Soils and Water in Your Landscape Mary Hattendorf Northern Water Spring Fair 2016
What is Soil? Hint: It s not dirt Soils are complex mixtures minerals, water, air, organic matter, and countless organisms that are decaying remains of once-living things. (Soil Science Society of America) Soils are vital to life on earth. Soils are capable of supporting plant life
And dirt is? Soil that is in the wrong place What you clean from your fingernails What gets on our clothes, our shoes, our floors If soil can no longer support life, it is dead and is therefore dirt
Why is Soil So Important? Soil supports plant growth Absorbs and emits gases and particles (CO2, H2O vapor, methane, dust) that modify the atmosphere Animal habitat Microorganism habitat Engineering/building Helps clean water that percolates through the soil
Natural (undisturbed) soils Formed in material deposited by water, ice, or wind Usually have distinct layers Have structure how soil particles are organized into aggregates Uncompacted Uneroded Support plant life
Soil Horizons O horizon mostly organic material A horizon topsoil where roots & organisms live B horizon subsoil where minerals accumulate C horizon Parent material Not all soils have all layers
How is Urban Soil Different? Natural soil has been dug, moved, inverted by people Construction often removes topsoil and leaves only subsoil Compaction is common
How is Urban Soil Different? Soil Composition By Weight Uncompacted 45% sand, silt, or clay 25% soil air 25% soil water 5% organic matter Compacted 74% sand, silt, or clay 12% soil air 12% soil water 2% organic matter
Soil compaction Consequences Decreased water infiltration Poor plant growth Roots can t grow through a compacted soil layer May spread laterally Shallow root zones Decreased water holding capacity (less pore space) Increased storm runoff/flooding/erosion Increased water pollution potential
Front Range soils Along the Fort Collins, Loveland, Longmont, Boulder corridor mostly heavy clayey soils Greeley area-more loams and sandy loams
Importance of Soil Texture Affects soil-water holding capacity Soil infiltration rate Plant root growth Soil aeration Soil percolation & drainage
Soil Particle Sizes
https://www.asu.edu/courses/gph111/weatherin gandsoils/soils/soiltextureanim.swf https://www.asu.edu/courses/gph111/weatheringandsoils/soils/ SoilTextureAnim.swf
https://www.asu.edu/courses/gph111/weatheringandsoils/soils/soiltexturean im.swf
https://www.asu.edu/courses/gph111/weatheringandsoils/soils/soiltext ureanim.swf
https://www.asu.edu/courses/gph111/weatheringandsoils/soils/soiltextureanim.swf
Can texture be changed? It is very difficult to change soil texture Clay soils can be amended to improve Infiltration rate Soil water holding capacity Drainage Soil aeration Objective is to create a variety of pore sizes
Soil Structure How soil particles are arranged into aggregates Peds are naturally formed soil aggregates It is desirable to have a variety of aggregate sizes Breakdown of soil aggregates causes many problems
Soil Structure Improves soil tilth (condition of the soil) Resists crust formation (occurs when aggregates are broken down as with rain beating on the soil) Soil infiltration rate improves
Soil Water-holding Capacity Sand = least Loam = most Clay = intermediate
How Water Moves in Different Soils (1) It takes twice as long for water in a clay soil to reach the same depth as water in a sandy soil.
How Water Moves in Different Soils-sandy, loamy, clayey https://www.youtube.com/watch?v=ego2fkuqwxc
Irrigating a Sandy Soil Smaller amounts, more frequently High soil infiltration rate large soil pores Low water-holding capacity Drainage becomes an issue if overwatered
Irrigating a Clay Soil Water deeply and infrequently Low soil infiltration rate small soil pores High water holding capacity Larger amounts of water Applied SLOWLY avoid runoff, ponding Cycle and soak
Irrigating a Loamy Soil Highest water holding capacity Wide variety of pore sizes Intermediate infiltration rate Water deeply and infrequently
How Water Moves in Different Soils loam-clay-loam layer 1 https://www.youtube.com/watch?v=ego2fkuqwxc
How Water Moves in Different Soils loam-clay-loam layer 2 https://www.youtube.com/watch?v=ego2fkuqwxc
How Water Moves in Different Soils loam-clay-loam layer 3 https://www.youtube.com/watch?v=ego2fkuqwxc
Irrigating a Layered Soil loam-clay-loam(similar to uncompactedcompacted-uncompacted) Water will permeate the heavy/compacted layer very slowly Irrigate with larger amounts less frequently, avoiding runoff cycle & soak if necessary Avoids continued saturation of loam layer from more frequent irrigation
How Water Moves in Different Soils loam-sand-loam layer 1 https://www.youtube.com/watch?v=ego2fkuqwxc
https://www.youtube.com/watch?v=ego2fkuqwxc How Water Moves in Different Soils loam-sand-loam layer 2
Irrigating a Layered Soil Loam-sand-loam (reacts similarly to compacted/non-compacted/compacted) Apply irrigation so that soil infiltration rate is not exceeded Use cycle and soak
Irrigating a Layered Soil Prevention of layered soil problems: Deep rip, chisel, till in any amendments Don t add topsoil of widely different texture Put down sod grown on similarly textured soil Aerate at least once per year
Plant Health & Water Conservation How to dig a Hole https://soilsmatter.wordpress.com/2016/03/24/isthere-actually-a-right-way-to-dig-a-hole-forplanting/
How to Dig a Hole
How to dig a Hole https://soilsmatter.wordpress.com/2016/03/24/is-there-actually-a-right-way-to-dig-ahole-for-planting/
How to dig a Hole Push and pry on the sides of the hole to loosen the soil https://soilsmatter.wordpress.com/2016/03/24/is-thereactually-a-right-way-to-dig-a-hole-for-planting/
Plant Health & Water Conservation Water deeply and infrequently heavy soils Develops better root zone Roots need air in the soil for proper growth and function Water only when the plant shows it needs water Use irrigation controller features Seasonal adjust Cycle and soak Turn it off!!
Seasonal Adjust for irrigation May 60% June 90% July 100% August 80% Sept 55% Oct 40%
Questions?