Lime applications increase extended sweetpotato transplant production in heated beds 1

This experiment was conducted to determine the effects of aged pine media (sawdust and bark) and lime amendments (0.0, 2.2, and 4.4 kg/m³) on the production of ‘Georgia Jet’ sweetpotato [Ipomoea batatas (L.) Lam.] transplants at four harvests. At the first harvest, transplant production with aged pine sawdust and aged pine bark increased quadraticaly and linearly, respectively, with increasing lime rates. Aged pine media did not differ in their effects on transplant number or mean transplant weight and length at the early (first two harvests) or extended (four harvests) harvest periods. Transplant numbers increased linearly, but mean transplant length decreased linearly with lime application during both periods. A reduction in mean transplant weight was also observed. The results of this experiment provide evidence that the positive effect of amending aged pine sawdust and bark with lime continues through an extended harvest period. Transplant production, however, decreased considerably following the second harvest. Greatest early‐ and extended‐season transplant yields were 1840 and 2200 transplants/m², respectively. Media pH or leaf mineral nutrient concentrations did not adequately reflect the yield responses.     

Leaf mineral nutrient concentrations or media pH affect Georgia Jet sweetpotato transplant number,length, and weight 1

The results of four experiments were combined to determine the relationships between leaf mineral nutrients or media pH and sweetpotato transplant production. The relative number of transplants and the relative mean transplant lengths or weights were determined by comparing the values obtained with unamended aged pine sawdust, a traditional medium. These values were regressed against leaf mineral concentrations and media pH. There was no relationship between relative transplant production and leaf nitrogen (N), potassium (K), or manganese (Mn) concentrations. Compared to sufficiency ranges for nearly mature sweetpotatoes, concentrations of N and K were low and Mn was sufficient. An upper value of 1210 mg/L leaf iron (Fe) was obtained for relative mean transplant weight, but concentrations of this mineral were not associated with relative transplant numbers or relative mean transplant lengths. Leaf calcium (Ca) and magnesium (Mg) concentrations were related to all three transplant characteristics directly, or indirectly through possible effects on leaf phosphorus (P) concentration or media pH. Compared to the established sufficiency ranges for nearly mature sweetpotato plants, Ca and Mg concentrations were low, P and Fe concentrations were sufficient, and zinc (Zn) concentrations were high.     

Effect of oleic and linoleic acids on the production of deep-fried odor in heated triolein and trilinolein

To determine sources of desirable deep-fried flavor in frying oils, degradation products from heated triolein and trilinolein with 5-31% polar compounds representing low to high deterioration were evaluated by purge-trap gas chromatography-mass spectrometry-olfactometry. (E,E)-2,4-Decadienal, 2-heptenal, 2-octenal, 2,4-nonadienal, and 2,4-octadienal produced deep-fried odor at moderate-strong intensities in heated trilinolein. However, unexpected aldehydes-2,4-decadienal, 2,4-undecadienal, 2,4-nonadienal, and 2-octenal (all <15 ppm)-were produced in triolein heated for 6 h. These dienals possibly were produced by hydroperoxidation and/or hydroxylation followed by dehydration of 2-alkenals. The 2-alkenals were produced from thermal decomposition of hydroperoxides, epoxides, and keto and dimeric compounds produced during the heating of triolein. These aldehydes produced low intensities of deep-fried odor in triolein. This information helps to explain sources of the deep-fried flavor that is characteristic of high linoleic frying oils but which is only at low intensity levels in high oleic frying oils.     

