Issue link: http://read.dmtmag.com/i/120609
Nutrients Soils & Orchard ground covers F or 21 years now, Dr. Ian Merwin has tended a 320-tree apple orchard on the eastern shore of Cayuga Lake near Cornell University's Ithaca campus. He's been studying the long-term effects of four different orchard floor management systems. A key question is, are there better arrangements than trees in herbicide-treated strips separated by alleys of grass, the system used by most apple growers? Merwin studies the effects on tree growth and yield, runoff and leaching of nutrients, and soil quality. The results have been surprising. In a nutshell, you can grow apples almost equally well over the long term in all four systems. But a simple postemergence herbicide program—two applications of glyphosate each year in May and July—generated the highest fruit yield, providing good orchard floor conditions for working and, surprisby Richard Lehnert ingly, good protection of the soil from erosion and runoff. The system that turned out to be the most different— and interesting—was one based on deep applications of bark mulch to keep tree strips weed-free. Merwin reviewed the results of this long-term study with growers during Southwest Michigan Horticulture Days in Benton Harbor, making a mixed-media presentation using PowerPoint and a speaker phone linked to his office in Ithaca, New York. Soil quality studied under four ground cover systems. The study began in 1992 when Royal Empire apples were planted on M.9/M.111 rootstock on a 10- by 20-foot spacing and trained to a vertical axe. Microsprinkler irrigation was used as needed. The soil is a heavy, silty clay loam, and high in organic matter (4 percent). Drainage tile was installed under the orchard so that both subsurface and surface runoff water could be collected and analyzed. Four systems Merwin has studied four orchard floor management systems: —Mowed red fescue turfgrass with no herbicides —Hardwood bark mulch, renewed every two years as it decomposed during the first ten years, and then every four years to the present. For the first five years, the mulch suppressed weeds, but over time, a glyphosate spray was necessary each May to control perennial weeds that became established in the mulch. —Glyphosate applied in May and July each year (the postemergence program) —Karmex, Solicam, and glyphosate herbicides applied in May each year (the preemergence program) Measurements are taken to see what effects the systems have on soil physical properties, tree physiology and yields, agrichemical runoff and leaching, and nutrient availability and recycling. Green Through Better Technology. a manner that is environmentally responsible. Traditional old, resulting in increased application rates and repeated calls to reduce or ban the very nutrients needed to accomplish your goals. Through the science of Redox, we have solutions that lower application rates by as much as 98 percent – including both phosphorus and nitrogen – while improving or maintaining crop quality and yields, without increasing the overall cost of treatments! Technical data demonstrates that Redox product solutions are the environmentally friendly choice for superior fertility management. But the results that matter are the show up in exceptional yields, and not in the streams. URE OF REDO X NAT CE www.redoxchem.com F TH Redox Chemicals, LLC Distributed By E P OW E R O Ask your GS Long Co. representative about how you can grow "green" while seeing more "black" on your bottom line. THE SCIEN G.S. Long Co. Contact Doug Anyan (509)949-9231 douga@gslong.com Yakima, WA, Wenatchee, WA and Hood River, OR www.gslong.com 12 April 15, 2013 GOOD FRUIT GROWER www.goodfruit.com