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.
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.