Water Regime and Nitrogen Fertilization for Rhodes Grass Irrigated with Municipal Waste Water on Sand Dune Soil

Abstract

AbstractThe use of municipal waste water for crop irrigation has advantages in increasing water supply and reducing the need for fertilization application. The objective of this research was to develop management for using secondary effluent for crop irrigation while reducing pollution hazards.A field experiment was conducted on a sand dune soil during 1978 and 1979 to determine the water requirement and fertilizer needs of Rhodes grass (Chloris gayana Kunth). There were four irrigation treatments, each at two levels of N fertilizer. The grass was irrigated with municipal effluent that received secondary treatment in settling ponds. The N concentration in the waste water used was about 18 mg/liter, which did not fully supply the needs of the crop. When 250 kg N/ha was added as (NH4)2SO4, an optimum dry matter yield of 12.0 metric tons/ha was obtained when irrigation was applied on the basis of 0.8 pan factor. Higher rates of fertilization and water application resulted in N seepage below the root zone. Any additional water resulted in increased drainage.Rhodes grass proved to be an efficient remover of N from effluent, and also prevented deep seepage and ground‐water pollution.