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Preliminary results of the combined production of duckweed Spirodela polyrhiza and common carp (Cyprinus carpio) in an aquaponic system
83-89Views:513As a result of population growth, increasin amount of food is needed, and agriculture is under an increasing burden to meet these needs. Traditional agriculture is often attacked due to its environmental impact. We must find alternative, environmentally friendly ways to produce more food. Aquaponics is a closed system in which we can produce both fish and plants at the same time. Duckweed species are small, aquatic, floating plants belonging to angiosperms. It can potentially be an alternative protein source, due to its high protein content, good amino acid supply, and rapid growth. Under suitable conditions, it doubles its weight in 2–4 days, and can reach a yield of 30 t ha-1 year-1in dry matter. It forms a carpet on top of the water and can be found in slow-moving or still waters. Since they are resistant to a wide range of nutrient concentrations, they are also suitable for cleaning wastewater (such as eutrophicated lakes, sewage reservoirs, liquid manure storage). Fish feed is the primary nutrient source for aquaponic systems, which usually contains fishmeal. If duckweed can be used as an alternative for fishmeal in the feed, it could improve the sustainability of the aquaponic and aquaculture systems. In this study, the aim was to develop an optimal harvesting protocol for duckweed Spirodela polyrhiza under aquaponic conditions. In a four weeks experiments, four harvesting protocols were set up, a control where only biomass measurements were made, a 25% group where 25% of the biomass at the time of measurement was harvested, and a 50% and a 75% group where at the time of measurement 50% and 75% of the biomass was harvested. Three replicates were used per treatment. We weighed the biomass every week and removed the amount corresponding to the group. Based on the preliminary results, it can be said that more biomass was obtained in the groups with the 25% harvesting protocol and the control group.
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The influence of biostimulators in the growth of some shrubs
49-52Views:178More sensitive than Mimosa pudica and more beautiful than any adornment detached from nature by man, the azalea (Azaleea
indica) gathers through its shapes a real symphony of colours and enchanting hues, of elegant shapes, having no rival in the flower world.
The azalea can multiply through seeds and vegetatively: seedlings, grafting, layering.
The widest reproduction method remains that through semilignified seedlings, a method that can be used throughout the year
avoiding the months less favourable for propagation by seedlings, with poor light: November and October. The best results are given by the
spring propagations by seedlings (February-March) and the summer propagations by seedlings (July-August). The rooting can last for 12-14
weeks until the seedlings can be transplanted in flower pots without risks.
A wide application in horticultural practice is the use of growth substances, that take part in the faster formation of roots and in a
higher percent for species of plants, that, normally, root with difficulty through seedlings. Under this aspect, many synthetical compounds
have proved to be very active (IAA, NAA, IBA, 2,4,5-T acid etc.) (3,4). -
The status of conservation and management of indigenous sheep breeds in South Africa - A review
79-91Views:851Indigenous sheep breeds in South Africa play an important role in local food security and they are adapted to local conditions. Their genetic and cultural values have to be recognised for national importance. The conservation of these breeds is very critical as most of them are already classified as endangered. The South African government has the initiative to attempt the conservation of these animals; however, it comes with several challenges. In addition to funding, breed conservation demands farmers to understand and recognise the role of such breeds in society. This is especially crucial in the rural communal lands where breeds are kept. Farmers that raise indigenous breeds should be taught the necessity of maintaining the purity of these breeds. Indigenous sheep breeds in South Africa are not favored by the commercial farmers and thus they are more vulnerable. This review outlines the nature of sheep farming and the conservation status of four indigenous sheep breeds in South Africa. The effort and challenges that are met in current conservation arrangements are discussed. Moreover, we emphasise on the conservation techniques that are employed in South Africa.
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Ecological Conditions of Agricultural Land Use in Transcarpathia
190-194Views:240The unbalanced anthropogenic effects for several decades resulted in significant technogen damages in the ecosystem of Ukraine. Excessive land development, including the use of slopes, effected the disintegration of the natural balance of lands – arable-lands, meadows, forests, and watershed areas – producing quite a negative effect on the landscape’s nature itself. It has to be stressed that according to other indexes, too, agricultural lands show a tendentious deterioration.
Erosion, caused by water and wind, is one of the most influential factors in the degradation of agricultural soils and in the reduction of the productiveness of benefital lands. Nowadays the degree erosion became significant and it directly endangers the existence of the soil which is a principal chain-link of the agricultural cultivation as well as an irreplaceable element of the biosphere.
The social and political changes in Ukraine’s life demand fundamental modernization in the land utilization both in ecological and in economical aspects. However, these aims can be realized only if, during the developments, we base on the up-to-date results of agronomics, and we do further research in the relations of agricultural land use and environmental protection. According to the latest theories, rational and environmental-safe agricultural production relates to the optimum correlation of the natural- and agricultural- ecosystems as well as to the reconstruction of agricultural areas built on the basis of environmental protection. -
Using integrated remote sensing methods in the Nagyerdő Natura 2000 area
19-24Views:585The more widely use of GIS, remote sensing technology provides appropriate data acquisition and data processing tools to build several national and international biodiversity monitoring system of environmental protection and natur conservation. The ChangeHabitats 2 is a similar international project, which uses airborne hyperspectral and airborne laser scanning (airborne LiDAR) sources beyond traditional data collection methods to build a monitoring system of Natura 2000 habitats. The goal of our research, on one hand, was to separate the most typical species of trees which can be found in the largest coverage in the research plots of Debreceni Nagyerdő Nature Reserve from field and airborne remote sensing data, use image classification that based on spectral and geometry (height) characteristics of the trees. On the other hand our goal was to evaluate the efficient use of the integration of mobilGIS, airborne hyperspectral and airborne LiDAR data collecting methods to complement or substitut of the traditional, field data collecting methods. We used ArcGIS 10.2 and Exelis 5.0 GIS software for data evaluation, in which the mosaicing, the selection of plots and the spectral image processing were carried out.