Effect of the Herbicide Paraquat on the Decomposition of Wheat Straw

The effect 1,1'-dimethyl-4,4'-bipridinium dichloride (paraquat) has on wheat residue decomposition was investigated in laboratory studies. Field dried straw containing 0.30% nitrogen and 42.9% C was incubated in laboratory bioreactors for 8 weeks. Treatment combinations per gram of straw were control (no paraquat or spreader), 0.26, 2.6, and 26 ng paraquat, 0.7 nl Valent X-77,0.26 ng paraquat plus spreader and 2.6 ng paraquat plus spreader. Decomposition was monitored by CO, production and dry weight changes. Neither paraquat nor its spreader, alone or in combination, were found to effect CO2 production or dry weight Ioss. Paraquat should not increase the rate of wheat straw decomposition at field application rates.     

The components of variation associated with sampling soil for the measurement of major and trace nutrients in grazed fields in S.E. Scotland

Abstract. The laboratory, spatial and temporal components of variation associated with sampling soil for the measurement of pH, organic matter and extractable P, K, Mg, S, Cu, and Co were studied over two years using soil samples from 15 farms in S.E. Scotland. On each farm a selected field was divided into 4–8 sectors, and sampled three times each year, in June, August and October, by bulking 25 cores taken in a 'W' pattern. Analysis of variance showed that inter-field variation was greater than that between sampling dates for most of the properties measured. Restricted Maximum Likelihood Estimation showed that for all elements except K and S the variation between fields was greater than that within a field. Temporal variation was usually smaller than spatial, but K and Co showed similarly small temporal and spatial variations. Variation associated with laboratory procedures was much less than either spatial or temporal variation except for S, most of the total observed variation of which resulted from laboratory error. It is suggested that the most cost effective field sampling technique is to split a field into sectors, sample each individually and analyse a bulked sample made up from the sectors.     

Multiple nozzles for producing small drops in a mist-blower spray machine

The biological effectiveness of deposits of binapacryl applied by a single high pressure nozzle was compared with similar deposits applied by twin low-pressure nozzles. Equal foliar deposit densities were obtained from the two systems but the single nozzles gave marginally better control of apple powdery mildew and fruittree red spider mite.     

Interpopulation Variations in Calcium Metabolism in the Stream Limpet, Ferrissia rivularis (Say)

Significant differences between populations occur in calcium uptake during growth within one species of freshwater limpet. These are not related to environmental differences and may involve genetically determined physiological races. Such variation is significant in relation to aspects of evolution in freshwater animals and is important in assessing radionuclide contamination.     

An evaluation of the API ZYM system as a means of classifying spirochaetes associated with swine dysentery.

Thirty-one strains of spirochaetes from pigs and two strains from poultry were tested in the API ZYM enzyme system. The spectrum of enzymatic reactions provided a means of differentiating between strains related to swine dysentery and strains not so related from pigs. The numerical coding system simplified the interpretation of the results.     

Diagnosis of swine dysentery using an absorbed fluorescent antiserum.

The specifity of a direct fluorescent antibody test for the detection of pathogenic Treponema hyodysenteriae associated with swine dysentery was improved by absorbing the original conjugated serum with a non pathogenic treponeme.