Where do you start? Managing Soil Health. Three parts to soil health 3/3/2014. First, have a yard stick to measure by

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1 Where do you start? Managing Soil Health By Donald A. Horneck, Ph.D. CCA, CPAg, CPSS Oregon State University - HAREC First, have a yard stick to measure by Three parts to soil health Rick Haney-soil test, a USDA-ARS researcher at the Grassland, Soil and Water Research Laboratory, Temple, Texas, a test that may be the missing link in soil evaluation, especially with cover crops. Cornell soil evaluation test Characteristics of a Healthy Soil 1. Good soil tilth 2. Sufficient depth. 3. Sufficient but not excess supply of nutrients 4. Small population of plant pathogens and insect pests 5. Good soil drainage 6. Large population of beneficial organisms 7. Low weed pressure 8. Free of chemicals and toxins that may harm the crop 9. Resistant to degradation 10. Resilience when unfavorable Haney soil test Microbial Activity Physical? 1

2 What does CO2 get you Haney correlation Correlation of yield to carbon Soil Health Calculation Assesses overall health of your system Values can range from 1 to over 50 Can be used to calculate cover crop input Calculation is asking the soil: What is your condition? Are you in balance? What can we do to help? Alternative agriculture The Haney test Solvita 1-day Organic Organic Organic Soil Health Sample ID all lbs per acre CO2-C C N C:N Calculation 20 yrs no-till; corn/soy rotation yrs no-till; cover crops 8 yrs; wheat/soy rotation years no-till; cover crops 8 years; wheat/soy rotation years no-till; corn/soy rotation years no-till; cover crops; lots of earthworms years no-till; no cover crops Conventional tillage; corn/soy rotation Undisturbed native soil yrs no-till; cover crops 8 yrs Conventional tillage; corn/soy rotation Low ground Sample from a woods High ground Simple - NRCS 1. Keep the soil covered as much as possible 2. Disturb the soil as little as possible 3. Keep plants growing throughout the year to feed the soil 4. Diversify as much as possible using crop rotation and cover crops Manures, composts? Moral increase SOM 2

3 Cornell test/evaluation Greenhouse grow-out Role of soil organic matter biological functions of SOM provides nutrients and habitat for organisms living in the soil provides energy for biological processes contributes to soil resilience (the ability of soil to return to its initial state after a disturbance, for example after tillage). chemical functions of SOM measure of nutrient retention capacity provides resilience against ph change main store of many key nutrients especially nitrogen and potassium. Soil organic matter is a key indicator of soil health because it plays a role in a number of key functions. physical functions of SOM binds soil particles into aggregates improving soil structural stability enhances water holding capacity of soil moderates changes in soil temperature. Quote Soil organic matter is a key indicator of soil health because it plays a role in a number of key functions. The size of the SOM bucket How much soil C or organic matter can your soil hold? Texture sandy smaller Climate hot smaller Rainfall dry smaller You will not turn a Columbia Basin sand (small bucket) into at prairie (large bucket) with management Virgin vs cultivated Soil zone Virgin Cultivated Brown Dark Brown Black Dark Gray Gray

4 Destructive to SOM? Tillage tillage tillage Removing residues Prunings Burning Increase OM Perennial crops Additions of compost Additions of manures Cover crops Fertilization (more biomass) No till Biomass vs oxidation Conclusions Organic matter is critical for soil health Lots of ways to increase it Small doses of anything are very unlikely to have an impact E.g. 1% OM in 12 soil = 40,000 lbs. of OM Might change soluble C Know what you are trying to change and measure it. Soil health complex There is always magic Questions? Soil Compaction Traffic when soil is wet Tilling wet (plastic) soils Heavy equipment and loads Uncontrolled traffic Contributing factors Can result in Reduced root growth Limited water infiltration, runoff, and erosion Ponding and poor aeration Drought sensitivity Increased cost of tillage Lower yields Practices That Can Increase Soil Organic Matter Levels: (The Importance of Soil Organic Matter in Cropping Systems of the Northern Great Plains, Overstreet and DeJong-Huges, University of Minnesota Extension, 2009) a Crop rotations by planting; o Cover crops to provide soil cover to reduce evaporation, erosion and runoff. o Perennial grasses to add above-the-ground as well as below-the-ground biomass. o Legumes for green manure purposes. o Planting crops/plants that produce greater biomass. a Incorporation of straw/crop residues (figure 6). a Reduced tillage to minimize soil carbon losses and to slow down organic matter decomposition processes. a Application of fertilizers on cover crops and legumes to produce more biomass. a Application of manure, plant material or other carbon-rich waste. a Using forage by grazing versus harvesting. NDSU 4

