Effect of exchangeable sodium percent on surface sealing
Abstract Laboratory studies were conducted to evaluate the effect of exchangeable sodium percent (ESP) on soil surface sealing and of surface sealing on infiltration and evaporation processes. Surface seals with hydraulic conductances 52.20 × 10 −3 , 49.20 × 10 −3 , 39.00 × 10 −3 , 33.00 × 10 −3 , and 17.91 × 10 −3 h −1 were attained on top of a sandy loam soil with ESP of 4 by placing a 5-mm layer of the same soil with ESP's 6, 10, 20, 30, and 60 respectively. Surface sealing increased with increasing ESP and appeared complete at ESP 30. Evaporation remained unaffected by the seals. Infiltration, however, was considerably reduced. Soil water profiles, which largely depended on the amount of infiltrated water, tended to become uniform. Equal moisture contents were also observed under evaporation.
Applied soil physics : soil water and temperature applications. Second Edition.
This textbook presents a practical approach to teaching basic concepts of soil water and heat flow, with numerous examples and problems to assist the student. Soil water content and soil water potential are discussed and related to water flow and evapo-transpiration. The book also considers the relationships of soil physics to climate and crop production. Heat flow and the temperature of soils are treated as basic concepts that allow estimates of real world diurnal and annual fluctuations.
On the fractionation of β-lactoglobulin and α-lactalbumin
Abstract Existing methods for the preparation of α-lactalbumin and β-lactoglobulin are examined critically. It is proposed that the most satisfactory method for the preparation of the whey protein fraction from bovine milk is (NH 4 ) 2 SO 4 fractionation. A number of new gentle procedures for the fractionation of the whey proteins are compared with some existing methods. The distribution of total protein at various stages is determined by total Kjeldahl nitrogen and the kind of protein by starch-gel electrophoresis. The effect of variables, such as pH, salt concentration and temperature on the separation of α-lactalbumin and serum albumin from β-lactoglobulin is studied. Differences in the behavior ( e.g. solubility) of genetic variants of β-lactoglobulin are noted. The solubility of each of the major whey proteins, under similar conditions to those used in the fractionation, is compared with its solubility in the whey protein mixture. The understanding gained of factors important in the fractionation is used in recommending new procedures for α-lactalbumin and β-lactoglobulin isolation.