Reuse of waste materials as growing media for ornamental plants

The use of different waste materials: pine bark, coconut fibre and sewage sludge as substrates in the production of ornamental plants was studied, with an special interest on the suitability of coconut fibre as growing substrate for conifer plants. The plant species tested were Pinus pinea, Cupressus arizonica and C. sempervirens and the substrate mixtures were: (1) pine bark, (2) pine bark with 15% of sewage sludge compost, (3) pine bark with 30% of sewage sludge compost, (4) coconut fibre, (5) coconut fibre with 15% of sewage sludge compost and (6) coconut fibre with 30% of sewage sludge compost. Substrates were physically and chemically well characterized, and 75-cm plants were grown on them for one year. Plant and substrate status were periodically tested along the experiment. As biosolid recycling is the main objective of the present work, the mixtures with 30% of composted sewage sludge will be the most convenient substrate to use. For C. sempervirens and C. arizonica, a mixture between pine bark or coconut fibre and 30% of biosolid compost in volume gave the best results, but the lower cost of the pine bark than the coconut fibre substrate indicated the use of the PB+30% CSS. For P. pinea the research of new combinations between waste products is recommended to attain better results.     

Use of pruning waste compost as a component in soilless growing media

The objective of this work was to study the use of pruning wastes compost (PWC) as a growing media component for ornamental plants. The main physical, chemical and biological characteristics of PWC were analysed in order to evaluate its suitability for use in soil-less cultivation. Six growth substrates were prepared by mixing PWC with peat (P), ground leaves (GL), sand (S) and spent mushroom compost (SMC) in different proportions. Two different pot experiments were carried out to test its characteristics of production using perennial ryegrass (Lolium perenne L.) and cypress (Cupressus sempervirens L.) as indicators and the different media as treatments. The growth experiments showed that PWC required mixing with a nutrient-richer material to produce higher results. Therefore, substrates containing SMC (PWC+P+SMC and PWC+SMC) seems to be the most adequate growing media. After the statistical analysis, we concluded that the PWC could be used as a growing media component.     

Physio-chemical characterization of indigenous agricultural waste materials for the development of potting media

Organic residues are an important factor that directly affects fruiting tree seedlings' health at earlier stages. It provides a suitable environment for seedling growth by providing better nutrient ions, water, and aeration. However, low organic contents and high shrinkage of most organic materials mostly deteriorate ideal potting media characteristics. Low aeration, high water, and nutrients leaching decrease seedling growth and cause a significant loss of valuable resources. That is why the current study was conducted to screen out the best indigenous materials based on particle size to produce good characteristics bearing potting media. For that, eight different ingredients, i.e., “sugarcane”, “coconut coir”, “wheat straw”, “rice straw”, “corn cob”, “leaf litter”, “farmyard manure”, and “sunflower heads” were collected. Initially, all the materials were air-dried and processes as per requirement. After grinding, three particles size (fine = < 2 mm, medium = 3 mm and coarse = 5 mm) were separated by sieving. Results showed that decreasing particle size in “rice straw”, “corn cob”, “farmyard manure,” and “sunflower head” decreased leachate pH. Higher EC in leachates was negatively correlated with particle size in all potting media ingredients. Except for farmyard manure, fine particle size increases the water-holding ability of potting media ingredients. However, air-filled porosity was associated with a decrease in particle size of potting media in gradients. In conclusion, farmyard manure, “sunflower heads”, “leaf litter” and “sugarcane” should be incorporated while making a combination for potting media. More investigations are suggested by mixing different particle size ingredients to prepare potting media.     

The use of psyllium (isubgol) as an alternative gelling agent for microbial culture media

Psyllium (Isubgol), the mucilage husk of Plantago ovata, was successfully used as an alternative gelling agent (5% w/v as ground husk for pouring medium and 4% w/v as ground husk in combination with 0.5% w/v agar for slant) for microbial culture. Most of the undesirable features of psyllium-gelled media (slant as well as pouring) were removed by adding the u.v.-treated (20min) or oven-sterilized (120^°C for 1h) psyllium as ground husk to autoclaved medium at 50–60^°C under aseptic condition just before pouring.     

