Western Crop Science of America
Conference
June 10-13, 2013
Pendleton, OR
Olga Walsh
Assistant Professor, Soil Nutrient Ma...
Cooperators
 Mr. Robin Christiaens, Research Asossiate,
WTARC, Conrad, MT
 Dr. Mal Westcott, Professor and Supt., WARC,
...
Objective
 To evaluate two sensors (GreenSeeker, and Pocket
Sensor) for developing NDVI-based topdress fertilizer N
recom...
Materials and Methods
 3 experimental sites: 2 dryland (WTARC, and on-farm
study (Lindsey Martin, Pendroy, Teton County),...
Materials and Methods
 4 replications
 4 preplant N rates (20, 40, 60, and 80 lbs N ac)
 2 topdress N fertilizer source...
Treatment
Preplant N
Fertilizer Rate,
lb N ac
Topdress N
Fertilizer Source
1 0 -
2 220 urea
3 20 urea
4 40 urea
5 60 urea
...
GreenSeeker
 Real-time active light source sensor
 Emits light at 670nm (red) and 780nm (NIR)
 Measures crop canopy ref...
Pocket Sensor
 Real-time active light source sensor
 Pre-calibrated to GreenSeeker
 Can be calibrated to any NDVI senso...
Concept Summary
1. How much
biomass is
produced ?
2. What Yield is
attainable without
addition of N?
3. How
responsive is
...
Yield
Trt
Preplant
N
Fertilizer
Rate, lb
N ac-1
Topdress
N
Fertilizer
Source
Mean spring wheat grain yield, lb ac-1
2011 2...
Prescribed N rates vs Yield
Site-
year
Trt
Preplant
N rate,
lb N ac-1
GS
NDVI
Prescribed
topdress N
rate, lb N
ac-1
Total ...
Results: GS vs PS
y = 2.0825x2 - 1.0582x + 0.4613
R² = 0.50
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
0.10 0.20 0.30 0....
Results: GS vs Yield
y = 3455.9x + 640.46
R² = 0.97
y = -2E+06x2 + 2E+06x - 361440
R² = 0.80
y = 24288x2 - 17481x + 7558
R...
Results: GS vs Yield
y = -157329x2 + 150526x - 32458
R² = 0.91
30
35
40
45
50
55
60
65
0.37 0.39 0.41 0.43 0.45 0.47 0.49
...
PS NDVI vs Yield
y = -79220x2 + 74697x - 14020
R² = 0.96
1500
2000
2500
3000
3500
4000
0.32 0.37 0.42 0.47
Springwheatgrai...
Total N applied vs Yield
 Strong polynomial relationships between the total amounts on N applied
(preplant plus topdress)...
Protein
Trt Preplant N
Fertilizer
Rate, lb N
ac-1*
Topdress
N Fertilizer
Source**
Mean grain protein content, %
2011 2012
...
Lessons Learned
 In both growing seasons, the rates generated by the
USA/Canada/Mexico Algorithm were not appropriate
for...
 Both sensors perform well and are useful in
predicting spring wheat grain yield potential mid-
season
 Algorithms devel...
Protein Yield concept
 Spring wheat is produced for its quality,
represented by high grain protein content.
 Evaluating ...
THANK YOU!
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Western crop science society of america conference oregon, 2013 - greenseeker-pocket sensor

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  • Western crop science society of america conference oregon, 2013 - greenseeker-pocket sensor

    1. 1. Western Crop Science of America Conference June 10-13, 2013 Pendleton, OR Olga Walsh Assistant Professor, Soil Nutrient Management Western Triangle Agricultural Research Center Montana State University Evaluation of Sensor-Based Technologies and N Sources for Spring Wheat
    2. 2. Cooperators  Mr. Robin Christiaens, Research Asossiate, WTARC, Conrad, MT  Dr. Mal Westcott, Professor and Supt., WARC, Corvallis, MT  Ms. Martha Knox, Research Specialist, WARC, Corvallis, MT  Lindsey Martin, Producer, Pendroy, Teton County, MT
    3. 3. Objective  To evaluate two sensors (GreenSeeker, and Pocket Sensor) for developing NDVI-based topdress fertilizer N recommendations in spring wheat in Montana  To determine whether sensor-based recommendations have to be adjusted depending on what N fertilizer source (liquid UAN, or granular urea) is used
    4. 4. Materials and Methods  3 experimental sites: 2 dryland (WTARC, and on-farm study (Lindsey Martin, Pendroy, Teton County), and 1 irrigated (WARC)  Choteau spring wheat variety  Comprehensive soil sampling - preplant fertilizer application rates for all nutrients except N  Plot size: 5’x 25’.
