wan were analyzed by electron capture gas chromatography for residues of organochlorine insecticides. More than 0.01 p.p.m. of dieldrin was present in soil from 16 fields, while four had no detectable residue. Heptachlor, heptachlor epoxide, endrin, and aldrin were present in soil from ten fields.Sweet clover and alfalfa collected from the same fields contained more than 0.01 p.p.m. of dieldrin in 16 samples. The highest level of dieldrin in soil was 0.3 p.p.m. and in plants was 0.1 p.p.m. DDT or its degradation products could not be detected in any plant or soil sample.
The effect of soil type on the uptake of dieldrin by wheat seedlings was studied using seven mineral soils containing 9 to 23 ppm of dieldrin. Although wheat seedlings grown in the sandy soils contained more dieldrin than those grown in the clay soils, there was no close relationship between sand, clay, or organic matter contents of the soils and the dieldrin contents of the plants. However, there was significant correlation between dieldrin uptake by wheat seedlings, the silt content of the soils, and the concentration of dieldrin in the soil water.
Median values of pH, conductivity, organic and inorganic carbon, and mechanical analyses are reported for nine solodized solonetz soils and eight solonetz-like soils. These data show that for solodized solonetz soils the A horizons are moderately acid, with the A, and A, horizons showing the greatest acidity. T h e B, is neutral, and the lower B and C horizons are alkaline in reaction. T h e solonetzlike profiles show a similar trend, but p H values are higher in the A horizons. Conductivity rises progressively from the Al horizon downward in the solodized solonetz group, whereas in the solonetz-like group the conductivity remains very low throughout.A regional Dark Brown prismatic profile is included for comparison.A PREVIOUS paper (Janzen and Moss, 1956) presented data on exchangeable cations, pH, and conductivity of solodized solonetz and solonetzlike soils of Saskatchewan. The present paper deals chiefly with the mechanical composition of the above soils, together with information on several additional profiles. Data for pH and conductivity and organic and inorganic carbon are also reported.T h e main objectives of the study were: ( I ) To confirm the field evidence of clay accumulation in the upper B horizons of solonetzic soils. (2) T o compare the mechanical composition of solodized solonetz and solonetz-like soils, in view of the evidence from previous studies that the latter soils show less solonetzic development.(3) T o compare the mechanical composition of solonetzic soils from widely separated locations within the Grassland Region of Saskatchewan, ranging from the semi-arid section of the southern portion to the sub-humid section of the northern limit of the Region (Brown to Black Soil Zones).Solodized solonetz soils are characterized by a leached A horizon, including a well-developed, light-coloured A, horizon. The B horizon is columnar-structured, with whitish coloured rounded tops, and surface coatings and organic staining on the sides of the columns. The B horizon is very hard when dry and is finer-textured than the A. T h e parent material is saline.The solonetz-like soils usually lack an A, horizon or if present it is very thin. T h e 13 horizon is prismatic to faintly columnar, finer-textured than the A horizon, but less hard and compact than the B horizon of the
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