E4-Lancaster Farming, Saturday, May 5,1990 ‘Fertigation’ (Continued from Page E 2) Small amounts “Small amounts of fertilizer, put right where the plants need it, can be a lot more valuable than sticking a couple of hundred pounds of fertilizer on the ground early in the year,” he said. “Not only do crops such as pepper and tomatoes need to have a good sour ce of nutrients, but they need to have a constant source of them.” The dilemma some growers face is that some fields in Lancaster County have had heavy manure applications and may contain a great deal of residual nitrogen, said Robinson. So the dilemma the test project faces is not the amount of nitrogen available, but how and when it should be applied. “If we put on as much fertilizer on our vegetables as Penn State recommended, we’d be just throw ing money away,” Robinson said. ‘ ‘Not that the crops don’t need that amount of nutrients, but we already have a good bit of nutrients in the soil that are being released from residual manure.” Different types of injectors, necessary for placing chemical fer tilizer into the irrigation lines, are available. “You can get Cadillac systems to inject fertilizer, and you can have very inexpensive sys tems,” said Robinson. “The first one we worked with was a home made device that just works on a suction principle with a venturi. A venturi is a narrowing in the sys tem. When you narrow the system, you increase the pressure one one side of it, and you decrease it on another. By closing valves on one side of the fertilizer injector to CALL OUR tiro EE! 1-800-333-0569 FOR THE REPRESENTATIVE IN YOUR AREA! 2525 Walden Avenue Buffalo, NY 14225 Dealerships Available drop the pressure, you’ll create a suction.” Because many farmers may have already invested in irrigation systems, the “delivery system for fertilizer is minimal,” he said. “The only cost is the injector $lOO to $2OO for a decent injector for a small system.” The project uses a tube that is inserted into a bucket of liquid fer tilizer. As the feed line pressure is dropped, the fertilizer is sucked into the irrigation line. Robinson emphasizes using caution and employing safety mea sures to make sure liquid fertilizer does not backflow into the main water system or into the well “Whenever you are using a fer tigation system to put fertilizer into the line, and particularly if you are trying to put pesticides in the line, it is very, very important that you include safety devices to prevent any back-siphoning of any of these ingredients into the well or water source.” The test plot has two check valves to stop any siphoning effect back into the well. Understanding management Overall, understanding nutrient management is important to imple menting good fertigation proce dures on the vegetable farm. “We have so much to learn about the residual value of man ure,” Robinson said. “The kinds of manure that are applied, the amount of manure, the manner in which it’s plowed in, whether or not there’s a lot of bedding with it seems to have some implication. “Fertigation probably has the The Leader In M *s- UffteCh INC - VINYL ♦ FENCING dm. HORSE FENCE HORSE FENCE FOR LANCASTER/HARRISBURG/YORK AREAS CALL: QUALTIY FENCING - (717) 354-9760 622 N. Shirk Road, New Holland, PA 17557 Already invested In previous applications at Leola, the less expensive, siphon Injector with a Venturi flow device drew 3-18-18 liq uid fertilizer from a bottle and into the Irrigation lines at the Leola test plot. After testing several different Injectors, the test project now uses a Dosatron injector, greatest value where there is not a of material you need,” saidHeller lot of residual nitrogen in the ick, “you can control the water soil,” he said. “The ability to put lines in such a way that only the smaller amounts right where you fertilizer that needs to be applied is need them is helpful.” applied.” Benefits have been numerous Applicators must be careful that from the ferdgation system in Leo- safety features on fertigator injec la. Last year, yields of tomatoes tor pumps and assemblies are have averaged 40 to 50 tons at installed so that excessive chemi slB,ooo to $20,000 of gross cals are not introduced into the ini income. gation lines. Also, farmers should “I guess you have to be doing something right when that is hap pening,” Robinson said. Trickle irrigation ‘ ‘We’re trying to determine how trickle fertigation can fit into the entire system of vegetable man agement,” said H. Bruce Heller ick, Lancaster County extension agent. The Leola Produce Auction program may provide insight into the effects of fertigation on one acre of land and how that type of application can reflect larger farms as a whole, according to Hellerick. “Because you have a method that ‘meters out’ the exact amount r/ 2 ” PICKET FENCE YAI be careful that “backflow” of water does not occur into the irri gation well or other source, according to Hellerick. Not only are local extension offices studying fertigation, but colleges and universities have begun their own programs to understand how to more effective ly regulate the application of fertil izers, herbicides, and pesticides. At the USD A Agriculture Research Service (ARS) Southeast Watershed Research Laboratory in Tifton, Georgia, Dr. Ralph A. Leo nard, soil scientist and project FENCE Application of fertilizers leader, is working on data obtained as the result of tests conducted using a computer model. Called Groundwater Loading Effects of Agricultural Management Sys tems, or GLEAMS, the model runs simulations for up to 50-year cycles. In one way, the computer model is being used to evaluate the leach ing potential of pesticides and her bicides under different chemical irrigation systems. “GLEAMS is a computer mod el that considers rainful and irriga tion inputs,’’ said Leonard. The data is collected over a 50-year simulation on the effects of chemi cal appligations through a water irrigation system. “We sample a wide analysis of chemical applica tions that’s one of the things we apply the model to.” Analyzes combinations GLEAMS analyzes a host of combinations, including soil, rain fall, pesticide use, and other fac tors, and examines the effects of applying a certain type of chemical pesticide or herbicide as it is applied at one time or in multiple, smaller doses. “We examine the question, ‘What if you put the chemical into the irrigation water versus putting it on the conventional sort of way, using a tractor sprayer or whatev er?’ We examine the potential of chemigation technology,” he said. GLEAMS also provides an analysis about potential results of groundwater movement after che migation, the method by which herbicides or pesticides are injected into an irrigation system, is used. Studies conducted at Tifton indicate that injection of chemical (Turn to Pago E 5) 3" PICKET FENCE POOL FENCE
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