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7 th International Wheat Conference November 29, 2005 Mar del Plata, Argentina

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TILLAGE INTENSITY, CROP ROTATION, and FERTILIZER TECHNOLOGY for SUSTAINABLE WHEAT PRODUCTION … NORTH AMERICAN EXPERIENCE. 7 th International Wheat Conference November 29, 2005 Mar del Plata, Argentina T.L. Roberts and A.M. Johnston Potash & Phosphate Institute. Introduction.

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TILLAGE INTENSITY, CROP ROTATION, and FERTILIZER TECHNOLOGY for SUSTAINABLE WHEAT PRODUCTION … NORTH AMERICAN EXPERIENCE

7th International Wheat Conference

November 29, 2005

Mar del Plata, Argentina

T.L. Roberts and A.M. Johnston

Potash & Phosphate Institute

introduction
Introduction
  • North America is a world leader in no-till crop production
extent of no tillage adoption worldwide million hectares 2004 05
USA25.3

Brazil23.6

Argentina16.0

Canada13.4

Australia9.0

Paraguay1.7

Indo-Gangetic-Plains 1.9

Bolivia0.6

South Africa0.3

Extent of no-tillage adoption worldwide, million hectares, 2004/05.

Spain0.3

Venezuela0.3

Uruguay0.3

France0.2

Chile0.1

Colombia0.1

China0.1

Others (estimate) 1.5

Total 94.6

Source: J. Hassell, Conservation Technology Information Center, personal communication

introduction1
Introduction
  • North America leads the world in no-till crop production
  • USA produces about 60 billion t wheat and exports 30 billion t
  • Canada produces 26 billion t and exports 18 billion t
northern great plains
Northern Great Plains
  • Total area about 125 M ha
    • 52 M ha in crop production
  • Wheat is the dominant crop, followed by barley and oats
    • Corn is dominant only in the southern regions
northern great plains1
Northern Great Plains
  • Canola is the dominant oilseed, grown mainly on the Canadian prairies
  • Dry peas and lentils … crop diversification option, but represent small proportion of cropping mix
northern great plains environmental conditions
Northern Great PlainsEnvironmental Conditions
  • Severe … cold winters and hot summers
  • Moisture is limiting
    • 300 to 500 mm of annual precipitation; 165 to 300 during the April to July growing season
  • Frost free period … 83 to 157 days
  • Soils are frozen for 4 to 6 months … minimizing microbial activity, nutrient release, and crop residue decomposition
no till wheat production
No-till Wheat Production
  • Farmers in Canadian prairies and Northern Great Plains pioneered wheat production in reduced tillage systems.
  • No-till, or direct-seeding, is used on about ~third of U.S. wheat farms and half the Canadian wheat area.
no till wheat production1
No-till Wheat Production
  • Erosion control is the main reason for adopting no-till in much of the world, but in Canadian prairies … improved moisture efficiency
soil zones of the canadian prairies
Soil zones of the Canadian prairies.
  • About 30 M ha of cultivated land
    • Spring wheat is the principal crop
  • Rotations … historically included high proportions wheat and summerfallow, but fallow has been declining and no-till area is increasing
no till area in the canadian prairies
No-till area in the Canadian prairies.

Source: B. McClinton, Saskatchewan Soil Conservation Association

trends in cropping intensity in the canadian prairies
Trends in cropping intensity in the Canadian prairies.

