Conclusions

• CASH soil health indicators lack sensitivity to quantify differences in long-term agronomic systems in southern soils.

• Soil health management recommendations for agronomic systems need to be adjusted to account for differences inintrinsic soil properties and agroecological regions.

• There is no relationship between crop yields and current soil health indicators.

Background

Soil Health Testing does not Differentiate Long-term AgronomicSystems in North CarolinaWayne Roper, Deanna Osmond, Joshua Heitman, Michael Wagger, Chris Reberg-Horton

1) Determine if soil health indicators can distinguish between cropping and tillage systems in North Carolina.

2) Compare soil test results and their implications for soil management recommendations.

3) Assess relationships between soil health testing and crop yields.

Methods and Materials

The study consisted of long-term research trials that represented mountain,piedmont, and coastal plain soil types of North Carolina

Mountain Piedmont Coastal Plain

City Mills River Reidsville Goldsboro

Established 1994 1984 1999

Plot Size and design

12.2 x 24.4 m (40 x 80 ft) 20 plots, CRD

5.8 x 15.2 m (19 x 50 ft)36 plots, RCBD

Various sizes12 plots, RCBD

Crops Vegetables (1994-2006)Corn (2006-2014)

Corn and soybean annual rotation Various vegetablesCorn and soybean annual rotation

Treatments(management)

NTCNTOCTCCTOCTX

- No-till chemical- No-till organic- Conventional chemical- Conventional organic- Conventional fallow

NTCIRSDSCPSCPFCPDSCPDFMPDSMPDF

- No-till chemical- In-row Subsoil - Spring- Disk - Spring- Chisel - Spring- Chisel - Fall- Chisel/Disk - Spring- Chisel/Disk - Fall- Moldboard/Disk - Spring- Moldboard/Disk – Fall

NTCRTOCTOCTC

- No-till chemical- Reduced-till organic- Conventional organic- Conventional chemical

Cover Crop Annual wheat and crimson clover in all plots

None Sudangrass, clover, vetch (org)Rye (conventional)

Soil Type Delanco silt loam Wedowee sandy loam Wickham sandy loam; Tarboro

Management History

Index Score

NCDA&CS Soil Testing

Results

CASH Soil Indicator Index Scores

Department of Crop and SoilSciences

Objectives

• More research is needed to determine the significance of soil health indicators in quantifying the effects of agronomic practices on soil properties and productivity.

• A current focus in soil research is ‘soil health’, which is the ability of soilto function as a sustainable vital ecosystem.

• Several physical, chemical, and biological soil properties have beenreferenced as indicators of soil health.

• The utility of these indicators for soil management recommendations in different agronomic systems is not yet clear.

Contact:

Wayne Roperwrroper@ncsu.edu3230 Williams HallNC State University

• All tillage and cropping systems, except Mountain NTO were rated low by the CASHregardless of the presence of cover crops or other conservation tillage practices.

• Essential plant nutrients were in sufficient quantity for every treatment.

• Biological soil indicators were rated low in each system and were the reason whymanagement systems were rated low overall.

Research Trials

MountainMills River

PiedmontReidsville

CoastalGoldsboro

Soil Sampling and Testing

Soil subsamples were collectedat random points within a plotand combined to produce arepresentative plot sample.

Approximately 470 cm3 (2 cups)of soil from the top 0-15 cmwas collected for soil testing byNCDA&CS.

Approximately 1400 cm3 (6cups) of soil from the top 0-15cm was collected for the CASH.

North Carolina Department of Agriculture & Consumer Services (NCDA&CS)

NCDA&CS soil testing extractsessential plant nutrients from soiland uses an index scale conversionto recommend fertility applicationsfor specific crops.

Cornell’s CASH evaluates chemical,physical, and biological soilproperties and makes generalmanagement recommendations ona 0-100 index scale.

Comprehensive Assessment of Soil Health (CASH)

Very High (85-100)

High (70-85)

Medium (55-70)

Low (40-55)

Very Low (0-40)

Score Descriptors(2015 rating scale)

NTC IRS DS CPF CPS CPDF CPDS MPDF MPDS NTC RTO CTC CTO0

10

20

30

40

50

60

70

80

90

100

NTC NTO CTC CTO CTX

NTC IRS DS CPF CPS CPDF CPDS MPDF MPDS NTC RTO CTC CTO

0

10

20

30

40

50

60

70

80

90

100

NTC NTO CTC CTO CTX

Comprehensive Assessment of Soil Health (CASH)

• Available Water Capacity• Surface Hardness• Subsurface Hardness• Aggregate Stability• Organic Matter• Soil Protein• Soil Respiration• Active Carbon• pH• Phosphorus• Potassium• Minor Elements

Ph

ysic

alB

iolo

gica

lC

he

mic

al

CASH Soil Indicators

CASH Overall Soil Health Score

Mountain Piedmont Coastal Plain

–––––––––––––––––––––––––––––––––––––––––––––––– Treatment ––––––––––––––––––––––––––––––––––––––––––––––––

–––––––––––––––––––––––––––––––––––––––––––––––– Treatment ––––––––––––––––––––––––––––––––––––––––––––––––

Pie

dm

on

tM

ou

nta

inC

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tal

• There was no statistical difference in humic matter (representative of organic matter) between agronomic systems with conservation tillage and those with intense tillage.

• Soil test levels of major plant nutrients were adequate (data not shown).

Crop Yields (* indicates years with statistically different yields between treatments in the trial)

Humic Matter (%)

Index Score

Coastal PlainPiedmont

Note: Lime and fertilizer was applied to all plots according to NCDA&CS soil test recommendations

Mountain

Acknowledgements:

Mountain Piedmont Coastal Plain

PiedmontMoldboard plowed plot (left) adjacent to a no-till plot (right) Funding from:

• Conventional no-till systems yielded more corn than moldboard plowing, but not more than other tillage systems.• No-till organic production in the mountains had better soil health scores than conventional production, but yielded less

corn because of weed competition (instead of soil constraints).

0.00 0.20 0.40 0.60 0.80

NTC

NTO

CTC

CTO

CTX

NTC

IRS

DS

CPF

CPS

CPDF

CPDS

MPDF

MPDS

0.00 0.20 0.40 0.60 0.80

NTC

CTC

RTO

CTO

Adam Howard, Wesley Childres, Tomas Moreno, Melissa Belland all research station personnel

*

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NTC NTO CTC CTO Rainfall

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