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In drainage research the collection and analysis of field data is important. [ 5 ] In dealing with field data one must expect considerable random variation owing to the large number of natural processes involved and the large variability of plant and soil properties and hydrological conditions.
Surface drainage systems are usually applied in relatively flat lands that have soils with a low or medium infiltration capacity, or in lands with high-intensity rainfalls that exceed the normal infiltration capacity, so that frequent waterlogging occurs on the soil surface. Subsurface drainage systems are used when the drainage problem is ...
In addition, land drainage can help with soil salinity control. The soil's hydraulic conductivity plays an important role in drainage design. The development of agricultural drainage criteria [3] is required to give the designer and manager of the drainage system a target to achieve in terms of maintenance of an optimum depth of the water table.
Emphasis continues to grow on the importance of soil sustainability. Soil degradation such as erosion, compaction, lowered fertility, and contamination continue to be serious concerns. [1] They conduct research in irrigation and drainage, tillage, soil classification, plant nutrition, soil fertility, and other areas.
It takes decades [116] to several thousand years for a soil to develop a profile, [117] although the notion of soil development has been criticized, soil being in a constant state-of-change under the influence of fluctuating soil-forming factors. [118] That time period depends strongly on climate, parent material, relief, and biotic activity.
The weight of casts produced may be greater than 4.5 kg per worm per year. By burrowing, the earthworm improves soil porosity, creating channels that enhance the processes of aeration and drainage. [17] Other important soil organisms include nematodes, mycorrhiza and bacteria. A quarter of all the animal species live underground.
Watershed delineation is the process of identifying the boundary of a watershed, also referred to as a catchment, drainage basin, or river basin.It is an important step in many areas of environmental science, engineering, and management, for example to study flooding, aquatic habitat, or water pollution.
The primary method of controlling soil salinity is to permit 10–20% of the irrigation water to leach the soil, so that it will be drained and discharged through an appropriate drainage system. The salt concentration of the drainage water is normally 5 to 10 times higher than that of the irrigation water which meant that salt export will more ...