The Decomposition Of Soil Organic Matter

The use of too much fertilizers, and in particular, of fertilizers with high concentrations of nitrogen, has been linked to reduced biodiversity (Xiankai et al. 2010). It becomes necessary to consider the detrimental effects of high concentrations of fertilizer in the reduced spaces. Fertilizers are salts, and therefore high concentrations of fertilizers can deplete the plant from water.

Poor soil management can lead to biological, chemical, and physical degradation, which can in turn negatively alter the activity of

Vast numbers and kinds of organisms, mainly microorganisms, inhabit soil and depend on it for shelter, food, and water. Plants anchor themselves in soil, and from it they receive essential minerals and water. Terrestrial plants could not survive without soil, and because we depend on plants for our food, humans could not exist without soil either (Wiley, 2013).

The pH of soil is important for the absorption of nutrients into the plant. Of the 17 needed plant nutrients 14 of them are acquired through the soil. Acidity is needed to break down and dissolve these nutrients. The nutrients are able to dissolve into the soil faster when the acid is acting as a solute. Another way the pH affects the soil is by influencing microorganisms. The bacteria is crucial in the growth and development of the plant, the bacteria’s role is to break down and decompose organic matter in the soil. If the pH of the soil is too high the acid will slow down and eventually stop the microorganisms. Most plants ideal pH is between 6-7, slightly acidic. Many plants are outliers and thrive in pH such as carrots and corn, which can withstand pH as low as 5.5. If the pH of the soil is too high for the desired crop farmers can add material such as limestone, and wood ashes to raise the pH to the desired level. The pH of the soil can also be changed naturally through the leaching of calcium, magnesium and sodium by rainwater. Carbon dioxide from rotting organic matter can also increase the pH of the soil. Acids can also be created organically in the form of sulfuric and nitric

A comprehensive investigation on how nutrients in waterways were increasing, was undertaken by a body of individual scientists and their findings were as follows;

Soil turnover - as soil is moved around by digging animals, organic matter is mixed through which distributes nutrients throughout the soil

Bioremediators need to be able to grow in order to remediate the soil of pollutants. The purpose of this research is to determine whether the presence of Stropharia rugoso-annulata in the soil will support and accelerate the growth of ryegrass in a mutualistic symbiotic relationship. If the growth of the ryegrass is accelerated and supported, the combination of the two bioremediators could potentially accelerate the degradation of PAHs in the soil. Techniques such as soil washing, soil flushing, vitrification, etc., exist to remediate contaminated soil. Although, these techniques are effective, they also disturb the natural environment to some degree. Bioremediation is often accomplished in situ resulting in minimal environmental disturbance. This study is being performed because healthy soil is a limited resource that needs to be preserved and replenished. The state of soil can impact the health of humans, animals, and ecosystems, therefore, it’s important to be able to monitor and control the pollutants in

The microbes found in soil go hand in hand with the microbes found in our bodies, especially the gut microbiome. Soil is used to grow various plants and crops which we then ingest. As stated in Healthy Soil Microbes, Healthy People, we have completely destroyed soil microbes by overusing fertilizers and pesticides just like how we have destroyed our gut microbes by ingesting processed foods and large amounts of antibiotics. Soil microbes, including bacteria and fungi, form symbiotic relationships with plant roots to help provide the plant with many nutrients needed to survive. In order to restore and improve the soil once again, we need to reintroduce bacteria and fungi that are capable of repairing the damage. Through recent technological advances, the soil microbiome was genetically sequenced. This allows farmers and other scientists to understand which microorganisms are

Soil respiration is a process which results in the production of carbon dioxide and can be affected by several factors including plant litter and temperature (Biology 208 Lab Manual 2017). With increasing temperatures, the amount of carbon dioxide released during soil respiration will increase (Schlesinger and Andrews 1999). The presence of plant litter in the soil results in increased soil respiration, and results in increased rates of carbon dioxide production (Xiao et al. 2014). This experiment is looking at the effects of temperature and type of plant litter on the rate of soil respiration. For the abiotic factor, we hypothesize that increasing the temperature will positively affect soil respiration rate as it will increase the rate of metabolism of the microorganisms. Soil placed in 30°C chamber will produce more carbon dioxide than the soil placed in the 15°C chamber. For the biotic factor, decreasing the carbon:nitrogen ratio in plant litter will positively affect soil respiration rate by speeding up the rate of decomposition of the plant litter. Therefore, soil with grass will decompose faster and have higher carbon dioxide production than soil with pine needle litter. The interaction between temperature and type of plant litter indicates that soil with grass litter and in a 30°C chamber will have the highest carbon dioxide production.

