Outline. Overview of Soil Methods. Ecosystem Services in the Soil. Why care about soils? What are biological soil crusts?

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Cornelius O’Brien’
5 years ago
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1 Overview of Soil Methods Outline Why do we care about soils? Biological soil crust Soil sampling methods Ecological Monitoring and Analysis (REM 357) Park Valley, UT Why care about soils? Basis for all life Determine plant communities, species and form Take 5,000-10,000 years to form Require protection from wind, water erosion: plants, rocks, soil crusts Ecosystem Services in the Soil Regulates hydrologic cycle Regulates biogeochemical cycles (N, C, P, S) Retains & delivers nutrients for plant growth Provides decomposition of organic matter and wastes Recycles nutrients via decomposition for plant growth Shelters seeds & provides physical support for plants Daily et al What are biological soil crusts? Biological soil crusts are a community of: Cyanobacteria Lichens Mosses Each plays a different role 1

2 Crusts are in a variety of habitats Great Basin Colorado Plateau Hot Deserts Sonoran Desert Mojave Desert Alaska Why are soil crusts important? Soil stability Soil fertility Soil moisture 2

3 Scattered Vegetation In deserts, plants give little protection to desert soils Hill slopes Soils held beyond angle of repose Soil Fertility Crusts convert atmospheric N into bio-available forms Soil Aggregates Site of microbial activity Increase water infiltration Enhance plant root environment Ni is a basic building block of all proteins Many desert soils are very low in N Capture Seeds Organic Matter Dust Dust contains high levels of nutrients Rough surface, sticky organisms retain dust Small particles hold more moisture Regions where BSCs are ecologically important 3

4 1. Biological soil crust 2. Soil moisture 3. Soil compaction 4. Infiltration 5. Soil stability 6. Soil texture 7. Bulk density 8. Soil chemistry Soil Methods Biological Soil Crust Methods Soil Moisture Line-point intercept or Quadrat Gravimetric Metal tins Time Domain Reflectometery Hydrosense Sensors Decagon Field Scout Densification of soil structure due to mechanical pressure Good soil structure Compacted soil Causes Construction Tire tracks Livestock Wildlife Recreation Effects of Reduces soil aeration Decreases oxygen supply to roots Alters soil structure Decreases root penetration Reduces water infiltration Increases runoff 4

5 Methods Surface compaction Pocket penetrometer Friendsofbidwellpark.org Methods Subsurface compaction Cone/impact penetrometer Methods Be careful!!!! Seed Drilling & Seed Drilling & 5

Infiltration Process of water moving from

cycling infiltration capacity & water and

soil biotic activity) Collecting a sample

Place ¼ diameter fragment of soil on sieve

6 Infiltration Process of water moving from surface into soil Affected by: Soil texture Pore size Presence of swelling clays Organic matter at surface Soil temperature Surface crusts How fast does water move into the soil? Area cannot be: 1.Steeply sloped 2.Very gravelly/rocky 3.Have dense root mats Infiltration Methods Units: cm/hr or mm/hr Degree of soil structural development and erosion resistance Soil structure is correlated with: erodibility soil organic matter cycling infiltration capacity & water and nutrient retention recovery processes (e.g. soil biotic activity) Collecting a sample Herrick et al. 2009; Vol. I p Place ¼ diameter fragment of soil on sieve in water 2. Observe: does it melt? 3. Wait 5 minutes 4. Lift out of water 5x 5. Rate on 1-6 scale 6

Soil Texture Soil probe Soil auger * Usually positive, but can be

Large increases in water repellency (after a very hot fire) can

of runoff water available to erode soils downslope.

Density Lower pore space = higher bulk density clay silt sand Soil

Micronutrients (Zn, Fe, Mn, Cu) Exchangeable cations (Mg, Ca, Na,

7 Soil Texture Soil probe Soil auger * Usually positive, but can be negative for hydrophobic (water-repellent) soils. Large increases in water repellency (after a very hot fire) can negatively affect soil and site stability by increasing the amount of runoff water available to erode soils downslope. Hydrometer Soil Texture Mass of oven dried soil Sample volume Bulk Density Lower pore space = higher bulk density clay silt sand Soil Chemistry Organic matter (C) Nitrogen Phosphorus Potassium Micronutrients (Zn, Fe, Mn, Cu) Exchangeable cations (Mg, Ca, Na, K) Sulfur Boron ph Cation Exchange Capacity (CEC) Salinity (electrical conductivity =EC) Sodium Absorption Ratio (SAR) 7

Soils of Palau. Diversity and Fertility. Palau Livestock Management Workshop March 23-25, Jonathan Deenik, PhD University of Hawaii

Soils of Palau. Diversity and Fertility. Palau Livestock Management Workshop March 23-25, Jonathan Deenik, PhD University of Hawaii Soils of Palau Diversity and Fertility Jonathan Deenik, PhD University of Hawaii Palau Livestock Management Workshop March 23-25, 2011 Outline Plant nutrition Soil fertility Soil composition Texture and