Studies on some solodic soils in north-eastern Queensland. 1. Morphological and chemical characteristics

Abstract

Morphological and chemical data are presented for solodic and solodized-solonetz soils occurring in north-eastern Queensland under a strongly seasonal summer rainfall. Mean annual totals range from 26 in, to 70 in. The soils have slightly acid sandy to loamy A horizons, often strongly bleached, and abruptly underlain by hard dense clay R horizons which are strongly alkaline at depth. Profiles show variable chemical properties but many surface elements show relatively little variability within or between areas sampled. Data for such elements may be interpolated for sites within the area studied. Major chemical features are low nitrogen and phosphorus levels which show little variation between areas sampled. The exchangeable calcium : magnesium ratio of surface soils is narrow but values do not suggest deficiencies or imbalance. In the subsoils magnesium and sodium are the dominant exchangeable cations. Exchangeable and acid-extractable potassium values are variable in surface horizons, and data indicate sufficiency in the lower rainfall areas with likelihood of deficiency under higher rainfall. The soils have several adverse physical properties.