Keys to Sustainable Lawn Care in Nebraska

Transcription

1 What is Sustainable Lawn Care? Keys to Sustainable Lawn Care in Nebraska Bill Kreuser No inputs Lawns can t exist without some maintenance Organic products and fertilizers Possible but know definition of organic in industry Not always better/safer/legal Minimizing inputs Less fertilizer/water/pesticides Changing expectations Expectations Lawns Require A Lot of Energy Physical Energy Chemical Energy Gasoline for equipment Manufacture of pesticides and fertilizer Energy to pump water Lawns are great carbon banks 1

2 What is Thatch? Slowly Decaying Plant Tissues Stems Dead crowns Leaf Sheaths Not clippings and roots Highly Lignified Tissue Why is Thatch a Problem Turfgrass crowns are exposed to elements Harbor pests Reduced water infiltration Easy to scalp during mowing Nothing good about TOO much thatch Keys to Sustainable Best Management Practices for an Above Average Lawn 1. Plant the correct grass/plant 2. Mow correctly 3. Precisely manage water and nutrient applications 4. Manage soil 5. Use pesticides as last resort! Plant the Correct Grass Mostly cool-season turf in NE Creeping: Kentucky bluegrass Bunch type: Tall fescue, perennial ryegrass Warm season exception Buffalograss Native to the Great Plains Creeping type grass 2

3 Kentucky bluegrass Fine leaf texture and mid to dark green color Spreads by lateral stems in the soil called rhizomes Average root system and water use (ET) Goes dormant during drought Good for cool/arid climates (Western NE) Common Kentucky Bluegrass Elite/Improved Kentucky Bluegrass Premium Kentucky Bluegrass 2.5 inch HOC 3.5 Inch HOC 0 Fert Apps 4 Fert Apps Turf Type Tall Fescue Dark green color with course to medium-fine texture Good heat tolerance Deep rooting turf but highest water use Tall Fescue Great for locations with temporary (short-term) drought Eastern NE, but exploring suitability in further west 4 Fert Apps 0 Fert Apps 2 Fert Apps 3

4 Perennial Ryegrass Perennial Ryegrass Fine texture and shiny dark green leaf Quick to establish Poor to moderate drought tolerance and avoidance Susceptible to summer diseases/insects Killed by extreme temperatures 0 Fert Apps 4 Fert Apps 2 Fert Apps Native to Great Plains Light green color and fine texture Warm-season grass (grows during summer Deep rooting + low water use Low (not no) maintenance Buffalograss 4

5 Sometimes Grass isn t the Anwser Questions Keys to Sustainable Best Management Practices for an Above Average Lawn 1. Plant the correct grass/plant 2. Mow correctly 3. Precisely manage water and nutrient applications 4. Manage soil 5. Use pesticides as last resort! 5

6 Benefits of Mowing Appearance Increase leaf density Remove damaged leaves Prevents seed heads from forming 6

7 Does Mowing Height and Frequency Affect Growth Rate Different Rationales: 1) Frequent mowing increases turfgrass growth rate because it is less stressful than scalping 2) Scalping cause the growth to grow slower and reduces mowing requirements 3) Mowing to the 1/3 rule is best for healthy turf while providing the minimal amounts of mowing Designed a Tall Fescue Mowing Study Treatments: Height of cut (2 or 3 ) Frequency of Cut (weekly, ¼ rule, 1/3 rule, ½ rule) Controls Never fertilized during the year and watered to 80% of pet nightly Measured clipping yield and turf quality all summer Explaining Mowing Frequencies 2" 3" Weekly - - 1/4 Rule /3 Rule /2 Rule ½ Rule Weekly ¼ Rule 1/3 Rule block 1 ½ Rule Weekly ¼ Rule 1/3 Rule ¼ Rule Weekly 1/3 Rule ½ Rule block 2 ¼ Rule Weekly 1/3 Rule ½ Rule ½ Rule 1/3 Rule Weekly ¼ Rule block 3 ½ Rule 1/3 Rule Weekly ¼ Rule At End of Season, Mowed All Plots to 2 or 3 and calculated total clipping production 7

