Student Essay Example
LABORATORY REPORT: MUTTAMA CATCHMENT
Different soil and water properties were analysed. By examining the effect of land management on the soil as well as the effect these activities have on the potential of eutrophication, conclusions were drawn about the state of the soil and the physiological effects of salt on a plants and animal life . Based on all data we have tested and the nature of the land of Muttama catchment, we hypothesize that increased flooding will lead to increased eutrophication which will have an effect of increasing the plant growth. The assessment of both water and soil eutrophication has been concluded by taking into account simple individual parameters like total nitrogen, total phosphorus etc. Different soil samples from different sites will be analysed for different qualities so as to determine how the varying salt concentrations, so too will the water. For all variables, increased salinity was found to have a negative effect on plant growth which served to negate the potential of eutrophication. This suggests that either the contents of the soil or the properties of the water negatively affect growth in plant cells.
Laboratory Report: Muttama Catchment
The objective of this lab report is to discuss the problems of salinity and the potential for eutrophication in the Muttama catchment. The specific categories selected to test the water samples were total nitrogen, total phosphorus, dissolved oxygen, dissolved organic carbon, alkalinity, and PH. The soil samples were also tested and the categories included: total soil carbon and nitrogen, total soil phosphorus, PH and EC, soil available P and N, e-CEC and ESP, and soil texture. The importance of analysing the relationship between several of the categories cannot be understated as they hold the key into answering conclusively, whether the potential of the eutrophication is undermined or otherwise. While eutrophication results in the nutrient enrichment of waterways, poor land management can result in catastrophic effects for the practice of agriculture where control of catchment processes needs to be stabilized, as the deterioration of water quality leads to poor water use. The major influence on the water eutrophication is a combined complex function involving these very same factors. Eutrophication can be accelerated by human activities and hence further waste (Gerritse et al. 1990; Skogen et al. 2004). The use of chemical fertilizers and detergents lead to increased nitrates which will result to accelerated eutrophication. The rivers and the ponds are filled with not only these nitrates but also the phosphates that are washed up to these bodies of water in sufficient quantity. This will have the effect of making water bodies shallow as the plants will increase and start choking the water bodies and the increased nutrients as the effect of animals in these bodies of water suffocating as the oxygen is limited and most of the fish and molluscs will eventually die.
Other human activities that have the effect of accelerating the eutrophication process include: the clearing of forests, human settlement, building of cities and industries. These activities have led to increased nutrients in the catchment and the eutrophication process has had both economic and social problems (Huisman & Hulot 2005). High percentages of catchment clearing have been responsible of the catchment areas losing nutrients to waterways.
The loss of these nutrients is also affected by the natural characteristics of the soil in the catchment areas. Some of the characteristics affecting the soil include the soil texture, the presence and amount of calcium compounds as well as iron.
The data also points to the fact that the catchment area as shallow water table level meaning that the area will run the risk of flooding as the increased soil salinity have a quite limited capacity to absorb rainfall. In highly saline soil chloride and Sodium are the most dominant ions by quite the margin. While these soils may still contain magnesium and calcium that are in quantities sufficient enough to provide the nutrients needed by the crops, they may contain appreciable quantities of gypsum. The Soluble carbonates are never present in these soils while the value of the saturated soil will always be less than 8.2, which is actually pretty close to neutrality. Hence the lack of soluble carbonates these results to a small change in the pH which has an effect of leading the water bodies to become eutrophic due to the lack of dissolved oxygen.
In the assessment of water eutrophication the concentrations of total phosphorus and total nitrogen are usually taken as the basic ones, however other chemical and physical evaluation parameters may also be taken into account and they might include: pH, and Dissolved Oxygen among others.
Soil salinity can be measured in several different ways. You can first use electrical conductivity (EC) which measures the conductivity of the soil solution or rather its ability to conduct electricity which is measured in (ds/m). Another method of measuring soil salinity is Total Soluble Salts (TSS) which refers to the total amount of soluble salts in the solution that is a soil –saturated paste and is expressed in milligrams per litre or parts per million (mg/L or ppm). Other less used but still relevant methods includes Sodium Adsorption Ration (SAR) and Exchange Sodium Percentage (ESP).
