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Irrigation and Drainage Topic 2071 Created by Torey Birchmeier

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Presentation on theme: "Irrigation and Drainage Topic 2071 Created by Torey Birchmeier"— Presentation transcript:

1 Irrigation and Drainage Topic 2071 Created by Torey Birchmeier http://ga-mac.uncc.edu/faculty/haas/geol3190/termpap/wilson,r/index.html http://www.danbury.org/org/stillriver/zone1_install.htm

2 Water Water Everywhere! 3/4 of the Earth’s surface is covered by water Less that 3% is fresh water This fresh water is not always in the right place at the right time

3 Irrigation verses Drainage Irrigation is applying water to the soil, other than natural precipitation Drainage is the removal of excess gravitational water from the soil by natural or artificial means http://ga-mac.uncc.edu/faculty/haas/geol3190/termpap/wilson,r/index.html

4 Irrigation waters Irrigation waters come from the following: –Normal precipitation –Surface water –Groundwaters

5 Surface Waters 75% of water used in the US is surface water Using surface water is cheap and easy The composition of surface water varies considerably The composition is critical for the uses of the water

6 Groundwater 20% of irrigation water comes from groundwater This water exists in underground reservoirs in deep soils These reservoirs are called aquifers Some aquifers will recharge in a few days, years or may take 3 to 4 years In some areas water is not replaced and surface land sinks

7 Managing water irrigation Two factors need to be considered when managing water irrigation –Water holding capacity of the soil –Water infiltration rate of the soil

8 Water Holding Capacity Water holding capacity is directly related to the soil texture Loam soil contains approximately 50% solid particles, 25% air and 25% water This soil will be half solid and half pore space Pore space is half air and half water

9 Water Holding Capacity One half of the water is available to the plant and one half is unavailable Lighter or sandier soils, holding capacity decreases Heavier soils increase holding capacity Soil compaction and organic matter affect water holding capacity

10 Water Holding Capacity Per Foot Sandy Soil.5 to.75 inches /foot Loam Soil.75 to 1.25 inches/foot Clay Soil1.25 to 2.0 inches/foot

11 Water Infiltration Rates (IR) Due to continuous pores in soil IR is rapid in sandy soil, slow in silt and slowest in clay soils Granular IR will increase infiltration rate Greater amount of coarser organic matter, the faster water will enter soil

12 Water Infiltration Rates Hardpan, crust and other restricting layers will affect water IR Wet soils do not have as high an IR as dry moist soils Compaction slows IR Warm soils absorb water faster than cool soils Frozen soils may not absorb water

13 Drainage One third of the cropland in Canada and US is artificially drained http://www.afcap.com/ShiningHope/Hope/CampHope1.html

14 Benefits of Drainage Properly drained soils warm faster in spring Entire field is more uniform in soil moisture Increases aerobic microbial activity Reduces the amount of toxic substances (salts, methane gas, sulfides)

15 Still Even More Benefits of Drainage Drained fields are adapted to a wider choice of crops Drained soils adds to the volume of soil to the root zone-more available nutrients thus a greater crop yield Drainage is essential for reclaiming alkaline soils

16 Two Common Drainage Systems Tiling Ditches http://www.geo.ed.ac.uk/~belize/dept/boothriv/threats.htm

17 Tiling Requires much planning and experience Can last for up to 100 years Involves laying of clay, concrete or plastic pipe in continuous sections Gravels is usually poured around tile to prevent soil from entering into the drain Allows water to move away from a parcel of land

18 Open Ditches Surface system of drainage Adapted to relatively flat acerages Ditches are designed to conform to the lands topography, land use and soil characteristics Ditches are usually parallel Requires continuous maintenance of the open ditches (removal of soil and weeds)

19 References Water use of the World. [On-line]: http://ga-mac.uncc.edu/faculty/haas/geol3190/termpap/wilson,r/index.html AFCAP at Work. [On-line]: http://www.afcap.com/ShiningHope/Hope/CampHope1.html Threats. [On-line]: http://www.geo.ed.ac.uk/~belize/dept/boothriv/threats.htm Zone 1 Instalation. [On-line]: http://www.danbury.org/org/stillriver/zone1_install.htm


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