Introduction:
The need to irrigate with waters high in sodium and soluble salts for use in agriculture has increased due to the understandable interest many societies have placed in storing fresh water resources – especially in areas with dry and semi-dry climates (Jalali & Ranjbar, 2009). Furthermore, disposing of nutrient-rich effluents to rivers, lakes and oceans can have serious environmental impacts such as water contamination and eutrophication (Balks et al., 1998). From these concerns arises the emerging trend to use wastewater (from agricultural, industrial or sewage sources) towards land applications (Halliwell et al., 2001). Although this solves the immediate concern of water body contamination, wastewater irrigation comes with its own set of problems if not carefully managed: degraded soil structure, increased erodibility, and decreased hydraulic conductivity, aeration and infiltration rates. These serious consequences affect soil tilth and can lead to decreased crop production (Güler et al., 2013). Although it has been previously suggested that the extent and severity of salt effected soils are relatively minor, more recent estimates state that 0.9 x 109 ha of soil in 75 different countries globally are affected in varying degrees to salinity and sodicity (Chi et al., 2011). Wastewaters contain many different organic and inorganic materials which can differ significantly from those found in irrigation waters that were traditionally applied (Halliwell et al., 2001). The presence of these effluent materials effectively increases the risk of encountering salinity and/or sodicity problematic soils. Soil salinity is defined as the occurrence of soluble salts in the soil solution while soil sodicity is the occurrence of sod...
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...lectrophoretic mobility of clay domains. However, at ESP percentages of less than 15-25%, clay domains are able to remain intact through a process called “demixing” – resulting from a non-random redistribution of calcium and sodium ions on clay domains. On the other hand, if the ESP increases well past levels of 15-25%, then platelet separation within the clay domains occurs. Macroscopic swelling increases sharply in these cases. Because of the demixing phenomena, swelling only occurs at high ESP values while dispersion is more dominant at lower ESP values (Halliwell et al., 2001). Swelling is the primary soil physical process associated with high exchangeable sodium percentages. The size of interaggragate pore spaces are markedly reduces following swelling. This results in a significant decrease in hydraulic conductivity and infiltration rates of affected soils.
Mississippi has a variety of different soils .The three general soils are 1) the river flood plain, known as the Delta, 2) a loess region, or bands of soils formed in windblown material that adjoins the Delta, and 3) Coastal Plain. The Mississippi Delta is better for growing row crop, while the loess and Coastal Plain region are better for animal production and forestry. The loess and Coastal Plain regions are divided based on similar soils, geology, climate, water resources, and land use called Major Land Resource Areas. The Mississippi Delta’s soil comes from sediments left by flooding various rivers in the region, rather than being a typical Delta formed by the mouth of a river. In the Delta most of the land is farmed, with three-fourths of the cropland to the north. Controlling surface water and drainage are major soil management issues. In the Delta soils are naturally diverse because of their alluvial origin. Particle sizes within the sediment decrease as distance from the originating stream increase. Another factor in Delta soil formation us surface water movement over time, because soils that formed under standing water have different properties than soils formed under moving water. Soils with large amounts of clay particles have unique features. When the soil is dry, small round aggregates form at the surface that look like shotgun buckshot, which is where the popular name for Delta clay soils “buckshot” came from. Soils with large clay content have very slow water filtration rates; this has led to significant aquaculture and rice production in the region. When floodwaters receded in the Delta, strong winds blew some of the dry sediment left by flooded river to the adjacent uplands to form the loess areas. Because of eas...
These soils are not as developed as other soil orders. Some soils that are categorized within Inceptisols that are common to this area are: Commerce, Mhoon, and Sharky. Commerce soils are found on the levee, composed of sand and silt, and are well-drained. Mhoon soils are found on the lower levee, composed of silty clay, and are poorly drained. Sharky soils are found in the backswamps, are very high in clay, and are poorly drained. However, there is a small portion of the western part of the parish that is of the Alfisol soil order. Alfisols are more developed than Inceptisols in such a way that there are more horizon distinctions that are visible. In the subsoil, there is an accumulation of clay and a dense layer which prevents a lot of leaching of materials from the surface. These soils tend to have the presence of aluminum and iron oxides throughout the soil profile. All the soils that are in this region each support different types of
As we have observed throughout the centuries, colonialism has immensely shaped the majority of countries of modern society. In the essay “The Impact of Colonization and Western Assimilation on Health and Wellbeing of Canadian Aboriginal People”, Cathy MacDonald & Audrey Steenbeek developed significant points that reflect as connections to the essay “Virgin Soils Revisited” emphasizing the devastating impact colonialism has had on the wellbeing and health initiatives imposed on the Native Americans and the Aboriginal people of Canada to this day. Both indigenous populations have endured the hardships of poor health, racial issues such as oppression, and cultural assimilations due to the long-lasting effects of colonialism.
Aquatic plants that are sensitive to high levels of salt are likely to die because the salt absorbs the water, causing plant cells to shrivel and die (Gould). When amphibians and other semi-aquatic freshwater organisms swim in salty water they too shrivel up and die, similar to a slug covered in salt (Siegel). Salt running into bodies of water is disrupting the food chain and killing thousands of organisms every day. Sodium chloride is the effective ingredient in both table salt and road salt (Rastogi). The only difference is that road salt is unfiltered and unpurified.