Methods and Equipment
Necessary materials: Plastic jars with screw-on lids, Portable handheld EC meter, 3 soil samples from each site, recording sheet and pen.
The process of conducting tests and determining the issues with salinity and eutrophication entailed using in situ testing equipment, which focused on measuring the components for determining salinity of the subject catchment area. For this exercise, field tests as well as laboratory tests were conducted to water, plant and soil samples from the area. Therefore, the equipment used in the field during sampling and testing included calibrated gauges for measuring salinity, conductivity, total dissolved solids, and temperatures of soil and water samples. For the alkalinity measurement of samples, different ion sensors were used with help from pH-Indicator paper to determine what values the concentrations of the ions imply. The map below shows the area of focus form which the samples were obtained.
Upon collection of the samples from the sites, they were checked with accompanying information list, which included records of dates, number, depths and samples obtained. To avoid any potential changes with the samples, soil samples that were collected for the purpose of salinity analysis and determination of potentials for eutrophication were analysed directly. Therefore, activities such as drying and preparation of the soil samples for analysis were conducted successively. In this instance at the laboratory, electronic oven with thermostat was used. The table below shows the soil samples and the sites from which they were obtained, as have been also demonstrated on the previous map.
The EC meters electrodes, which are some of the equipment used during this exercise, are rinsed in distilled water and dried gently with a piece of tissue. The electrodes should be also moved around to eliminate bubbles which would have reduced contact with the water being measured and electrodes. The temperature of the electrodes should also be put in check at temperatures of 25 degree Celsius as they can offset the readings you take. The reading is then taken by immersing the electrode in the 10ml of water you collected or if you allowed it to settle without filtration, on the settle soil. In such a situation you should avoid electrode contact with the soil or at least minimize it.
The other soil and water properties are measured by using the collected soil samples where the nutrients are concentration of nitrate and phosphorus which are determined by the colour comparator. In the case of pH, accurate measurements are only taken by a pH meter that has a glass rode.
Results and Analysis
The landscape of the catchment area has formed on recent quaternary alluvium. Parent materials of the catchment area consist of gravel, sand, silt, and clay deposits. The topography of the area generally depicts narrow alluvial plains, terraces and current floodplains with gradients of <1%. The average elevation range for Muttama catchment area is 240-260 with general rise of a range between 315m and 340m towards north of Coontamundra. The place also features a relief of <9m towards the north with a deep, alluvial and non-tributary stream channels. The climatic zone of the area can be described as 2C with extensively cleared eucalyptus woodlands as the major vegetation. The following table shows the physical summary of the Muttama catchment area.
Drainage and depth
100cm with 45cm for rooting
100cm with 70m as the rooting depth
20cm with <20cm rooting depth
Particle distribution, water holding capacity, and soil moisture content
The soil moisture of the Muttama catmint area, based on the depth of the sample sites, ranges from moderate to imperfect considering that soil is shallow. With alluvial as the main constituent of the area landscape, temperatures are relatively high. With the shallow depths, the area has considerably high water retention capacity due to impermeable feature of the texture characterised by compactly distributed particles.
The analyses conducted for this stage focused on determining the major non-mineral macronutrients and primary macronutrients. Dry-plant weight such as carbon (C) was explored and tested for in this experiment. Nitrogen (N) and Phosphorus (P) were the major focus for macronutrient testing, which also supported in determination of salinity properties of the catchment area. The processes to determine the concentrations of nitrates and phosphates, amongst other constituents of the subject soil, form the solutions of the samples resulted on the following values.
The above absorbance results against concentrations of the macronutrients of the soil samples produced the follwing graph.
A line graph of P concertation values against absorbance potentialFigure 1:
Considering the depth against concentration of the soil, the following distribution line graph was obtained.
Overall, the higher salt concentrations were found to be at the water bodies of the catchment area. This was found to be true for all variables tested, which included soils from the multiple sites. In some soils samples the pH was quite high above the normal as well as the high levels of nitrogen and phosphorus. There were, however, some outliers where there appeared high salt concentration of about 0.37 which supported the growth of plants. There was a relationship identified between the total nitrogen and total phosphorus where it was noted that the concentration of total nitrogen was high if the concentration of total phosphorus was high. This can be explained by the fact that these two nutrients have the same sources. This means that they are both transported to the waterways from land, industries, and urban areas. Although there were small inconsistent parts of the data, they could simply be explained by specific causal reasons as this could account for the scatter related data when you its graph are drawn.
