Influence of phosphate sorption on dispersion of a Ferralsol

Abstract

Soil dispersion induces soil erosion and colloidal leaching. Nutrients are lost at the same time and this causes water contamination. Phosphate is an essential element for living organisms. Because phosphate influences soil dispersion and it is an important limited resource, this influence must be evaluated well in order to diminish negative effects on soil structure. In this paper, we firstly evaluated the influence of phosphate sorption on soil dispersion by calculating repulsive potential energy between soil particles. Ferralsol, which is a typical soil in rainy tropical regions, was used as the material. The dispersion-flocculation phenomena were investigated with absorbance of soil suspension under different pH, phosphate adsorption and electrolyte concentration in an Na-NO₃-PO₄ system. The repulsive potential energy was calculated based on the diffuse double layer theory and the measured zeta potential. We indicated that the measured absorbance increased with the increase of the repulsive potential energy. The repulsive potential energy increased with increasing phosphate sorption up to about 5 to 20 mmol kg^?1 at all pH, and it induced the soil dispersion, because phosphate sorption increased the negative charge of the soil. After its peak, it decreased with increasing phosphate sorption because the electrolyte concentration increased and the electrolyte screened the electric field near the soil surface. The repulsive potential energy also increased with increasing pH because of the increase of the negative charge of the soil. Even at low pH, after a certain amount of phosphate sorption, the soil dispersed due to the increase of repulsive potential energy, although the soil flocculated before phosphate application. Because the soil dispersion causes soil and phosphorus loss, the influence of soil pH and phosphate sorption on the soil dispersion should be considered for good soil management.     

Water mobility in multicomponent model media as studied by 2H and 17O NMR

Molecular mobility of water was studied in a microbiological media containing complex and heterogeneous mixtures of cellulose, l-sorbose, and orange serum broth (OSB) using (2)H and (17)O high-resolution NMR. All mixtures showed Lorentian (17)O NMR spectra but complex (2)H NMR line shapes. Sorbose, when solubilized, caused line-narrowing where as cellulose-OSB mixtures showed wide peaks with flat plateaus. Presence of liquid or solvent water had a profound effect on a marked increase in T(2) relaxation time observed in sorbose-containing samples. (17)O NMR data were not composition dependent, while (2)H NMR data were highly sorbose dependent.     

Effects of lactulose supplementation on the growth of bifidobacteria and biotransformation of isoflavone glycosides to isoflavone aglycones in soymilk

Bifidobacterium animalis subsp. lactis bb12 and B. longum 20099 were used to hydrolyze isoflavone glycosides (IG) to biologically active forms, which are isoflavone aglycones (IA), in soymilk (SM) prepared from soy protein isolate (SPI) and SM supplemented with 0.5% (w/v) of lactulose (SML). Supplementation of lactulose significantly ( p < 0.05) enhanced the viable counts of B. animalis subsp. lactis bb12 and B. longum 20099 up to 2.34 and 2.15 log CFU/mL, respectively. Bifidobacterium animalis subsp. lactis bb12 and B. longum 20099 utilized 3.32 and 3.75 mg/mL of lactulose at 24 h of incubation, respectively. Supplementation of lactulose also appeared to be a key factor in decreasing the pH of SML. The biotransformation of IG to IA was enhanced significantly by 6.8-17.1% and 12.8-13.5% in SML by B. animalis subsp. lactis bb12 and B. longum 20099, respectively. However, the presence of lactulose in SML showed the stimulating effect on B. longum 20099 only after 12 h of incubation. Isoflavone aglycones ranged from 69.5 to 77.1% of total isoflavone compounds in SML after incubation.     

Rice genetic diversity at farm and village levels and genetic structure of local varieties reveal need for in situ conservation

Rice genetic diversity partitioning between farms, varieties and, within-variety diversity, were analysed in two villages of Maritime Guinea with contrasted agroecological conditions. One thousand and two hundred individual plants belonging to 45 accessions collected in eight farms were genotyped using 10 SSR markers. The molecular variance was evenly shared between and within accessions, while the farm effect was almost nil. Local varieties had a multi-line genetic structure. The number of multilocus genotypes was proportional to the utilisation rate of the variety in the village. The F _ST values between different accessions of each variety were significant which indicated low genetic consistency in the variety names. This varietal structure could mainly be explained by the migration phenomenon and the high varietal turnover. Compared to allelic diversity, multilocus genotypic diversity seemed to be the most suitable indicator of the quantitative distribution of diversity at different management scales (accession, farm and village). The within- and between-farm F _ST values were in the same order of magnitude. The within-farm diversity was not farm-specific but quantitatively high, i.e. up to 50% of the total genotypic diversity of a given village. Given the relative importance of the within-variety diversity, the in situ approach stands out as the most effective solution. As farms do not host specific diversity the in situ approach could be implemented by working with a small number of farms.     

