Mineral element concentration of two barley cultivars in relation to water deficit and aluminum toxicity

The separate and combined effects of water and Al stress on concentrations of P, K, Ca, Mg, Fe, Mn, Zn, Cu, B, Al, Sr, and Ba were determined in tops of ‘Dayton’ (Al‐tolerant) and ‘Kearney’ (Al‐sensitive) barley (Hordeum vulgäre L.) grown in an acid, Al‐toxic, Tatum subsoil (clayey, mixed, thermic, Typic Hapludult). Plants were grown 4 weeks in a plant growth chamber at high (pH 4.7) or low (pH 6.6) Al stress. During the last 2 weeks they were also subjected to low (‐20 to ‐40 kPa), moderate (‐40 to ‐60 kPa), or high (‐60 to ‐80 kPa) water stress. In general, Al stress had a greater overall effect on mineral element concentration of tops than water stress. Aluminum stress significantly decreased concentrations of P, Ca, and Mg and increased concentrations of Zn, Sr, and Ba, irrespective of the cultivar or water stress treatment. Cultivar differences in Mn concentration were observed with Al stress under all water stress conditions. In each case, Mn concentration was lower in ‘Kearney’ than in ‘Dayton’. Potassium, Ca, and Mg were lower in ‘Kearney’ than in ‘Dayton’ only at low and moderate water stress, under low Al stress, ‘Kearney’ had significantly higher concentrations of K and Ca than did ‘Dayton’ under all water stress conditions. The effects of water stress on mineral element concentration varied greatly with cultivar, Al stress treatment, and severity of water stress. Under high Al stress, increasing drought conditions from low water stress (‐20 to ‐40 kPa) to high water stress (‐60 to ‐80 kPa) significantly increased the concentrations of Ca, K, Zn, Sr, and Ba in Al‐sensitive ‘Kearney’ and reduced the concentrations of Zn, Sr, and Ba in Al‐tolerant ‘Dayton'; P and Mg concentration were unaffected by water stress. In contrast, under low Al stress, a corresponding increase in water stress significantly increased the concentrations of Ca and reduced that of P in ‘Kearney’ and increased Ca and B concentration in ‘Dayton'; Mg concentrations were unaffected in either cultivar. Thus, it appears that Al stress and water stress had opposite effects on Ca accumulation in barley tissue.     

Changes in ureide synthesis,transport and assimilation following ammonium nitrate fertilization of nodulated Soybeans 1

The effect of ammonium nitrate fertilization on ureide synthesis, xylem transport and assimilation was examined in four week old nodulated soybean plants. In nodules the activity of 5‐phosphoribosylpyrophosphate amidotransferase, a key enzyme of ureide biosynthesis, declined 75%, while enzymes of purine oxidation (xanthine dehydrogenase and uricase) showed no response to nitrogen treatment. Xylem sap concentrations of allantoin and allantoate, as compared to untreated controls, were reduced by about 85% and 65%, respectively. Despite the substantial decline in ureide synthesis and transport, allantoate concentration in leaves of ammonium nitrate treated plants increased by about three‐fold. No ureide accumulation was observed in leaf tissue following a suppression of ureide formation in nodules by allopurinol, an inhibitor of xanthine dehydrogenase. In the pathway of ureide assimilation in leaves, application of inorganic nitrogen had no effect on activity of allantoinase, but caused a 50% drop in activity of allantoate amidohydrolase. Therefore, the observed accumulation of allantoate in soybean leaves in response to nitrogen fertilization was due to new ureide synthesis in plant tissues other than nodules, or to retardation of ureide degradation in leaves caused by the alternative source of nitrogen.     

Mycorrhizal colonization and nutrition of wheat and sweet corn grown in manure‐treated and untreated topsoil and subsoil

Dry bean yields (Phaseolus vulgaris L.) were raised to similar levels as the topsoil by manure application to eroded or leveled Portneuf silt loam soil (coarse‐silty mixed mesic Durixerollic Calciorthid). Only soil organic matter and zinc (Zn) content of leaf tissue were correlated with improved yields. Manure application increased mycorrhizal colonization and Zn uptake in pot experiments with dry bean which would explain the increased yields in the field. A field study was conducted to see if similar effects of manure and mycorrhizal colonization could be observed in field grown spring wheat (Triticum aestivum L.) and sweet corn (Zea mays L.). This study was conducted on existing experiments established in the spring of 1991 at the USDA‐ARS farm in Kimberly, Idaho, to study crop rotation/organic matter amendment treatments on exposed subsoils and focused on mycorrhizal colonization as related to topsoils and subsoils treated with conventional fertilizer (untreated) or dairy manure. Mycorrhizal root colonization was higher with untreated than with manure‐treated wheat and sweet corn. Root colonization was also higher in subsoil than in topsoil for wheat, but there were no differences between soils for sweet corn. Shoot Zn and manganese (Mn) concentrations generally increased with increased root colonization for both species (except between soils with corn Mn contents). Wheat shoot potassium (K) concentration was increased by manure application, but the affect declined with time, was the opposite of colonization and was not observed with sweet com. Phosphorus (P), calcium (Ca), magnesium (Mg), iron (Fe), and copper (Cu) concentrations either were not influenced or were erratically affected by mycorrhizal colonization. Yields of wheat were highest for manure‐treated subsoil and topsoil compared to untreated soils. Mycorrhizal colonization was different between conventional and manure‐treated soils and between topsoil and subsoil and these differences increased Zn and Mn uptake, but they did not explain the improvement in wheat yields obtained with manure application.     

