Impact of soil texture on the distribution of soil organic matter in physical and chemical fractions

Previous research on the protection of soil organic C from decomposition suggests that soil texture affects soil C stocks. However, different pools of soil organic matter (SOM) might be differently related to soil texture. Our objective was to examine how soil texture differentially alters the distribution of organic C within physically and chemically defined pools of unprotected and protected SOM. We collected samples from two soil texture gradients where other variables influencing soil organic C content were held constant. One texture gradient (16-60% clay) was located near Stewart Valley, Saskatchewan, Canada and the other (25-50% clay) near Cygnet, OH. Soils were physically fractionated into coarse- and fine-particulate organic matter (POM), silt- and clay-sized particles within microaggregates, and easily dispersed silt-and clay-sized particles outside of microaggregates. Whole-soil organic C concentration was positively related to silt plus clay content at both sites. We found no relationship between soil texture and unprotected C (coarse- and fine-POM C). Biochemically protected C (nonhydrolyzable C) increased with increasing clay content in whole-soil samples, but the proportion of nonhydrolyzable C within silt- and clay-sized fractions was unchanged. As the amount of silt or clay increased, the amount of C stabilized within easily dispersed and microaggregate-associated silt or clay fractions decreased. Our results suggest that for a given level of C inputs, the relationship between mineral surface area and soil organic matter varies with soil texture for physically and biochemically protected C fractions. Because soil texture acts directly and indirectly on various protection mechanisms, it may not be a universal predictor of whole-soil C content.

Beryllofluoride mimics phosphorylation of NtrC and other bacterial response regulators

Two-component systems, sensor kinase-response regulator pairs, dominate bacterial signal transduction. Regulation is exerted by phosphorylation of an Asp in receiver domains of response regulators. Lability of the acyl phosphate linkage has limited structure determination for the active, phosphorylated forms of receiver domains. As assessed by both functional and structural criteria, beryllofluoride yields an excellent analogue of aspartyl phosphate in response regulator NtrC, a bacterial enhancer-binding protein. Beryllofluoride also appears to activate the chemotaxis, sporulation, osmosensing, and nitrate/nitrite response regulators CheY, Spo0F, OmpR, and NarL, respectively. NMR spectroscopic studies indicate that beryllofluoride will facilitate both biochemical and structural characterization of the active forms of receiver domains.

Map of the Huron River Valley from Surveys made in 1905-08 by Gardner Stewart Williams [Map 5109]

Argo Pond , ca. 1905-1909: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1905 by Gardner Stewart Williams [Map 5107]

Arboretum, 1905: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1905 by Gardner Stewart Williams [Map 5106]

Geddes Pond, 1905: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1907 by Gardner Stewart Williams [Map 5105]

Vivienne Farm, 1907: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1907 by Gardner Stewart Williams [Map 5104]

Fleming Creek, 1907: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1906-07 by Gardner Stewart Williams [Map 5103]

Superior Pond, ca. 1906-1907: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1907 by Gardner Stewart Williams [Map 5102]

Leforge Road, 1907: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1907 by Gardner Stewart Williams [Map 5101]

Ypsilanti, 1907: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1905-1909, by Gardner Stewart Williams.

Ann Arbor, ca. 1905-1909: Map of the Huron River Valley, revised 5/11/1915

Utilisation of ionic liquid solvents for the synthesis of Lily-of-the-Valley fragrance {beta-Lilial (R); 3-(4-t-butylphenyl)-2-methylpropanal}

The Heck arylation of 2-methylprop-2-en- I -ol in ionic liquids and organic solvents is reported using a range of homogeneous and heterogeneous palladium catalysts. Higher activity is observed in the ionic liquid media compared with N-methyl pyrrolidinone and under solventless conditions. The ionic liquid-catalyst system may be recycled easily with little loss in activity, although significant palladium leaching from the heterogeneous catalyst was observed. In the case of Trans-bis(2,3-dihydro-3-methylbenzothiazole-2-ylidene)diiodopalladium (11) reported to be highly active for this transformation, significant induction petiods were observed indicating that nanoparticles may be responsible for the catalysis. Using the ionic liquid Heck reaction, a recyclable synthesis for the fragrance beta-Lilial((R)) has been developed. (c) 2004 Elsevier B.V. All rights reserved.

Report to the government of Saskatchewan on wheat marketing,

Mode of access: Internet.

Map of the Huron River Valley from Surveys made in 1909 by G. S. Williams. 5123 [Tuttle Hill Road-Harris Road]

Tuttle Hill Road-Harris Road, 1909: Map of the Huron River Valley

Map of the Huron River Valley from Surveys made in 1909 by G. S. Williams. 5122 [Whittaker Road-Huron River Drive]

Whittaker Road-Huron River Drive, 1909: Map of the Huron River Valley