Effects of Tillage System on NutrientEffects of Tillage System on Nutrient Availability and Management

Prepared for 2007 MABA Convention

by Clain Jones, Extension Soil Fertility Specialistl i j@ d 406 994 60 6clainj@montana.edu; 406 994-6076

No-till Relevance

50%tal)

Wi t Wh t 2004

35%40%45%

% o

f tot Winter Wheat, 2004

20%25%30%

age

(%

10%15%20%

Acr

ea

0%5%

MT ID CO NE WY UT West USNo

Till

MT ID CO NE WY UT West USN

Data from Conservation Technology Information Center

Conservation Tillage

80%l)

Wi t Wh t 2004

60%

70%

% o

f tot

a Winter Wheat, 2004

40%

50%

eage

(%

20%

30%

40%

ge A

cre

0%

10%

20%

ns. T

illa

0%

MT ID CO NE WY UT West USCon

Questions for youQuestions for you

• Is the majority of all of your clients’Is the majority of all of your clients acreage in no-till? Yes, No?

• Who recommends different N fertilizer• Who recommends different N fertilizer rates for no-till than for till?

Objectives todayObjectives today

• Discuss how tillage reduced tillage or noDiscuss how tillage, reduced tillage, or no till can affect nutrient availability

• Show the effects of tillage system on yield• Show the effects of tillage system on yield and protein responses to nitrogen (N)Sh th ff t f till t• Show the effects of tillage system on vertical ‘stratification’ of phosphorus (P)

d P il bilitand P availability

BasicsBasicsTillage ‘mineralizes’ more N than no-till, g ,

especially in short term.Why?

1. Soil Aeration: bacteria and fungi work faster with oxygen.

2 B k i ti l d ll id2. Breaks up organic particles and colloids: More surface area faster decomposition

3 Temperature slightly higher in spring under3. Temperature slightly higher in spring under tillage, due to less shading/darker surface: Higher temp faster breakdown

Basics continuedBasics, continuedWhen N fertilizer is surface broadcast, ,‘immobilization’ will be higher on no-till than tilled fields.Wh ?Why?Bacteria and fungi use fertilizer N in breaking down stubble at surfacestubble at surface.Solution? Add 10 lb N/ac more for each ½ ton stubble thatAdd 10 lb N/ac more for each ½ ton stubble that remains on surface IF broadcast N (stubble weight = ~1.5 x grain weight).

How does tillage affect O.M. in Montana?Montana?

Tillage effect on soil organic carbon, 2002.Tillage effect on soil organic carbon, 2002.

35

NT CT

a

Measured SOC (0 to 20-cm) Bricklemyer, 200335

NT CT

a

Measured SOC (0 to 20-cm) Bricklemyer, 2003

1 ) 25

30

a aa

ab α = 0.1

1 ) 25

30

a aa

ab α = 0.1

SOC

(t

ha-1

20

25

ba

a

b

bSOC

(t

ha-1

20

25

ba

a

b

b

15

a

b15

a

b

Chester Conrad E Conrad W Ft. Benton St. Johns Simpson

10

Chester Conrad E Conrad W Ft. Benton St. Johns Simpson

10

Organic matter and organic N h i hchanges with management

Is building O M free?Is building O.M. free?

• NO!NO!• It takes N to ‘grow’ O.M.:

T i 1% O M i 6 i h t kTo gain 1% O.M. in upper 6 inches takesabout 1,000 lb N/acre extra N.(assumes 20:1 O.M.:N ratio)

• Need more N in first few years afterNeed more N in first few years after converting to NT to attain same response as CT Less N in long-termas CT. Less N in long term.

N response curves differ between h d l NTshort- and long-term NT

Spring Wheat

From Miller et al. 2004 Why is there a larger difference with protein than with yield at high N?

QUESTIONS SO FAR?QUESTIONS SO FAR?

What if don’t add anymore N to NT h CT fi ld ?than to CT fields?