8 First Year Results Cumulative Clippings Over Time No Scalping Good Quality No Scalping Good Quality Mowing Best Management Practices Mow at 2 to 3 inches Higher to keep out weeds Reduced water use Mow to 1/3 rule: 3 to 4.5 inches Reduces number of total mowings Keeps turf healthy and dense Doesn t scalp the turf Return clippings! Questions Keys to Sustainable Best Management Practices for an Above Average Lawn 1. Plant the correct grass/plant 2. Mow correctly 3. Precisely manage water and nutrient applications 4. Manage soil 5. Use pesticides as last resort! Why do we water? 2% for Metabolism 98% for Cooling 8

9 Large Differences in Annual Precip Annual Precip < Water Loss All Plants Resist Drought Stress Drought Avoidance Drought Tolerance Plant Response to Drought Stomata Close Leaf growth slows Root growth increases Cell division slows Cells accumulate sugars Leaves and roots die Cells break/die Plant dies Short Drought Prolonged Drought Minutes Days Weeks Months Season Turf Needs Water Precision Water Management Key Know How Much is Required Monitor Soil Moisture Proper Placement Uniformity in Soil 9

10 Irrigation Basics Amount and frequency change throughout the growing season Under-Irrigation Wilt Insufficient Rootzone Moisture (under-watering) Slow growth (recuperative potential) Wilt Hard surface Susceptible to insect pests Thatch accumulation Excessive Irrigation Brown patch Excessive Irrigation Algae / moss Poa annua Leaching Anerobic soil Shallow rooting Denitrification Thatch accumulation Algae Moss Black layer Poor stress tolerance Poor quality playing surface (rutting, divoting) Poor shear strength Disease (pythium blight, brown patch, etc ) Waste of water ($$$$$) 10

11 How much water is lost? Evapotranspiration (ET) is the amount of water lost from soil evaporation and transpiration Parameters? Directly measure ET Estimate potential ET Satellite data Don t Water to 100% pet Crop coefficients (K c ) available for turf Cool-season turf 60 to 80% of pet Warm-season 40 to 60% pet Can be much lower Deficit Irrigation works when there is occasional rain Homeowner Irrigation BMP Turn off the irrigation systems TDR Probe Monitor Soil Moisture When you see drought symptoms then turn on the irrigation Apply an inch of water Turn System Back Off 11

12 Moderate Drought Stress Increases Plant Health Deficit Irrigation TNC in turfgrass roots (mg g -1 ) Light & frequent Deep & infrequent Keeps things consistently dry Uses less irrigation Reduces nutrient and pesticides leaching Requires closer monitoring 0 June July August September Fu, J., and P. H. Dernoeden Carbohydrate metabolism in creeping bentgrass as influenced by two summer irrigation practices. J. Am. Soc. Hortic. Sci. 133(5):p Optimize irrigation applications Check your systems Nozzle wear and uneven heads Minutes vs inches Monitor soil moisture Adjust run times and change nozzles Recognize wilt and then water Irrigation Distribution Uniformity There is no universal amount of water to apply Questions Minutes vs. Inches 12

13 Clippings lb/m 2/14/2017 Why Fertilize Turf? The Essential Nutrients Qualitative Reasons Color Leaf density Recover from traffic Recover from environmental stress Replace nutrients as they become unavailable Leaching, volatilization, runoff, removal Fixation and Immobilization Primary & Secondary Nitrogen (N) Phosphorus (P) Potassium (K) % N - % P 2 O 5 - % K 2 O Calcium (Ca) Magnesium (Mg) Sulfur (S) Micronutrients Iron (Fe) Manganese (Mn) Molybdenum (Mo) Zinc (Zn) Boron (B) Chlorine (Cl) Copper (Cu) Nickel (Ni) Silicon??? All Nutrients Are Important We Don t Maximize Yield Like a Crop Turfgrass growth controlled by the most limiting nutrient Nitrogen almost always the limiting nutrient Nitrogen Low N High N N Rate lb/m/yr How Much Nitrogen to Apply? Too much Nitrogen Yield unimportant Depends on turfgrass application Performance Quality Current recommendations are historical Goldilocks Method Reduced root growth Decreases stress tolerance - esp. water Excessive thatch development Increased mowing requirement Increases incidence of many diseases brown patch, snow mold, gray leaf spot, take-all patch 13

