EFFECTS OF A FEW PLANT SPECIES ON SOIL PHYSICAL PROPERTIES

Abstract

Seven plant species, Bambusa bambos, Cassia siamea, Casuarina equisetifolia, Ceiba pentandra, Eucalyptus tereticornis, Leucaena leucocephala and Tectona grandis, each raised as woodlots in a farmer's holding at Coimbatore, India (11°20' N; 77°10' E; 310m a.s.l) were investigated for their effects on soil physical properties relative to a site without vegetation and a cultivated soil in the proximity. The age of the plants ranged between 6 and 8 years except for Ceiba pentandra which was 15 years. Compared to the vegetationless site, a distinct improvement in soil properties like bulk density, porosity, waterholding capacity and volume expansion was evident under Casuarina equisetifolia, E. tereticomis. Ceiba pentandra and L. leucocephala, whereas soils under other plant species exhibited no change. Compared to the cultivated field, a debilitation in soil physical properties was associated with several plant species. Thus bulk density increased under B.bambos, Cassia siamea, Ceiba pentandra and T. grandis. Waterholding capacity and porosity registered a decline notably with Cassia siamea. No soil under any plant species proved superior to the cultivated field. The beneficial effects of plants on soil fertility need further investigation.