National inventory of organic wastes for use as growing media for ornamental potted plant production: case study in Spain

An inventory of materials suitable for use as growing media for ornamental potted plant production in Spain has been prepared. Special attention has been paid to solid organic wastes generated by production, industrial and consumer activities. Information obtained from this study has been organised into two data bases. Data base 1 contains the "General Characteristics" file of more than 105 materials. In this file, data are available regarding generation points, material availability, uses, cost, disposal expenses, etc. Data base 2 is comprised of the "Specific Properties" file of 63 materials selected from data base 1. The main physical, chemical and biological properties of these materials as container media have been characterised, and the results obtained have been compiled. Finally, a computerised data bank has been created which can be found in the home page of the Spanish Ministry of Agriculture, Fisheries and Food (http://agritel2.mapya.es/sustratos/).     

Spatial root distribution of plants growing in vertical media for use in living walls

Background and Aims

For plants growing in living walls, the growth potential is correlated to the roots ability to utilize resources in all parts of the growing medium and thereby to the spatial root distribution. The aim of the study was to test how spatial root distribution was affected by growing medium, planting position and competition from other plants.

Methods

Five species (Campanula poscharskyana cv. ‘Stella’, Fragaria vesca cv. ‘Småland’, Geranium sanguineum cv. ‘Max Frei’, Sesleria heufleriana and Veronica officinalis cv. ‘Allgrün’) were grown in three growing media (coir and two of rockwool) in transparent boxes under greenhouse conditions. Root frequency was registered and the activity of individual root systems was studied via ¹⁵N uptake and plant dry weight was measured.

Results

Plants in coir had stronger root growth in all parts of the medium than plants in rockwool. Upwards root growth was limited for plants in the middle or lower parts of the medium and ¹⁵N measurements confirmed that only plants in the bottom of the box had active roots in the bottom of the medium. The species differed in root architecture and spatial root distribution.

Conclusions

The choice of growing medium, plant species and planting position is important for a living wall as it affects the spatial root growth of the plants.     

Characterising the fine sediment budget of a reach of the River Swale,Yorkshire, U.K. during the 1994 to 1995 winter season

Suspended sediment budget dynamics for a 55 km reach of the lowland River Swale, Yorkshire, U.K. are investigated for the period October 1994 to June 1995. Particular attention is paid to 11 storm events occurring between October 1994 and April 1995. Each of these storms produced significant suspended sediment transport. Variations in sediment dynamics, for example suspended sediment concentrations, hysteresis patterns and storm peak lag times through events and between the upstream and downstream ends of the reach are examined. Net sediment loss from the reach occurred during the extremely wet four month winter period from December 1994 to April 1995. Patterns of reach sediment storage are concluded to represent a combination of channel bed erosion and/or deposition, bank erosion and floodplain deposition. The implications of these patterns for sediment modelling are discussed.     

Predictions of the AIDS epidemic in the U.K.: the use of the back projection method

Back projection methods are used to predict the yearly number of new AIDS diagnoses and the number of new HIV infections, to the end of 1992. The AIDS, but not the HIV, predictions are insensitive to the choice of incubation period distribution. A wide range of predictions is consistent with the AIDS diagnoses in years up to 1987, but limited ancillary information on the relative rates of new HIV infection in 1984 to 1987 can be used to narrow this range. The range of prediction based on AIDS reports to the end of 1988 is lower and narrower than the range based on reports to the end of 1987. The number of new AIDS cases in 1992 appears likely to fall in the range 1000-3000.     

