Extraction, gas-liquid chromatographic detection, and quantitation of hexachlorophene residues from plant tissues high in lipid content

A method has been developed for the extraction, cleanup, derivatization, detection, and quantitation of hexachlorophene (HCP) residues from 2 types of plant storage tissue high in lipid content. Wet soybean or peanut tissue was homogenized and extracted with ethyl ether and chromatographed on silica gel to remove the neutral lipids. The cleaned up sample was methylated with diazomethane and the dimethoxyhexachlorophene was eluted from a second silical gel column and chromatographed on a 6' glass column packed with 3% OV-1 or 3% SE-30 on Gas-Chrom Q. The instrument detection limit for the 63Ni electron capture detector was less than 0.1 ng for dimethoxyhexachlorophene and about 1 ppb HCP residue in plant issue. Recovery of 10-420 ppb HCP added to tissue averaged 90.9 +/- 5.7%. Interfering substances were removed, column life was increased, peak sharpness was increased, and tailing of the parent compound was decreased by using appropriate column chromatography.     

Chemical Control of the Pine Shoot Moth, Rhyacionia buoliana (Denis and SchiffermUller) (Lepidoptera: Tortricidae) in Seed Orchards in Britain

In 1970 and 1971 a high population of Rhyacionia buoliana (Denisand SchiffermÜller), the Pine shoot moth, appeared in aseed orchard of Pinus contorta Douglas ex Loud, in Wiltshire.The opportunity was taken to compare several alternative insecticideswith DDT. Field trials in March and August showed that fenitrothioncan be used as an alternative to DDT to control the Pine shootmoth.     

A comparison of some red and yellow earths in tropical queensland and northeast Brazil

Red and yellow earths are kaolinitic and generally sesquioxidic soils having massive B horizons with porous, earthy fabrics and weak profile differentiation but usually displaying a gradual increase in clay content with depth. They are widespread in tropical Queensland and northeast Brazil where comparable climates prevail although the vegetation is markedly different. Their parent materials are mostly quartzitic sedimentary rocks or unconsolidated sediments and the soils occur in a wide variety of topographic and geomorphic situations. In both regions it is probable that many of the soils have not formed under the present climatic conditions.Profile morphology, drainage, silt and clay contents, clay mineralogy, and soil chemistry have been compared and contrasted between the red and yellow earths within and between the two regions. Canonical variate analysis has shown that, on the basis of surface soil chemical attributes, the red earths can be separated from the yellow earths within each region and that the Queensland soils can be separated from the Brazilian soils.     

Chemisch-mineralogische und mikromorphologische untersuchung einer eutrophen (Ramann-) braunerde des Budapester Hügellandes

In spite of the fact that Ramann's concept of Braunerde was extensively used throughout the world, some pedogenic processes and soil properties which are important for the formation and existence of Brown Forest Soils (eutrophic brown earths) are still not well known. Hence, a soil was investigated which was classified as a “Braunerde” by Ramann in 1909. The main question was, whether there might be soil constituents such as inorganic amorphous substances (allophanes) which are able to stabilize the brown-earth fabric, or to inhibit clay migration. From chemical data as well as from the magnitude of the pH-dependent CEC, it was deduced that there are no appreciable amounts of allophanes within the soil. The fabric, however, seems to be stabilized by colloid-chemical flocculation of the clay particles caused by large amounts of carbonates and silicates deposited with the parent material (loess). The decalcified solum is still rich in silicates, especially sand and coarse-silt-sized micas and feldspars (60–200 and 20–60 μm fractions, respectively). Since - in comparison - loesses and loess-derived soils of the Central German mountain region contain less silicates, mainly in fine and medium silt fractions (2–6 and 6–20 μm diameter, respectively), the coarser-grained silicates were assumed to be important for maintaining the Ca²⁺ and Mg²⁺ saturation of the soil by continuous weathering and thus stabilizing the brown-earth fabric.Although the soil is saturated predominantly with Ca²⁺ and Mg²⁺ ions, clay migration proceeds within the upper horizons. This was shown by calculation of the amounts of clay formed by breakdown of micas originally present in the parent material (“clay formation balance”), as well as by micromorphological studies. Furthermore, micromorphological studies and x-ray diffraction data gave some evidence for the migration of preferably finest grained montmorillonitic clays (smectites) penetrated by organic substances (humus). This kind of “selective clay migration” was assumed to be caused by high Ca²⁺ (or Mg²⁺) concentrations in soil solution required for flocculation of humus-penetrated (humus-coated) smectites. From the occurrence of these “humus-smectites” the possibility was assumed that the soil studied has been developed from a former Chernozem type.Quantitatively, clay migration does not reach the amounts of clay formation (breakdown of micas) accompanied by precipitation of iron oxides on mineral surfaces (“Verbraunung”). Thus, the soil profile visually and macromorphologically clearly exhibits the features of brown earths. On the other hand, however, some clay migration was observed. Hence, the soil was classified as a “brown earth with some clay migration” (“schwach durchschlämmte Braunerde”).Judging from the results of the “clay formation balance” an appreciable pedogenic (autigenic) clay formation from weathering products of feldspars was excluded for the soil studied.     