5 ptdocs.nsf/all/agdex e09.htm Compost vs manure 5

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9 Traditional Soil Testing Methods Putting it Together: Using Soil Biology to make Recommendations Luke Baker, Ph.D. Will Brinton, Ph.D. January 8 th, 2014 Soil ph Recommendations % Organic Matter Where is the soil biology in this equation? Rick s Work to Support this Testing Microbial Activity Soil Analysis Sample Extraction Shake for 10 minutes, 4 grams of soil to 40 mls of H3A and water After filtering 4 grams each 40 grams 9

10 What H3A and water? Water is nature s solvent Organic C and N What is H3A? Organic acid extract used to mimic the organic acids exuded by plant roots During extraction it has a solution ph similar to that of the soil (i.e. mimics soil ph) Organic acids are easily neutralized by calcareous soils, which allows the soil ph to dominate the ph of the extract Contains citric, malic, and oxalic acids Microbial Activity Measuring Soil Bacteria and Fungi Very Complex System Organic Carbon Microbial Population CO2 O2 - Soil microbes require compounds for both growth and energy - Soil microbes take in O2 and release CO2 - This CO2 release is coupled with energy production, nutrient cycling, and microbial growth Soil is a Living Body How we can estimate 10

11 TEST PROCESS Solvita Test Pre-dried soil Pre-dried soil is bottom moistened 2- Insert CO2-sensitive probe into sample jar; 3- Read probe after 24h for ppm CO2-C; Range: ppm 4. Microbial Activity Soil Organic Carbon and Total Nitrogen from Water Extract -Instrument is unique in that it sparges (gets rid of) in (carbonates) by adding an acid right before analysis Soil Organic C: % OM From Rick Haney From Rick Haney 11

12 Soil-water total N (Pool 1) 3/3/2014 Microbial Activity Soil-water inorganic N (Pool 2) Soil-water organic N (Pool 3) Measuring a pool that we never considered in the past water extractable organic N is readily available to microbes and if C:N is right will become readily available to plants Microbial Activity C:N is more sensitive because this is the amount of C and N the soil microbes use Want ratio between 8:1 and 15:1 not Organic crediting N if above 20:1 N & P release Organic C:N Microbial Activity Soil Health Calculation From Rick Haney 12

13 Axis Title 3/3/2014 Soil Health Calculation Assesses overall health of your system Values can range from 1 to over 50 Can be used to calculate cover crop input Calculation is asking the soil: What is your condition? Are you in balance? What can we do to help? Other Useful Measurements P Saturation Using Al and Fe content to estimate liming Micronutrients This is down the road Some results Solvita 1-day CO2- C Organic C Organic N Organic C:N Soil Health Calculation Table 1. Total nitrogen and nitrogen from 15 N-labeled urea recovered in above-ground biomass and soils at five locations where Kentuc Plant N above-ground Soil N to 24 inches 15 N fertilizer recovery Total 15 N fertilizer Total 15 N fertilizer Location lb. N per acre lb. N per acre % 170 C B Culver A A A Madras 192 C 89 A 6923 B 51 AB 93 A Herm A 62 B 3045 C 30 CD 62 B Herm B 46 C 6256 B 14 D 40 C Pullman 139 D 41 C A 43 BC 56 BC Chart Title Solvita 1-day CO2-C Organic C Organic N Organic C:N Haney soil health index 13