The existence of soluble organic forms of N in rain and drainage waters has been known for many years, but these have not been generally regarded as significant pools of N in agricultural soils. We review the size and function of both soluble organic N extracted from soils (SON) and dissolved organic N present in soil solution and drainage waters (DON) in arable agricultural soils. SON is of the same order of magnitude as mineral N and of equal size in many cases; 20-30 kg SON-N ha -1 is present in a wide range of arable agricultural soils from England. Its dynamics are affected by mineralisation, immobilisation, leaching and plant uptake in the same way as those of mineral N, but its pool size is more constant than that of mineral N. DON can be sampled from soil solution using suction cups and collected in drainage waters. Significant amounts of DON are leached, but this comprises only about one-tenth of the SON extracted from the same soil. Leached DON may take with it nutrients, chelated or complexed metals and pesticides. SON/DON is clearly an important pool in N transformations and plant uptake, but there are still many gaps in our understanding.

No abstract

No abstract

No abstract

Holland's Vocational Preference Inventory was administered to 373 undergraduates. The inventory consists of 6 scales corresponding to Holland's six personality types and 5 other scales. The 11 scales of the inventory were intercorrelated and factor analyzed. Six common factors were obtained: (a) Conventional Economic, (6) Feminine, Social, (c) Social Desirability, (d) Material World Orientation, (e) Status, and (/) Artistic. The distances between each pair of the six personality types in the six-dimensional space defined by the common factors were computed and compared with Holland's (1971) hexagonal model of the relationships among the six types. The placement of the six personality types in six-dimensional space by factor analysis corresponded closely to Holland's model. Holland (1966) hypothesized six personality types which he called Realistic, Intellectual, Social, Conventional, Enterprising, and Artistic. Each personality type was defined in terms of the occupations for which persons conforming to it were training or at which they were working.Holland (1971, p. 13) also presented a hexagonal model depicting the relationships among the six personality types. Each type is represented by one of the points of a regular hexagon. The distance along a straight line between any two points in the model indicates the relative dissimilarity between the two corresponding personality types. The order of personality types around the hexagon is Conventional, Realistic, Intellectual, Artistic, Social, Enterprising, and back to Conventional. The hexagon is presented in Figure 1.From the model, pairs of personality types may be divided into three classes based on the relative distance between the personality types in the pair. One class is the three pairs of diametrically opposed types (i.e., Intellectual-Enterprising, Real-1 Requests for reprints should be sent to Eugene