Let us look at a general example in our daily life; When buying a new car which does not contribute anything to our income, on the contrary is only costing us money, we spend time selecting the correct car for the purpose; it may be a family car for 3 or a larger family of 5. Will it only be used in town to work and back for Mom or will it double as mom’s Taxi or for dad as a car over the weekend and a workhorse during the week. Will a one-liter small car do, or must it have a 3-liter turbo Diesel to do the job? What about fuel consumption, a very touchy subject; isn’t it?
Planning to buy a new center pivot you have already identified the need to irrigate a crop for which you have high expectations of enabling the profits you envisaged. You have calculated the costs and risks. With this done you should also have determined the hectares to be irrigated and the adequate availability of water.
It is time to get quotations for the equipment. After a quick internet search you come up with a few companies supplying center pivots. You send mails to all the relevant companies requesting a center pivot system quotation. After sharing mails, information or maybe you had a visit to your farm you receive the quotations one by one. You look at the prices, love this or that and decide to buy product X.
STOP: Have you looked at the detail? Are you getting what you require to do the job optimally? The price can only be evaluated and compared if you know what you are receiving for the price quoted.
Let us look at a few of these factors:
- What is the center pivots’ design mm application per day (24 hours); If this is too low for your crop, area, soil or climate, your machine may run non-stop but not have enough capacity during the critical growth stages of your crop or dry spells, resulting in crop damage while irrigating due to insufficient water. Suppliers should know the correct figure in different areas and for different crops. Also test that with experienced irrigation farmers in your area. A correct system designed will deliver enough water during peak season with no rain. You buy a center pivot to improve the crop yield and quality as well as it to be an “insurance policy” against dry spells, therefore you cannot work only on average requirements.
- So why not over design the mm per day capacity of the system to be safe? With every mm we increase the system design, it will also result in an increased pump size, pipe size, pivot cost and therefore the project capital expenditure.
- Under designing the mm per day will result in a cheaper system but increase your risk exponentially of yield or crop loss.
- What is the total kW required by the system? Factors affecting the total kW required to run the system are influenced by the water source (surface water or borehole), the distance of the water source from the land to be irrigated as well as the static height of the terrain. These are factors you cannot change or do anything about. What we do have control over will be the following: The size of the pipe line supplying water to the center pivot and the size of the center pivot pipes of each tower. Increasing the sizes of the pipes will decrease the friction loss and lower the running costs.
- So why not over size everything? Increasing pipe sizes will increase the system capital expenditure dramatically.
- Under sizing of pipe lines will drop the system price but exponentially increase the kW required to pump the water and therefore also the running cost.
There is a fine balance to the above. Many years ago when the cost of energy was less of a factor in irrigation there was a tendency to lean over to the slightly smaller sized pipes. Currently it is obvious that the extra capital expenditure for larger diameter pipes are quickly set off against the savings in running costs.
Therefore, also compare the main line and center pivot pipe sizes of the quotations as well as the center pivot inlet pressures.
- What sprinkler package have been quoted? There are large price differences between entry level sprinkler systems and high end, high tech sprinkler systems. So why pay more?
- Entry level sprinklers have been measured to have losses of up to 40% of the water pumped in windy dry conditions compared to water measured in the soil. This is not a quality issue but a design factor of the cheaper sprinklers compared to more expensive high tech sprinklers. All pivot sprinklers available today are of good quality.
- Good quality high end, high tech sprinklers have been measured to achieve between 95% and 97% and even more (product dependent) of water pumped, measured in the soil! Although capital cost of the high end system is more, this is a “no-brainer”.
- Have you thought about your own time, risk and safety? What safety systems are supplied? What control panel is included? If you buy the standard or entry level control panel, can it easily and cheaply be upgraded to an automated or internet controlled system to assist in the above or do you have to replace the panel at a high cost to achieve the above? Why is this important?
- With power failures you have the risk of a pivot shutting down and a pump continuing to pump water. This will not only waste water (and power) but wash out valuable nutrients on that strip, causing a loss in yield. Basic safety measures included to avoid the above will be more expensive but is essential.
- When your system has shut down due to power or a safety issue, do you know about it or do you only discover it the next day when your irrigation cycle should have been completed. In peak dry season the loss in valuable irrigation time can be devastating.
- Do you have to go to your pump or machine to stop or start after dark? Such an action can be risky these days and can be done and monitored safely from your home by an internet connected pivot control system.
- If you buy an internet control system for your center pivot, is there a yearly cost applicable and what does it cost?
Ask the questions. You are investing your money in a long term project which will have an impact on your operations’ profitability. You have the right to know!
At Senter360 we pride ourselves to supply the best optimized irrigation systems, backed by decades of experience, to our clients by not cutting costs on critically important items but supplying our clients with above standard, value for money, high quality systems.
Visit us: www.senter360.co.za