Extra nitrogen needed for parks, gardens and sporting fields irrigated with tertiary effluent

Abstract

This study was conducted to determine the effects of tertiary treated effluents on the performance of 20 tropical turf grasses growing in Brisbane, Queensland, Australia. Its performance under moderate concentrations of salinity and sodium were also studied. It was found that the grasses irrigated with effluents were only 60% of the height of those in potable plots, while clipping weights were less than 15%. Effluent water can affect the growth of turf grasses by affecting soil salinity, soil sodium concentrations or plant nutrient concentrations. There was inadequate concentrations of nitrogen in the effluent to support the growth of the grasses, whereas there were adequate concentrations of phosphorus and potassium, and possibly excess concentrations of sulfur, calcium and magnesium. The salinity, sodium and chloride in the effluent would probably affect only the growth of the sensitive species. The sodium hazard for the soil was also low. There were only a few differences in the responses of the various cultivars, with most grasses requiring supplementary fertilizer application, at least with nitrogen.