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Site Specific N Fertilizer
An increasing number of farmers are contemplating the use
of site-specific nitrogen (N) applications to Corn (Zea mays L.) as a
way of maximizing yield potential while minimizing fertilizer costs. The
objective of this 3-yr (1998, 1999, and 2000) experiment was to evaluate the
spatial structure of yield response and develop a method for predicting
site-specific N requirements.
Four experimental N rates (50, 110, 160, or 220 kg ha-1),
and two tillage systems (chisel till and zone-till) and two crop rotations
(Corn-corn and corn-soybean (Glycine max L.)) were superimposed over
a 12 ha field in central New York State with a complex of Honeoye-Lima,
Kendaia, and Lima soils ranging from moderately well to poorly drained
soils. Pre-sidedress soil nitrate tests (PSNT) showed significant spatial
structure but were poorly correlated with crop N response, indicating that N
fertilizer recommendations based on PSNT results cannot simply be applied in
a site-specific management approach.
Tillage treatments did not have significant effects on the
spatial structure of yield and were generally comparable in N response.
Spatial Yield response analysis showed limited regionalization of both yield
and profit response to N, suggesting that site-specific application of
nitrogen is impractical. The greatest source of variability in N requirements
was observed in the annual effects of weather, specifically early season
temperature and precipitation. Optimal N rate varied from 110 kg ha-1
for the dry years 1999 and 2000 to 220 kg ha-1 for 1998, with a
warm wet spring. Annual variations in optimum N rate were not well
correlated with annual yield differences and yield potential itself does not
appear to be a strong predictor of N needs.
<Read the entire article>
Site-Specific N.pdf
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Profit response for
4 N fertilizer rates
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N Research Publications
- Katsvairo, T, W.J. Cox,
H.M. van Es, and M.A. Glos. 2003 Spatial yield responses of two
corn hybrids to two N levels. Agronomy Journal (accepted for publication).
- Katsvairo, T, W.J. Cox, and
H.M. van Es. 2003. Spatial growth and soil responses of two
corn hybrids to two N levels. Agronomy Journal (accepted for publication).
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van Es, H.M., K.J. Czymmek, and Q.M. Ketterings. 2002.
Management Effects on N leaching and Guidelines for an N Leaching Index in
New York. J. Soil Water Conserv. 57(6): 499-504.
- Delgado, J., C. Cox,
H.M.. van Es, and W. Reeves. 2002. Nutrient Management in the USA:
A Joint Symposium. J. Soil Water Conserv. 57 (6):
- Sogbedji, J.M., H.M. van Es, J.L. Hutson, and L.D. Geohring.
2001. Fate of N fertilizer and green manure in clay loam and loamy sand
soils: I Calibration of the LEACHM model. Plant and Soil 229(1): 57-70.
- Sogbedji, J.M., and H.M. van Es. 2001. Fate of N fertilizer
and green manure in clay loam and loamy and soils: II Validation of the
LEACHM model. Plant and Soil 229(1): 71-82
- Sogbedji, J.M., H.M.
van Es, S.D. Klausner, D.R. Bouldin, and W.J. Cox. 2001. Spatial
and temporal processes affecting nitrogen availability at the landscape
scale. Soil & Tillage. Research 58 (3-4) 233-244.
- Sogbedji, J.M., H.M. van Es, C.L.
Yang, L.D. Geohring, and F.R. Magdoff. 2000. Nitrate leaching and N budget
as affected by maize N fertilizer rate and soil type. J. Environm. Qual.
29:1813-1820.
- Karunatilake, U., H.M.
van Es, and R.R. Schindelbeck. 2000. Soil and crop response to plow
and no-tillage after alfalfa-maize conversion on a clay loam soil. Soil and
Tillage Res. 55/1-2:31-42
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