Average rotation length*

Soil zone 1976 1980 1985 1990 1995 1998

Brown 1/1.1 1/1.1 1/1.3 1/1.3 1/1.3 1/1.6

Dark Brown 1/1.4 1/1.5 1/2.1 1/2.2 1/3 1/4

Black and Gray 1/2.2 1/2.6 1/4.9 1/4.9 1/6.7 1/10

*Interpret rotation 1/1.1 as one year fallow to 1.1 year in crop

Source: Campbell et al., 2002

cropping systems
Cropping Systems
  • Growers now incorporate cereals, oilseeds, pulse crops, and forages into their rotations.
  • Wheat still dominates, but the improved water conservation gives growers greater flexibility.
soil changes related to tillage
Soil Changes Related to Tillage
  • Tillage accelerates the natural processes of soil degradation
    • Erosion, salinization, and acidification increase
    • amount and quality of organic matter decreases
  • Reduced tillage … greater crop residues accumulate on the soil surface
when residues accumulate
When residues accumulate …
  • Less wind and water erosion … improved soil quality
  • Increased water infiltration and less evaporation
  • Cooler soil temperatures … slower nutrient release, reduced diffusion, less root growth
when residues accumulate1
When residues accumulate …
  • Changes in nutrient cycling … increases in N immobilization … eventually increased N mineralization
  • Immobile nutrients tend to accumulate at the soil’s surface
  • Soil pH may decline
  • Fertilizer management becomes more important
effect of zero and conventional tillage on p and k distribution in a manitoba silty clay
70

1300

60

1200

Conventional Till

Conventional Till

50

1100

Zero Till

Zero Till

Phosphorus, mg/kg

40

1000

Potassium, mg/kg

30

900

20

800

Silty Clay Soil

10

700

Silty Clay Soil

600

0

0

5

10

15

20

25

30

35

40

45

0

5

10

15

20

25

30

35

40

45

500

Depth, cm.

Depth, cm.

400

300

Effect of zero and conventional tillage on P and K distribution in a Manitoba silty clay

Source: Grant and Bailey, 1994

fertilizer management
Fertilizer Management
  • Fertilizer management in no-till seeding requires careful management to optimize nutrient use efficiency
    • Soil characteristics, climate, crop type, and agronomic practices impact nutrient use efficiency
fertilizer management1
Fertilizer Management
  • N is the most yield limiting nutrient world wide, followed by P and K
  • Broadcasting N onto surface covered residue is not efficient
fertilizer management2
Fertilizer Management
  • In-soil band placement of N is usually the most effective … reduces immobilization, but applying all the crop’s N requirements can be challenging
  • P and K applied in bands minimizes fixation and increases early season uptake … especially when applied as a starter
yield increase from starter p in a saskatchewan fallow wheat wheat rotation 1967 2004
Yield increase from starter P in a Saskatchewan fallow-wheat-wheat rotation, 1967-2004

Mean

Fallow = 342 kg/ha

Stubble = 197 kg/ha

Source: R.P. Zentner, Agriculture and Agri-Food Canada

slide22
F-W-W (N+P)

F-W-W (N)

Influence of starter P on soil test P in the wheat phase of a Saskatchewan fallow-wheat-wheat rotation, 1967-2004

Olsen P, kg/ha

Source: R.P. Zentner, Agriculture and Agri-Food Canada

fertilizer management3
Fertilizer Management
  • All P needs for wheat can be safely applied at seeding … not so for N and K
  • Too much N and K can reduce germination and delay emergence resulting in poor stands and lower yields
fertilizer management4
Many factors influence how much fertilizer can be safely applied with the seed

Row spacing

Seed bed utilization (SBU)

Soil texture

Soil moisture

Fertilizer Management
  • Soil variability
  • Fertilizer placement
  • Seed furrow opener
  • Fertilizer source
  • crop
row spacing
30 cm

10 cm

20 cm

Row Spacing
  • The amount of fertilizer that can be safely applied with the seed decreases as row spacing increases
  • Row spacing ranging from 10 to 30 cm … higher concentrations of P in wider rows had no effect on yield (SK and MB research)
seed bed utilization
Seed Bed Utilization
  • Measure of the amount of soil used for applying fertilizer.
  • Calculated as:

Width of seedrow

%SBU =

X 100

row spacing

seed bed utilization1
25%

12%

8%

30 cm

10 cm

20 cm

Seed Bed Utilization
  • Assuming a 2.5 cm seed row (knife opener) and a 10 cm row spacing

SBU = 2.5/10 x 100 = 25%

seed bed utilization2
Seed Bed Utilization
  • Heavier textured soils tolerate more N because the increased cation exchange and water holding capacity reduces ammonia toxicity … a major cause of germination and seedling damage
approximate safe rates of urea n kg ha that can be applied with wheat
Approximate Safe Rates of Urea-N (kg/ha) that can be applied with wheat.

2.5 cm spread

(Disc or knife)

Row spacing, cm

15 23 30

SBU, %

17 11 8

Light 22 17 17

Medium 34 28 22

Heavy 39 24 24

Source: Henry et al., 1995

approximate safe rates of urea n kg ha that can be applied with wheat1
Approximate Safe Rates of Urea-N (kg/ha) that can be applied with wheat.

