Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
Which center pivot design is the best for African soil?
Are there any modern center pivot irrigation designs, with improved water management, which save water?
Alternatively, which irrigation design do you consider the most efficient and why?
Look on websites for NESPAL at the University of Georgia in Tifton GA, USA, and Stripling Irrigation in Camilla, GA, USA, for timely research on GPS, soil moisture, remote monitoring. Dr. George Vellitis is leading research at NESPAL.
Best of luck.
Published by Kathleen Rugel
Solar powered towable pivot system with center tower are available. This helps in more energy efficient and water saving irrigation..ideal in Africa
Published by Suresh Kumar.S
The Water Network research team has consolidated an answer to the above question.
Further input from members is welcome and appreciated.
Center pivot irrigation is a type of crop irrigation with rotating equipment with sprinkles around the pivot.
Center pivots were water-powered in the past and now most of them are operated by electric motors.
Center pivot irrigation consists of pipes with sprinkles along them and wheeled towers for moving.
The water is fed to the sprinklers from the pivot point and can be directly leading to a groundwater source.
The outer point of the equipment does not spin at the same speed as the inner point.
Angular velocity is the rate of change of angular displacement of a rotating body.
It is a pseudovector which specifies the rotational speed of the object and the axis around the object is rotating:
, 
* Formulas are represented in 2D.
The formulas clearly show that the speed is greater at the outer point of the circle.
Since equal water supply is needed everywhere, the nozzle size is the biggest at the outer circle point. The size of the nozzles drops to the inner pivot point.
Center pivots are usually not made larger than 500 m in radius.
Center pivots can be set to rotate the full circle or only a part of it, for best irrigation coverage and to avoid overlapping. Various combinations can be applied:
Pivots can even irrigate the corners without wasting water by attaching swing arms to the ends of the pivots.
Center pivot advantages:
greater water efficiency
reducing labor
easy to install and last for at least 25 years
easily movable from field to field
possibility to remotely monitor and operate the equipment
Disadvantage:
great installing costs
Center pivots can save water by applying fertilizers, insecticides, and herbicides while irrigating.
The most important thing in the design is to correctly select the nozzle type based on the type of soil. Finer nozzles should be used for fine particle soil types (silty clay). Fine droplets are achieved with higher pressure and increased diffusion plate properties. Fine droplets should be used where wind is not a concern.
Good quality sprinklers generally irrigate with large droplets to reduce evaporation and so that they are not instantaneously distributed on the soil surface.
Pivots can be applied for a variety of crops and it is easy to modify them and adjust sprinkler height and application rate to best match the soil’s intake rate and ability to absorb water.
Throw distance should match the infiltration rate of the soil or efficiency is lost due to runoff. As the wetted throw distance is increased, the rate at which water is applied can be reduced.
Pressure in the center of the pivot should be regulated for:
uniform depth of water application
controlled droplet size and throw distance
flexibility in system operations
Height of the system determines the water distribution uniformity – the higher the nozzles, better the uniformity. However, the spacing between the sprinklers should be adjusted so that there is no overlapping.
Another factor which affects uniformity is a uniform travel speed . If the tires are wet, they can be slippery. To maintain speed uniformity part circle sprinklers, combined with the use of boombacks can be applied so that the water is applied behind the direction movement.
Image source: http://www.nelsonirrigation.com/media/resources/Pivot_pocketguide.pdf
The application rate depends on the type of soil and crop.
There are 2 types of application rates:
Average application rate (AAR) – rate of water application over the wetted area.
It is the average value if the wetting uniformity is assumed, for which the application rate is applied at the outer circle.
Instantaneous application rate (IAR) – peak intensity of the applied water at a point.
Image: Fixed and rotating stream
Image source: http://www.nelsonirrigation.com/media/resources/Pivot_pocketguide.pdf
Rotating and spinning equipment at low pressure has 2 benefits:
increasing the soak time
low application rates.
Find the pivot diagram for calculations here – starting with page 14 http://www.nelsonirrigation.com/media/resources/Pivot_pocketguide.pdf .
Sources:
Published by Water Network Research, Official research team of The Water Network
Thank you all for the contributions
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
Dear Musaope,
you got a very detailed answer here above.
I would only add one point to address the problem fully: Once the proper central pivot is in place, the operator should take care of the evaporation factor. As you well know, in hot and arid areas, it can reach up to 50%, even if the best pivot is installed.
One way to stop evaporation and reduce the amount of irrigation water by up to 50% is to use a liquid mulch (see www.guilspare.com as an example).
Best of luck,
Laurent
Published by Laurent Selles, WIPO Green Board Advisor, Geneva
Thank you so much I really appreciate
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
In my opinion to save water always adjust speed of CP to matches application rate with the soil infiltration rate (to avoid ponding of water). U can use center pivot from well renowned company having best R & D in the field. Check sprinklers installed on CP alongwith pressure regulator/compensater which shall be of good quality and work as per design to avoid wastage of water.
Published by Zia ur Rehman, Mr.
VALLEY PIVOT WITH VRI ZONES OR INDIVIDUAL SPRINKLER CONTROL. REQUIRES A SOIL MAP.
Published by Paul Moat, Project Sales and Design
Hi Musaope.