Ultraviolet-B radiation in a row-crop canopy: an extended 1-D model

A decrease in stratospheric ozone may result in a serious threat to plants, since biologically active short-wavelength ultraviolet-B (UV-B 280–320 nm) radiation will increase even with a relatively small decrease in ozone. Numerous investigations have demonstrated that the effect of UV-B enhancements on plants includes reduction in grain yield, alteration in species competition, susceptibility to disease, and changes in plant structure and pigmentation. To determine the physiological effects on plants of any increases in UV-B radiation, the irradiances at the potential sensitive plant surface need to be known. A number of radiative transfer models exist but because of the importance of sky diffuse radiation to the global UV-B irradiance, models designed to estimate photosynthetically active radiation or total solar radiation may not accurately model the UV-B. This paper compares spatially and temporally averaged measurements of the UV-B canopy transmittance of a relatively dense maize canopy (sky view: 0.27°) to the estimations of two one-dimensional models differing mainly in the handling of sky radiance. The model that considered the distribution of sky radiance tended to underestimate the canopy transmittance, the model that assumed an isotropic sky radiance distribution tended to overestimate the canopy transmittance. However, the assumption concerning the sky radiance distribution accounted for only about 0.01 of the model error. Consequently, the sky radiance distribution is probably not important in modeling such dense crop canopies. The model that overestimated transmittance and had the generally larger errors, a modified Meyers model, used the assumption of uniform leaf angle distribution, whereas in the other model, designated the UVRT model, leaf angle distributions were estimated by sample measurements. Generally this model would be satisfactory in describing the statistically average UV-B irradiance conditions in the canopy. This model may also be applied to other dense plant canopies including forests.     

Tests for the depolymerization of polyacrylamides as a potential source of acrylamide in heated foods

This study was conducted to test the possibility that polyacrylamides used in agriculture may contribute to acrylamide formation in heated foods by thermal depolymerization. Two samples of polyacrylamide with low molecular weights of 1.5 and 10 kDa were used to test for in-chain and end-chain depolymerization. They were added as aqueous solutions to filter paper for heating in a drying/dry environment and added to a cooking oil for heating in a fatty environment. The heating conditions were 175 degrees C for 15 and 30 min, respectively. Both regimens were tested in the absence and presence of the redox-active metal ions Fe(III) and Cu(II), and all tests were conducted without the exclusion of atmospheric oxygen. There was no evidence of any significant depolymerization of polyacrylamide to free acrylamide monomer, <0.04%. In fact, residual levels of acrylamide present already in the low molecular weight polymers were seen to fall by 50-80% on heating. Consequently, it is concluded that even if polyacrylamides were to contaminate agricultural crops and foods derived therefrom (which itself is an unproven suggestion), there is no evidence that the polymers would depolymerize on heating of the food to form acrylamide in any significant amount.     

Investigations of La Rioja terroir for wine production using 1H NMR metabolomics

In this study, La Rioja wine terroir was investigated by the use of (1)H NMR metabolomics on must and wine samples. Rioja is a small wine region in central northern Spain which can geographically be divided into three subareas (Rioja Alta, Rioja Baja, and Rioja Alavesa). The winemaking process from must, through alcoholic and malolactic fermentation, was followed by NMR metabolomics and chemometrics of nine wineries in the Rioja subareas (terroirs). Application of interval extended canonical variate analysis (iECVA) showed discriminative power between wineries which are geographically very close. Isopentanol and isobutanol compounds were found to be key biomarkers for this differentiation.     

Co-Orientation in Gender Preferences for Mass Media Usage Among Benue Farmers

This study examined the extent of agreement between male and female farmers’ usage of mass media. Data collected from 250 farmers in Benue, Nigeria using a structured questionnaire showed that 79.6% could read and write and revealed a disparity in the use of television, mobile phones, the Internet, and newspapers. The Mann-Whitney U test showed significant differences in the use of television (.013), the Internet (.044), and newspapers (.082), indicating non-alignment positions. Alignment in the nonuse of production guides and journals/magazines (dmr = 0) and near alignment for radio (dmr = 1) was observed. We recommend that stakeholders in the agricultural delivery system make use of mass media that are gender-relevant in disseminating farm messages.     

Identifying and selecting for genetic diversity in Papua New Guinea sweetpotato Ipomoea batatas (L.) Lam. germplasm collected as botanical seed