Relative importance of protons and solution calcium concentration in phosphate rock dissolution by organic acids

A series of experiments was conducted to quantify the relative contribution of protons and other mechanisms to the dissolution of phosphate rocks (PRs) from six countries in solutions of low-molecular-weight-aliphatic organic acids. The amounts of P and Ca released after 3 d of incubation at 28°C were determined in all the experiments. In the first experiment the solubility of the PRs < 500 μm particle size) in 100 M (25 mL g^-1 PR) oxalic, tartaric, and citric acids was compared with that in three mineral acids and four chelating compounds. There were no differences in the amount of P released by the mineral acids, but the organic acids released more P than could be accounted for by protonation. The chelating compounds were the least effective. In the second experiment, 1 g each of Sri Lanka and Togo PRs was incubated with 2.5 mmol of the organic acids using three acid concentration (mM) : acid volume ratios (250:10, 100:25, and 25:100). The amount of P dissolved from the PRs and the amount of acid remaining in the filtrate were about the same for all three treatments. A mixture of the organic acids and the respective Na-salts was prepared at six different acid: salt ratios in the third experiment. Total acid concentration in all the solutions was 100 mM. Higher proportion of the Na-salt in the mixture decreased PR dissolution, while the amount of the acid remaining in the filtrate increased. The Ca concentration in the filtrate showed an opposite trend. The results indicated that PR dissolution by the organic acids was initially dependent on protonation, which accounted for only 13–38% of the amount of P dissolved. Most of the amount of P dissolved could therefore be attributed to other mechanisms. Removal of dissolved Ca from the solution appears to be the major factor controlling the subsequent dissolution of the PRs. The ability of tartaric and oxalic acids to dissolve effectively the PRs was attributed to the formation of an insoluble calcium compound which was precipitated from the solution. For the use of organic acids as a potential amendment for improving the P availability of PRs, the Ca binding power of the organic acids should also be considered.     

Characteristics and Aquaculture Information Needs of Crayfish Farmers in Akwa-Ibom State,Nigeria

This study investigated the characteristics and aquaculture information needs of crayfish farmers in Akwa-Ibom State of Nigeria. Ninety crayfish farmers formed the sample for the study. Percentage, mean score, and multiple regression were used in data analysis. The findings show that the respondents had no extension contact and no access to crayfish and agriculture-related information. Information on adaptation to the effects of climate change on aquatic animals, especially crayfish, was needed by these farmers. Primary occupation, monthly income from crayfish enterprise, household size, and number of extension contacts were determinants of output on crayfish. The restriction of fishing activities on traditional festival days was a challenge, while the use of modern boats and durable nets were strategies for improving harvesting of crayfish.     

Engagement Through Information: Supporting Technology Commercialization

ABSTRACT

This article provides a framework for encouraging further dialogue concerning the role of information professionals in supporting the technology commercialization efforts of entrepreneurs, researchers, and small businesses. After a brief introduction to the technology commercialization process, the roles of university engagement in commercialization activities are discussed. The paper concludes with questions for consideration focused on the role of the information professional.     

Preparation and Inter Laboratory Analysis Of a Compost Reference Material

A “compost reference material” was prepared by blending four milled MSW-derived compost products. Samples were sent out to 18 laboratories from across Canada. These laboratories were supplied with proposed analytical methodology and asked to analyze for 11 metals. Fourteen laboratories complied. The data was handled using analysis of variance. Copper, zinc and lead demonstrated greater variability than did the other eight metals. No significant correlation was observed among concentrations of these three metals. Reported data are represented graphically using grouped box plots. Results suggest that regulatory agencies should consider total analytical variance when evaluating compost metal assays.     

