What New Equipment Is Available to Improve N-Use Efficiency?

1
What New Equipment Is Available to Improve N-Use
Efficiency?

• W.R. Raun and J.S. SchepersOklahoma State
  University, and USDA-ARS

2
(No Transcript)
3
Worldwide N Fertilizer Savings
4
SCIENCE Magazine

• Excess nitrogen flowing down the Mississippi each
  year is estimated to be worth 750,000,000
  (Science, Malakoff, 1998)
• NUE in cereal production30 or 80 ?

5
NUE in Cereals

• Author Crop Method Year Location NUE (grain)
• Varvel Corn 15N 1990 NE 43-53
• Russelle Corn Diff. 1981 NE 46
• Raun Corn Diff. 1989 NE 30-40
• Olson Wheat 15N 1984 KS 27-33
• Bronson Wheat 15N 1991 CO 53
• Raun Wheat 15N 1999 OK 21-32
• Lees Wheat 15N 2000 OK 38-41
• Westerman Sorghum 15N 1972 IL 51
• Varvel Sorghum 15N 1991 NE 48
• DeDatta Rice 15N 1988 Asia 37-47

6
Review

• Yield Goals average of last 3-5 years 30
• Nebraska study showed that farmers overestimated
  yield by 2 Mg ha-1 (32 bu ac-1), resulting in an
  excess of 35 kg N ha-1 (Schepers et al., 1986)
• Over-optimistic yield goals were the largest
  contributor to excess N applications with average
  yield goals exceeding actual yields by over 15,
  only about 30 of the fields were within 5 of
  the yield goal (Daberkow et al., 2001)

7
Review

• Preplant Nitrate Test (PPNT)
• Important component of crop available N and
  should be utilized whenever possible. Can be
  subtracted from the yield goal requirement
• Bundy and Andraski (2004) noted the importance of
  preplant soil NO3-N measurements from the 0-60 cm
  depth for improved N recommendations in winter
  wheat.
• N Mineralization
• (Buchholz et al., 1981) Adjust N recommendations
  for the texture of a soil, CEC, organic matter
  content, and crop growing season temperature
  (cool-season vs. warm-season crops)
• N credits
• Use of crop histories that give a legume N credit
  of 50 to 200 kg N ha-1 for a previous alfalfa
  crop (depending on stand, years since alfalfa,
  and forage harvest management) or 15 to 50 kg N
  ha-1 for previous soybeans.

8
Review

• For all systems, it is important to account for N
  contributed from other sources
• Manures, legume residues, irrigation water,
  rainfall (mass balance)
• Amino Sugar N (Mulvaney, Hoeft, and Khan)
• 33 to 1000 greater for non-responsive sites
  versus N responsive
• Responsive (lt200 mg kg-1)
• Non responsive (gt 250 mg kg-1)

9
Whole-crop system (Meisinger, 1984) N in the
aboveground crop, the root system, and in the
soil organic and inorganic N pools
(transformation-balance)
It is useful for the long-term evaluation of a
soil-crop system because it allows estimation of
the systems N recovery efficiency.
10
Advances

• Equipment that will help improve nitrogen
  management for cereal crops includes
• use of hand-held active sensors
• aerial photography
• satellite imagery

11
Advances

• Sufficiency concept(Varvel, 30 lbs N applied
  when sufficiency lt 95)
• Most significant improvement for mid-season N
  management has come via the use of N reference
  strips or N rich strips first promoted by the
  USDA-ARS group in Nebraska.

12
15 Year Average103
Are Cereal NUEs 100?
15 Year Average38
13
100 27 63
76 56 20
126 40 Difference 86 lbs N/ac
50 NUE
14
MSEA, 1995-2004, Shelton, NE
135 lb N/ac
Avg. 48

NUE 17 37 20 55 34 58
66 55 78 57
133 92 41
136 67 69
138 47 91
Grain N Uptake Difference, lb/ac
82 182 138

