Irrigation Management: An Agronomist’s Perspective

Darrin M. Dodds

Mississippi State University

Photo courtesy of Texas AgriLife Extension Service

General Thoughts on Irrigation

• Irrigation is one of the best tools that we have yet it is the least well understood

• Water for irrigation is becoming an increasingly precious resource – San Joaquin Valley

• We must become better stewards of this resource

Typical Irrigation Questions

• When can I stop irrigating? – Growth stage – Depends on your irrigation system – Soil texture

• When should I start irrigating? – Depends – When irrigation usually starts

• How long should I wait between irrigations?

Transitioning to Irrigation

• Variety selection

• Management of vegetative growth

• Insect management

– Plant bugs

– Stink bugs

Yield

1300

1350

1400

1450

1500

1550

1600

1650

1700

1750

ST 5288 - No PGR ST 5288 - 1 PGR ST 5288 - 2 PGR

Lbs

Lin

t/A

cre

Dryland

Irrigated

Transitioning to Irrigation

• Variety selection

• Management of vegetative growth

• Insect management

– Plant bugs

– Stink bugs

Plant Height

0

5

10

15

20

25

30

35

40

45

ST 5288 - No PGR ST 5288 - 1 PGR ST 5288 - 2 PGR

Inch

es

Dryland

Irrigated

Transitioning to Irrigation

• Variety selection

• Management of vegetative growth

• Insect management

– Plant bugs

– Stink bugs

Irrigation Advantages

• Potential for increased crop production

• Increased land value

• Herbicide activation

• Fertigation

On-Farm Experiments

• Interest in improving irrigation management

• Decagon and Watermark soil moisture sensors installed at Bush Farms near Money, MS – Equipped with wireless communication

• Evaluate the effectiveness of soil moisture sensors for

scheduling irrigation – Ease of use – Yield – Water savings

Bush Farms – Money, MS

22.3 ac

6/25 7/11 8/2

22.3 ac

7/10 8/8

18.7 ac

6/30 7/26 8/5

29.4 ac

7/5 8/7

Total Water Used

0

500000

1000000

1500000

2000000

2500000

3000000

3500000

4000000

4500000

5000000

NW - 3 Irr. SW - 3 Irr. NE - 2 Irr. SE - 2 Irr.

Tota

l Gal

lon

s

Water Utilization

11.3

12.6

15.8 16.1

2.2 2.9 3

2.3

0

2

4

6

8

10

12

14

16

18

NW - 3 Irr. SW - 3 Irr. NE - 2 Irr. SE - 2 Irr.

Pumping Time

Acre Inches

Yield

1409 1401

1518

1482

1340

1360

1380

1400

1420

1440

1460

1480

1500

1520

1540

NW - 3 Irr. SW - 3 Irr. NE - 2 Irr. SE - 2 Irr.

Lbs

lin

t/ac

re

Lessons Learned

• We must continue to fine tune our production systems – Intervals between watering?

• We can produce high yields with less water – Where is the edge?

• Using sensors without wireless communications – PITA

Using Moisture Sensors

• Sensor installation requires time and technique – How many sensors are required for accurate

scheduling? – Must be done each year

• The ability to view data from office improves

efficiency

• Education is needed regarding values provided by sensors

Thank You

• Chris Bush and family

• Cotton Incorporated

• Lyle Pringle

• Jerry Singleton

• My contact info:

• darrind@ext.msstate.edu

• 662-418-1024