    5. 5. Materials and Methods  4 replications  4 preplant N rates (20, 40, 60, and 80 lbs N ac)  2 topdress N fertilizer sources (granual – urea, 46-0-0, and liquid – urea ammonium nitrate (UAN), 28-0-0)  Topdress N fertilizer rate determined using NDVI obtained using GreenSeeker and Pocket Sensor at Feekes 5 growth stage
    6. 6. Treatment Preplant N Fertilizer Rate, lb N ac Topdress N Fertilizer Source 1 0 - 2 220 urea 3 20 urea 4 40 urea 5 60 urea 6 80 urea 7 20 UAN 8 40 UAN 9 60 UAN 10 80 UAN Treatment Structure
    7. 7. GreenSeeker  Real-time active light source sensor  Emits light at 670nm (red) and 780nm (NIR)  Measures crop canopy reflectance at 200 readings /sec  Outputs Normalized Difference Vegetative Index (NDVI)  Equivalent to a plant physical examination  NDVI is correlated with: Plant biomass Plant chlorophyll Crop yield Water stress Plant diseases, and Insect damage
    8. 8. Pocket Sensor  Real-time active light source sensor  Pre-calibrated to GreenSeeker  Can be calibrated to any NDVI sensor  NDVI can be directly compared independent of what sensor is used to sense the crop  Cost ~ 25% of GreenSeeker cost  No storage capability 2010 2012
    9. 9. Concept Summary 1. How much biomass is produced ? 2. What Yield is attainable without addition of N? 3. How responsive is the crop to N? 4. What Yield is attainable with addition of N? YPN = INSEY*RI NDVI = (NIR-red)/(NIR+red) INSEY = NDVI/GDD>0 RI = NDVI (NRS) /NDVI (FP)
    10. 10. Yield Trt Preplant N Fertilizer Rate, lb N ac-1 Topdress N Fertilizer Source Mean spring wheat grain yield, lb ac-1 2011 2012 WTARC WARC WTARC WARC Martin 1 0 - 829 (f) 1822 (e) 4229 (d) 3512 (f) 1698 (c) 2 220 urea 2378 (a) 3335 (abc) 4433 (d) 4981 (e) 1837 (bc) 3 20 urea 1369 (e) 2488 (d) 4797 (c) 5121 (de) 1995 (ab) 4 40 urea 1388 (e) 3061 (bc) 5178 (a) 5299 (bcde) 1996 (ab) 5 60 urea 1662 (cd) 3453 (ab) 5140 (abc) 5746 (abc) 2072 (ab) 6 80 urea 1925 (b) 3558 (a) 5262 (a) 5273 (cde) 2115 (a) 7 20 UAN 1298 (e) 2907 (cd) 4824 (bc) 5563 (abcd) 1997 (ab) 8 40 UAN 1465 (de) 3136 (abc) 4958 (abc) 5674 (abcd) 2065 (ab) 9 60 UAN 1771 (bc) 3004 (bc) 4951 (abc) 5862 (ab) 1980 (ab) 10 80 UAN 1935 (b) 3210 (abc) 5160 (ab) 5871 (a) 2027 (ab) •Preplant fertilizer N was applied as urea. • ** Topdress fertilizer N rates for Treatments 3-10 were determined based on the NDVI values obtained using GreenSeeker. •The means in the same column followed by the same letter are not significantly different, p<0.05. Consistently, there were no substantial differences in grain yields associated with topdress fertilizer N source (urea vs UAN) at any of 5 site-years. This indicated that topdress N fertilizer rates do not need to be adjusted based of fertilizer sources used, i.e. the same N rates should be prescribed whether urea or UAN is applied.
