Ecosystem irrigation as a means of groundwater recharge and water quality improvement.
Semi-natural heath vegetation consisting mainly of Deschampsia flexuosa, Holcus mollis, Agrostis canina, Pteridium aquilinum and Chamaenerion angustifolium was irrigated during 4 periods in 1970-1 with a total of 5.406 m polluted river water; potential evapotranspiration during this time was 250 mm. Estimates of percentage cover in Apr. 1970 and May 1971 showed no significant effects of irrigation on botanical composition. Yields of standing herbage in Apr. and June 1971 were increased by irrigation.There was considerable retention of nutrients by the soil/plant system.<new para>ADDITIONAL ABSTRACT:<new para>[267.8]Polluted river water was applied to lowland heath vegetation on Bunter Sandstone by sprinkler irrigation. The vegetation yield was increased considerably but there was no change in the plant species balance. At 1.58 m depth, water quality was improved with respect to alkalinity, total hardness, BOD, phosphate and anionic detergents. Potassium content and electrical conductivity were reduced to a lesser extent. Ammonium-nitrogen was reduced but sometimes nitrate-nitrogen levels increased.