Lower levels of arsenic in rice

By using pivot irrigation

A report published in the American Chemical Society journal ('Environmental Science & Technology') reveals that the use of center-pivot irrigation to grow rice can reduce the concentration of arsenic in rice. The concentration found is 50 times lower than rice grown under flood irrigation.

At present, many research projects are being carried out about the use of pivot irrigation in growing rice, rather than the traditional field flooding methods, in the United States and worldwide. This particular study took place in Italy.

Consumers are concerned about this matter worldwide, especially in the regions where rice is a staple food source, as it is extremely toxic and carcinogenic. Arsenic is found throughout the environment—in water, air and soil. Human activities also add arsenic to the environment. Rice comes from all over the world and is grown very differently from region to region, which may greatly vary the levels of arsenic within the same kind of product.

Arsenic can be absorbed by the rice plant, particularly in fields with continuous flooding.

As demand for rice increases, a solution to this issue is needed. Growers must identify a profitable method to grow rice with center pivot sprinkler irrigation.

Electric pivots versus hydrostatic systems

There are five major manufacturers of center pivot irrigation systems and irrigation technology: T-L Irrigation, Valley (also known as Valmont Irrigation), Raintex Irrigation, Reinke and the Lindsay Corporation. 
Center pivot systems were originally designed to operate on square fields. With the introduction of electric drive machines, center pivots started to be used on many field shapes.
T-L Irrigation manufactures hydrostatic Pivots, (the machine is powered by water propelling the pivot around the field).

The other manufacturers' equipment is powered by 480 volt electricity. The propelling motors and other equipment start and move forward when told to do so by sensors, not in a continuous motion.

Center-Pivot irrigation: benefits to the crop

 

Many crops around the world take benefit from center pivot irrigation: soybeans, corn, sunflowers, edible beans, sugar beets, alfalfa, wheat...Center pivots have been used successfully in very large fields, with the pivot itself being as much as one-quarter mile in length.
The sprinkler heads are positioned along its length. There are many different nozzle configurations available. Big guns can be placed at the end of the pivot overhang to allow the water system to reach even the farthest edges of a field.

Typically pivots work on flat fields, but even fields can benefit from this type of irrigation system. Many farmers are finding that center pivot irrigation satisfies many of their crops' consistent water needs.

Pivot irrigation in Georgia

In Southwest Georgia there are more than 6,000 center pivots used to water peanuts, cotton and corn. Farmers have control over how much water the irrigation nozzles spray as they pass over fields. Small fields can vary in topography and soil types, with some places wetter or drier than other places in the same field.

VRI technology

The concept is simple: apply water when and where crops need it. Don't apply it where they don't. VRI technology uses computer maps, global positioning systems, soil sensors and software to control where and how much water the nozzles on a center pivot spray on crops.

Growers want to irrigate more precisely, but don't have the time or level with higher-tech gadgets. The more time-consuming technology steps have been eliminated to make the system easier for farmers to use.

Instead of having to create computer maps of fields, this system has a simple "push-button" feature. A farmer can start the center pivot over a field. When it gets to a location he doesn't want to apply water, the farmer pushes the button to train the system not to water that area. Once the system passes this area, he pushes the button again to resume watering only the crop. This can be done in as many as 8 locations in the same field.

The water efficiency of VRI has been tested on farms in Georgia and found it can reduce the water use in a field by as much as 15% annually without sacrificing crop yield.