Measuring Soil Health - Assessment Tools · 2017-01-17 · Biological Soil Health Indicators...
Transcript of Measuring Soil Health - Assessment Tools · 2017-01-17 · Biological Soil Health Indicators...
Measuring Soil Health -Assessment Tools
Jeff Hemenway NRCS – Soil Health Specialist
Soil Health Indicators
• Chemical • Physical • Biological
Chemical Physical
Biological
What are we talking about? • Nutrient Deficiency/loss
• Loss of Soil Organic matter • Loss of Biological diversity • Soil Compaction • Erosion • Soil Salinitization • Sodification • Others (etc.)
Chemical Soil Health Indicators
• Nutrient Supply (N, P, K) micros– (Conv. Lab Analysis)
• Potentially Mineralizable Nitrogen – (Haney)?
• Soil pH • CEC • Salinity and Sodicity
– EC- Sat. Paste vs 1:1 – SAR
4
5
Physical Soil Health Indicators • Soil Structure (granular, subangular, platy) • Soil Pores/Macropores • Aggregate Stability (Wet, Jornada) • Bulk Density/Compaction • Infiltration (single ring) • Surface residue/litter • Surface Crusting • Available Water Holding Capacity
Biological Soil Health Indicators
– Microbial Biomass (PLFA) – Soil Respiration (Solvita) – Potentially Mineralizable Nitrogen –
(Haney)? – Plant Roots (number/mass) – Other Indicators (Arthropods, earthworm) – Others
Soil Degradation Spiral Poor Land Management
Aggregation Degradation
Compaction & crusting
Water & Wind Erosion Plant Growth
Yield
Reduced Soil Productivity
Soil Biology
30003500400045005000550060006500700075008000
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
Year
So
il C
(g
m-2
)
Conventional Tillage
Reduced Tillage
53% of 1907
61% of 1907
SOIL C LOSS/ORGANIC MATTER LOSS
-100 -80 -60 -40 -20 0 20 40
Soil
Carb
on C
onte
nt
Years Before Present | Years After
Management Changes(HIGH)
(LOW)
Native Prairie Row Crop Agriculture
Intensive Tillage ?
CRP Grass ?No Tillage ?Cover Crops ?
Stover Removal ? Sustainable Production?
FarmerDecisions
South Dakota Acres Under No-Till Farming on All Planted Cropland
Tillage is Destructive to soils What things change when you stop tilling the soil?
• Soil pores remain continuous • Soil aggregates form and are not destroyed • Soil Food Web increases and diversifies • Weed seeds are not planted • Water is captured (infiltration) and stored
(AWC) • Bulk density increases slightly; then stabilizes • Soil fungi and earthworms increase • Microarthropods increase
Dynamic Soil Properties -2008
• Study was initiated in 2008 to look at – Effect of management/invasive species on soils – Further define causes of transitions between states
• What are the dynamic soil properties – Color/organic matter – Soil aggregate stability – Bulk density/porosity – Microflora and microfauna – Carbon:Nitrogen ratio – Infiltration
Dynamic Soil Properties Study Sites
DSP Study sites
2008 &2013 2012 &2013
2012
2014
2009
2009
2008
2016
2015
2015
Dynamic Soil Properties
Barnes – Loamy ecological site 2008 Study site Duel County, SD
Dynamic Soil Properties study site
Similar to Rapid Carbon Assessment protocol Paired sites are located on same soil, but widely different management
Study Site 1 – Bruce, Steve and Lance collect soil samples on the native state. The soil series is Barnes.
Invaded State
89% Introduced species (5 species)
11% Native grasses and forbs (6 species)
(by weight)
Native / Invaded State
88% Native grasses, forbs & shrubs (19 species)
12% Introduced species (3 species)
(by weight)
Barnes soil
Infiltration
0
5
10
15
20
25
Rotation Continuous
5
0.55
Inches/hr
Bulk Density
0
0.2
0.4
0.6
0.8
1
1.2
1.4
BulkDensity (g/cm3)
0-3" 3-6"
Horizon
Native
Invaded
Soil Aggregate Stability
0.00.51.01.52.02.53.03.54.04.55.05.56.0
Stability Rating
Surface 0-3" 3-8" 8-12"
Horizon
NativeInvaded
Infiltration – There were dramatic differences between the two states in infiltration rates. On the invaded grass state, the second inch of water took more than 5 times longer to enter the soil. After the initial wetting, the infiltration rate was approximately 2.17 inches/hour for the native state, and 0.55 inches/hour for the invaded.
