THE EFFECTS OF HARVESTER ANT MESSOR-CAPENSIS NEST-MOUNDS ON THE PHYSICAL AND CHEMICAL-PROPERTIES OF SOILS IN THE SOUTHERN KAROO, SOUTH-AFRICA

Soils of Messor capensis nest-mounds had a higher infiltrability, but were drier than inter-mound soils after a rain event of 26 mm at the end of the hot, dry summer and after 59·5 mm of frontal rains in winter. Soils of M. capensis nest-mounds contain significantly more organic matter, phosphorus, potassium and nitrogen than soils of inter-mound spaces. Plants growing on mounds generally contained more leaf nitrogen than plants in inter-mound spaces. A bioassay, using radishes grown in soils from ant nest-mounds showed fewer symptoms of nutrient deficiencies, grew faster, had lower root:shoot ratios and were significantly heavier at harvest than those grown in inter-mound soils. © 1993 Academic Press Limited.