Use of Composted and Fresh Spent Tea Grinds As a Potential Greenhouse Substrate Component

In the United States, the market for freshly brewed, ready-to-drink tea has grown exponentially during the last 20 years. Along with generating more product, tea brewers have also produced more waste. Spent tea grinds (STG) are the finely ground waste product of the tea brewing process. STG's high water-holding capacity and organic nature make it a potential replacement for common substrate components such as pine bark (PB) and peat moss (PM). In an experiment, Lantana camara L. 'New Gold' and Nephrolepis exaltata L. 'Bostoniensis', were grown in various substrates for 10 weeks on a raised bench in a greenhouse. Four substrates, which were 100% STG, 1:1 mixture of cocomposted PB:STG, Fafard® 3B, and a composted 1:1 mixture of PB:STG, were evaluated in this experiment. Substrates either contained a preplant incorporated, complete fertilizer ^(+F), or contained no exogenous fertilizer ^(?F). Lantanas grown in tree bark compost (TBC)^+F and a 1:1 mixture of PB:STG^+F had the greatest growth index at harvest, while STG^+F was not different than TBC^+F. Lantanas grown in TBC^+F, Fafard® 3B^+F, and a 1:1 mixture of PB:STG^+F had the highest shoot dry weights at harvest. No differences existed in growth index or shoot dry weight of boston fern. Substrate leachate pH was at the high end, or slightly above, a recommended range for the duration of the experiment for substrates containing TBC, but plant growth was not reduced.     

Initial habitat response to incised channel rehabilitation

• 1. Incised stream channel aquatic habitats typically are severely degraded. After the primary knickpoints or knickzones have passed, base flows are limited to shallow channels flanked by sandy berms within the enlarged high-flow channel. Riparian vegetation, woody debris and pool habitat are in short supply, and stream systems become disengaged from their floodplains.
• 2. We hypothesized that habitat recovery might be accelerated in channels that have incised and are regaining equilibrium through deposition of sandy berms by placing rock spurs in the channel and by planting woody vegetation on the berms. On the basis of literature review and a pilot study, planting designs were developed for a large-scale field experiment: 2550 1.5 m long cuttings of native willow (Salix spp.) 2–25 cm in diameter were planted 1–1.2 m deep along the base-flow channel of an incised stream. A ridge of stone was placed on the water side of the plantings, and 17 rock spurs were constructed by extending existing spur dikes from the opposite bank.
• 3. Woody cover along the treated bank increased from 38% to 66% of bankline after one growing season. Survival of individual plantings was reduced from an estimated 60% to an observed 34% by competition from the exotic kudzu vine, Pueraria lobata. Mean depth and mean scour hole depth, corrected for stage variation, increased 44% and 82%, respectively. Mean scour hole width increased 130%. The mean length of fish and the number of fish species approximately doubled, while the total weight of fish captured by a unit of sampling effort increased by an order of magnitude.

     

A climatological basis for conserving groundwater and reducing overflow in aquaculture ponds in the Southeast United States

Drop-fill water management schemes for aquacultural ponds reduce both groundwater use and effluent release. A drop-fill scheme assumes that pond water level will be allowed to decrease to the “drop” depth before makeup water is used to return it to the “fill” depth, which is typically some fraction (e.g., 1/2) of the drop depth. This paper compares predicted performance of drop-fill schemes at five sites in the Southeast U.S. (Thompsons, TX, Stuttgart, AR, Stoneville, MS, Clemson, SC, and Fairhope, AL). The locations were chosen to assess the effect of the east–west precipitation gradient and the south–north change from maritime to continental characteristics on the drop-fill approach in this region.

Performance of the drop-fill schemes was based on calculated daily water balances for ponds using 40-year (1961–2000) precipitation (P) and evaporation (E) records at the sites. Pond evaporation is assumed to be 0.8 × pan evaporation. Since performance differences based on regional P minus E (P−E) records was the subject of this work, ponds were assumed identical in other respects (i.e., all ponds were assumed to be levee-type and to have zero infiltration).

Simulated drop-fill schemes tested included (in cm): 0/0, 5/2.5, 10/5, 15/7.5, 20/10, 25/12.5, 30/15, 45/22.5, 60/30, 90/45, and 120/60. Each scheme was simulated using daily time steps for 40 years at each site. Results suggested that rigorous adherence to even a modest drop-fill scheme results in substantial reductions in both groundwater use and effluent release. It also appears that P−E conditions at all sites allow implementation of more aggressive drop-fill schemes in properly designed ponds that will require no supplemental groundwater for most years. This was also true with respect to effluent release at three of five sites. At two sites, precipitation was sufficiently large that zero effluent years were either not predicted (Fairhope) or relatively uncommon (Clemson) for any drop-fill scheme.