2.0 MEANING OF SOIL USE
Soil is the top layer of the earths surface in which plant can grow, consisting of rock and mineral particles mixed with decayed organic matter and having the capability of retaining water
POLLUTANT ON SOIL USE
Soil contamination or soil pollution is caused by the present of venotiotic (human –made) chemicals or other alternation in the natural soil environment. It typically caused by industrial activity, agricultural chemicals or improper disposal of waste.
The main mason why the soil become contaminated is due to the presence of man made waste. The waste produced from nature itself such as dead plants, carcasses of animals and rotten fruits and vegetable only add to the fertility of the soil. However, our waste products are full of chemicals that are not originally found in nature and lead to soil pollution
With the rise of concrete buildings and roads, one part of the earth that we rardy see is the soil. It has may different names, such as dirt, mud and ground. However, it is definitely very important to us. The plants that feed us grow in soil and keeping it healthy very important to us. The plants that feed us grow in soil and keeping it healthily is essential tomaintaming a beautiful plant, however, like all other forms of nature, soil also suffers from pollution. The pollution of soil is a common thing these days, and it happens due to the presence of man activities.
The waste produced from nature itself such as dead produced from nature itself such as dead plants, carcasses of animals and rotten fruits and vegetables only adds to the fertility of soil. However, our waste products are full of chemicals that are not originally found in nature and lead to soil pollution.
MAIN CAUSES OF SOIL POLLUTION
1. Industrial Activity: Industrial activity has been the biggest contribution to the problem in the last century, especially since the amount of miming and manufacturing has increased. Most industries are dependent on extracting minerals form the earth. Whether it is iron over or coal, the by products are contaminated and they are nod disposed off in a manner that can be considered safe. As a result , the industrial waste lingers in the soil surface for a long time and makes it unsuitable for use
2. Agricultural Activities: Chemical utilization has gone up tremendously since technology provided us with modern pesticides and fertilizers. They are full of chemicals that are not produced in nature and cannot be broken down by it. As a result, they seep into the ground after they mix with water and slowly reduce the fertility of the soil. Other chemicals damage the composition of the soil and make it easier to erode by water and air. Plants absorb many of these pesticides and when they decompose, they cause soil pollution since they become a part of the land.
2.2 EFFECT OF SOIL USE TYPES ON SOIL FORMATION
The three primary textual classes of soils are basically a product of the mineral make-up of the soil. This further depends on the parent materials other factors that influence soils formation includes climate, topography, animals and vegetation (Adams et al, 1999).
On rocks and rock debris, plant growth begins with mosses and llichens, which help to statulge the loose materials by hiding and reducing wind speed over the surface. Furthermore, dead plants becomes incorporated in the young soil together.
As a young soil deepens, large are able to develop. Their roots help stahilne the soil further and along with carbonic acid they produce, extend the depth of weathering soils. Adams et al (1999) added that although the process can take very long time, its speed in increased when the particle becomes finer and living organisms becomes established. Finally, the type of parent material determines the specific type of soil formed, for instance, guards mineral forms sand soil while limestone forms clay etc
EFFECT OF SOIL USE TYPES ON SOIL PROPERTIES
Legume vegetation cover improve soil phosphorus. This is supported by Agboola (1975) who reported that in Nigeria, a single season intensive follow with crotalorie specie, succeeded in increasing the available phosphorus content of a field soil from 7.8kg /ha to 12.1kg/ha. In another experiment, under sowing legumes in maize reduced the uptake of available phosphorus by some 50% within four growing seasons. Agbola and Feyemi (1972) concluded that the legumes were able to keep the phosphorus in an increase as the clay content increases. This increase depends on two mechanisms. First, bonds between the surface of clay particles and organic matter retard the decomposition process. Second, soils with higher clay content increase the potential for aggregate formation.
Macro aggregates physically protect organic matter molecules from further mineraligation caused by microtonal attack for example, when earthworm casts and the large soils particles they contain are split by the joint action of several factors. (climate, plant growth and other organisms), nutrients are released and made available to other components of micro-organisms under similar climate conditions, the organic matter accumulation not only through its effect on soil texture (Mcgary, 1996). Soils developed from inherently not material, such as basalt, are more fertile than soils formed from granitic material, which contains less mineral nutrients.