Long-term effects of five ameliorants on a saline-sodic soil of South Africa

The effects of five ameliorants for saline-sodic soil reclamation on certain chemical and physical soil properties over a four-year period of observation are reported. Of these ameliorants, three are conventionally used (gypsum, sulphur, manure); the other two are for this purpose either unusual (potassium sulphate) or relatively unknown (molasses meal). Results published in a previous paper demonstrated that molasses meal had a very rapid-acting favourable effect on most soil physical properties whilst soil chemical conditions remained essentially unchanged. The effect on physical properties was presumably due to soil aggregation by the polysaccharide component of molasses meal. As a follow-up this paper shows, however, that this aggregation does not last long; the rigidly arid climatic conditions under which this experiment was carried out apparently do not favour the preservation of structural bonds consisting of polysaccharide gums. Consequently, a gradual decline of structural conditions took place after the second year. Although initially not as effective as molasses meal, gypsum and sulphur retained their favourable influence on physical properties over a longer period. Potassium sulphate and farmyard manure provided virtually no benefits.     

Gibbsite and halloysite decomposition in strongly acid podzolic soils developed from granitic saprolite of the Bayerischer Wald

The present study reports the occurrence of gibbsite and halloysite in soils derived from granitic saprolites and from glacial deposits formed from granitic saprolites of the Bayerischer Wald (Germany). Both minerals are common in soils of this area. They were formed in the initial stages of weathering, most probably before the Pleistocene and in a warmer climate. Under present conditions halloysite and gibbsite are unstable in the surface soils, as indicated by a decrease in gibbsite concentration towards the surface and by an undersaturation of the equilibrium soil solution with respect to both minerals. It is assumed that the strongly acid conditions and the high concentration of organic compounds in the surface horizons lead to dissolution of gibbsite and possibly to transformation of halloysite to kaolinite.     

Adsorption sur les argiles de deux lipopolysaccharides rhizosphériques

The adsorption with time has been measured of two well characterized lipopolysaccharides onto aqueous suspensions of a montmorillonite, a kaolinite and an illite at one fixed polymer-clay ratio. The clays were prepared in the Fe⁺⁺⁺ or Ca⁺⁺ forms by washing with FeCl₃ or CaCl₂ followed with water. The competitive sorption of the two polymers was measured also in the presence of an equal concentration of a protein or a basic amino-acid. Sorption of the polymers by themselves was approximately proportional to the external areas of the three clays and independent of the exchangeable cation. The presence of the protein inhibited completely the adsorption of both polymers onto the Ca⁺⁺ clays, but usually enhanced sorption onto the Fe⁺⁺⁺ clays. Sorption in the presence of the amino-acid differed both for each polymer and according to the form of the clay. Possible reasons for the various sorption patterns are discussed.     

Factors influencing the loss of organic carbon from wheat roots

Wheat plants were grown in an atmosphere containing ¹⁴CO₂ at temperatures of 10°C or 18°C for periods from 3–8 weeks. The plant roots were maintained under sterile or non-sterile conditions in soil contained in sealed pots which were flushed to displace respired ¹⁴CO₂. The ¹⁴C content of the shoots, roots and soil was measured at harvest. The loss of ¹⁴C from the roots, expressed either in terms of total ¹⁴C recovered from the pots or ¹⁴C translocated to the roots, ranged from 14.3–22.6%, mean 17.3% or 29.2–44.4%, mean 39.2%, respectively. The presence of soil microorganisms significantly increased ¹⁴CO₂ release from the rhizosphere but had no effect on the ¹⁴C content of the soil. Fractionation of 6 m HC1 hydrolysates from sterile and non-sterile soils showed the presence in all soils of material behaving as neutral sugars and amino acids, in quantities representing 5.9–9.2% and 13.4–17.2% of the soil ¹⁴C content for the sugar and amino acid fractions respectively. It is proposed that a major loss of root carbon resulted from autolysis of the root cortex. Root lysis was increased by soil microorganisms, apparently without penetration of the plant cell walls.     

Diurnal changes in acetylene reduction in field-grown cowpeas and soybeans

The effects of five environmental factors on variation in the rate of C₂H₂ reduction in two cowpea (Vigna unguiculata L. Walp.) and two soybean (Glycine max L. Merrill) cultivars were examined at two stages of growth in the field. Diurnal changes in C₂H₂ reduction, estimated as μmoles C₂H₄ produced·g^?1 nodules·h^?1, over a 30 h period were compared with changes in soil, canopy and air temperatures, global radiation, and vapour pressure deficit. Although the environmental factors showed one maximum and one minimum during a diurnal cycle, the C₂H₂ reduction rate in nodulated cowpea roots showed two peaks: one between 0600–1200 and another between 1800–2400 and two minima: one between 1200–1600 and another between 2400–0600. Variation in C₂H₂ reduction in soybean nodules did not show any definite pattern. Vapour pressure deficit appeared the most likely factor influencing the decline in C₂H₂ reduction between 1200–1600.The rate of C₂H₂ reduction in cowpeas was greater at the pre-flower than at the early pod-fill period; the rate in soybeans was not greatly different at early flower or early pod-fill.