6 resultados para Soil fertility evaluation

em Aquatic Commons


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Despite the expenditure of huge amounts of money and human effort, the Green Revolution has largely failed to benefit the vast majority of the rural poor in Africa: those smallholding farmers who sell little, if any, of what they grow and rely almost entirely upon natural soil fertility, rainfall and traditional broodstock and seed varieties. New approaches on food production and income generation in the rural areas must be found if this sector of agricultural community is to be assisted. Integrated resources management (IRM) in general, and integrated agriculture-aquaculture (IAA) in particular, may offer some solutions in cases where the classical methods of improving farm output have failed and/or been unsustainable.

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Different problems have been created on the downstream territory, especially on Bheramara on the bank of mighty river Padma. The study is preferred to assess the impacts on river flow of Ganges water, and on fisheries, agriculture, irrigation, groundwater, livelihood, and biodiversity because of Farakka Barrage. Information were collected from various respondents among which 42% is farmer, 12% is fisherman, 36% is businessman and 10% is service holder. It is evident from this study that 65% of crops production were directly affected by Farakka Barrage, in which 34% crops were damaged due to scarcity of water, lowering the ground water level, less access to rainwater, etc. and 66% crops were invent for increasing char land, increasing soil fertility for the use of agrochemicals. Irrigation has been adversely affected because of 35% insufficient flow of water and 65% lowering the ground water level.

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The purpose of the project is to improve our understanding about best management practices that can be utilized on diked managed wetlands in Suisun Marsh for reducing the occurrence of low dissolved oxygen (DO) and high methylmercury (MeHg) events associated primarily with fall flood-up practices. Low DO events are of concern because they can lead to undue stress and even mortality of sensitive aquatic organisms. Elevated MeHg levels are of concern because MeHg is a neurotoxin that bio-magnifies up the food chain and can cause deleterious effects to higher trophic level consumers such as piscivorous fish, birds, and mammals (including humans). This study involved two years (2007-2008) of intensive field data collection at two managed wetland sites in northwest Suisun Marsh and their surrounding tidal sloughs, an area with prior documented low DO events. In addition, the study collected limited soils and water quality field data and mapped vegetation for three managed wetland sites in the central interior of Suisun Marsh, for the purpose of examining whether wetlands at other locations exhibit characteristics that could indicate potential for similar concerns. In Year 1 of the study, the objective was to identify the baseline conditions in the managed wetlands and determine which physical management conditions could be modified for Year 2 to reduce low DO and MeHg production issues most effectively. The objective of Year 2 was to evaluate the effectiveness of these modified management actions at reducing production of low DO and elevated MeHg conditions within the managed wetlands and to continue improving understanding of the underlying biogeochemical processes at play. This Final Evaluation Memorandum examined a total of 19 BMPs, 14 involving modified water management operations and the remaining five involving modified soil and vegetation management practices. Some of these BMPs were previously employed and others have not yet been tested. For each BMP this report assesses its efficacy in improving water quality conditions and potential conflicts with wetland management. It makes recommendations for further study (either feasibility assessments or field testing) and whether to consider for future use. Certain previously used BMPs were found to be important contributors to poor water quality conditions and their continued use is not recommended. Some BMPs that could improve water quality conditions appear difficult to implement in regards to compatibility with wetland management; these BMPs require further elaboration and feasibility assessment to determine whether they should be field tested. In practice for any given wetland, there is likely a combination of BMPs that would together have the greatest potential to address the low DO and high MeHg water quality concerns. Consequently, this report makes no sweeping recommendations applicable to large groups of wetlands but instead promotes a careful consideration of factors at each wetland or small groups of wetlands and from that assessment to apply the most effective suite of BMPs. This report also identifies a number of recommended future actions and studies. These recommendations are geared toward improving the process understanding of factors that promote low DO and high MeHg conditions, the extent of these problems in Suisun Marsh, the regulatory basis for the DO standards for a large estuarine marsh, the economics of BMPs, and alternative approaches to BMPs on diked managed wetlands that may address the water quality issues. The most important of these recommendations is that future BMP implementation should be carried out within the context of rigorous scientific evaluation so as to gain the maximum improvement in how to manage these water quality issues in the diked managed wetlands of Suisun Marsh.

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This is the Wetland resource evaluation and the NRA's role in its conservation: Classification of British wetlands report produced by the National Rivers Authority in 1995. This R&D document provides a clear classification for wetlands in England and Wales. The classification incorporates many of the existing ideas on the subject but avoids some of the problems associated with other classifications. A two-layered 'hydrotopographical' classification is proposed. The first layer identifies situation-types, i.e. the position the wetland occupies in the landscape, with special emphasis upon the principal sources of water. The second layer identifies hydrotopographical elements, i.e. units with distinctive water supply and, sometimes, distinctive topography in response to this. This system is seen as an independent, basic, classification upon which it is possible to superimpose additional, independent classifications based on other features (e.g. base-status, fertility, vegetation, management etc.). Some proposals for such additional classifications are provided.

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Physical characteristics of waterlogged and saline soils of five districts, namely Rohtak, Faridabad, Gurgaon, Sonipat and Jhajjar, of Haryana were studied to evaluate the aquaculture potential. The soil samples from 76 sites were procured and analysed for pH, electrical conductivity, soil particles and water retention capacity, since the knowledge of these parameters is essential for the preliminary evaluation of a site for aqua-farming. Six soil types were identified and clay-loam was observed to be the maximum at 45 (59.21%) sites, followed by silty-clay loam at 14 (18.42%), sandy-clay loam at six (7.89%), silty-loam at four (5.26%), sandy-loam at four (5.26%) and loam at three (3.94%) sites. The pH of soil indicated moderate to high alkaline conditions ranging between 8.01and 9.00 at 53 (69.73%) sites, 9.01 and 10.00 at 17 (22.36%) sites, and low between 7.01 and 8.00 at six (7.89%) sites. The electrical conductivity was found to range between <1 and 10 mmho cmˉ¹ with the value of <1.0 mmho cmˉ¹ at 36 (47.36%) sites. The water retention capacity was observed mostly to be moderate. The paper describes the interrelationship between these parameters with reference to the suitability for aqua-farming.

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The study was carried out by measuring plant height, length of leaves, width of the leaves, length of inflorescent, length of inflorescent tip were also measured with a measuring tape. Number of tillers per plants was counted. Soil auger was used to take soil samples randomly from ten different locations in Tomas Dam Kano states Nigeria. At the depths of 0-5cm, 5cm 13 10cm, 10cm 13 15cm. The soil samples were put into polyethylene bags and labelled according to their depth for mineral analyses. In the two season calcium, nitrogen and phosphorus constitute the highest concentration of the minerals at 0 155 cm depth. There is no significant differences in terms of mineral composition between wet season and dry season. (P<0.005).There is significance differences between plant Length of inflorescent and length of inflorescent tip when the two season are compared. KEYWORDS: Typha grass, field, agronomic evaluation,