According to the experiment areas that were to within close proximity of waterways reported low levels of phosphorus and this is supported by earlier studies that show eutrophication along the rivers is quite high as the area is prone to erosion and run off. This is also true for the other nutrients that were tested along the river banks. The tables in appendices 1, 2, and 3 illustrate values of alkalinity, organic carbon amount in the area, and water pH results, which were then used to determine implications for the salinity of the area, hence eutrophication potentials.
Eutrophication can be defined as the collective impacts of rapid and excessive growth of phytoplankton, which then result in imbalanced primary and secondary macronutrients in a particular area, hence its productively (Yang et al. 2008). According to Garg et al. (2002), the potential of eutrophication of a particular area is impacted by the different physical and chemical properties of soil or water of a site. Whilst flooding occurs, different soil particles of different characteristic are washed away from certain points of a scape to others. It is these activities that result in different chemical as well as physical properties of the resultant soil, which also describes its salinity (Nielsen et al. 2003; Paerl et al. 2004). Basically, the salinity of water or soil water in a particular area is determined by the concentration of soluble carbon, nitrogen and phosphorus. According to Blomqvist et al. (2004) and Conley et al. (2002), places like seas and oceans, and even soils around such places, tend to have high concentration of nitrogen and phosphorus. This perspective implies that the soil or water is most likely to be saline. However, it can be argued that it can support he excessive growth of phytoplankton to the extent to which imbalance of productively is caused. Inglett & Reddy (2006) explain that features such as porosity, particle distribution, drainage, rooting depth, water retention capacity, and moisture content are some of the factors that would determine whether the temperature and the available primary macronutrients can support plan growth. Therefore, just as determined for the Muttama catchment area, potential of eutrophication is determined by the ability of the soil to regulate its concentration of the concerned nutrients, temperature, moisture contents, and the ability to drain enough water to prevent logging.
For Muttama area, the results of this experiment indicate that the catchment area has potential for eutrophication. The shallow water tables contain high saline water and as a result when the water table rises it should end up bringing salt to the surface, which resulted into the varying results of the soil samples collected in this part of the catchment area. This is because the subsequent runoff later resulted in the salt being pushed back into the waterways. The presence of high phosphorus and nitrogen nutrients in the waterways agrees with the initial hypothesis that their presence will indicate a large potential of eutrophication (Grasshoff et al. 2009). The water creeks and the rivers are the major sources of nutrients. The extensive clearing of vegetation has effects that are never apparent at the given time but this leads to ground water recharge. This leads to water logging and thus there is increased salinity that has a lot of problems associated to it. However, more sensitive organic indicators for evaluating water eutrophication are required to further investigate the potentials of eutrophication and its implication against the salinity properties of the area.
While eutrophication results in the nutrient enrichment of waterways, poor land management can result in catastrophic effects for the practice of agriculture where control of catchment processes needs to be stabilized, as the deterioration of water quality leads to poor water use. The major influence on the water eutrophication is a combined complex function involving these very same factors, which include the concentration of the primary macronutrients, amongst others. Eutrophication can be accelerated by human activities and hence further waste. The use of chemical fertilizers and detergents lead to increased nitrates which will result to accelerated eutrophication. The rivers and the ponds are filled with not only these nitrates but also the phosphates that are washed up to these bodies of water in sufficient quantity. For Muttama area, the results of this experiment indicate that the catchment area has potential for eutrophication. Due to the low depths, the shallow water tables contain high saline water and as a result when the water table rises it should end up bringing salt to the surface, which resulted into the varying results of the soil samples collected in this part of the catchment area. This high salinity is as well caused by the subsequent runoff later resulted in the salt being pushed back into the waterways. The presence of high phosphorus and nitrogen nutrients in the waterways agrees with the initial hypothesis that their presence also indicates a large potential of eutrophication in the area.
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