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Assessing soil properties and tidal behaviors as a strategy to avoid environmental degradation in developing new paddy fields in tidal areas

Assessing soil properties and tidal behaviors as a strategy to avoid environmental degradation in developing new paddy fields in tidal areas
Agriculture, Ecosystems and Environment
نام ژورنال: Agriculture, Ecosystems and Environment
نویسنده یا نویسندگان مقاله: Markus Anda, Djadja Subardj
زبان: انگلیسی
سال انتشار یا تایید مقاله: 2013
شماره صفحات: 90-100
فرمت فایل: PDF
حجم فایل: 1.31 مگابایت
شناسه DOI:
قیمت: رایگان
   
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Fluviomarine areas are promising for development of new paddy fields if fragile soil properties, natural water logging and tidal behaviors receive strategic management to avoid environmental degradation. Three transects were established to investigate the complexity of sediment and tidal attributes. Soils were sampled from each horizon of profiles and key mineralogical and chemical properties analyzed. An upper fluvial derived zone was characterized by exchangeable Ca as the dominant cation (decreasing concentration with depth) and pyrite was absent. A lower zone derived from marine sediment was dominated by exchangeable Mg (increasing concentration with depth) accompanied by pyrite. The dominance and distribution of Ca and Mg indicate the origin of sediment in tidal areas. These acid sulfate soils have limited nutrient reserves being dominated by quartz in the sand fraction. The clay was dominated by kaolinite and illite and a variable proportion of vermiculite, resulting in variation of CEC values, being high with vermiculite. Pyrite position from soil surface varied from 25 to 100 cm (mostly 50–60 cm) depending on thickness of fluvial zone and local slope morphology. Significant variations in tidal amplitudes led to the separation of fluviomarine areas into neap-spring tide zone (NSZ), spring tide zone (SZ) and non-flooding tide zone (NZ). Zoning allowed the selection of the SZ with low tidal amplitude and NZ as being suitable for new paddy field development. A potential drop of soil pH from 5 to 2 may occur with serious consequences for paddy field and watercourses (huge acidity and dissolved metals at toxic levels) if pyrite is exposed to oxidation conditions (e.g. drainage system lowering water level below pyrite position). Water management through “controlled drainage” should be applied to avoid pyrite oxidation, soil degradation and poor water quality. This includes dimension (depth and width) of drainage canals and maintaining water levels above the pyrite zone through control using floodgates thereby ensuring pyrite zone remains under reducing conditions.