EFFECT OF SOIL USE TYPE OF SOIL PH
In principle, trees and shrubs can reduce the acidifying effect of leaching young (1982) reported that whether tree litter can be a significant means of raising PH on acid soil is doubtful, owing to the order of longitude involved, expect through the release of bases that have been accumulated dung many years of tree growth, as in forest clearance or the (Chitemene ) system of shifting cultivation. Young (1982) further stated that the situation is different with respect to checking acidification. in the first place, if the tree compocont is employed as the means l for fertility maintenance, then no trend towards acidification, this is in order of 0.1 PH point per year. The recycling of bases in trees litter could quite probably be sufficient to counteract an effect of this magnitude.
Soil PH or soil units. The PH scale goes from 0 to 14 with PH7 as the neutral point. As the amount of hydrogen ions in the soil increases, the soil PH decreases, thus becoming more acidic, and l ;from PH 7 to 14, the soil is increasingly more alkaline or basic. According to Vermeer (1996), a soil PH of 6 has 10 times more hydrogen ion than a soil PH lern adrerse to crop growth ion occur naturally in some regions, it can also be indued by acid rain or soil contamination from acid or bases. With bread et al, (1998) supported this view by stating that the role of soil PH is to control nutrient availability to vegetation
The principal macro nutrients (calcium, phosphours, nitrogen, potassium,, magnesium, sulphur) prefer neutral to slightly alkaline soils, calcium, magnesium and potassium are susually made available to palnts through cation exchange surface of organic material and clay soil surface particles
Observation by veratna )1997) showed that addition of one of ground plant material per 20g of soil raised the organic content of the oil to 1.86%, PH 6.4 niitegen content 0.18%. letroy et al (1999) reported that while audifiation increases the initial availability of these cutions, the residual soil moisture concentrations of nutrients cations could fall to alarmingly low levels after initial nutrient up take moreover there is one simple relationship of PH to nutrient availability because of the complex combination of soil types, soil moisture regimes and meterological factors. Excess of organic matter can have a lowering effect on the PH value of most soils (mbagwu and piccolo, 1990)
EFFECT OF SOIL TYPE IN SOIL ORGANIC MATTER
When plant residues are returned to the soil, various organic compounds undergo decomposition. Decomposition is a biology process that includes the physicial breakdown and biochemical transformation of complex organic molecules of dead material into simpler organic and inorganic mdecules.
Decomposition oforganic matter is largely a biological process that occurs naturally. Its speed is determineby three major factors soils organisms, the physical envieornment and the quantity of the organic matter (Brussaard, 1994) . in the decomposition process, different product are released, carbon compounds
Successive decomposition of dead material and modified orgnic matter results in the formation of a more complex organic matter called l humus. This process is called humification. Humus affect soil properties . as it slowly decomposes, it colours the soil darker, increases soil aggregation and aggregate stability, increases the CES (The ability to attract and retain nutrients), and contributes N,P and other nutrients. Soil organisms, including micro –organisms, use soil organic matter as food. As they breakdown the organic matter, excess nutrients (N,P and S) are released into the soil in forms that plant can use. This released by micro-organisms are also soil organic matter. This waste materials is less decomposable than l the original plant and aimal materials, but it can be used by a large number of organisms (levelle and spain, 2001). By breaking down carbon structures and rebuilding new ones or storing the C into their own biomass, soil biota plays the most important role in nutrient cycling process and, thus, in the ability of a soil to provides the crop with sufficient nutrients to harvest a healthy product (FAO, 2002). The organic matter content, especially the more stable humus, increases the capacity to store water and store (Sequester) from the atmosphere (Linn and Dovan, 1984), organic matter serves as a nuturient store from which basic cations are slowly decomposes, it colours the soil darker, increase soil aggregation and aggregate stability, increases the CEC (The ability to attract and retain nutrients), and contributes N,P and other nutrients
Soil organisms, including micro organisms, are soil orgnic matter as food. As they break down the organic matter, excess nutrients (N, P and S) are released into the soil in form that plant can use. This release process is called mineralization. The waste material is less decomposable than the original plant and animal material, but it can be used by a large number of o0rgnisms (Lavelle and Spain, 2001). By breaking down caibon structures and rebuilding new one sor storing the C into their own biomass, soil biota plays the most important role in nutrient cycling process and, thus, in the ability of a soil to provide the crop with sufficient nutirients to hearvest a helthy product (FAO 2002). The organic matter content, especially the more stable humus, increases the capacity to store water and store (Sequester ) from the atmosphere (LINN AND Doran, 1984). Organic matter serves as a nutrient store from which basic cations are slowly released into the soil. It account for over 80% cation exchange capcity (CEC) OF THE HUMINAL TROPICALsoil (AGBOLA AND FAGHENRO 1985). The type of vegetation determines the type of cover and quality of organic matter in the soil. Legume according to Brady and Weil (1999), makes riche organic matter than grasses and gmelina covers. Mineral colloid and organic matter constitute the soil exchange complex being negatively charged (Nwingyi, 1977).
