Root systems and root:mass ratio-carbon allocation under current and projected atmospheric conditions in arable crops

1995 ◽  
Vol 187 (2) ◽  
pp. 221-228 ◽  
Author(s):  
P. J. Gregory ◽  
J. A. Palta ◽  
G. R. Batts
Keyword(s):  
Carbon Allocation ◽  
Root Systems ◽  
Atmospheric Conditions ◽  
Arable Crops

Delivering improved phosphorus acquisition by root systems in pasture and arable crops

2021 ◽  
pp. 589-648
Author(s):  
Richard J. Simpson ◽  
◽  
Rebecca E. Haling ◽  
Phillip Graham ◽  
◽  
...  
Keyword(s):  
Root Systems ◽  
P Efficiency ◽  
Arable Crops ◽  
Soil P ◽  
P Acquisition ◽  
Pasture Legumes ◽  
P Balance ◽  
Low Efficiency ◽  
Effective Use

Improving low efficiency of phosphorus (P) use in agriculture is an imperative because P is one of the key nutrients underpinning sustainable intensification of food production and the rock-phosphate reserves, from which P fertilisers are made, are finite. This paper describes key soil, root and microbial processes that influence P acquisition with a focus on factors that can be managed to ensure optimal use of fertiliser, and development of root systems for improved P acquisition. A case study describes grasslands in southern Australia where the P-balance efficiency of production is very low, mainly because soils are P deficient and moderately to highly P-sorbing. Use of soluble P fertiliser, P-banding and soil testing to guide soil P management ensures effective use of P fertiliser. Progress towards improved P efficiency using pasture legumes with high P-acquisition efficiency is outlined. Development of a ‘whole-of-system’ understanding for effective P acquisition by roots is highlighted.

scholarly journals North America’s oldest boreal trees are more efficient water users due to increased [CO2], but do not grow faster

2019 ◽  
Vol 116 (7) ◽  
pp. 2749-2754 ◽  
Author(s):  
Claudie Giguère-Croteau ◽  
Étienne Boucher ◽  
Yves Bergeron ◽  
Martin P. Girardin ◽  
Igor Drobyshev ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Carbon Allocation ◽  
Stomatal Density ◽  
Anthropogenic Emissions ◽  
Atmospheric Conditions ◽  
Dual Isotope ◽  
Water Users ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Due to anthropogenic emissions and changes in land use, trees are now exposed to atmospheric levels of [CO2] that are unprecedented for 650,000 y [Lüthi et al. (2008) Nature 453:379–382] (thousands of tree generations). Trees are expected to acclimate by modulating leaf–gas exchanges and alter water use efficiency which may result in forest productivity changes. Here, we present evidence of one of the strongest, nonlinear, and unequivocal postindustrial increases in intrinsic water use efficiency (iWUE) ever documented (+59%). A dual-isotope tree-ring analysis (δ13C and δ18O) covering 715 y of growth of North America’s oldest boreal trees (Thuja occidentalis L.) revealed an unprecedented increase in iWUE that was directly linked to elevated assimilation rates of CO2 (A). However, limited nutrient availability, changes in carbon allocation strategies, and changes in stomatal density may have offset stem growth benefits awarded by the increased iWUE. Our results demonstrate that even in scenarios where a positive CO2 fertilization effect is observed, other mechanisms may prevent trees from assimilating and storing supplementary anthropogenic emissions as above-ground biomass. In such cases, the sink capacity of forests in response to changing atmospheric conditions might be overestimated.

Selective Corrosion of brazed joint between BNi-2 filler metal and stainless steel 316

1996 ◽  
Vol 54 ◽  
pp. 218-219
Author(s):  
H. S. Kim ◽  
R. U. Lee
Keyword(s):  
Stainless Steel ◽  
Filler Metal ◽  
Surface Preparation ◽  
Optical Microscope ◽  
Heating Element ◽  
Incomplete Fusion ◽  
Atmospheric Conditions ◽  
Leak Test ◽  
High Temperature Side ◽  
Inconel 600

A heating element/electrical conduit assembly used in the Orbiter Maneuvering System failed a leak test during a routine refurbishment inspection. The conduit, approximately 100 mm in length and 12 mm in diameter, was fabricated from two tubes and braze-joined with a sleeve. The tube on the high temperature side (heating element side) and the sleeve were made of Inconel 600 and the other tube was stainless steel (SS) 316. For the filler metal, a Ni-Cr-B brazing alloy per AWS BNi-2, was used. A Helium leak test spotted the leak located at the joint between the sleeve and SS 316 tubing. This joint was dissected, mounted in a plastic mold, polished, and examined with an optical microscope. Debonding of the brazed surfaces was noticed, more pronounced toward the sleeve end which was exposed to uncontrolled atmospheric conditions intermittently. Initially, lack of wetting was suspected, presumably caused by inadequate surface preparation or incomplete fusion of the filler metal. However, this postulation was later discarded based upon the following observations: (1) The angle of wetting between the fillet and tube was small, an indication of adequate wetting, (2) the fillet did not exhibit a globular microstructure which would be an indication of insufficient melting of the filler metal, and (3) debonding was intermittent toward the midsection of the sleeve.

Recent Progress In High-Resolution Shadowing For Biological Transmission Electron Microscopy

1990 ◽  
Vol 48 (1) ◽  
pp. 510-511 ◽  
Author(s):  
Heinz Gross ◽  
Katarina Krusche ◽  
Peter Tittmann
Keyword(s):  
Heavy Metal ◽  
High Resolution ◽  
Freeze Drying ◽  
Atmospheric Conditions ◽  
Vacuum Equipment ◽  
Transmission Electron ◽  
Gas Atmosphere ◽  
Gas Molecules ◽  
Residual Gas ◽  
Backing Layer

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.

Root systems biology

2014 ◽  
Keyword(s):  
Systems Biology ◽  
Root Systems

MUELLER ALLOY 3140

Alloy Digest ◽  
1983 ◽  
Vol 32 (1) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
Copper Alloy ◽  
Heat Treating ◽  
Lead Content ◽  
Atmospheric Conditions ◽  
Excellent Corrosion Resistance ◽  
High Copper ◽  
Screw Machine

Abstract MUELLER Alloy 3140 is a high-copper alloy with moderate strength, a rich bronze color and excellent corrosion resistance. Its lead content gives it excellent machinability which makes it suitable for screw-machine applications. Its uses include many screw-machine products, decorative hardware, pickling crates and parts to resist severe atmospheric conditions. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-451. Producer or source: Mueller Brass Company.

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