High yield and nutritional quality of rice for animal feed achieved by continuous irrigation with treated municipal wastewater

Paddy and Water Environment - Two consecutive pilot-scale experiments were conducted to investigate the potential reuse of treated municipal wastewater (TWW) as an irrigation source for cultivating...     

女人三国

4.0、3.0和2.0,她们之间本不应该有交点,但因为对网球的痴迷程度都是7.0,于是这三个在各自圈子里红得发烫的人,走到了一起。     

Evaluation of soybean for resistance to soybean rust in Vietnam

Soybean rust, caused by Phakopsora pachyrhizi Sydow, is a severe foliar disease of soybean [Glycine max (L.) Merr.] that occurs throughout most soybean producing regions of the world. The objective of this research was to evaluate selected soybean genotypes for resistance to soybean rust in Vietnam. Five field experiments in Vietnam were completed from 2006 to 2009. The area-under-the-disease-progress-curve (AUDPC) was calculated for each soybean genotype based on four disease assessments taken during the reproductive growth stages. AUDPC units among soybean genotypes in each experiment differed (P < 0.05). Over the five experiments, the resistant check DT 2000 was most often the genotype with the lowest AUDPC units while the sources of rust resistance (Rpp1-5) did not always have low AUDPC units in each experiment, although PI 230970 (Rpp2) appeared to be more stable. A few genotypes with non-characterized genes for resistance, such as PI 398998, PI 437323, and PI 549017, had the lowest AUDPC units in at least one of the experiments. These genetic resources may be useful for host plant resistance studies and breeding soybeans for rust resistance in Vietnam and other locations like Brazil and the United States that have more recently been inundated with soybean rust. A significant (P < 0.001) experiment × genotype interaction was found when the AUDPC data of 14 soybean genotypes tested in Experiments 1, 2, and 3 were combined and analyzed. This result indicates the potential importance of changing fungal races and/or biotypes that occur in the rust population.     

Barnacle culture: background,potential and challenges

There are approximately a dozen species of commercially interesting barnacles worldwide, some of which have been cultured on a semi‐industrial scale. These species are listed and information is provided with regard to geographical distribution, landings and prices. Traditionally, ‘goose’ barnacles (four species) are considered to be the most important for consumption. World production already stands at 500 tonnes year^?1, but this species has not been cultured to date. Some ‘acorn’ barnacles are also consumed (seven species), with harvest levels per species that do not exceed 200 tonnes year^?1 and selling prices that can reach US$17/kg. ‘Acorn’ barnacle culture on a world scale is still developing. Nevertheless, production has occurred on a semi‐industrial scale; specifically, spat have been collected from the wild and grown in suspended systems. Farming trials have focused on two species of acorn barnacles: Austromegabalanus psittacus (Molina 1782) ‘picoroco’ in Chile and Megabalanus azoricus (Pilsbry 1916) ‘craca’ in Portugal. The large‐scale production of these crustaceans will depend on the optimization of spat collection from the wild and/or the parallel development of mass production technologies for larvae (hatcheries). In addition, further development will be achieved by opening up new markets for commercialization.     

The potential of informal institutions for marine fisheries management—A case study of a coastal commune in Vietnam

The potential of informal institutions for sustainable management of marine fisheries was examined. The study is based on both primary data collected through two group discussions and interviews and secondary information, including material related to fishing gear operation and whale worship. It shows that informal institutions, including fisher groups, fishing community norms, fisher's knowledge and whale worship have potential to strengthen institutional, ecological, social and community aspects of sustainable fisheries development. Although these informal institutions are not able to fix completely all the problems faced by formal institutions, they are able to complement and consolidate formal institutions to manage marine fisheries effectively. The findings of this study suggest it is imperative that formal institutions should be improved simultaneously with informal institutions to enhance current management for sustainable marine fisheries development.