According to Ekpe (2002), Orgaic matter is a store house for plant nutrients is also the cementing in soil structure and aggregate formation. Ekpe (2002) also noted that soil organic matter help to improve the soil water holding capacity and hydraulic conductivity. Excess of organic matter can have a lowering effect of the PH value of most soils
Furthermore, with time iron oxides of the soil are soluvilized and leached specially in the tropic where activities of micro organism are high
EFFECT OF SOIL USE TYPES ON EXCHANGE BASE
Organic mater from vegetation cover contain exchangeable bases in varied quantities. These mineral nutrients are important components of the vegetation bio-system which it releases to the soil on death and decomposition. The efficiency of the use of vegetation to improve on soil properties is dependent on the stage of growth of the vegetation. In legume, maximus effect is achieved at flowering stage while in grasses it is somewhat earlier (MULLERN SAMANN AND KOTSCHI 1994) Gmelina cover is reported to be effective only when it is about 12 month old.
The exchangeable incorporated in soil by organic matter resulting form vegetation cover are similar to those from any other form of organic matter. The exchangeable bases content of soil differ depending on the parent material vegetation cover, cropping history and soil management practices employed finally, economic justification of the use of organic fertilizer lies in the necessary to cope with prevalent increase in the cost of mineral fertilizer and reduction in the waste of nutrient result from on under utilization of organic residue (FAO 2002).
EFFECT OF ORGANIC MATTER ON SOIL CHEMICAL PROPERTIES
organic matter affect both the chemical and physical properties of the soil and its overall health (FAO, 2000) properties influenced by organic matter include: soil structure, moisture holding capacity, diversity and captivity of soil organisms, both those that are beneficial and harmful to crop production and nutrient availability (Vieria and Van Wambeke 2002).
However, it also influence the effect of chemical amendments, fertilizers pesticides and herbicides. Organic matter has been known to be a major natural source of both macro and micronutrient. Organic matter has many benefits in the and porosity and increase in the number of macropores, and thus to greater infiltration rates. Increased levels of organic mater and associated soil fauna lead to greater pore space with the immediate result that water infiltrates more readuy biotur batting activities of earth worms and other macro organism and channels left in the soil by decayed plant roots. Rainwater infiltration increased from 20mm/h under conventional tillage to 45mm in under no tillage’s. Over a long period, improved organic matter promotes good soil structure and macroporsity , water infiltrates easily similar to forest soils
In addition organic matter contribute to the stagility of soil aggregates and pores through the bounding or adhesion properties of organic matrials, such as bacterial waste products, organic gls, fungal hyphas and worm secreteions and casts (tate et al, 2004)
Moreover organic matter intimately mixed with mineral soil materials has a considerable influence in increasing moisture holding capacity. Especially the topsoil, where the organic matter stoe form which basic cations are slowly released into the soil. Ortanic matter accounts for over 80% cation exchange capacity (CEC) of the humed tropical soils (Agboola and faghenro, 1985) . the quantity of organic matter in the soil at any given time is an indication of the capacity of the soil to renew the supply when the nutrient in solution have been utilized. Mineral colloid and organic matter constitute and soil exchange complex, being negatively charged (Nwiniyi, 1977) organic matter contributes very significantly to the soil cation exchange capacity. Through exchange processes plant can take up exchangeable cation which are important as nutrient (Wezel et al 2000)