A total of 141 Ipomoea batatas (L.) Lam. accessionsderived from botanical seed originally collected from 26 sites in 4 Provinces inPapua New Guinea, a secondary center of genetic diversity for sweetpotato, weregenetically analyzed. Two hundred Amplified Fragment Length Polymorphism (AFLP)markers were identified and utilized in the analysis. Relatedness amongaccessions was estimated by analyzing the AFLP data using the Dice coefficientof similarity and UPGMA methods. The molecular analysis revealed relativelylimited genetic diversity within and between sites. Genotypes collected in agiven region often displayed molecular marker variability similar to thatobserved over the entire sampled area. However, a subset of 14 genotypes derivedfrom seed collected from New Ireland island differed from genotypes collected onNew Guinea island. Estimates of genetic diversity-based similarity valuescalculated from the AFLP data indicated a moderate level of diversity (0.767mean coefficient of similarity) across all plant materials analyzed. Threemethods of selection were evaluated for their efficacy in capturing themolecular marker diversity within the plant materials in the form of a subset.They were random, stratified-random (geographic based), and marker-assistedselection (MAS). MAS was the most efficient. A Maximally Diverse Subset (MDS) of12 genotypes capturing 92% of the molecular marker diversity was identified.     

Constraints for potato production in the tropics

Potato tuber yields in the tropics are extremely low compared to those of temperate zones. The low yields merely reflect the inability of the current technology to overcome soil and environmental constraints. Given the various constraints affecting potato production in the tropics, few viable soil and crop management options remain. This paper reviews key constraints for potato production, assesses the impact of indigenous and/or adapted technology in managing them, and examines basic relationships describing productivity changes as management takes place. The overall intent of this paper is to outline the scientific basis for developing management strategies to sustain and improve potato production in the tropics.     

An Efficient ELLAM Implementation for Modeling Solute Transport in Fractured Porous Media

The goal of this study is to introduce an adaptation of the Eulerian-Lagrangian localized adjoint method (ELLAM) for the simulation of mass transport in fractured porous media, and to evaluate the performance of ELLAM in such a case. The fractures are represented explicitly using the discrete fracture model. The velocity field was calculated using the mixed hybrid finite element method. A sound ELLAM implementation is developed to address numerical artifacts (spurious oscillations and numerical dispersion) arising from the presence of fractures. The efficiency of the developed ELLAM implementation was further improved by taking advantage of the parallel computing on shared memory architecture for the tasks related to particles tracking and linear system resolving. The performance of ELLAM was tested by comparing its results with the Eulerian discontinuous Galerkin method based on several benchmark problems dealing with different fracture configurations. The results highlight the robustness and accuracy of ELLAM, as it allows the use of large time steps, and overcomes the Courant-Friedrichs-Lewy (CFL) restriction. The outcome also shows that ELLAM is more efficient when fracture density is increased.     

Physical and Chemical Changes in Container Media in Response to Bark Substitution for Peat

Physical and chemical properties of container media are important factors in controlling the supply and movement of water and nutrients for nursery plant growth. The objectives of this study were to evaluate the physical and chemical properties and quality of media formulated with systematic substitution of composted pine bark (bark) for sphagnum peat (peat) in the presence of sand. Ten formulations were prepared that contained 40-90% bark, 0-50% peat, and 10 or 20% sand by volume. Increasing the percentage of bark increased the percentage of coarse particles, and linearly decreased the medium-sized particles in media in either 10% or 20% sand. Increasing the percentage of bark in the media significantly decreased water holding capacity, whereas bulk and particle densities and total porosity were influenced by the interaction of bark x peat x sand. Increasing the percentage of bark increased electrical conductivity and total C, P, K, Ca, Fe, Cu and Zn. Availability of nutrients were also increased by increasing percentages of bark. Substitution of bark for peat did not influence the pH of the formulated media. Our results suggest that formulated media with 70 to 80% composted pine bark and 10 to 20% peat (V/V) exhibited physical and chemical properties considered optimum for the growth of container nursery plant crops.     

A mechanism for hydrochloric acid production in cloud

A theoretical model describing the general interaction between atmospheric trace gases, such as S0₂, NH₃, C0₂ and 0₂, chemical reactant gaseous product H₂SO₄ and hydrometeors containing NaCl is proposed to study a possible mechanism for HCl production in non-precipitating cloud and the determination of the pH value of cloud droplets. Four different cloud droplet distributions have been used to estimate the upper limit of the amount of gaseous HCl released into the atmosphere resulting from the evaporation of cloud droplets. It is shown that the acid production and the amount of HCl released depend on the following factors: (a) the temperature of the cloud; (b) the oxidation rates; (c) the ambient concentration of SO₂, NH₃, and H₂SO₄; (d) the life cycle of the cloud; and (e) the liquid content of the cloud. This proposed chemical model also predicts a pH value spectrum depending on the cloud droplet distribution. Field measurements for the dependence of pH value on particle size and spatial distribution of gaseous HCl are recommended.     

