use with energy balance methods, weekly crop growth and development parameters, leaf N status, canopy reflectance, and crop yield. Water use rates varied across years and soil types. Water use efficiency varied across N application rates with the lowest efficiencies at the extremes in N application rates. Variation in yield with N showed that yields varied within N rates because of soil type. Leaf N status throughout the season provided an indication of crop response to available N. In 2000, we modified the treatments to a more proactive N management program and were able to achieve the highest N use and water use efficiencies we had observed in this field. Understanding the N and water interactions provides an understanding of yield variation across fields.