Nitrogen is one of the macro nutrient needed for maximum growth production and yield of crop. Nitrogen is very important for protein synthesis and nuclicic acids sysnthesis. Nitrogen is one of the essential elements. It is utilized by plant for making proteins and chlorophy (Watkins et al 2006). Overation by agbooola (1982) showed that organisms cannot use gaseous nitrogen except some few species of bacteria and blue green alge that are capable of utilizing the gaseous nitrogen form the soil. Gaseous nitrogen bacterial called Azotobacter Clostridum and Rhospirllum living in the soil, nitrogen fixing bacteria (Sysmbiotic bacteria), the species of phizobuim such as R leguminosarium have symbiotic association with roots of some leguminous plant such as groundnut , beans and crotalaria, furthermore, these sysmbiotic bacteria enter the root hair walls of the lequmes and multiply thus causing swellings or nodules in the infected cells karl and Johannes (1994) noted that the most glaring effect of grass cultivation on nutirient economy of the soil is ntitrogen enrichment. Gasser (1964) asserted that organic nitrogen not only increase tutrifying activities of micro organism but also decreases nitrogen losses by increasing cation exchange capacity. Crop reside added to the soil fixed nitrogen in soil during the early state of decomposition of solube carbohydrate. This is that succeeding crop suffered. Nitro deficiency (Agboola, 1982. Ahmed et al, 1969) and Azevedo and stout, 1979) . they recommended supplemental nigtrogen to achieve a C.N ration of less than 15:1 this organic source according to their report could also come from animal droppings .
3. Waste disposal: finally, a growing cause for concern is how we dispose of our waste while industrial waste is another way in which we are adding to the population every human produces a certain amount of peronsal waste products by way or urine and feces
While much of it mores into the sewer the system, there is also a large amount that is dumped directly into landfills in the form of diapers. Even the swer system ends at the landfill, where the biological waste pollutes the soil and water. This is because our bodies are full of toxins and chemicals which are now seeping into the land and causing pollution of soil
4. Accidental oil spills: Oil leaks can happened during storage and transport of chemicals. This can be seen at most of the fuel stations/. The chemicals present in the fuel deteriorates the quality of soil and make them unsuitable for cultivation. These chemicals can enter into the ground water through soil and make the water undrinkable
5. Acid rain: acid rain is caused when pollutants present in the air mixes up with rain and fall back on the ground. The polluted water could dissolve away some of the important nutrients found in soil and change the structure of the soil
2.1 EFFECT OF POLLUTANT ON SOIL USE
1. On health of human
Considering how soil is the reason we are able to sustain ourselves, the contamination of it has maor consequences on our health. Crops and plants grown on polluted soil absorb much of the pollution and then pass these on to us. This could explain the suddn surge in small and terminal illnesses long term exposure to such soil can affect the gentic make up of the body causing congential illnesses and chronic health problems that cannot be cured easily. In fact, it can sicken the livestock to a considerable extent and cause food poisioning over a long period of time . the soil polluation can even bad to wide spread famines if the plants are unable to grow in it
2. On growth of plants: the ecological balance of any system gets affected due to the widespread contamination to the soil. Most plants are unable to adapt when the chemistry of the soil changes so radically in a short period of time. Fungi and bacteria found in the soil that bind together begin to decline, which creates an additional problem on soil erosion
The fertility slowly diminishes, making land unsuitable for agriculture and any local vegetation to survive. The soil pollution causes large tracts of land to become hazardous to health unlike deserts, which are suitable for its native vegetation, such land cannot support most form of life.
3. decreased soil fertility : the toxic chemicals l present in the soil cand decrease soil fertility and therefore decrease in the yield then contaminated soil is then used to produce fruits and vegetables which lacks quality ad nutrients and may contain some poisonous substance to cause serious health problems in people consuming them.