A Robust Management Option to Simultaneously Enhance Soil and Environmental Quality and

Sustain Crop Yields

Upendra Sainju

USDA-ARS

Northern Plains Agricultural Research Laboratory

Sidney, MT

Introduction

Intensive management practices in the last several decades have increased crop yields but also reduced soil and environmental quality by increasing soil erosion and acidity, N leaching, and greenhouse gas emissions (CO2, N2O, and CH4).

Little information is available about the impact of management practices that can simultaneously increase soil and environmental quality and sustain crop yields.

Improved management options are needed to increase soil C and N sequestration, reduce N fertilization rate and the potential for N leaching, mitigate greenhouse gas emissions, and sustain crop yield.

Objectives 1. Evaluate the effects of tillage, cropping sequence,

and N fertilization on dryland soil C and N levels, global warming potential, and crop yields and quality. 2. Identify management practices that Increase soil C and N sequestration, Decrease N fertilization rate, Reduce N losses through leaching, surface

runoff, volatilization, denitrification, and greenhouse gas (N2O) emissions.

Reduce net global warming potential and greenhouse gas intensity, and

Sustain crop yields and quality

Materials and Methods Treatments • Four tillage and cropping sequence (main

plot):

No-till continuous malt barley (NTCB)

No-till malt barley-pea (NTB-P)

No-till malt barley-fallow (NTB-F)

Conventional till malt barley-fallow (CTB-F)

• Four N fertilization rates: (split-plot)

0, 40, 80, and 120 kg N ha-1

Randomized complete block with three replications

Traditional farming practice: CTB-F with

80 kg N ha-1

80 kg N/ha

0 kg N/ha

Pea

No-till Conventional till

Malt barley

Materials and Methods (contd..) Location: Sidney, MT Annual precipitation: 357 mm Air temperature: -8oF in January to 23oC in July and August Soil: Williams loam Duration: 2006-2011 Parameters: Soil organic C Soil total N Soil residual N (NH4 + NO3)-N Amount of N fertilizer applied N balance Global warming potential Greenhouse gas intensity Annualized grain yield Malt barley grain protein concentration Malt barley grain plumpness

160.0

170.0

180.0

190.0

200.0

210.0

0 40 80 120

CTB-F (49)† NTB-F (192)

NTB-P (470) NTCB (-195)

Linear (CTB-F (49)†) Linear (NTB-F (192))

Linear (NTB-P (470)) Linear (NTCB (-195))

LSD (0.05)

Mean Soil Organic Carbon (0-120 cm) (2006-2011)

Soil

org

anic

C (

Mg

C h

a-1)

N fertilization rate (kg N ha-1)

† Number in parenthesis indicate soil C sequestration rate (kg C ha-1 kg -1 N)

15.0

15.5

16.0

16.5

17.0

0 40 80 120

CTB-F (-3.3)† NTB-F (5.8)

NTB-P (30.0) NTCB(-0.5)

Linear (CTB-F (-3.3)†) Linear (NTB-F (5.8) )

Linear (NTB-P (30.0)) Linear (NTCB(-0.5) )

LSD (0.05)

Mean Soil Total Nitrogen (0-120 cm) (2006-2011)

Soil

tota

l N (

Mg

N h

a-1)

N fertilization rate (kg N ha-1)

Sainju (2013). Agron. J. 105:1253-1263.

† Number in parenthesis indicate soil N sequestration rate (kg CNha-1 kg -1 N)

50.0

100.0

150.0

200.0

250.0

0 40 80 120

CTB-F NTB-F NTB-P NTCB Linear (CTB-F) Linear (NTB-F) Linear (NTB-P) Linear (NTCB)

Mean Residual Soil Inorganic Nitrogen {(NH4 + NO3)-N} Content (0-120 cm) (2006-2011)

N fertilization rate (kg N ha-1)

LSD (0.05)

Soil

ino

rgan

ic N

(kg

N h

a-1)

Sainju (2013). Agron. J. 105:1253-1263.

Total Amount of Nitrogen Fertilizer Applied (2006-2011)

N f

ert

ilize

r ap

plie

d (

kg N

ha-1

)

N fertilization rate (kg N ha-1)

Amount of N fertilizer requirement = Desired N rate –Soil NO3-N content at 0-60 cm

0

100

200

300

400

500

0 40 80 120

CTB-F NTB-F NTB-P NTCB

-2,000

-1,500

-1,000

-500

0

500

0 40 80 120

CTB-F NTB-F

NTB-P NTCB

Poly. (CTB-F ) Poly. (NTB-F )

Poly. (NTB-P ) Poly. (NTCB )

LSD (0.05)

Estimated Nitrogen Balance (2006-2011)

N b

alan

ce (

kg N

ha-1

) N fertilization rate (kg N ha-1)

N balance = Total grain N from 2006 to 2011 + Surface residue N in 2011 + Soil total N in 2011 – Soil total N in 2006 – Total N fertilizer applied from 2006 to 2011

Sainju (2013). Agron. J. 105:1253-1263.

