Title: Rodale Institute - 30 year trial results, organic vs conventional
A 30 year comparison of organic and conventional agricultural systems in the US has come up with some interesting results. After 30 years, the Rodale Institute says its organic yields match conventional yields, and outperform conventional in drought years. Its organic systems have built rather than depleted soil organic matter, used 45% less energy, produced 40% less greenhouse gases, and were more profitable. Rodale started the trial in 1981 to study what happens during the transition from chemical to organic agriculture. In the first three years yields declined, but then matched the conventional system. The trial comprised three farming systems: manure-based organic, legume-based organic and a conventional system using synthetic fertiliser. In 2008 each system was divided in two to compare traditional tillage with no-till practices. The organic systems use Rodale’s no-till roller crimper, and the conventional system uses herbicide applications and no-till specific equipment. The organic systems include up to seven drop rotations in eight years, compared with two conventional crops in two years. The organic systems improved soil carbon levels, particularly in the manure system, and had 15-20% more water moving through the soil, resulting in reduced runoff and more groundwater recharge. [Photo: View of the farming systems trial at Rodale]
Organic corn yields were 31% higher in drought years, outperforming genetically engineered drought-tolerant varieties which increased 6.7-13.3% over conventional non-drought varieties. Organic corn and soybean crops tolerated higher levels of weed competition while producing equivalent yields to their conventional counterparts.
Overall, Rodale found that the organic system were nearly three times more profitable than the conventional systems, and economically competitive even without a price premium. Their most profitable grain crop was organically grown wheat, and the least profitable was conventional corn. On the energy side, diesel fuel was the biggest input into the organic systems, while nitrogen fertiliser was the biggest input into the conventional systems. The biggest greenhouse gas emissions were direct inputs from fuel use and seeds for the organic systems, and fertiliser production and fuel use for the conventional system.
Source: Article in AgToday November, 2011, written by Rebecca Lines-Kelly, NSW DPI, Wollongbar. Email: rebecca.lines-kelly@dpi.nsw.gov.au
