CROPS CAN BE IRRIGATED WITH LIME-TREATED ACID-MINE DRAINAGE

The possible use of lime-treated acid mine drainage (AMD) for irrigati on of agricultural crops was investigated. A field screening trial of 20 agronomic and pasture crop species was established at Landau Collie ry Kromdraai Opencast Section (near Witbank, Mpumalanga Province), on a sandy acid soil. The objectives were to monitor crop response to spr inkler irrigation with lime-treated AMD and changes in soil chemical p roperties due to irrigation with this saline (gypsiferous) water. Cons iderable increases in yield of irrigated crops were observed, compared with rainfed cropping. Shallow rooting depths were, however, recorded for most crops, possibly due to high soil acidity, soil compaction an d P deficiency in deeper layers. No symptoms of foliar injury were not ed. Fluctuations in soil salinity levels were recorded depending on ra infall pattern, whilst soil pH(H2O) increased after three years of irr igation. Lime-treated AMD could be an additional resource in mining ar eas, provided that irrigation and fertilisation practices are managed correctly.