1.2
21.027.6
109.2
0.0
20.0
40.0
60.0
80.0
100.0
120.0
Native Invaded
Elap
sed
Tim
e (m
in.)
1st Inch2nd Inch
Carbon/Nitrogen Ratio
• No appreciable difference • Organic matter
– Total amount not greatly different – Distribution significantly different – better
distribution of organic matter in the soil profile under rotationally grazed
Glomalin
• An indicator of arbuscular mycorrhizal fungi activity.
• Native grass site had 20% more glomalin in the soil profile compared to the invaded grass site. – Is this enough of a difference to be considered a
trigger for the effect on infiltration? – Would the change in glomalin be sensitive enough
to use as an early warning sign?
Dynamic Soil Properties - Sampling Protocol Notes: Proposal Rapid carbon protocol plus Soil Sampling Standard Cluster sampling – i.e. central pedon plus four cardinal satellites - 30 meters from center 5 cm - surface subsample BD sampling all horizons Complete morphological soils description – (i.e. – 232) Single ring infiltration – central pedon plus all satellites Total carbon Inorganic carbon -Active carbon, POM, permanganate test?, humic acids? - Note: May need to do carbon on all horizons ; not just A horizons. Ec pH Soil Aggregate stability – A horizon(s) Central pedon – sampled for soils characterization Plant Sampling NRI procedure – 5 plot total harvest Point Intercept procedure Duff layer collection – measure thickness?
•2012 Study Site Mellette County, SD
Dynamic Soil Properties- (i.e. Soil Change with Management) 2012 Study Site Mellette County, SD
Mellette County Kube soil
Rotational Grazing Hayland
Mellette County Kube soil
Hayland Rotational Grazing
Mellette County Kube soil
Hayland Rotational Grazing
Mellette County Kube soil
Hayland Rotational Grazing
Mellette County Kube soil
Hayland Rotational Grazing
Kube Soil – Native Range site
Infiltration Rates
SD002-1 30 sec.
SD002-2 2 min.25 sec.
SD002-3 34 sec.
SD002-4 50 sec.
SD002-5 6 min. 47 sec.
Average - 2 min. 13 sec.
Kube Soil – Cropland si
Infiltration Rates
SD001-1 3hr. 57 min.
SD001-2 34 min.
SD001-3 37 min.
SD001-4 52 min.
SD001-5 2 hr. 29 min.
Average - 1hr. 41 min.
• 2014 Study Site Walworth County, SD
Native Range
Cropland/New range seeding
Cropland/New range seeding Grass/Alfalfa prior to 2011, No-till Oats/peas 2012, Sorghum/sudan in 2013, Range seeding in 2014: Big Bluestem, Side Oats grama, Green Needlegrass. Indiangrass, Switchgrass, Little Bluestem, forbs
Native Range Dominant and subdominant species (in order of dominance) are: Smooth bromegrass, Kentucky bluegrass, western wheatgrass, needleandthread, crested wheatgrass, and western snowberry.
Mobridge Cropland – Range Seeding
Mobridge Native Rangeland
Infiltration Rate -2nd Inch 005A 17 min. 6 seconds 005B 22 min. 30 seconds 005C 1 min. 30 seconds 005D 6 min. 18 seconds 005E 14 min. 30 seconds Ave. 12 min. 23 seconds
Infiltration Rate -2nd Inch 006A 48 minutes 006B 3 hrs 35 minutes 006C 4 hrs 50 minutes 006D 16 minutes 006E 26 minutes Ave. 1 hr 59 minutes
What we “know” so far • Management actions can be taken to degrade
or improve soil health – more emphasis needs to be placed on this.