14 Not Enough Nitrogen Just Right Nitrogen Reduced shoot density Increased weed invasion esp. clover and crabgrass Increased reliance on pesticides May need to completely renovate if weeds win Unsafe playing conditions Unattractive Increases incidence of certain diseases Rust, red thread, dollar spot Good green color Moderate growth rate Optimum tolerance to environmental stresses High shoot density but vigorous root system Good recuperative potential Poor turfgrass performance (putting greens) Clipping Removal & Aeration Turfgrass N Cycle Fertilizer Denitrification & Volatilization OM accumulates as turf ages Fixation Atmospheric Deposition Organic Nitrogen Complex structure Immobilization (Plant & Microbe Uptake) Mineral Nitrogen (NH 4+, NO 3-, NO 2- ) Mineralization Microbe Dependent Leaching & Runoff Source: Gaussoin and Shearman, 2003; Gaussoin et al., 2006 Soil OM increases with time Adds fertility From a well established lawn area N uptake from clippings (~1#/M) N uptake from soil (~1#/M) N uptake from fert (~1#/M) Qian et al., 2003 Starr and DeRoo,

15 Slow SOM build-up reduces N requirements Nitrogen leaching from over-fertilizing established turf MSU Monmouth Lysimeters Nitrogen Fertilization BMPS Amount of N required changes as turf ages New lawn 2-6 applications a year Established lawn 0-3 applications a year Kentucky bluegrass and perennial ryegrass need more than tall fescue or buffalograss Frank et al., 2006 Timing critical Average Fertility Requirements Grass Species Average Lawn High Maintenance Kentucky bluegrass Perennial ryegrass lbs N/1000 ft 2 1-4* Tall fescue Fine fescue Buffalograss When to apply fertilizer Cool-season turf 1. Late summer (Aug-September) Balanced N source (50% WSN 50% WISN) 2. Mid-spring (Late April) After initial spring growth surge (balanced source) 3. Mid-summer (June) Slow release or organic nitrogen (WISN) Water in and don t apply to drought stress turf 4. Mid-fall (mid-october) 1. Quick release (WSN) 2. Not too late.recommendation has changed When to apply fertilizer Warm-season turf 1. Early summer (May to June) 2. Mid-summer (July to early Aug) Balanced nitrogen source Water in and be careful during drought periods Soil Test for Other Essential Nutrients Estimate plant available nutrients Monitor changes in soil nutrients Peace of Mind 15

16 Cation Exchange Capacity K + - Ca Mg 2+ H + We Can Test for Everything but N Primary & Secondary Nitrogen (N) Phosphorus (P) Potassium (K) Calcium (Ca) Magnesium (Mg) Sulfur (S) Micronutrients Iron (Fe) Manganese (Mn) Molybdenum (Mo) Zinc (Zn) Boron (B) Chlorine (Cl) Copper (Cu) Nickel (Ni) Proper Sampling Collecting a Representative Sample Take a Composite Representative Sample Consistent Sampling Depth and Time of Year Consistent Soil Testing Lab or Method Proper Sampling Representative Areas Mineral soils vs. sand or constructed soils Areas built at different times Areas cut out of forest vs. old agricultural land Areas of drastically different soil type How Deep? Where the roots are 16

