Nitrogen Use Efficiency Workshop

Canopy Reflectance Signatures: Developing a Crop Need-Based Indicator for Sidedress

Application of N Fertilizer to Canola

Dr. Bao-Luo Ma

Research Scientist – Crop Physiology

Eastern Cereal and Oilseed Research Centre (ECORC), Ottawa, ON

613-759-1521, baoluo.ma@agr.gc.ca

Canada

Introduction

• Canola:• Is the important source of edible oil after soybean• < 2% erucic acid in oil and <30 µmoles glucosinolates g-1

canola meal. • Rapeseed: 25-45% erucic acid and 50-100 µmoles

glucosinolates

• Becoming an important crop in the Eastern Canada:• canola offers growers a good return• an excellent rotation crop/alternative crop• operation of TRT has brought canola growers closer to

a crushing and refinery plant• canola acres are poised for significant growth

Challenge for growers and industry

• Ensure a stable supply of high quality oilseed• Improve canola productivity • Cultivar more resilient to climate variability• Adoption of best management practices• Minimizing negative impacts on environment• Nutrient management, key to increase yield

and oil content • Need tools for best nutrient management

Soil Sampling Grid Sampling a 52 Acre Field

1 sample every 2.5 acres21 samples per field

1 sample every 0.625 acres83 samples per field

1 sample every 0.156 acres333 samples per field

The large spatial variability reduces the effectiveness of using soil N as a tool for fertilizer recommendation for improved NUE.

Nutrient availability and canopy signature

0 30 60 90 120 150 1800.60

0.65

0.70

0.75

0.80

f(x) = 0.000504546790476191 x + 0.697028575714286R² = 0.666876011450706

2005

ND

VI

0 30 60 90 120 150 1800.50

0.55

0.60

0.65

0.70

f(x) = − 0.000324931547619047 x + 0.583632053571429R² = 0.851529642616759

2006

ND

VI

pH = 6.9, warm spring pH = 6.0, cool spring

Crop response to soil pH• Most field crops grow best in soils with slightly acid

reaction (pH 7.0 – 6.5)

• Almost all plant nutrients are available in optimal for plant growth

• pH < 6.0, likely deficient in Mg, Ca, K

• Strongly acid soil (pH < 5.0, Al, Fe, Mn toxicity)

• pH >7.0, Fe, Mn, Zn, Cu unavailable for plant growth

Objectives

Build knowledge of oilseed crop for Eastern Canada

• Develop a crop need-based indicator to be used for canola recommendations;

• Develop nutrient best management practices for growing canola in eastern Canada

Materials and Methods

Experimental Locations

1) Central Experimental Farm, Ottawa, ON (2011, 2012, 2013)

2) North Bay, ON (2012, 2013)

3) Guelph, ON (2012, 2013)

4) Two sites in QC

5) One site in NB

6) One site in NS

Experimental Design

A field experiment with combinations of preplant and sidedress N fertilizer as urea, was arranged in a RCB design with 4 replications in each site-year.

• Preplant: 0, 50, 100, 150, 200 kg N ha-1

• Sidedress: 50+50, 50+100, 50+150 kg N ha-1

• Hybrid: Bayer InVigor 5440 (LL) (in 2011 & 2012), InVigor 5440 and L150 (2013)

• In all site-years, research plot experiments

• In North Bay, a 50 ac field with preplant fertilizer strips and a plot study also nested in the field in 2013

Data Collection

1) Soil samples (0-30 cm) at seeding, sidedress, early flowering and after harvest.

2) Biomass sampling and leaf area measurements from rosette to 20% flowering

3) Canopy reflectance measurements using two sensors: Greenseeker and CropScan from pre-sidedressing to early flowering

5) Final yield @10% moisture6) Yield components7) Straw and grain N concentrations

Results

conola-treatment-4

conola-treatment-1

conola-treatment-3

conola-treatment-2

conola-treatment-2

conola-treatment-2 conola-treatment-3

conola-treatment-1

conola-treatment-4

conola-treatment-4

conola-treatment-1

conola-treatment-3

conola-strip-9

conola-strip-8

conola-strip-7

conola-strip-1

conola-strip-11

conola-strip-10

conola-strip-12

conola-strip-2

conola-strip-4

conola-strip-5

conola-strip-6

conola-strip-3

0 100 20050 Meters

Canola

±48 mx 290 m(157 feet x 951 feet)

48 mx 400 m (157 feet x 1312 feet)

48 mx 290 m

48 mx 290 m

48 mx 290 m

48 mx 290 m

48 mx 400 m

48 mx 400 m

48 mx 400 m

48 mx 400 m

48 mx 400 m

48 mx 400 m

North Bay field demonstration plots

Mean calculated from yield map based on strips

Treatments (kg N/ha) mean dry yield (Kg/ha)1. 0 26192. 50 27093. 100 27594. 150 2771

North Bay field demonstration plots 2012

0 20 40 60 80 100 120 140 160 180 2000.30

0.35

0.40

0.45

0.50

0.55

f(x) = − 0.00000547413371 x² + 0.0008140241 x + 0.49224879743R² = 0.509338022385675

f(x) = − 0.00000223619057 x² + 0.00029151813 x + 0.43495304514R² = 0.788897064687071N