Calculations Net global warming potential based on soil respiration (GWPR) (Mosier et al., 2006): GWPR = CO2 equivalents (farm operations + N fertilization + soil respiration + N2O flux + CH4 flux) - CO2 equivalent (previous year’s crop residue). Net global warming potential based on soil organic C (GWPC)(Robertson and Grace, 2004; Mosier et al., 2005; Liebig et al., 2010): GWPC = CO2 equivalents (farm operations + N fertilization + N2O flux + CH4 flux) - CO2 equivalent (Soil organic C). Net greenhouse gas intensity based on soil respiration (GHGIR): GHGIR = GWPR / Annualized grain yield. Net greenhouse gas intensity based on soil organic C (GHGIC): GHGIC = GWPC / Annualized grain yield.

-2500

-2000

-1500

-1000

-500

0

500

CTB-F NTB-P NTCB

Mean Net Global Warming Potential (GWPR) and Greenhouse

Gas Intensity (GHGIR) Based on Soil Respiration (2008-2011)

-1.5

-1

-0.5

0

0.5

N fertilization rate 0 kg N ha-1 80 kg N ha-1

G

HG

I R

G

WP

R

(kg

CO

2 e

q. k

g-1 g

rain

)

(kg

CO

2 e

q. h

a-1)

LSD (0.05)

LSD (0.05)

Sainju et al. (2014). Soil Sci. Soc. Am. J. 78:248-261

0

500

1000

1500

CTB-F NTB-P NTCB

Mean Net Global Warming Potential (GWPC) and Greenhouse Gas

Intensity (GHGIC) Based on Soil Organic Carbon (2008-2011)

0

0.2

0.4

0.6

0.8

1

LSD (0.05)

LSD (0.05)

0 kg N ha-1 80 kg N ha-1 N fertilization rate

GH

GI C

G

WP

C

(kg

CO

2 e

q. k

g-1 g

rain

)

(k

g C

O2 e

q. h

a-1)

Sainju et al. (2014). Soil Sci. Soc. Am. J. 78:248-261

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 40 80 120

CTB-F NTB-F NTB-P NTCB Poly. (CTB-F) Poly. (NTB-F) Poly. (NTB-P) Poly. (NTCB)

Average Annualized Malt Barley Grain Yield (2006-2011)

N fertilization rate (kg N ha-1)

LSD (0.05)

Gra

in y

ield

(M

g h

a-1)

Sainju et al. (2013). Agron. J. 105:1-12

10.0

11.0

12.0

13.0

14.0

15.0

0 40 80 120

CTB-F NTB-F NTB-P NTCB Poly. (CTB-F) Poly. (NTB-F) Poly. (NTB-P) Poly. (NTCB)

Average Malt Barley Grain Protein (2007-2011)

N fertilization rate (kg N ha-1)

LSD (0.05)

Gra

in p

rote

in c

on

c. (

%)

Sainju et al. (2013). Agron. J. 105:1-12

60.0

65.0

70.0

75.0

80.0

85.0

90.0

0 40 80 120

CTB-F NTB-F NTB-P NTCB Poly. (CTB-F) Poly. (NTB-F) Poly. (NTB-P) Poly. (NTCB)

Average Malt Barley Grain Plumpness (2007-2011)

N fertilization rate (kg N ha-1)

LSD (0.05)

Gra

in p

lum

pn

ess

(%

)

Sainju et al. (2013). Agron. J. 105:1-12

Improved vs. Traditional Farming Parameter NTB-P/40-80 vs. CTB-F/80† ___________________________________________________________ % Soil organic C 11 Soil total N 3 Residual soil inorganic N -32 Amount of N fertilizer applied -54 N balance 125 Global warming potential (Soil respiration) 622 Global warming potential (Soil organic C) 73 Greenhouse gas intensity (Soil respiration) 455 Greenhouse gas intensity (Soil organic C) 79 Annualized grain yield 44 Malt barley grain protein conc. -13 Malt barley grain plumpness 24 ______________________________________________________________ • † Number indicates N fertilization rate (kg N ha-1)

Conclusions Compared to traditional conventional till malt barley-fallow with 80 kg N ha-1, no-till malt barley-pea with 40 to 80 kg N ha-1 in dryland cropping systems can be used as a robust management option to

Increase soil C and N sequestration

Reduce N losses through leaching, volatilization, denitrification, and surface runoff

Decrease N fertilization rate

Mitigate greenhouse gas emissions

Sustain crop yields and quality

Acknowledgements

Joy Barsotti Michael Johnson

Jana Seright Mark Gaffri

Emily Reese Tyler Stevens

Ethan Schaff Andrew Lenssen

Christopher Russell Johnny Rieger