Soil erosion is one of the most important forms of land degradation that threatens continued and sustained agricultural production in Ghana. The most severely affected areas are the three northern regions especially Upper East Region, where large tracts of land have been destroyed by water erosion leading to soil depth reduction and decline in soil fertility. This study was carried out in Talen...

Approaches to soil management, including problems of soil degradation and low soil fertility, have recently undergone major changes. The former view was to concentrate on achieving high levels of production from the more fertile areas, leaving the marginal lands for extensive use only. Steeply sloping and highly drought-prone areas were preferably not to be cultivated at all. Soil constraints w...

Alfred Hartemink is a soil scientist at ISRIC in Wageningen. Prior to his current position he was lecturer in soil science at the University of Technology in Papua New Guinea. He holds an MSc in soil science from Wageningen Agricultural University, and has worked as a soil surveyor and soil fertility specialist in Tanzania, Zaire, Indonesia, and for ICRAF in Kenya. Dr Mike Bourke is an Adjunct ...

MSS. intended for publication and books, etc.,intended for review should be sent to The Editor of Science, Garrison-onHudson, N. Y. THE SCIENTIFIC BASIS OF THE ILLINOI,S SYSTEM OF PERMANENT SOIL FERTILITY' IT is practically impossible to cover, in an adequate way, the scientific principles underlying the Illinois system of permanent soil fertility in the brief space of time allotted me on the p...

A number of tests to study the yield response of cotton and soybean to several fertility programs, under conventional, no-till, and stale-seedbed production systems were established at the Cotton Branch Station near Marianna, Ark. Soil samples (0 to 6 inches) were collected prior to planting and extracted using the Mehlich3 procedure (extraction ratio of 1:7), with nitrate-N measured with a sel...