Diff 100
lbs N/ac
50 NUE
15
Optimum N Rate (Grain N Uptake Max Yield Grain
N Uptake Check)/0.50
16
Optimum N Rate (Grain N Uptake Max Yield Grain
N Uptake Check)/0.50
17
Calibration Stamp2002-2004
Ramped N Rich Strip2005
Agron. J. 2005 97 338-342
18
Ramped N Rich StripVisual InterpretationOptical
Sensing
NDVI
RI 1.5
RI 1.5
Distance
0 50 100 150
N Rate
19
Response Index NDVI, N Rich Strip NDVI,
Farmer Practice
Residual NLegume creditsMineralizationManureNi
trate in rainfall and/or irrigation water
20
Can RI Be Predicted in Corn?
MullenAgronomy Journal 95347-351 (2003)
21
RI versus NUE
22
Predicting Yield Potential in Corn
NDVI, V8 to V10

INSEY
Days from planting to sensing
23
NDVI at F5

INSEY
Days from planting to sensing, GDDgt0
Winter Wheat
Units biomass, kg/ha/day where GDDgt0
24
Mid-Season Yield Potential
Biomass produced per day growth rate yield
potential
25
8.9
6.3 Mg 80.0 kg N
1975 2.5
11.3
1978 7.4
3.8 Mg 48.6 kg N
Difference in Grain N Uptake of 31.4 kg NAt an
application efficiency of 50, 1.25 Grain NN
Fertilizer Requirement Differed by 62.8 kg N
26
nue.okstate.edu
Rainfed and Irrigated Corn
27
(No Transcript)
28
CORN, YPCV Applicator
29
Variable N Application in Wheat(0.4m2 resolution)
30
10 Field Trials GreenSeekerTM Field Sprayer (OSU
Wheat)
2001
Treatment Pre-Trt. N, lb/ac Trt. N, lb/ac Total N, lb/ac Yield, bu/ac Net Rtn, /ac
N-Rich Strip 94 0 94 44.6 110
Var. Rate 56 23 79 39.8 100
Fixed Rate A 56 35 91 37.3 91
Fixed Rate B 58 24 82 35.4 85
Field Rate 73 20 92 34.6 82
31
Equipment Improvements

• Various products from Capstan will assist in
  delivering more accurate rates of liquid and
  gaseous forms of N.
• Pulsed Width Modulation Flow (uncouples flow
  rate from supply pressure)
• Rapid response - actuation frequency.
• Dynamic control ranges up to 101
• Individual control of each atomizer
• VERIS pH probes and EC mapping devices will also
  assist in monitoring field variability.

32
CanadaArgentinaMexico
Optical Sensing Nitrogen Management Group
2005 International Corn Trials 2006 International
Corn Trials Planned
33
Regional Trial, LCB, OK Pioneer 33B51 BT
Preplant N Topdress N Total N Applied Grain NUE
Treatment lb/ac lb/ac lb/ac bu/ac
Check 0 0 0 149 -
200-Pre 200 0 200 226 0.25
40-Pre,40-Top 40 40 80 214 0.54
40-Pre, 80-Top 40 80 120 194 0.25
40-Pre, 120-Top 40 120 160 210 0.25
40-Pre, 160-Top 40 160 200 219 0.23
0-Pre, N Suff. NE 0 110 110 201 0.31
40-Pre, N Suff. NE 40 60 100 215 0.44
0-Pre, NFOA-OSU 0 27 27 174 0.61
40-Pre, NFOA-OSU 40 32 72 221 0.67
0-Pre, Missouri 0 50 50 186 0.49
40-Pre, Missouri 40 50 90 218 0.51
0-Pre, Virginia Tech 0 51 51 176 0.35
40-Pre, Virginia Tech 40 51 91 224 0.55
34
N Budget
N Use Efficiency
minus Check N
35
Summary

• Cereal NUE lt 50
• Mid-season prediction of yield using optical
  sensors and an N Rich Strip (RI) can improve NUE
  and profit
• W- N rates too conservative
• Sufficiency approach can lead to increased NUE
• W- Multiple Applications, not yield based

36
Summary

• Algorithms for improved N fertilizer
  recommendations (Optical Sensing Nitrogen
  Management Group) are forthcoming (Waseca, MN,
  Aug 2006)
• Variable N application using real-time optical
  sensing is commercially available with
  demonstrated increases in NUE
• Chlorophyll meters offer increased sensitivity
  versus active sensors beyond corn canopy closure
• W small leaf area, labor intensive