Growing media constituents determine the microbial nitrogen conversions in organic growing media for horticulture

Vegetables and fruits are an important part of a healthy food diet, however, the eco‐sustainability of the production of these can still be significantly improved. European farmers and consumers spend an estimated €15.5 billion per year on inorganic fertilizers and the production of N‐fertilizers results in a high carbon footprint. We investigated if fertilizer type and medium constituents determine microbial nitrogen conversions in organic growing media and can be used as a next step towards a more sustainable horticulture. We demonstrated that growing media constituents showed differences in urea hydrolysis, ammonia and nitrite oxidation and in carbon dioxide respiration rate. Interestingly, mixing of the growing media constituents resulted in a stimulation of the function of the microorganisms. The use of organic fertilizer resulted in an increase in amoA gene copy number by factor 100 compared to inorganic fertilizers. Our results support our hypothesis that the activity of the functional microbial community with respect to nitrogen turnover in an organic growing medium can be improved by selecting and mixing the appropriate growing media components with each other. These findings contribute to the understanding of the functional microbial community in growing media and its potential role towards a more responsible horticulture.     

Use of cereals as basal medium for the formulation of alternative culture media for fungi

Summary The feasibility of developing alternative media to different culture media particularly potato dextrose agar was assessed using local cereal species as the basal media. Three cereal meal extracts – corn, sorghum and millet – were prepared, using them as substitute for the potato in potato dextrose agar. Potato dextrose agar (PDA) was the standard set up with which the performances of the formulated media were compared. Eight genera of fungi (Aspergillus niger, Fusarium moniliforme, Penicillium sp., Cercospora sp., Curvularia palescens, Botryodiplopodia sp., Rhizopus sp. and Rhodotorula rubra) were isolated and pure cultures of each species aseptically inoculated onto the three different formulated media including PDA and allowed to grow. Their growths were measured at 24, 48, 72, and 96 h after inoculation, using diameter of growth as an index. The set up was repeated thrice for each species on the three formulated media and the control (PDA). Growth of all the fungal species were observed to be about the same or sometimes better in the formulated media relative to those on the standard set up, except for Rhodotorula rubra. The radius of growth of F. moniliformehad an average of 15 + 0.58 mm on corn-dextrose agar relative to 12 mm on PDA at 96 h while Cercospora sp. measured 30 + 0.58 mm on millet-meal dextrose agar relative to 37 + 1.16 mm at 48 h. Botryodiplopodia sp. grew through the whole diameter of the plate (covering the total length of the radius of 45 mm) in both sorghum-meal and PDA at 96 h.     

Seasonality of sediment skewness as a geochronological tool for the Humber salt marshes,U.K.

Understanding the patterns of marsh growth hasprimarily been based on modeling. Empiricalverifications of such models are difficult. This isattributed to the inability of available techniques togenerate past annual accretion rates from marshsediment cores and the need for an extremely longobservation period if a set of present day accretionrates is to be collected and used for such a purpose.Hypothetically, the large variation in temperaturebetween summer and winter, occurring on some saltmarshes, affects the viscosity of the tidal watersinundating and consequently the characteristics of thesediments deposited on the marsh surface. Thevariability of characteristics between seasonallydeposited sediment can be used as annual markers toderive annual accretion rates. Sedimentationexperiments at various temperatures and detailedanalyses of core sediments, cut at 1 mm. intervals,from two selected Humber marshes, were conducted totest the hypothesis.The sedimentation experiments showed that sedimentskewness, a sedimentological characteristic used toindicate the symmetry of the sediment distributioncurve about the mean, is most sensitive to variationsin water temperature and can be used as annual markersin marsh sediments. Detailed sedimentological analysesof two Humber marsh cores showed skew variabilityfollows a low magnitude cyclicity throughout bothcores. Using a 3 year time lag period and thenegative skew peaks as annual markers, correlationbetween a set of peak negative skew values, occurringwithin a dated section of the core, and the averagesummer field temperatures was found to bestatistically significant. The period for sediment toaccumulate within the dated section was calculated toequal the period derived from the dateable pollutanthorizons respectively. Additionally, the annualaccretion rates derived using the negative skew peaksas annual markers are comparable to the observedaverage annual accretion rates previously reported.     

