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Reporting
Period:
September 1, 1999 to August 31, 2000
Objectives:
1. Using
experimental water quality analyses and crop yields by soil water
holding
capacity (depth), validate APEX for irrigated corn yields, and NO3-N,P,
and
sediment in irrigation runoff losses.
2. After
characterizing the experimental field at the NPRF, compare the field
average
corn yield using VRT inputs by soil depths with the average field
yield using
uniform applications.
3. To
estimate the long-term probabilities of NO3-N losses exceeding safe
drinking
water standards and soil erosion using VRT technology vs. uniform
applications of
inputs.
4. To
estimate the economics of precision agriculture.
A. Summary
of Progress:
The 2000
corn year was a hot, dry year resulting in most VRT-nitrogen treatments
receiving substantially less than 1.0 PET irrigation applications. Nevertheless,
irrigated
corn yields were obtained from all treatments but no irrigation runoff
samples were
taken during the growing season. 1998-00 average yields with low N fertilizer
of
120#/ac and shallow soil (less than 30") were 161.2 bu/ac while
the medium soil
depth of 31 to 48" with medium N of 180 #/ac averaged 13 bu/ac
less or 148.4
bu/ac.
The highest
N rate of 240#/ac with a deep soil of over 48" yielded 155.9
bu/ac during the 1998-00. Average1998-00 yields of 150.5 bu/ac and 170.3
bu/ac
using a uniform rate of 240#/ac on the medium and shallow depth soils
respectively
were 2 to 9 bu/ac higher than the yields using reduced VRT-N rates.
B. Education/technology
transfer: NPRF Field Day
C. Milestones
achieved:
D. Publications:
E. Precision
agriculture proposals: USDA-IFAFS "Present and Future Adoption
of Precision Farming Technologies in the South."
F. Precision
Agriculture meetings attended/papers (posters) presented: Presented
1998-99 water quality results and GIS soil depth and initial nitrogen
maps of the 1998 NPRF research site to the W-190 western irrigated regional
research group.
G. Other
Developments: A decision to reduce mid-project funding by 60% for
completing objectives #1 and #3 in FY01 will limit the work plan significantly
from that previously submitted.
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