• Management of cropland and grassland has a potentially large effect on infiltration/runoff.
• We need to sample-N,P,K micros S, Zn,Cl • A number of soil parameters are showing more
promise – C, OM, Structure, WAS, BD, EC, Infiltration.
Soil Health in South Dakota Predicting Infiltration Rates
Predicting Infiltration rates for Grazing lands and Cropland
• Based on plant community and management for both systems
• Grazing land • ESD Plant community and grazing management
• Cropland • Crop rotation and tillage system
RAINFALL INFILTRATION KIT
Grazing land ESD Plant Community – Management Scale
Both the plant community and the type of management are rated on a five-tier scale. Plant community (comparisons are to the respective ecological site description): 1 – Native plant community 2 – Plant community dominated by native plants 3 – Non-native cool-season grasses and/or short warm-season grasses have increased to the point of being co-dominant with native species which are normally considered dominant in the reference plant community. 4 – Non-native cool-season grasses and/or short warm-season have increased to the point of being dominant. 5 – Non-native cool-season grasses and/or short warm-season grasses have increased to the point of being completely dominant. If present, native species are difficult to find.
Grazing land ESD Management: 1 – Prescribed grazing is applied according to the Prescribed Grazing Conservation Practice Standard (528). 2 – Most aspects of the Prescribed Grazing Conservation Practice Standard (528) are applied, but not consistently. 3 – Typically this includes grazing at moderate stocking rates, but grazing periods cover most of a season (seasonal) or nearly for the entire season (season-long 4 – This typically includes moderate to heavy stocking rates that are applied season-long. Livestock often occupy the area for most of the growing season. 5 – This typically includes very heavy stocking rates for extended periods, often for the entire growing/grazing season. To determine the plant community/management scale rating, rate each using the scales above, then multiply the two numbers together. The overall rating will range from 1 to 25.
34 locations, 7 MLRAs, 8 ecological sites
Cropland Crop Rotation and Plant Diversity Management Scale Both the rotation and the tillage system are rated on a five-tier scale. Rotational System 1– Diverse cropping system that includes all four crop types. Perennials as well as cover crops are part of the system. Contains at least two thirds high residue crops – manure or grazing is part of the management system. 2 – Cropping system that includes all four crop types incorporated into the crop sequence. Contains at least two thirds high residue crops. 3 – Cropping system that includes at least 3 crop types in the cropping sequence. Contains 50-60% high residue crops with cover crops are part of the rotational system. 4 – Cropping system includes 2 crop types with 50% high residue crops or high residue mono-cropping systems. 5 – Mono-cropping system with a low residue crop
Cropland Tillage System: 1) No-till/strip-till - The soil is left undisturbed from harvest to planting except for strips up to 1/3 of the row width (strips may involve only residue disturbance or may include soil disturbance). 2) Ridge-till - The soil is left undisturbed from harvest to planting except for strips up to 1/3 of the row width. Planting is completed on the ridge and usually involves the removal of the top of the ridge. Planting is completed with sweeps, disk openers, coulters, or row cleaners. Residue is left on the surface between ridges. 3) Mulch-till – Full-width tillage that involves one or more tillage trips, disturbs the entire soil surface and is done prior to and/or during planting. Tillage tools such as chisels, field cultivators, disks, sweeps or blades are used. 4) Reduced-till (15-30% residue) - Full-width tillage that involves one or more tillage trips, disturbs the entire soil surface and is performed prior to and/or during planting. There is 15-30 percent residue cover after planting or 500 to 1,000 pounds per acre of small grain residue equivalent throughout the critical wind erosion period. 5) Conventional-till or intensive-till - Full-width tillage that involves one or more tillage trips and disturbs the entire soil surface and is performed prior to and/or during planting. There is less than 15 percent residue cover after planting, or less than 500 pounds per acre of small grain residue equivalent throughout the critical wind erosion period. Generally involves plowing or intensive (numerous) tillage trips.
Actual Values 2nd Inch
Actual Values 1st Inch