393-7 Plant-Based Approaches for in-Season Detection of Nitrogen Stress in Potato.

Poster Number 1434

See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: Nitrogen Use Efficiency and Management
Wednesday, October 24, 2012
Duke Energy Convention Center, Exhibit Hall AB, Level 1
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Tyler Nigon, Carl Rosen and David Mulla, Department of Soil Water & Climate, University of Minnesota, St. Paul, MN
Poster Presentation
  • Tracking N status of potato 2012 Nigon.pdf (2.9 MB)
  • Potato (Solanum tuberosum, L.) yield and quality are highly dependent on the availability of nitrogen (N) during the crop’s critical growth stages. One technique that can be used to optimize N availability to the crop is to apply split applications of post-emergence N fertilizer. However, the optimum timing and rate of split applications can vary from year to year because of variation in the weather. To overcome this variation, growers can base post-emergence N fertilizer applications on plant measurements, e.g., petiole nitrate-N (NO3-N) concentration, because they are more responsive to N stress and are easier to obtain than soil fertility measurements. A field experiment with five N treatments ranging from 34-270 kg N ha-1 was conducted in 2010 and 2011 at the Sand Plain Research Farm in Becker, MN to evaluate the effectiveness of using different plant measurements to monitor in-season N stress for two potato varieties (Russet Burbank and Alpine Russet). Measurements were taken on multiple dates throughout the season and included: petiole, leaflet, and entire leaf samples analyzed for both NO3-N and total N concentration; chlorophyll meter readings (SPAD); and spectral indices such as NDVI, NDI2, and SR8 calculated from narrowband reflectance obtained with a Cropscan multispectral radiometer. Of the tissue samples, leaflet N and entire leaf N had the best relationship with Grade A tuber yield, especially at the mid- to late growth stages (r2 = 0.21-0.67). However, NDVI and NDI2 had a better relationship with Grade A tuber yield than any of the tissue samples at all growth stages (r2 = 0.40-0.87). These data suggest that ground based canopy-level spectral data (NDVI or NDI2) are better suited to make in-season N fertilizer recommendations than plant tissue samples because they are affected by leaf area in addition to plant N status.
    See more from this Division: S04 Soil Fertility & Plant Nutrition
    See more from this Session: Nitrogen Use Efficiency and Management