Institut für Agrartechnologie und Biosystemtechnik

Possibilities of using the drip irrigation laterals on centre pivot irrigation

machines

Jano Anter, Dr. Heinz Sourell, Hans-Heinrich Thörmann,

Federal Research Institute for Rural Areas, Forestry and Fisheries, GermanyInstitute of Agricultural Technology and Biosystems Engineering

27 June 2012, Adelaide

German National Committee of ICID (GECID)

2Jano Anter, Hans-Heinrich Thörmann, Dr. Heinz Sourell

3Jano Anter, Hans-Heinrich Thörmann, Dr. Heinz Sourell

Contents

• Irrigation in Germany

• Advantages & disadvantages of drip irrigation and center pivot

• Steps to mobile drip irrigation

• Technical aspects

• Costs analysis

• Summary

4Jano Anter, Hans-Heinrich Thörmann, Dr. Heinz Sourell

Irrigation in Germany

• 3% of the agricultural land are irrigated in Germany

• Humid climate, dry periods, sandy soils

• Cultures worth of irrigation: i.e. Potatos, Sugar beets

• Use of modern irrigation techniques

• The techniques are developed in terms of claims by farmers:- Water distrubtion - Intensity of labour - Water-efficient - Energy consumption

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Water distribution-systems

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Advantages & disadvantages of drip irrigation

+High water use efficiencyLow water lossesLow energy requirementsPossibility of chemigation

-High total costsHigh labour requirements for the assembly and disassembly

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Advantages & disadvantages of center pivot with sprinkler

+Full-Automatic machine managementLow labour requirementsModerate capital requirementSimple to use

-Water lossesWind drift High energy requirements

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Operating costs

Center Pivot

Drip Irrigation

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Steps to mobile drip irrigation

Drip irrigation Center pivot

Mobile Drip Irrigation

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Installation of mobile drip irrigation by centre pivot

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Field experiments

The Center pivot consisting 9 towers

The total lenght of this pivot machine was approximately 428 m

The total irrigated area of about 57 ha

Drip tubes distance: 0.75 m

In the field investigations, two operating pressures were used at the inlet of the drip tubes (50 kPa and 100 kPa)

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Emitters

Mobile drip irrigation needs emitters that have:

• High discharge (8 l/h & 10 l/h)• Low distance between them (0.15 m)

To reduce the lenght of drip tubes and the numbers of emitters

• High emission uniformity (over 95 %)• Low coefficient of variation (lower than 5 %)

To enhance irrigation water distrubtion on the soil surface

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Length of drip tubes at two pressures

- The lenght of the drip tubes is dependent upon the emitter discharge and the distance from the pivot point

- The lenght of the drip tubes increases as the distance from the pivot point grows

- For the stability of the centre pivot irrigator, additional friction force is

important

- The friction force at 50 kPa were higher than the friction force at 100 kPa (2470 N & 1743 N at the ninth tower)

- This force is suitable for the electric motors which are mounted on each tower.

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Length of drip tubes at two pressures

0

3

6

9

12

15

18

21

0 50 100 150 200 250 300 350 400 450

Lateral length of center pivot, m

Leng

th o

f dr

ip t

ubes

, m

50 kPa

100 kPa

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Costs analysis (Capital requirement)

Item Unit Center Pivot sprinkler

Stationary drip irrigation

Mobile drip irrigation

Irrigated area ha 57.55 57.55 57.55Water required m3/ha 200 64 160No. of irrigations per season 5 12.5 5Total water required m3/ha per season 1000 800 800Energy requirement kWh/(ha*a) 360 128 208Total working time h/ha/season 0.5 9.975 0.75

Capital requirement (Initial cost)

€ 60,572 132,20056,225 * 15,487**

71,722 (Total)* = Pivot machine without sprinklers** = Only drip tubes, emitters and regulators

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Costs analysis (Operating costs)

276209

906

590

158 127

0100200300400500600700800900

1000

SDI MDI CPSIrrigation system

Tot

al y

early

cos

ts,

Eur

o/ha

One season

Two seasons

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Summary

• High water efficiency / Water saving up to 20%

• Energy conservation up to 40%

• The total costs of MDI were close to the total costs of a CP

• For the same area we need only 1,6 % respectively of the tubes that would needed for a SDI

• Filtering of the water can become important

• Further experiments with other plants is necessary

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Many thanks for your attention!