On the Efficiency of the Direct Substitution Approach for Reactive Transport Problems in Porous Media

Nonlinear reactive transport problems can be solved using the Operator Splitting (OS) approach, where transport and reaction processes are separated or the Direct Substitution Approach (DSA) where chemical and transport equations are solved simultaneously. The OS techniques can be very attractive, but are known to introduce splitting errors with SNIA (Non Iterative OS) and have low convergence rate with SIA (Iterative OS). These problems are avoided with DSA which is more robust than OS schemes. On the other hand, DSA is more complicated and very demanding in terms of computing time and memory requirements. This can make DSA less efficient than OS schemes especially for fine discretizations and chemically simple problems. In this work, DSA, SIA and SNIA are combined with a new sparse direct (unifrontal/multifrontal) solver. The efficiency of this solver is not dependent on the matrix conditioning. The performance of the three approaches is studied for two transport problems with simple and difficult chemical reactions and for different number of unknowns. Results show that when combined with an efficient sparse direct solver, DSA is more efficient than SIA and SNIA even for chemically simple problems and large number of unknowns.     

Possible mechanism for involvement of cysteine in aroma production in wine

Under conditions close to those of wine, that is, low pH, aqueous medium, and low temperatures, this work describes N-(2-sulfanylethyl)-2-oxopropanamide (1), a new intermediate in the formation of 2-acetylthiazole from methylglyoxal and cysteine. 1 was characterized by MS, derivatization MS, and (1)H and (13)C NMR and was synthesized from 2-sulfanylethanamine and ethyl pyruvate. A formation pathway for 2-acetylthiazole from methylglyoxal and cysteine is proposed, in which 1 is a new intermediate in Maillard-type reactions in systems under mild conditions.     

Soil and Minespoil Fill as Media for Renovation of Nitrogen and Phosphorus in Domestic Wastewater

Development of Appalachian coal mining regions of the USA has been severely hampered by lack of domestic waste disposal technologies suited to fills. The suitability of on-site wastewater treatment and disposal systems (OSWTDS) in fill material is uncertain due to the effects of surface mining on soil physical properties. This research was conducted to evaluate the potential for renovation of N and P present in domestic wastewater by fills produced from mining operations. Nitrogen and P were chosen because of their potential adverse environmental impacts. Soil-fill (a mixture of Jefferson, fine-loamy, siliceous, mesic Typic Hapludult and Muskingom, fine-loamy, mixed, mesic Typic Dystrochrept soils) and minespoil (spoil)-fill (blasted rock material associated with the Taggart Marker and Low Splint Bench coal seams of the Upper Middle Wise Formation) were used in this study. Septic tank effluent (STE) and sand filter effluent (SFE) were applied to spoil-fill columns at four loading rates (0, 5.4, 10.8, and 21.6 L m^-2d^-1) and spoil-fill columns at one loading rate (21.6 L m^-2d^-1) for a period of 20 wk. Renovation of wastewater was assessed by determining the concentration of N and P present in column leachate. Reduction of inorganic N (NO₃ ^- + NH₄ ⁺), based on N/Cl ratios, ranged from 14.9 to 32.1% after the varying application rates of STE and SFE passed through the soil columns. However, leachate NO₃ ^--N concentrations were still above the 10 mg^-1 drinking water standard. The quantity of P emerging from the spoil-fill columns (3.0 mg P L^-1) was higher than anticipated and may be related to the indigenous P present in the minespoil. Sorption of P in the soil-fill column decreased with increased STE and SFE application (reductions ranged from 99.1 to 74.4%). Results from this study indicate that there is potential for renovating wastewater in OSWTDS in selected soil-fill areas in reclaimed minelands.     