17 Depth Inches How Deep? Mehlich 3 Phosphorus ppm Keys to Consistent Soil Testing When: Early Spring Where: Representative soil areas How Deep: Be consistent, 4 good depth Which Lab: Use same lab you trust always Micronutrients: Who cares tissue testing best % decrease in soil P with addition of 1 inch of soil! Need to be consistent to monitor changes over time!! Great Fertilizer Grade Diversity Blended Fertilizers Mixture of fertilizer sources Nutrient release character release Addition of other nutrients Suited to address different turf requirements Starter (high P 2 O 5 ) Winterizer (higher K 2 O) Micronutrients additions Plants Control Nutrient Uptake Not Turf Managers What s the ideal fertilizer ratio for turfgrass? 17

18 Tissue Content (% dry weight) Tissue Content (% dry weight) Change in Soil Test Levels (Three Years ppm) 2/14/ Fertilizing Soils With Sufficient Nutrients Does Not Affect Turf 62ppm Soil Test Phosphorus 180ppm Soil Test Potassium 6 5 N drives uptake of other nutrients Fertilizer Ratio: Soil Test P: 62ppm Soil Test K: 180ppm Leaf N Leaf P Leaf K Leaf N Leaf P Leaf K Pounds of N-P 2 O 5 -K 2 O Fertilizer Applied Annually to 1000 ft Annual Nitrogen Fertilization Rate (lbs/1000 ft 2 ) The Ideal Fertilizer Ratio? Nitrogen-only fertilization can be very effective Ratio Changed Soil Test Levels Fertilizer Ratio: Soil Test P: 62ppm Soil Test K: 180ppm 57 Gradual decline in other soil test nutrients levels with N only fertilization Treat the soil like a nutrient bank account Nutrient Losses = Fertilizer Additions Annual Nitrogen Fertilization Rate (lbs/1000 ft 2 ) Soil Test P Soil Test K Approximate* Ideal Fertilization Ratios Grass Species Root Zone Soil Mowing Clipping Management Annual Ideal Fertilizer Ratio Cool-season lawn and Native soil Clippings Removed athletic field species (Kentucky bluegrass, Clippings Returned perennial ryegrass) Sand-based soil Clippings Removed Questions?? Clippings Returned Creeping bentgrass turf Native soil Clippings Removed Clippings Returned Sand-based soil Clippings Removed Clippings Returned * Actual ideal fertilizer ratio varies depending on local environment (soil, precip, ect.) 18

19 Keys to Sustainable Best Management Practices for an Above Average Lawn 1. Plant the correct grass/plant 2. Mow correctly 3. Precisely manage water and nutrient applications 4. Manage soil 5. Use pesticides as last resort! Slowly Decaying Plant Tissues Stems Dead crowns Leaf Sheaths Not clippings and roots Highly Lignified Tissue What is Thatch? Thatch Management Strategies Species Selection Nitrogen Fertilization Mechanical Removal Renovation ph modification, avoid pesticides, inoculate with microbes 19

20 Differences in Species and Variety Mechanical Removal Higher Thatch Potential Lower Thatch Potential Core Aeration Dethatcher Power Rake Kentucky bluegrass Fine fescue Roughstalk bluegrass Perennial ryegrass Tall fescue Improved varieties Older common varieties Manual Raking Fun Implications for Management Aeration Impact Tine Size (in.) Tine Size and Surface Area Chart Spacing (in.) Holes/ft 2 Surface Area of One Tine Percent Surface Area Affected 1/ % 1/ % 1/ % 1/ % 5/ % 20

21 Still Benefits to Aeration Timing Thatch Removal Increased water infiltration Cores dilute some thatch as topdressing Increased soil aeration Reduced soil compaction Avoid Early Spring, Mid-Summer, and Late Fall Power Raking Dilution Can Be the Solution Topdressing buries thatch Enhances microbial breakdown Materials Sand Compost Extreme Thatch Accumulation Call for Complete Renovation Turf.unl.edu 21

22 Best Management Practices for an Above Average Lawn in Central NE 1. Plant Tall Fescue or Buffalograss 2. Mow grass to 3 when it reaches Water deeply when drought stress is visible 4. Fertilize when grass looks yellow (late spring and early fall) 5. Manage water and fertilizer to limit thatch; remove in spring 6. Use pesticides as last resort! Bill Kreuser wkreuser2@unl.edu 22