    11. 11. Prescribed N rates vs Yield Site- year Trt Preplant N rate, lb N ac-1 GS NDVI Prescribed topdress N rate, lb N ac-1 Total N rate, lb N ac-1 N rate difference , lb N ac-1 Grain yield, bu ac-1 Yield gain, bu ac-1 1 WTARC, 2012 2 220 0.3 62 282 -178 74 (d) +14 6 80 0.5 24 104 88 (a) 2 Martin, 2012 5 60 0.3 0 60 +37 35 =6 80 0.4 17 97 35 3 WTARC, 2011 6 80 0.4 9 89 - 42 32 (b) +10 7 20 0.3 27 47 22 (e) 4 WTARC, 2012 3 20 0.5 13 33 +91 80 (c) +8 6 80 0.5 24 124 88 (a) • As in the first growing season, in 2012, Spring Wheat (Canada) Algorithm and Generalized Algorithm did not prescribe any topdress N fertilizer to be applied at any of the 3 experimental locations. • The recommended application rates generated by the Sensor-Based Nitrogen Optimization Algorithm (USA/Canada/Mexico) ranged from of 0 lb N ac-1 at Martin in 2012 to 99 lb N ac-1 at WARC at 2012, depending on the NDVI values • Sensor-based generated topdress N rates did not always optimize grain yields. • Some rates were excessive (1), (2); Some rates did not make sense (3); Some rates made sense (4)
    12. 12. Results: GS vs PS y = 2.0825x2 - 1.0582x + 0.4613 R² = 0.50 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.10 0.20 0.30 0.40 0.50 0.60 0.70 PocketSensorNDVI GreenSeeker NDVI Relationship between GreenSeeker NDVI and Pocket Sensor NDVI, WTARC and WARC, 2011, and WTARC, WARC, and Martin, 2012. y = 1.2049x - 0.1196 R² = 0.91 0.25 0.30 0.35 0.40 0.45 0.50 0.37 0.39 0.41 0.43 0.45 0.47 0.49 PocketSensorNDVI GreenSeeker NDVI Relationship between GreenSeeker NDVI and Pocket Sensor NDVI, WTARC and WARC, 2011, and WTARC, WARC, and Martin, 2012. NDVI values are averaged by treatment over all five site-years. There was a strong relationship observed between NDVI values obtained with GreenSeeker and with Pocket Sensor. Understandably, the relationship was improved dramatically when mean NDVI values averaged by treatment were used (R2 = 91 vs R2 = 50)  importance of replication when taking the canopy reflectance readings because it helps to account for spatial variability present within a field
    13. 13. Results: GS vs Yield y = 3455.9x + 640.46 R² = 0.97 y = -2E+06x2 + 2E+06x - 361440 R² = 0.80 y = 24288x2 - 17481x + 7558 R² = 0.39 y = 7452.3x - 1134.3 R² = 0.96 y = 7408.9x - 917.65 R² = 0.75 0 20 40 60 80 100 120 0.2 0.3 0.3 0.4 0.4 0.5 0.5 0.6 0.6 0.7 Springwheatgrainyield,buac-1 GreenSeeker NDVI martin-12 warc-12 wtarc-12 wtarc-11 warc-11 •Strong linear relationship was observed between GS NDVI and yields at 4 of 5 site-years - GS NDVI values predicted 75 to 97 % of variation in grain yields. • At WARC in 2012, 80% of variation in yields was explained by variation in NDVI; however, unexpectedly, the observed trend was: the higher NDVI, the lower the yield – Negative slope. •Labus et al. (2002): “early season NDVI were not consistent indicators of wheat yields”. Extensive study in Montana, - the strength of NDVI-yield relationships was highly dependent on site-specific and region-specific characteristics. • Crop reflectance measurements aim not to predict yield, but estimate yield potential.
    14. 14. Results: GS vs Yield y = -157329x2 + 150526x - 32458 R² = 0.91 30 35 40 45 50 55 60 65 0.37 0.39 0.41 0.43 0.45 0.47 0.49 Springwheatgrainyield,buac-1 GreenSeeker NDVI • Relationship between mean GreenSeeker NDVI values and mean spring wheat grain yields (averaged over site-years) at WTARC and WARC, 2011, and at WTARC, WARC, and Martin, 2012. • GreenSeeker NDVI was able to predict 91 % of variation in spring wheat grain yields across site-years (R2 = 0.91)
    15. 15. PS NDVI vs Yield y = -79220x2 + 74697x - 14020 R² = 0.96 1500 2000 2500 3000 3500 4000 0.32 0.37 0.42 0.47 Springwheatgrainyield,lbac-1 Pocket Sensor NDVI Relationship between mean Pocket Sensor NDVI values and mean spring wheat grain yields (averaged over site-years) at WTARC and WARC, 2011, and at WTARC, WARC, and Martin, 2012. • Robust linear relationship was also evident between PS NDVI and yields at 3 of 5 site-years in 2011 and 2012, where spring wheat grain yield was predicted midseason with 83 to 92 % accuracy. • When averaged across site-years, PS NDVI values collected at Feekes 5 growth stage were able to predict 96 % of variation in spring wheat grain yields.