DVI

Jun 10

0 20 40 60 80 100 120 140 160 180 2000.60

0.65

0.70

0.75

0.80

f(x) = − 0.00000835 x² + 0.0017065 x + 0.66805R² = 0.979927072891164

f(x) = − 0.00000319285714 x² + 0.00058407143 x + 0.65323571429R² = 0.374320164364229

ND

VI

Jun 13

0 20 40 60 80 100 120 140 160 180 2000.65

0.70

0.75

0.80f(x) = − 0.00000438571429 x² + 0.00105014286 x + 0.73362142857R² = 0.914104168568959f(x) = − 0.00000519285714 x² + 0.00114207143 x + 0.71343571429R² = 0.909891156462585

ND

VI

Jun 17

0 20 40 60 80 100 120 140 160 180 2000.60

0.65

0.70

0.75

0.80

f(x) = − 0.0000056785714 x² + 0.0013982143 x + 0.6919071429R² = 0.898519785972393f(x) = − 0.0000081714286 x² + 0.0020172857 x + 0.6434428571R² = 0.941650243073888

ND

VI

Jun 21

0 20 40 60 80 100 120 140 160 180 2000.65

0.70

0.75

0.80

f(x) = − 0.00000091428629 x² + 0.0003468573 x + 0.7440285686R² = 0.805895516421257

f(x) = − 0.0000034666671 x² + 0.0011320001 x + 0.6953333303R² = 0.88593726927437

ND

VIJun 25

2013 Ottawa Plot Exp.Seeding: May 6Sidedress: June 14pH = 6.3

0 50 100 150 2000.40

0.45

0.50

0.55

0.60

0.65

0.70

0.75

0.80

f(x) = − 1.05761790947491E-05 x² + 0.00270965752890626 x + 0.453500769290827R² = 0.914306594104017

f(x) = − 6.35984227652709E-06 x² + 0.00186957576733155 x + 0.62033840214044R² = 0.972112626949863

CropScan (R670,R780)N

DVI

2013 North Bay Plot Exp.Seeding: May 14Sidedress: June 18

pH = 7.5

0 1 2 3 4 5 6 7 8 90.62

0.64

0.66

0.68

0.7

0.72

0.74

0.76

0.78

0.8

0.82

f(x) = − 0.00327673253 x² + 0.04099165388 x + 0.66240863275R² = 0.959235306426636

Soil NO3-N (ug g-1)

Ca

no

py

Re

fle

cta

nc

e (

ND

VI)

Ottawa - 2012

0 2 4 6 8 10 12 14 16 180

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

f(x) = − 0.00067050954 x² + 0.02368880007 x + 0.53425923854R² = 0.628309674504979

Soil N03-N (ug g-1)

Ca

no

py

Re

fle

cta

nc

e (

ND

VI)

Ottawa - 2011

Relationship between canopy reflectance and soil NO3-N at the early flowering stage

Seeding: May 11, 2011Sidedress: Jun 14pH = 7.1

Seeding: May 14, 2012Sidedress: Jun 14pH = 6.5

0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.751000

1200

1400

1600

1800

2000

2200

2400

2600

2800

3000

f(x) = − 2631.09701622599 x² + 10378.2471281689 x − 3485.14503490147R² = 0.999647047531634

Canopy Reflectance (NDVI)

Yie

ld (k

g h

a-1)

Greenseeker-June 21

Ottawa - 2011

Relationship between canopy reflectance and yield

Ottawa -2012

0.7 0.71 0.72 0.73 0.74 0.75 0.76 0.77 0.78 0.791000

1100

1200

1300

1400

1500

1600

1700

1800

1900

2000f(x) = 0R² = 0

Canopy Reflectance (NDVI)

Yiel

d (k

g ha

-1)

Greenseeker - June 27

Canola yield response to N

Conclusions• Canola seed yield responded to N fertilizer

positively, more so with sidedress application;• For each kg N ha-1, seed yield increased by 9.7 for

preplant application, by 13.7 kg ha-1 for sidedress;• Drought severely affected canola response to N;• There was a close relationship between NDVI and

soil NO3-N, between NDVI and seed yield;

• Canopy reflectance expressed as NDVI delineated N treatments at sidedress stage;

• Reflectance signatures were affected by soil conditions such as low pH, cool temperatures;

Conclusions (cont’d)• There is a small window for sidedress, but late

delineation of N effects by NDVI is a big challenge;• It is possible to estimate N requirement by measuring

canopy reflectance. • Multi-site, multi-year data are needed to account for

environmental extremes, spatial and temporal variability, and to derive NDVI – N rate algorithms;

• Need to examine the balance between N:S and the optimum range of other nutrients;

• Variable rate application of N using precision technology will play an important role.

Acknowledgements• ECODA: Rory Francis, Etienne

Tardiff, Don Smith• Professional: D. Smith, C.

Caldwell, P. Scott, A. Vanasse, H. Earl, J. Shang

• Technical support staff and students