Glomalin is a type of protein that works as a natural glue preventing soil from washing away. The producer of this protein is a type of fungi, which is torn by tillage during plowing. However, research shows that farming without tillage (silvopastoral systems for example) has the opposite effect because it leads to an increase of fungi and glomalin. The fungi carries minerals to the plants in exchange for carbon, which the plant takes from the atmosphere; therefore grazing areas such as rangelands and pasture lands can play an important part in restoring lost carbon soil (Niman, 28-30). Grass is also capable of producing soil carbon. According to the UK Soil Association, “Grass has high root densities, fine root hairs, and high mycorrhizal fungal levels, all of which increase soil aggregation. Animal manures and compost also promote soil carbon, again reinforcing how including animals in farming benefit carbon sequestration” (qtd. in Niman, 31). Niman concludes that while converting grassland to croplands does cause carbon losses, converting cropland into grass results in carbon gains (Niman, 32). In a study by the University of Maryland, field tests on 6 different continents consistently showed that the areas with grazing animals had a greater plant diversity than those without animals. These scientists argue that “the absence of animals rather

The diversity of soil invertebrates is very important to our ecosystem, because most soil invertebrates are responsible for key soil processes such as nutrient recycling, nutrient retention, formation of soil structure, and decomposition rates. Invertebrates are one of the most dominant groups of animals in the world. Recent studies show that animals may constitute as much as 23% of the total diversity of living organisms (Lavelle et al., 2006).

Erosion removes the surface soils, containing most of the organic matter, plant nutrients, and fine soil particles, which help to retain water and nutrients in the root zone where they are available to plants. Thus it affects the productivity of plants. The remaining, the subsoil, tends to be less fertile, less absorbent and less able to retain pesticides, fertilizers, and other plant nutrients. There are over 17,000 soil types recognized worldwide. They vary widely in structure, erodibility, fertility, and ability to produce crops. A generalized soil profile for a humid, temperate climate is showed. When the natural vegetation is cleared for agriculture, soils become exposed to erosion and loss of soil fertility. The removal of the above-ground natural

The high water content of these soils causes the chemistry to be primarily reducing rather than oxidizing as it is in most other soils. Most of the reactions are mediated by biological activities. Such a chemical environment means that the rate of decomposition of organic matter is relatively slow. The reduced carbon in the organic matter of saturated soils is the source of energy and electrons to drive the redox reactions (Schipper et al, p. 923). Under slightly reducing conditions, the process of denitrification breaks down nitrate (NO3-) into N2 "through intermediates including nitrite (NO2) and N2O" (McBride, p. 265). Under strongly reducing conditions, some of the N2 is transformed into NH4- through plant enzyme-catalization in a process called nitrogen fixing. Reducing conditions also change sulfate (SO42- ) into H2S a noxious smelling gas. Much of the hydrogen sulfide is dissolved and dissociated in the water where the sulfide interacts with Fe2+ form iron sulfides. In more moderately reducing conditions the iron can be contained in siderite (Fe CO3). In both instances the solubility of iron is greatly reduced (McBride, p. 266). Saturated soils tend to decompose organic matter slowly, transform nitrates, and reduce the solubility of metals such as iron. The reduced iron results in gleying (greyish-green coloration) of the soil and in the case of fluctuating water levels mottles

Biogeochemical cycles are important to the sustainability of all life. Chemical elements necessary for the growth and reproduction of all organisms have a limited quantity on earth at any one time, other than the occasional meteor that brings with it new matter. It is therefore important that the recycling of these chemical elements is efficient. Autotrophs are the basis of almost all ecosystems. The rate that autotrophs produce and transfer energy is vital to the capacity of organisms that can inhabit these ecosystems. To understand the rates in which certain species’ leaves decay and release the energy stored within them can demonstrate how quickly the energy becomes available to organisms in higher trophic levels.

From a practical point of view, anionic polyacrylamide (PAM) has been commonly used as a soil conditioner to reduce erosion by clay flocculation and binding particles and stabilizing the outer aggregate surfaces. Moreover, PAM is highly resistant to microbial degradation, with a decomposition rate of ∼10% yr-1, which has led to its efficient use as a soil conditioner for long periods. Wu et al. (2012) revealed that PAM showed a minor effect on 14C allocation in plant parts and soil in a short-term 14C labeling study. Except the observations of PAM biotransformation, little information is available on the PAM efficiency on the microbial activity in soils. In contrast, the agronomic benefits of biochar (BC) application to improve soil quality and increase SOM is growing. Applying BC improves the physicochemical properties of soil and maintains C and N sources, owing to a pronounced increase in plant growth and yield. Moreover, wood biochar decreased the soil bulk density and enlarged diameter of aggregates, thereby reducing soil loss. However, little is known about the effect of BC on soil microbial populations and activities. BC or PAM showed minor effect on the decomposition of SOM based on CO2 evolution because of the stability of these conditioners. A high portion of 14C- maize residues were stabilized in the soil after adding BC and PAM as the binders by the occlusion of labile residue-C into aggregates. Understanding the short-term dynamics of C caused by PAM or BC is