    16. 16. Total N applied vs Yield  Strong polynomial relationships between the total amounts on N applied (preplant plus topdress) was observed at all 5 site-years.  The highest topdress N rates prescribed did not result in increase in grain yield, but in most cases, caused yield reduction. y = -0.0007x2 + 0.264x + 15.397 R² = 0.97 y = -0.0014x2 + 0.4024x + 35.272 R² = 0.81 y = -0.0012x2 + 0.2704x + 73.691 R² = 0.86 y = -0.0021x2 + 0.5048x + 71.991 R² = 0.60 y = -0.0004x2 + 0.0972x + 30.071 R² = 0.66 0 20 40 60 80 100 120 0 50 100 150 200 250 Grainyield,buac-1 Total N rate applied, lb N ac-1 wtarc-11 warc-11 wtarc-12 warc-12 martin-12
    17. 17. Protein Trt Preplant N Fertilizer Rate, lb N ac-1* Topdress N Fertilizer Source** Mean grain protein content, % 2011 2012 WTARC WARC WTARC WARC Martin 1 0 - 9.5 (bc) 14.1 (bcd) 9.6 (a) 11.5 (e) 14.3 (b) 2 220 urea 9.7 (ab) 16.4 (a) 15.4 (a) 14.9 (a) 16.7 (a) 3 20 urea 9.5 (bc) 14.6 (bc) 10.5 (a) 14.0 (abc) 15.3 (a) 4 40 urea 9.7 (a) 13.1 (d) 11.1 (a) 14.1 (abc) 15.7(a) 5 60 urea 9.4 (c) 15.2 (ab) 11.6 (a) 13.9 (bc) 15.9(a) 6 80 urea 9.6 (ab) 15.1 (ab) 12.8 (a) 14.4 (ab) 16.2 (a) 7 20 UAN 9.6 (abc) 14.5 (bc) 10.6 (a) 12.9 (d) 15.6 (a) 8 40 UAN 9.5 (abc) 13.5 (cd) 11.0 (a) 13.4 (cd) 15.8 (a) 9 60 UAN 9.5 (bc) 14.3 (bcd) 12.0 (a) 14.0 (abc) 16.0 (a) 10 80 UAN 9.5 (bc) 15.1 (ab) 13.0 (a) 14.3 (abc) 16.4 (a)  The highest preplant N rate was associated with the best protein content.  Topdress N rates did not optimize grain protein at any of the 5 site-years.  At irrigated site, WARC, urea resulted in significantly higher grain protein content, compared to UAN (15.4 vs 14.3)  At dryland sites, WTARC and Martin– no significant differences in grain protein content associated with N source.
    18. 18. Lessons Learned  In both growing seasons, the rates generated by the USA/Canada/Mexico Algorithm were not appropriate for grain yield optimization  Much higher rates were prescribed for the irrigated site (WARC) compared to those for dryland sites WTARC and Martin. This makes sense since the expected yield potential at the irrigated site was much greater  However, grain yields obtained at WTARC were just as high as at WARC yield potential was either underestimated at WTARC or overestimated at WARC  Separate algorithms developed for dryland spring wheat and for irrigated spring wheat production systems
    19. 19.  Both sensors perform well and are useful in predicting spring wheat grain yield potential mid- season  Algorithms developed in other regions do not provide the topdress N rates appropriate for Montana spring wheat varieties and growing conditions  It is expected that this study will continue for one more growing season at 3 experimental locations to expand database and to summarize results  Future studies are needed to pinpoint the rate of N loss due to volatilization and immobilization and other pathways in Montana wheat production systems for improved N recommendations. Lessons Learned
    20. 20. Protein Yield concept  Spring wheat is produced for its quality, represented by high grain protein content.  Evaluating NUE in spring wheat should take into an account both grain yield and protein content.  Combining yield and protein into protein yield, as proposed by Jackson (1998) makes sense because N is vital to both yield and protein production.  Protein Yield = grain protein content (%) * grain yield (lb ac-1)
    21. 21. THANK YOU!

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