Issue link: http://read.dmtmag.com/i/481870
38 APRIL 1, 2015 GOOD FRUIT GROWER www.goodfruit.com A machine has been developed to install the film in long continuous bands. This prototype, manufactured by Bron SWRT, Woodstock, Ontario, can be seen in action in a video at bronrwf.com. A n exotic idea—hatched 50 years ago in plant science and agricultural engineering laboratories at Michigan State University and stalled by odd events in the deserts of Libya—has been resurrected and is starting to bear fruit. It could greatly change how crops, including tree fruits, are grown on sandy soil and/or in desert conditions. It dramatically changes how effi ciently crops use water and the nutrients that water carries. The system, called Subsurface Water Retention Technology (SWRT), is being developed by Dr. Alvin Smucker, a Michigan State University professor of soil biophysics. Here's how it works: Sheets of polyethylene fi lm are installed about 24 to 27 inches underground using a special machine. The fi lm is installed in a trough shape that holds water, whether applied by irrigation or natural rainfall. The bar- rier stops the natural downward percolation that results in losses of valuable water and fertilizer from the root zone and into groundwater. If there is too much water, it overfl ows the contoured trough so that roots can't be fl ooded and drowned. The U-shaped troughs are installed side by side, at slightly dif- ferent depths, so that roots can explore around and below the barriers. Smucker was a graduate student at Michigan State University in the 1960s, working with Professors A. Earl Erickson and Clarence M. Hansen, when they developed a machine to lay a thin asphalt layer under sandy soils to create a barrier to downward water percolation. It worked. Smucker says farmers who had small test plots on their farms back then may not even know why, today, 50 years later, the grass is greener and the crops yield better there. He says he can fi nd the plots using Google Earth and see, from the lush condition of the vegetation, that these barriers are still at work. The machine and the process was described in glowing terms in the September 17, 1966, issue of Michigan Farmer magazine (co-written by the writer of this article). Entitled "Asphalt under the Earth," the article estimated that the process would make farmable land out of 10 million acres in Michigan alone. One machine So what happened? Why didn't this become standard industry practice? As Smucker tells it, the researchers built just one machine. The concept was tested in several countries, but in most places test plots were installed by hand. Smucker tells of working for three weeks with 270 Chinese workers in Taiwan to bury a thin layer of asphalt to test the concept for growing rice and sugar cane. The team also decided to test the concept in Libya, a des- ert country in North Africa. They sent their only machine there. That was 1969, the year a coup led by Muammar al-Gaddafi overthrew the government. To reduce foreign imperial infl uence in his country, he nationalized the oil industry. He also sequestered their machine. Irrigation Subsurface Water Retention Technology could revolutionize irrigated agriculture. by Richard Lehnert Percolation BARRIERS