A study was made of the growth of rhizobia outside the host plant in three high humus mixtures and a mineral soil. Rhizobia grew better in pure cultures than in an unsterile base. Incubation in Erlenmeyer flasks gave, as a rule, higher counts than in paper cartons. Addition of a mixture of sucrose, calcium carbonate, sodium chloride, dipotassium phosphate, and magnesium sulphate led to increased numbers of rhizobia in pure culture in all bases used, and produced increased numbers in the unsterilized mineral soil also. Addition of this mixture to the unsterile high humus bases increased the total numbers of bacteria, but not the number of rhizobia. When the bases were sterilized, the highest counts of rhizobia were obtained in the high humus bases. When sterilization was not carried out, the greatest numbers of rhizobia occurred in the mineral soil. In tightly stoppered flasks that did not permit aeration, the rhizobia appeared to die out completely when stored for more than a few days, whereas in loosely stoppered flasks the counts remained at a high level until the base became desiccated.

No abstract

Effects of steam sterilization and recontamination with original soil, on certain physical, chemical, and biological properties of four Alberta soils were investigated. The soils were Edmonton black loam, Vegreville black fine sandy loam, Gros Ventre brown loam, and Fallis gray silt loam. Certain physical properties were affected by steam sterilization as follows: (1) capillary rise of moisture was greatly retarded in all four soils following sterilization; (2) the percentages of the different separates as determined by ordinary mechanical analysis were not changed significantly by sterilization; (3) water-holding capacity and moisture content at the 'sticky point' were slightly reduced, and, in three of the soils, shrinkage was slightly increased by sterilization, but these effects were of uncertain significance; (4) the pH values of these soils were not changed appreciably by sterilization. The following chemical changes were produced by steam sterilization: (1) water-soluble phosphate was generally greatly increased and water soluble sulphate somewhat increased by sterilization. Easily soluble phosphorus (soluble at pH 3) was increased by about one-third in the two black soils rich in organic matter, but not in the other soils; (2) ammonia accumulated rapidly in the sterilized recontaminated black and brown soils for four to six weeks, and then returned to normal in 8 to 12 weeks. Ammonia accumulated less rapidly and to a smaller degree in the gray soil; (3) nitrification was suppressed for about 6 to 10 weeks in the sterilized recontaminated soils, but was later more active in these soils than in the unsterilized (especially in the black soils rich in organic matter).

A study was made of several factors influencing the growth and survival of rhizobia in humus and soil cultures. Screw-capped glass jars were more satisfactory than the foil-lined cardboard cartons used commercially for packaging of seed inoculation cultures because contaminants were excluded and moisture retained more effectively. Refrigeration of the cultures reduced water losses and proved to be an excellent method of maintaining large numbers of living bacteria for a long time. The addition of sucrose to the humus cultures ordinarily produced large increases in numbers of rhizobia, as determined by plate counts, and the addition of various inorganic nutrients generally produced smaller increases. In general, any particular element stimulated growth only if the level of that element in the soil used as a base was below optimum. Nitrate and sucrose stimulated growth when either was used alone, but together they greatly depressed growth.

A study of 'the relationship between the characteristics and life experiences of entrepreneurs' has just been completed at the University of Derby. The four-fold purpose of this study, was to: identify and evaluate from existing literature the personal traits and characteristics of entrepreneurs and the main factors or life experiences which may affect their characteristics; identify from the authors primary research, the personal traits and characteristics of entrepreneurs; to identify from the authors primary research which factors or life experiences affect particularly the characteristics of entrepreneurs; and, finally, to assess whether there is any correlation between the characteristics and life experiences of the entrepreneurs investigated in this study and those identified by other academic studies 'tend to be rebels, outsiders, and original thinkers who take risks and break new ground, constantly on the look-out for new opportunities'. It is the belief that entrepreneurs possess a cocktail of qualities distinguishing them from the average person that has ignited the interest of economists, sociologists, psychologists and academics in understanding the entrepreneur, and resulted in a mass of information becoming available. LITERATURE REVIEW This section aims to highlight and evaluate the various traits identified with entrepreneurs, and then establish whether entrepreneurs are born with these traits, or whether, they are shaped and developed through their life experiences. Put simply the purpose of this review is to establish whether entrepreneurs are 'born or made'.