2.5 cm spread 7.5 cm spread

(Disc or knife) (Sweep)

Row spacing, cmRow spacing, cm

15 23 30 15 23 30

SBU, % SBU, %

17 11 8 50 33 25

Light 22 17 17 45 34 28

Medium 34 28 22 56 45 39

Heavy 39 24 24 67 56 45

Source: Henry et al., 1995

specialized seeding equipment
Specialized Seeding Equipment
  • Many growers have adopted the use of specialty seeding equipment that places fertilizer in a separate band from the seed

No-Till Seeding Original Equipment

No-Till Seeding Present Equipment

slide33
Stealthtm Opener

2.5 cm

2.5 cm

slide34
3.8 x 7.2 cm

3.8 x 3.8 cm

urea and anhydrous ammonia nh 3 are the two main n sources used by the region s farmers
Urea and anhydrous ammonia (NH3) are the two main N sources used by the region’s farmers
  • NH3 is common in higher moisture regions, where higher N rates are required to optimize yields
sulfur is the third most limiting nutrient in the northern great plains
Sulfur is the third most limiting nutrient in the Northern Great Plains
  • Estimated 30% of the acreage in Canadian prairies is S deficient
  • SO4-S soil test is difficult due to variability of SO4 in the field and release of organic S

S deficient wheat

s fertilizer
S Fertilizer
  • S is normally applied as elemental S or as as SO4
  • Elemental S requires microbial oxidation
    • Temperature, moisture, aeration, pH and particle size influence oxidation
  • Application of elemental S in the spring or near planting is not recommended for annual crops because oxidation is too slow
    • Mixtures of bentonite and elemental S are available which increase the dispersion of S particles and increase oxidation rates
average wheat yield response to applied s in alberta soils with no previous s application
Average wheat yield response to applied S in Alberta soils with no previous S application

-S +S* Yield No. of

--- kg/ha --- inc., % trials

Gr. Wooded soils 1422 1619 14 12

Breton‡ 949 1830 93 20

U of A§ 2482 2731 10 8

* 15 kg S/ha as Na2SO4

‡ Average total S=100 mg/kg, § Average total S=670 mg/kg

Source: Doyle and Cowell, 1993

average wheat yield response to applied s in alberta soils with 20 year history of s application
Average wheat yield response to applied S in Alberta soils with 20-year history of S application

-S +S Yield No. of

--- kg/ha --- inc., % trials

Breton‡ 1 774 1178 52 5

2 2059 2225 8 5

3 1690 2737 62 5

4 2523 3641 44 4

U of A§ 1 3379 3659 8 4

2 1999 2023 1 4

* 15 kg S/ha as Na2SO4

‡ Average total S=100 mg/kg, § Average total S=670 mg/kg

Source: Doyle and Cowell, 1993

effect of n p and s fertilization on wheat yields in alberta
Effect of N, P, and S fertilization on wheat yields in Alberta.

Treatment N P2O5 S Yield Yield Inc.

------------- kg/ha ------------- %

1 0 0 0 2310 --

2 0 0 22 2550 10

3 18 22 0 2480 7

4 18 22 22 3020 31

Source: Doyle and Cowell, 1993

influence of n and p on wheat grown on fallow and stubble in a dark brown soil in southern alberta
Influence of N and P on wheat grown on fallow and stubble in a Dark Brown soil in southern Alberta.

Rotation sequence,

13-yr Ave. yield, kg/ha

Fertilizer, kg/ha Fallow wheat Stubble wheat

N P F-W F-W-W F-W-W Cont. W

0 0 2775 2332 1203 1156

0 20 2802 2641 1176 1284

45 0 2722 2460 1519 1505

45 20 3031 2654 1908 1747

Letters in bold face represent the phase of the rotation the yield was determined.

Source: Campbell et al., 1990

concluding comments
Concluding Comments
  • Understanding soil nutrient behavior and its implications to fertility management is important to maximize nutrient use efficiency and wheat production in no-till
  • Soil testing is the best available tool to estimate soil nutrient levels and make appropriate fertilizer recommendations
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