Describe the types of farming that occur in the savannah biome in the Sahel region.
The problem of water shortage is one of the major limiting factors in food production and agriculture development in the arid and semi arid regions. Reclaimed water is one of the most significant available water resources that shall be consumed in agriculture and urban landscape maintenance. In order to investigate the impact of water quality and its application method on olive trees this experiment was carried out during 2010-2012 in the semiarid central part of Iran on young olive trees. The trees were irrigated by a new subsurface-leaky irrigation (SLI) system and surface irrigation in line with irrigation with recycle and clean water for 24 months. The results revealed that SLI system could enhance trees growth, leaf area, Fv/Fm and photosynthesis by68, 26, 4 and 42% respectively, although it decreased leaves soluble sugars (47%). In addition, irrigating trees by SLI system using reclaimed water could increase N and Mg uptake 138 and 8% respectively. Plants irrigated with RW showed improved growth (42%) leaf area26% and photosynthesis 23.4% compared with CL water. Furthermore Mg, Na, K, P and N surprisingly increase 12, 59, 30, 7, and 92 % respectively in leaf tissue in application recycle water. In overall, this experiment showed that recycled water could be a favorable resource for olive trees irrigation and SLI irrigation system was more efficient in irrigation in this research.
The differences seen in the soil may be due to addition of carbon/ nitrogen which can change and alter the C:N ratio. The greater C:N ratio the more extracellular polymers are released which help hold the aggregates together and better its stability. The lower the C:N ratio the worse the aggregate stability and the faster the aggregate will crumble away as can be seen in both a slaking test and the alfalfa treatment.
NaCl can dramatically affect the plants growth, it can either increase or decrease its growth cycle. Sodium decreases soil permeability, which reduces the flow of water affecting its germination. Sodium is not absorbed by plants, however, chloride is. Chloride damages the plants tissue resulting in the reduction of growth, it also dehydrates plants through osmotic stress. Osmotic stress decreases the amount of nutrients absorbed by plants slowing down the growth and development (Taiz, & Zeiger,
Uehara, G. and G. Gillman, 1981, The Mineralogy, Chemistry, and Physics of Tropical Soils with Variable Charge Clays: Boulder, Colorado, Westview press.
I am particularly surprised how the agricultural industry inflicts these problems on themselves, by excessive use of sewage systems and pollutants which find their way to local rivers [Fig 1.]. The trophic state (i.e. the natural nutrition factors) and biodiversity of lakes and rivers are greatly effected by the main nutrients involved, nitrates and phosphates. The transition occurs mainly between a mesotropic state, with an average biological productivity to a eutrophic state where there is a larger production of organisms due to high nutrient concentrations. Tropical reservoirs in particular often become eutrophic.
Agriculture also leads to soil erosion, both through rainfall and wind. This soil can damage the aquatic ecosystems it ends up in, an...
There are countless sources of water pollutions that exist today due to our industrious and technologically advanced lifestyles. However, the most vexing is caused by the most basic necessity for survival, Agricultural Pollution. Agricultural Pollution is defined as, “ liquid and solid wastes from all types of farming activities, including run-off from pesticide and fertilizer use, and from feedlots; erosion and dust from ploughing; animal manure and carcasses; and crop residues and debris. In essence Agricultural Pollution is a nonpoint source water pollutant since it comes from various locations and cannot be pinpointed” (EPA-web). Although there are many practices already in place that will decrease the pollution, increase productivity, and save farmers money in the long run, the farmers are careful to change practices.
The article evaluates the efficiency, effectiveness, social, economic and environmental impacts of the drip irrigation system. The drip irrigation system has the potential to increase the agricultural productivity and also to reduce water usage required for irrigation. It is a system of pipes and tubing located under the soil. Water is passed through these pipes which end at near the roots of the plants. This makes the water loss minimal. Initial stage is designing the system and its installation follows it. The article states the advantages and disadvantages of the system and also cites evidence with regard to the social, economic and environmental aspects.
Soil salinity is said to be “bad” for plant growth but is this really true? Is it just a big misunderstanding? Is it really the salts 'fault'? Are there no solutions to fixing this problem? These are some of the questions many people should be asking before deciding if salt is a friend or foe. Instead of just following whatever others say, people should know exactly how soil salinity is affecting crops and why this is happening. To know our enemy, in this case 'the salt', experiments has to be done, results must be gathered and processed and there must be an explanation to understand the different outcomes and results. We decided to find out everything about soil salinity and how it affects plant growth because plants are a huge part of our life, we live and breathe because of them and we want them to flourish. First, these are some information and questions that will make it easier to understand the whole concept altogether.
Urbanization: Soil is considered as water reservoir. Urbanization acts in creating amount of impermeable surface due to construction of buildings, roads, drainage, sewage, flood relief channel etc. It reduces the amount of infiltration and percolation. Water tends to experiment the runoff process rather than infiltration. This contributes to increase in