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Fluid Journal : Fluid Journal 2005-2007
16 Fluid Journal SPRING 2007 years averaged 0.8% higher after UAN injection. In all trial fields, the amount of N application was equal. Summer barley. There are several N fluids available for farmers. In a field experiment with summer barley, different fluids have been point injected (80 lbs/A of N or 90 kg N/ha). Compared to the conventional spraying of UAN (Figure 3), all injected fluids containing urea showed a yield decrease compared to the UAN sprayed treatment, while injection of ammonium sulfate solution showed a slightly higher yield. Similar results led to recommendations that urea- containing fluids are less suitable for injection fertilization in cereals, while urea seems not to be harmful for dicotyledons. Other crops. For sugar beets, similar yield and quality have been found in 2-year experiments on two different sites. Good experiences have been reported for vegetable yields and quality after fluid injection. Depending on the vegetable species, yields are higher or similar after fluid injection compared to common fertilizer surface applications. With regard to quality, vegetables regularly show 0 30 60 90 120 N treatment 0 UAN surf. sprayed AS point inj. UAS point inj. NTS point inj. UAN point inj. ALZON point inj. UAN surf. band Av. fert. Yield bu/A a lower nitrate content compared to conventionally fertilized plants. Experimental data for grassland are still lacking, but a long-term field experiment to determine yield and quality response of permanent grassland to UAN injection began in the spring of 2006. Injection studies with UAN on cool-season forage grasses in the USA have indicated superior performance compared to identical surface broadcast applications. Ecological aspects In field studies, German scientists have reported 42 percent lower nitrate leaching in plots fertilized with fluid injection, compared to the conventionally fertilized plots (data not shown) The same procedure was used to measure nitrate leaching below open field plots with intensive vegetable cultivation, where N fertilization is commonly higher than approximately 225 lbs/A of N (250 kg N/ha). Injected UAN and surface- applied calcium ammonium nitrate were compared, both methods of placement with the same amount of N. Averaging three winter and two summer periods, researchers found that nitrate leaching decreased by 32 percent in N injection. Conclusion Experimental data available for German cropping conditions are encouraging, as most experiences show that fluid injection fertilization results in similar or higher yield response (depending on the crop) compared to conventional surface application. Injection of N solutions especially shows less environmental impact with regard to nitrate leaching and ammonia volatilization. These results and positive experiences of farmers using fluid injection have increased interest of governmental and environmental authorities as well as farmers' advisory organizations. Positive agronomic experimental results that continue to build interest in fluid injection in Germany are owed principally to 1) favorable experiences of farmers who have used this fertilization strategy, and 2) an increasing amount of data that demonstrate its positive environmental potentials. Dr. Kuecke is research scientist, Institute of Crop and Grassland Science, Braunschweig, Germany. Figure 3. Yield effect of placement of different liquid N fertilizers on summer barley, Braunschweig, Germany, 2002.
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