Distinguished U.S. soil scientist departs

Press, 3 September 1982, Page 16

Distinguished U.S. soil scientist departs

A senior American scientist, who has made valuable contributions to understanding New Zealand's grassland environment, has left Ruakura at the end of a year-long stay. Professor Robert L. Fox holds the Chair of Agronomy and Soil Science at the University of Hawaii in Honolulu to which he will be returning. Professor Fox came to New Zealand at the beginning of August last year to take up a National Research Advisory Council senior science 'fellowship.. Although he has been based in Hamilton at the Ruakura Soil and Plant Research Centre, he has travelled widely in both the North and South Islands studying soils and collecting samples for analysis at the Ruakura laboratories. Soil fertility and chemistry are his particular areas of expertise and while in this country he has made a special study of the residual effects of phosphatic fertiliser, the likely long term effects to be expected, the cumulative effects of repeated applications, and the possibilities for the future in the use of this important material. His New Zealand work has dealt with both rock and super phosphate and the results have contributed to a better understanding of the elements involved in clover and pasture responses to phosphatic applications, ac-

cording to Ruakura colleagues. Professor Fox has determined that the residual effect of topdressed phosphate is much longer lasting than was previously thought — although contained in a very shallow soil band. His work has shown that concentrations in this shallow band are as much as 10 times more than plants require and are present for considerable lengths of time. Working with other Ruakura soil scientists, he has also studied lime'phosphate interactions and their relationships with phosphate solubility and soil pH. An experimental concept he introduced during his stay is known as the “continuous function" or "continuous variable" design of plot layout. This involves setting out. for example, a range of phosphate applications along one axis of a trial plot, and varying pH levels among another at right angles to the first. •Using this method the responses of plant material within the plot can be measured at stations giving all the possible combinations of the two variables. When Professor Fox returns to Hawaii, where soils of volcanic origin are similar to others in this country, he will find applications for some of-the information he has gathered in New Zealand. ' He believes the pasture

knowledge he has gained here will be valuable in Hawaii where not a great deal has been done to intensify livestock production from grassland. His work there in the past has been concerned primarily with the requirements of tropical crops such as sugar cane and pineapples. Although Professor Fox has been based in Hawaii for more than 20 years, he has also worked in such diverse locations as Turkey, Nigeria, and the continental United States.

A particular interest he has followed in many of these places is the importance of sulphur as an ingredient in efficient plant nutritive requirements. Currently he is keen to assess the status of sulphur along a transect line right across the Pacific Basin. Results he has gathered in New Zealand, the southernmost point, will contribute to this study, as will those he obtains in Western Samoa during a stopover on his return to Hawaii. From work done so far. Professor Fox believes that naturally occurring sulphur levels appear to be higher in the Northern than in the Southern Hemisphere. There may be a correlation explaining this situation which links the much greater degree of industrialisation occuring in the Northern Hemisphere.