There are many brands of centre pivot that would work in your conditions - as long as they are designed properly. Make sure you have a soil survey done first so the whole system, especially the sprinkler package, can be designed to suit the soil characteristics. Centre Pivots perform well over a large range of soils and a large range of crops. Efficiency will depend on good deign, good installation and most of all good management.
Peter Smith, Sapphire Irrigation Consulting
Published by Peter Smith, Principal at Sapphire Irrigation Consulting
Take a look at LESA or LEPA center pivot systems here:
https://www.bpa.gov/EE/Sectors/agriculture/Pages/LEPA%20and%20LESA.aspx
Published by Nigel Pickering, Research Associate Professor at Washington State University
What is an African Soil? Is there anything like that?
Published by Abba Ahmed
Hello Musaope, I'm attaching a new paper that discusses water saving strategies in irrigated agriculture. I hope it's helpful to you!
Published by Brian Richter, Sustainable Waters - Presudent
Reply to your question can be given if one knows the Total Area, General slope, Water Source Location , Crop/Crops grown, Power source and availability per day basis.
Under all circumstances, in African Climatic Non-Coastal Conditions, it is best to opt for low pressure Sprinkling opting for medium size droplets so that evapo-transpiration losses are low to moderate. Friction drop should also be minimised so that recurring energy costs are low.
Published by LOKESH PUNJ, A B.TECH. Agr Engg, PGDM-SPA IIMA (1977-9) 25 yrs in Water Piping / Irrigation/Infra Projects
French English
BonjourLa revalorisation des eaux usées pour une agriculture -biologique- productive est de loi la meilleure, la plus performante, la plus économique, la plus écologique et la plus productive.
La capture des eaux usées domestiques est , à profusion en illimité.
le liquide qui sert à l'arrosage contient tous les éléments de fertilisant pour la terre agronomique.
Mais son grand avantage réside dans le fait qu'il est prêt à l'emploi immédiat. Prêt immédiat à l'emploi définit aussi qu'il va " fertiliser " la biodiversité immédiatement à toute les étapes de son développement.
Il va rendre plus fort, plus productif la biodiversité et lui permettre de mieux se défendre contre les attaques nocives.
il n'existe rien de meilleur sur le marché
Hello The revaluation of wastewater to productive - organic - farming is Bill the best, strongest, most economical, greenest and most productive.
The capture of domestic wastewater is < free >, galore in unlimited.
The liquid output of the water treatment process used to watering contains all of the elements fertilizer to agricultural land.
But its great advantage lies in the fact that it is ready for immediate use. Immediately ready to use sets as he'll------"fertilize------" biodiversity immediately at all stages of its development.
It will make it stronger, more productive biodiversity and allow him to better defend themselves against harmful attacks.
There is nothing better on the market
at what scale will be that and whats the roi
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
I have written many times that there are systems that : - purify the waste water and direct them for irrigation, while very low rates, because of the small energy consumption is only 0.5 kW per 1 m3. WE INVITE YOU TO SEE THIS MARVELOUS EQUIPMENT IN ACTION.
Published by Sergey Tumentsev, Очистка сточных вод at Amiad Water Systems
great where is that
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
We have a Solar Powered Constant / Continuous Move Pivot Irrigator, covering maximum of 75 Acers. The drive is independent of Power. Constant Move makes the machine move in straight line, avoiding frequent start / stops improving water distribution efficiency, and life of the machine. This may be very useful for Africa.
Published by Dr. Padmakar Kelkar, CEO at Bright Stars Electronics
More details on this irrigator Dr. Padmakar
Published by Atieno Rakwach, Director at Japmor Kenya
if possible you may email me on musaope@sutsol.solutions so that we can talk more
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
Great thats what am looking at I think we need to discuss more on that really. Having something that uses free energy thats superb
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
Centre Pivot designs are generally very similar these days. The major factors to look at are your nozzle/spray package choice and the sizing of the pipes of the pivot. nozzles spread the water to allow for soil infiltration and water distribution. Pivot pipes largely determine energy consumption at your pump (friction losses increase energy consumption with smaller pipes). The better nozzles/sprayers usually cost a little more (think i-Wob) as do the larger pipe sizes to minimise friction losses. A good choice for Africa is the South African made Senter360. DM me if you want contact details for their MD.
Published by Rob Cloete, Viable solutions encompassing waste, water, and bioenergy in mining, agriculture, and industry
Your question is very general. Irrigation design depends on many factors including : water availability, scales (small or large ), weather condition, crop type , and soil type ....
If you have a large scale, center pivot is best option provided you consider the balance between the irrigation discharge rate and the soil infiltration .
Published by Hadi Muhammed, Researcher
yes it was more general yet targeting input from people of diverse fields. I wanted something that is more like cost effective and energy efficient. That reduces water loss by evaporation while minimising on energy across all soil types like for instance in southern africa were i am based
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
yes it was more general yet targeting input from people of diverse fields. I wanted something that is more like cost effective and energy efficient. That reduces water loss by evaporation while minimising on energy across all soil types like for instance in southern africa were i am based
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
I would advise you to contact Rain Bird's agriculture section to get best advise and recommendations. Try to contact Mr. Ed. Johnson if he is still with Rainbird.
Published by Mir Sarfaraz Ali Khan
do you have contacts
Published by musaope mtamba, Director and Chief Consultant at Sutsol Hitech Solutions
