Soil Nutrient Research. The release of nutrients from sandy materials is being 

 studied in a series of laboratory experiments. A range of conditions and various 

 materials are used. The immediate aim is to develop a technique suitable for the 

 characterization of sandy materials which would be of great value for the regional 

 site research. 



Numerous soil samples were analyzed for regional site research. New analyti- 

 cal techniques were selected and new laboratory layouts were developed to improve 

 the accuracy and efficiency of analyses. 



Soil Moisture Research. The greatest part of the soil moisture programme 

 during this period was concerned with moisture deficit-tree growth relations. 



Experimental study plots within a 27-year-old red pine plantation on a dry 

 sand site in Essa Township were thinned to varying degrees (immediately prior to 

 the 1964 growing season). Measurements of current soil moisture and current dia- 

 meter growth were made at frequent intervals throughout the growing season. Half 

 of the plots were irrigated to maintain near-optimum moisture conditions. The 

 newly-acquired nuclear equipment, used for all moisture measurements, performed 

 in a highly satisfactory manner. The study is being continued, but it is premature 

 at this time to forecast quantitative relationships between moisture deficit and 

 growth. 



A new technique was developed for using a polyethylene surface shield with 

 the neutron depth-probe for the determination of moisture contents within the top- 

 most surface soil layer. This has been written and submitted for journal publication. 



A manuscript, reporting earlier studies on the equipotential zone above water 

 tables, was prepared with a view to journal publication. 



The soil moisture study in Essa Township and the determination of the water 

 balance of the site regions of Ontario, were accepted as projects for the Interna- 

 tional Hydrologic Decade. 



LAND PRODUCTIVITY RESEARCH 



The objective of land productivity research is to rate the potential of physio- 

 graphic land classes for various uses, such as the production of farm, timber and 

 wildlife crops and for recreational activities. This is done by observing the produc- 

 tion on the same land class under various stages of plant succession, cultural prac- 

 tices and soil conditions. From the various levels of production on the same land 

 class a value is selected which represents the potential of that specific land class. 

 This rating, known as land-use capability, is one type of site evaluation. 



The most intensive studies of site evaluation have been conducted in the 

 development of a system of rating the land for the production of wood. During this 

 fiscal year, an amplified classification has been applied to the landscape units of 

 the 11 eastern counties of Ontario which comprise the pilot area studied under 

 A.R.D.A. 



One member of the staff is working in co-operation with Professor D. Love 

 of the Faculty of Forestry, to obtain detailed production data with regard to yields 

 and costs of red pine production on the common sites planted to that species. A 

 co-operative report on red pine is being prepared. A similar study of maple and 

 other hardwoods has been under way in the unit for some time. It is planned to 

 extend co-operative effort this year to studies of hardwood and spruce. 



The physiographic framework for the evaluation of land for wildlife produc- 

 tion and for recreational use has also been developed. A report on the principles 

 and methods of evaluating land for wildlife production has been prepared by the 

 leader of the unit, working with two wildlife biologists. Similar studies in recre- 



243 



