Tuesday, 8 November 2005
6

Using Remote Sensing to Manage Nitrogen in Sugarbeets.

Jason Ellsworth1, Jared E. Hobson1, April Leytem2, and Bryan Hopkins1. (1) University of Idaho, PO Box 1827, 315 Falls Ave, Evergreen Bldg., Twin Falls, ID 83303-1827, (2) USDA-ARS, USDA-ARS, 3793 N 3600 E, Kimberly, ID 83341-5076

Variable-rate nitrogen fertilization is a management practice that is more and more common in production agriculture. Unfortunately, effective use of variable-rate technology is limited by a lack of methods to assess site-specific soil N status. Soil texture may be a simple and stable method of obtaining information to use in guiding variable-rate N fertilization. Two sugar beet fields were chosen in south central Idaho to represent the variability in the area. In each field N treatments of 0.5x, 1.0x, and 1.5x of the recommended N fertilizer rate were established in 24 row strips the length of the field replicated 3 times. In each field, fifteen test areas, encompassing the three treatments in a replication were selected to capture the variability in the field. Soil texture was determined for each test area. While one site showed no difference in yield and sugar content among nitrogen treatments, the other site showed a 5-ton yield increase and a 2% sugar content increase at the lowest rate when compared to the middle rate. There was no difference in yield and sugar content between the lowest and highest nitrogen rates. Petiole nitrate values at one site were an average of 5800 ppm higher in the clay loam test areas compared to the silt loam test areas. Soil texture is an important consideration when determining variable-rate nitrogen recommendations for sugar beets. Soil texture is a one-time soil test that can be combined with remote sensing and other information to build sound variable-rate nitrogen recommendations.

Handout (.pdf format, 501.0 kb)

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