• Study site: Moccasiny• Researchers: C. Chen and C. Jones• 9-yr NT (NTNT) side by side with 30+ yr CT (CTCT). CT

= one sweep tillage pass per year (Reduced Till?)= one sweep tillage pass per year (Reduced Till?)• Organic Matter in top 6 inches was same after 9-yr.• Part of NT converted to CT in 2005 (NTCT)• Part of CT converted to NT in 2005 (CTNT)• Four systems: Fallow, spring pea (grain), winter pea

(forage) and spring wheat All seeded to winter wheat in(forage), and spring wheat. All seeded to winter wheat in Fall 2005.

Moccasin, 200530

Spring Wheat Grain YieldAfter 9 yr of Identical N Rates

20

25

bu/a

cre)

After 9-yr of Identical N Rates

NTCT

15

in Y

ield

(b NT

10

SW G

rai

0

5

Data from C. Chen

0 20 40 60 80 100 120Nitrogen Units (lb N/acre)

Moccasin, 2006

60

70

e)

Winter Wheat Grain Yield following Fallow

50

d (b

u/ac

re

NT

CT

30

40

Gra

in Y

ield NT

20WW

G

Why the difference?

0

10Data from C. Chen

Why the difference?

0 20 40 60 80 100 120Nitrogen Units (lb N/acre)

Moccasin, 2006

70

80

Winter Wheat Grain Yield following Winter PeaAfter 10-yr of Identical N Rates

50

60

(bu/

acre

) After 10 yr of Identical N Rates

CT

40

50

rain

Yie

ld

NT

20

30

WW

Gr

Is difference due to N??

0

10Data from C. Chen

00 20 40 60 80 100 120

Nitrogen Units (lb N/acre)

Spring Nitrate-N (2006) after 10-yr f Id i l N Rof Identical N Rates

90C Chen

70

80

(lb/

ac)

CTNT

C Chen

Why different?

40

50

60

l Nitr

ate-

N

20

30

40

Sprin

g So

i

0

10

S

Fallow Winter Pea Spring Pea Spring Wheat

Previous Crop

Moccasin, 2006

60

70

Winter Wheat Grain Yield following Spring

50

(bu/

acre

)

CT

30

40

ain

Yiel

d

NT

10

20

WW

Gra

Why the difference?

0

10

0 20 40 60 80 100 120

Data from C. Chen

0 20 40 60 80 100 120Nitrogen Units (lb N/acre)

How do grain yields between NT and CT i th M t t di ?

---

CT compare in other Montana studies?• Bricklemyer and

Miller, 2006• Six sites: NT-CT

small plot study.• Data: From 2nd

f iyear of ongoing study.

Wheat Yields for NT, CT, after Fallow, d C ti C i (2004)and Continuous Cropping (2004)

Wheat Yeild (2004)Average NT yield was 13% higher than average CT yield

50

60

30

40

(bu

ac-1

)

10

20Yiel

d (

0

10

Chester Collins Conrad Great Falls Kremlin PowerSite

No-till Tilled Alternate Yr Continuous

Take home messages on NTake home messages on N

• More N will be needed in first few yearsMore N will be needed in first few years after conversion to NT, ESPECIALLY when surface broadcast (10 lb N/1000 lb (stubble) .

• In “mid-term” (5-10 yr?), similar N will be ( y )needed to maximize yield.

• In long-term, less N will be needed to gmaximize yield and protein, especially when more N was added in short-term.

QUESTIONS SO FAR?QUESTIONS SO FAR?

Basics on PBasics on P• Soil pH controls P availability more than p y

mineralization does. Different than N.• SO, tillage expected to affect P less than N.• Soil pH is generally somewhat less near surface

of no-till field, which should increase P availability near surfaceavailability near surface.

• Some are asking if P is concentrating near P subsurface bands more in NT than in tilled subsu ace ba ds o e t a t edsystems, and if so, how is this affecting P availability?

P Stratification in Alberta (Lupwayi et al., 2006)Olsen P (ppm)

m)

dept

h (c

mS

oil

1998-99 1999-2000

Stratification appears dependent on:

• YearYear

• Crop

• Tillage

Wheat P uptake was not different between tillage p gsystems, suggesting stratification differences did not greatly affect overall P availability.

0

Does P stratification happen here in Montana?

e (in

.)0

2LSD (0.05) = 5.1 ppm

l sur

face

4

J d Ch

rom

soi

l

6

8

Jones and Chen, Moccasin

Dep

th f

10NTNTNTCTCTNTCTCT

Ol P ( )0 2 4 6 8 10 12 14 16 18 20

12CTCT

September 2005Olsen P (ppm) September 2005

Is Olsen P the only P fraction that could be affected by tillage?

