Ecological Studies under Varying Regimes of Regulating Underground Water on the Drainage Flow Quality
2008
Banishka, N. (Institute of Melioration and Mechanization, Sofia (Bulgaria)) | Stoyanova, A. (Institute of Agriculture, Kyustendil (Bulgaria))
In a lyzimeter site, located in the Experimental field of the Institute of Land Reclamation and Agricultural MechanizationSofia, four regimes were realized in 24 lyzimeter containers, simulating real functioning situations of operative drainage-irrigation and controlled drainage systems. The quality of drainage flow was followed in two levels of maize fertilizing. From the water samples taken from the drainage flow during the vegetation period of maize in 20062007, from variants with fertilizing rate T1 N24 P16 K16 and from variants with fertilizing rate T2 N34 P26 K26, a low nitrate contents were observed in the drainage flow, which was under the allowed concentrations for underground water 50 mg/l. Increased nitrate content was obtained solely in the drainage flow of the variant, where the action of a conventional drainage system was simulated and no irrigation was conducted. During the test years, for 2 fertilizing rates, the highest yield of grain maize was received in the variant, simulating the operation drainageirrigation system with subsurface irrigation.
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