Method for the quantification of acid production by plants in gel

Abstract

Hydrogen (H⁺) and hydroxyl ion (OH^‐) production by the tropical grass, Brachiaria humidicola, is quantified using a method in which the plants are grown in soil then transferred to agar gel for 24 h. The amount of H⁺ and OH^‐produced was calculated from the pH of the melted gel and the gels’ buffer curve. Values were obtained for plants of different ages and with nitrogen (N) supplied in the gel as nitrate (NC₃ ^‐), ammonium (NH₄ ⁺), or ammonium nitrate (NH₄NO₃) and compared with data calculated using the sum of H⁺ changes in differently colored zones of the gel. Daily H⁺ and OH^‐ production increased with plant age and total dry matter for the NH₄ ⁺‐ and NO₃ ^‐‐fed plants, respectively. By integrating the data over time, a value of 0.33 mmol H⁺ plant^‐1 was obtained for the total H⁺ production over 62 d. The proposed method was sufficiently rapid and versatile to allow the comparison between plant species or genotypes, which were grown using a variety of nutrient supplies. This procedure may indicate how acid production affects plant nutrient acquisition and aid the prediction of soil acidification by different plant species or cultivars.     

Desorption Characteristics of Three Mineral Oxides and a Non-crystalline Aluminosilicate for Supplying Phosphate in Soilless Root Media

The objective was to evaluate phosphate desorption characteristics of synthetic hematite, goethite, and allophane and commercial alumina after loading at maximum adsorbed phosphate levels to determine their potential to release phosphate at a constant, low level to sustain plant growth in soilless media and reduce phosphate leaching. Desorption isotherms were measured at pH 6.4 ± 0.1 using a continuously stirred-flow reactor. The time period during which dissolved phosphate was maintained within the range of 5–0.2 mg·L^?1 phosphate-P decreased in the order: allophane (12.4 d) > alumina (4.6 d) > goethite (3.6 d) > hematite (1.9 d). Allophane released the most phosphate during the desorption process (40% of maximum adsorbed phosphate; 12.7 mg?g^?1) followed by alumina and goethite (19–20%; ≈2.5 mg?g^?1) and lastly hematite (5%; 0.1 mg?g^?1). Allophane demonstrated the greatest potential as a phosphate-charged source for soilless root media, in amount and duration of phosphate release.     

Corn Wastes and Peanut Shell as Growing Media for Production of Red Radish Plants in Soilless System

ABSTRACT

Peat is considered the conventional growing medium in most soilless culture systems. The high cost of peat and the urgent need of agricultural wastes recycling encouraged the scientists and soilless culture users to search for an alternative growth medium where optimal growth conditions are achieved and help in the safe disposal of wastes. In the current study, peanut shell (PS) and corn wastes (CW) were used as growing media in comparison to peat moss (PM). The tested organic wastes and peat moss were examined with sand at three mixing ratios (1:1 “M₁”, 1:2 “M₂” and 1:3 “M₃” raw material: washed sand, respectively). Red radish (Raphanus raphanistrum subsp. sativus) plant were cultivated in 5 kg pots filled with the instigated growing media. Most of the recoded growth parameters were found in PS and PM growing media, while the lowest ones were found in CW. PS medium contained available N and P higher by 141 and 29% above the PM media. Although the peat moss gave the highest values in the measured growth characteristics, its high price decreased the net profit. The highest net profit value was obtained from PSM₂ followed by PSM₁ and PSM₃. According to the obtained results, the characteristics of the growth media derived from peanut shell qualify them for use in the production of red radish in soilless culture systems.     

Activity and concentration of polyphenolic antioxidants in apple juice. 1. Effect of existing production methods

Apples are an important source of flavonoids in the human diet. The effect of processing apples into juice on polyphenolic antioxidant content and activity is described. Raw juice obtained from Jonagold apples by pulping and straight pressing or after pulp enzyming had an antioxidant activity that was only 10 and 3%, respectively, of the activity of the fresh apples. The levels of flavonoids and chlorogenic acid in the juice were reduced to between 50% (chlorogenic acid) and 3% (catechins). Most of the antioxidants were retained in the pomace rather than being transferred into the juice. Apparently, most of the antioxidant compounds are absorbed to the solid matter of the pomace. In apple juice, 45% of the total measured antioxidant activity could be ascribed to the analyzed antioxidants. For three apple cultivars tested (Elstar, Golden Delicious, and Jonagold), the processing methods had similar effects. The results indicate that processing can have a major impact on the bioactivity of products.