Peracetic acid oxidation as an alternative pre-treatment for the anaerobic digestion of waste activated sludge

Anaerobic digestion is generally considered to be an economic and environmentally friendly technology for treating waste activated sludge, but has some limitations, such as the time it takes for the sludge to be digested and also the ineffectiveness of degrading the solids. Various pre-treatment technologies have been suggested to overcome these limitations and to improve the biogas production rate by enhancing the hydrolysis of organic matter. This paper studies the use of peracetic acid for disintegrating sludge as a pre-treatment of anaerobic digestion. It has been proved that this treatment effectively leads to a solubilisation of organic material. A maximum increase in biogas production by 21% is achieved. High dosages of PAA lead to a decrease in biogas production. This is due to the inhibition of the anaerobic micro-organisms by the high VFA-concentrations. The evolution of the various VFAs during digestion is studied and the observed trends support this hypothesis.     

Insulin research in China and the U.K

Insulin has been extensively studied since it was discovered by Banting and Best in 1921. Early in 1934, Dorothy Crowfoot and John Desmond Bernal obtained the first X-ray diffraction photograph of an enzyme protein: pepsin. In 1935, they took another photograph of a protein hormone: insulin. The chemical structure of protein was unknown until the amino acid sequence of bovine insulin was solved by Fred Sanger and colleagues in 1955. In 1958, the chemical synthesis of bovine insulin started in China through a nationwide collaboration of three institutions: the Institute of Biochemistry in Shanghai, the Institute of Organic Chemistry in Shanghai and Beijing University. The total synthesis of bovine insulin in crystalline form was accomplished in 1965. The success of the synthesis of the first protein in vitro greatly encouraged young researchers in China. Not long afterwards, the project of structural analysis of insulin crystal was carried out in China through the collaboration of the Institute of Biophysics, the Institute of Physics and Beijing University, and succeeded in 1971. In Dorothy Hodgkin's laboratory in Oxford, X-ray diffraction studies of insulin crystals were resumed after about 30 years, and the structure of rhombohedral insulin crystal was solved in 1969. Through insulin research, the Institute of Biophysics in Beijing and the Institute of Biochemistry in Shanghai established scientific collaboration and personal friendship with Dorothy Hodgkin's laboratory in Oxford, and later Guy Dodson's laboratory in York and Tom Blundell's laboratory in London. In 1975, Dorothy Hodgkin wrote a short note, 'Chinese work on insulin' in Nature, anticipating closer scientific exchange between the East and the West. In 1982, a bilateral meeting between the Biochemical Societies in the U.K. and China was held in Oxford. Now, the second bilateral meeting held in Shanghai will further promote the collaboration between our two countries.     

Climate change and the green energy paradox: the consequences for twaite shad Alosa fallax from the River Severn, U.K

A stock-recruitment model with a temperature component was used to estimate the effect of an increase in temperature predicted by climate change projections on population persistence and distribution of twaite shad Alosa fallax. An increase of 1 and 2° C above the current mean summer (June to August) water temperature of 17·8° C was estimated to result in a three and six-fold increase in the population, respectively. Climate change is also predicted to result in an earlier commencement to their spawning migration into fresh water. The model was expanded to investigate the effect of any additional mortality that might arise from a tidal power barrage across the Severn Estuary. Turbine mortality was separated into two components: (1) juvenile (pre-maturation) on their out migration during their first year and on their first return to the river to spawn and (2) post-maturation mortality on adults on the repeat spawning component of the population. Under current conditions, decreasing pre-maturation and post-maturation survival by 8% is estimated to result in the stock becoming extinct. It is estimated that an increase in mean summer water temperature of 1° C would mean that survival pre and post-maturation would need to be reduced by c. 10% before the stock becomes extinct. Therefore, climate change is likely to be beneficial to populations of A. fallax within U.K. rivers, increasing survival and thus, population persistence.