Acid phosphatase (AP) activity was determined in 14 hill land soils of the Appalachian region. Soil samples were obtained from surface (A or Ap) and subsurface (E, BA, Bt, or Bw) horizons during spring, and subsamples were stored field‐moist at 4 °C and air‐dry (AD) for 36 wk prior to determination of AP activity. The average AP activities of surface and subsurface horizons stored field‐moist at 4 °C were 1.7 to 1.9 times higher than those of AD samples. The average AP activity of air‐dry surface horizons was 3.3 times higher than that of subsurface horizons. Significant positive relationships were found between the AP activities of AD and 4 °C samples, and total C and N content of soils. Positive relationships were observed between AP activities and various forms of soil P. The original soil moisture content by weight or volume and percent water‐filler pores (% WFP) were significantly related to AP activities of surface soil horizons. Each soil type has its own inherent level of phosphatase activity.
Six legume species and several varieties within the species were grown in a greenhouse pot experiment using the Bt horizon of a Lily (Typic Hapludult) soil. Lime treatments were 0 and 2.2 g Ca(OH) 2 /kg soil. Liming increased the soil pH from 4.6 to 6.2. The species and varieties responded differentially to lime. Both shoot and root growth of legumes showed a significant species and lime interaction effect. Based on tolerance index groups for shoot growth, alfalfa varieties were classified as very sensitive, red clovers and white clovers as sensitive and Essex soybean and Carroll birdsfoot trefoil as tolerant to the acid soil. The remaining legumes were grouped as moderately tolerant to the acid soil. Liming increased shoot concentrations of Ca in all the legumes and reduced concentration of Mg, K, and Zn. Species and varieties within species differed significantly in concentrations of all mineral elements studied except Mg. Further significant differences in elemental composition were observed due to both lime and lime species interactions. In the 1079
A simple, relatively rapid liquid chromatographic method has been developed for the determination of sulfamethazine (SMZ) in milk at levels in the low ppb range. The method is based on extracting SMZ from milk with chloroform, evaporating the chloroform, dissolving the residues in hexane, extracting into buffers, and chromatographing the buffer solution. The method has been shown to determine levels as low as 5 ppb reliably. Levels ≥7 ppb have been confirmed by gas chromatography/mass spectrometry after derivatization of extracts from fortified, incurred, and shelf milk. Intralaboratory recoveries and percent coefficients of variation are satisfactory. Sulfadimethoxine and sulfaquinoxaline can also be determined by the method. Application of the method to other dairy products is being investigated.
Climatically controlled growth rooms were used to evaluate performance of 23 red clover cultivars in a nutrient culture system at 5 levels of Al (0, 25, 50, 75 and 100 μM). The shoot and root growth of all the cultivars was reduced by Al. Considerable reduction in growth was observed at Al levels beyond 50 μM. The efficiency ratio (ER) (mg shoot dry matter per mg shoot element) for P declined with increasing Al. ER values for Ca and Mg declined slightly with increasing concentration of Al to 50 μM but then increased considerably with increasing Al. In the absence of Al, Redman, K4-184 and Chesapeake showed the highest ER for P, Ca and Mg, respectively. However, in the presence of 50 μM Al, Altaswede had the highest ER for P and Mg, and Redland showed the highest ER for Ca. In the presence of 50 μM Al, Florie, Norlac and Redmor gave the lowest ER values for P, Ca, and Mg. The growth and ER for P, Ca, and Mg in the presence or absence of Al appears to be different among the various red clover cultivars tested. The presence of a Swedish line in its parentage has improved ER for P and Mg in Altaswede. The ILL-2 as a parental line improved Ca ER in Redland and Redmor. In Florie, the presence of line ILL-1 and cultivar Lakeland as parents gave the lowest ER for P. Genetic diversity for P, Ca, and Mg uptake efficiency was observed among the cultivars tested.
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