Average P concentration in top 6 inches for different P fractions

140

160NTNTNTCTCTNT

ppm

)

100

120CTNTCTCT

otal

P (

60

80

To

20

40

b a a a

Resin-P Bic-P NaOH-P HCl-P Olsen P0

b

Extractions Jones and Chen, Moccasin

But the proof is in the pudding…meaning P f

30

c) 0 lb N/ac

uptake is likely best indicator of P availability

No differences in P uptake between tillage

25

b P 2

O5/a

c 0 lb N/ac80 lb N/aca

ababab

No differences in P uptake between tillage systems when N rate was optimized.

15

20

upak

e (lb bc

cdd d

10

15

ound

P u d

5

Abo

vegr

o

0NTNT NTCT CTNT CTCT

A

Is P being ‘stranded’ near the surface i d d till t ( hin reduced till systems (esp. when

broadcast or seed-applied)?pp )

• Apparently, yes.• Where should P be applied for best uptake?

We regressed P uptake against Olsen P (and resin P) for each 1.2 inch layer to find the depth with the highest correlation and thus possibly b t d th t l Pbest depth to apply P.

Correlation between Olsen P and ‘Resin P’ for h 1 2 i l d P t k (M i )each 1.2 in. layer and P uptake (Moccasin)

T able 2 . C orrela tion coefficien ts betw een O lsen P an d resin -P con cen tra tion s an d abovegroun d P

O lsen P R esin Pr 2-va lue r 2-va lue

D ep th (in .)

up take in in d ividua l soil layers an d averaged soil dep th s.

In d ividua l layers 0 - 1 .2 0 .46** 0 .12N S

1 .2 - 2 .4 0 .46** 0 .17N S2 .4 - 3 .6 0 .57*** 0 .35*3 6 4 8 0 50** 0 13N S

Best correlation at 2.4 to 3.6 in. below

3 .6 - 4 .8 0 .50** 0 .13N S4 .8 - 6 .0 0 .17N S 0 .005N S

A veraged dep th s0 - 2 .4 0 .53** 0 .19N S0 3 6 0 57*** 0 28*

soil surface.

0 - 3 .6 0 .57*** 0 .28*0 - 4 .8 0 .59*** 0 .30*0 - 6 .0 0 .57*** 0 .27*0 - 8 .3 0 .54**0 - 12 .0 0 .42**2 4 4 8 0 60*** 0 32*2 .4 - 4 .8 0 .60*** 0 .32*

respectively

N S , n ot sign ifican t a t P = 0 .05 * , ** , *** sign ifican t a t P< 0 .05 , 0 .01 , 0 .001

0

How much available P is there at 2.4 to 3.6 inches deep?

e (in

.)0

2LSD (0.05) = 5.1 ppm

surfa

ce

4

m s

oil s

6

epth

fro 8

10NTNTNTCT

0 2 4 6 8 10 12 14 16 18 20

De 10

12

CTNTCTCT

Olsen P (ppm)0 2 4 6 8 10 12 14 16 18 20

Take home messages on PTake home messages on P

• There may be some slight, yet not significant,There may be some slight, yet not significant, differences in P availability between tillage systems.

• Olsen P measured to 6 inches appears to be a good estimate of available P, regardless of tillage system.

• P should be placed approximately 3 inches b h il f id di ibeneath soil surface to avoid stranding it near surface, especially in reduced till systems.

ConclusionsConclusions• N rates need to be increased in short term NT to

maximize yield and build organic matter This willmaximize yield and build organic matter. This will save on N in long-term.

• P rates can be based on Olsen P levels in upper 6P rates can be based on Olsen P levels in upper 6 inches, and do not need to be adjusted based on tillage system.

• Placement of both N and P may be as important as rate in optimizing yield in reduced till systems.

For more informationFor more information

• Soil Fertility Website:Soil Fertility Website: http://landresources.montana.edu/soilfertility

• Cropping Systems Website:• Cropping Systems Website: http://scarab.msu.montana.edu/CropSystems