Cost Water quantity Water Quality Field dimensions Soil type Tillage operations

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2 Cost Water quantity Water Quality Field dimensions Soil type Tillage operations

3 Installation costs for a quarter section: Subsurface Drip=$1300/acre 155 acres of irrigated land Center Pivot=$575/acre 125 acres of irrigated land Life expectancy Subsurface Drip=22 years Center Pivot=25 years Source: K-State SDI Program

4 Equivalent maintenance costs/inch Lower Insurance cost because system is underground and not as susceptible to damage Source: K-State SDI Program

5 Yes, Simply due to increased acreage: Given: $3.5/inch water costs Center Pivot=24 inches Subsurface Drip=18 inches Equivalent yields 220 bu/acre $5.75/ bu Corn Subsurface drip pays out $62/acre more than Center Pivot Source: K-State SDI Program

6 Yes, higher corn price will increase benefit: Given: $3.5/inch water costs Center Pivot=24 inches Subsurface Drip=18 inches Equivalent yields 220 bu/acre $7.00/ bu Corn Subsurface drip pays out $113/acre more than Center Pivot Source: K-State SDI Program

7 No, Lower corn price will decrease benefit: Given: $3.5/inch water costs Center Pivot=24 inches Subsurface Drip=18 inches Equivalent yields 220 bu/acre $4.25/ bu Corn Subsurface drip pays out $0/acre more than center pivot Source: K-State SDI Program

8 Corn Water Use Pattern Irrigation system must be able to meet peak water use rate or crop will be lost.

9 An average peak water demand of 0.3 inches/day for a 125 acre pivot will require a pumping capacity of at least 800 gal/min Assumes 90% application efficiency Assumes 100% application Uniformity????? Also assumes insufficient subsoil moisture and no rainfall Would likely need in excess of 1000 gal/min if subsoil was depleted.

10 Date Daily ET (inches) Soybeans Cotton Sorghum Corn

11 Daily ET (inches) Soybeans Cotton Sorghum Corn Date

12 Daily ET (inches) Soybeans Cotton Sorghum Corn Date

13 Goal was to maintain soil moisture above 50% of field capacity Early season and late season irrigation was applied at a frequency to minimize drainage

14 Water Balance (inches) gpm/acre (400) gpm/acre (600) gpm/acre (800) 8 gpm/acre (1000) gpm/acre (1200) /11 4/30 6/19 8/8 9/27 Date

15 10.0 Water Balance (inches) gpm/acre (400) 4.8 gpm/acre (600) 6.4 gpm/acre (800) 8 gpm/acre (1000) 9.6 gpm/acre (1200) /11 4/30 6/19 8/8 9/27 Date

16 Water Balance (inches) gpm/acre (400) 4.8 gpm/acre (600) 6.4 gpm/acre (800) 8 gpm/acre (1000) 9.6 gpm/acre (1200) /11 4/30 6/19 8/8 9/27 Date

17 Limited water availability can be over come by: Pre watering Splitting the circle into crop rotation Increasing uniformity or efficiency Subsurface drip will do both

18 Depending on the Uniformity and efficiency of the pivot system: Subsurface drip can decrease water requirement by as much as 40% Rule of thumb is a 25% decrease in water requirement

19 Improve efficiency results from: Elimination of Canopy Interception Elimination of drift and evaporation loss during irrigation Reduction in evaporation from soil surface

20 Under full Irrigation drip is cost effective only if irrigated acreage is increased bushels from 155 acres or 125 ($6.5/bu) =Gain of $124/acre or $6.2/acre-inch of water Corn Yield (bu/acre) inches can produce 198 or Bushels ($6.5/bu) =Gain of $160/acre or $11/acre-inch of water Pivot Irr. Req. SD Irr. Req Inches Economic analysis was conducted using K-state Spreadsheet

21 Important when designing the filtration and treatment components of the system Need to know the chemical, physical and biological components of the water Can affect the cost of the system

22 The ability adjust to the size and shape of a field is distinct advantage of SDI Field size is limited by water supply The number of zones and zone size are dictated by system flowrate, field shape, topography and dripline characteristics. Manufactures can provide detailed plans based on these characteristics

23 Subsurface drip can be used in any soil type. Emitter rates and spacing can be adjusted to allow uniform delivery of water Sandy soils present challenges to prevent drainage during crop establishment.

24 Highly automated Irrigation timing Reduced weed pressures due to dry soil surface No need to turn system off for field operations Fertigation is simple and supplies nutrients directly to root system. Crop health??

25 Water use during crop establishment Excess drainage while trying to water up crop Everything is underground!! Can make it difficult to isolate problems Learning curve As with most drastic changes in production the cons can easily out weight the pros if that is your interest But given effort to adapt Drip will increase efficiency

26 K-state website: