Geography & History Notes | KCSE, NECTA, ZIMSEC & GCSE

  T he following are types of soil water movement infiltration soil water movement infiltration is the process by which water on the ground surface enters the soil. infiltration rate in soil science is the measure of the rate at which soil is able to absorb rainfall or irrigation. it is measured in inches per hour or millimeter per hour. the rate decreases as the soil becomes saturated infiltation can be visualized by pouring water into grass filled with dry powdered soil, slightly tamped. the water seeps into the soil and becomes darker as it is wetted factors affecting the infiltration rate the following factors affects the infiltration rate of soil water or moisture in the soil the soil moisture content: the soil water infiltrate faster (high infiltration rate) when the soil is dry than when it is wet.as the consequence, when irrigation water is applied to a field the water at first infiltrate easily, but as the soil becomes wet, the inflitration rate decreases. soil texture: co...

  Soil organic matter (SOM) is the organic matter component of soil, consisting of plant and animal residues at various stages of decomposition, cells, and tissues of soil organisms, and substances synthesized by soil organisms. The following are factors affecting decomposition of soil organic matters: Temperature: Cold periods retard plant growth and OM decomposition. Warm summers may permit plant growth and humus accumulation.  Soil moisture: Extremes of both arid and anaerobic conditions reduce plant growth and microbial decomposition. Near or slightly wetter than field capacity moisture conditions are most favourable for both processes.   Nutrients: Lack of nutrients particularly N slows decomposition.   Soil PH: Most of the microbes grow best at pH 6 – 8, but are severely inhibited below pH 4.5 and above pH 8.5.   Soil Texture: Soils higher in clays tend to retain larger amounts of humus.   Other Factors: Toxic levels of elements (A...

  Soil erosion is wearing away of soil particle due to action of erosion agents such as moving water, ice and wind.Erosion, whether it is by water, wind or tillage. Soil erosion involves three distinct actions – soil detachment, movement and deposition. Topsoil, which is high in organic matter, fertility and soil life, is relocated elsewhere "on-site" where it builds up over time or is carried "off-site" where it fills in drainage channels.  Soil erosion reduces cropland productivity and contributes to the pollution of adjacent watercourses, wetlands and lakes. water erosion is the result of rain detaching and transporting vulnerable soil, either directly by means of of rain splash or indirectly by rill or gully erosion The following are forms of water erosion Rain drop or splash erosion Erosion preceded by the destruction of the crumb structure due to the impact of falling raindrop on the surface of soil is termed as splash erosion. Sheet erosion It is the fairl...

  Soil is the mixture of minerals, organic matter, gases, liquids, and the countless organisms that together support life on Earth. Soil composition is an important aspect of nutrient management. While soil minerals and organic matter hold and store nutrients, soil water is what readily provides nutrients for plant uptake. Soil air, too, plays an integral role since many of the microorganisms that live in the soil need air to undergo the biological processes that release additional nutrients into the soil. Soil is composed of both organic and inorganic matter, and it is essential for life on earth to exist.  Soil is composed of: Mineral Particles: Mineral particles are the largest ingredient and make up approx 45% of soils . They are the original rock that got broken down by weathering and erosion to form the basis of soil. The type of rock that was broken down to form it is called the parent rock. The broken down rock produces minerals such as calcium, phosphorus, and potas...

  The following are Soil Conservation methods Crop rotation This is the planting of different crops on the same piece of land. it can also be defined as the movement of crops from site to site on the farm in a planned sequence This helps to control monoculture and its effects. advantages of crop rotation it interrupts pest-host cycles and prevent the buldup of pests weed and pathogens. it allows crops to access nutrients from different soil depths basing on their rooting characteristics intergrating cover crops and fallow periods into rotation help build soil organic matter and improve aggregation Afforestation and re-afforestation here, trees are planted in areas where they have been cleared or areas where trees have never been planted. The planted trees help in controlling the effects of heavy raindrops and the speed of the wind, which are major agents of erosion . Mulching This is the covering of soil with different materials e.g. grass so that it can be able to store moisture i...

  Soils are alive! A variety of soil organisms live in the soil . These include bacteria, fungi , microarthropods, nematodes, earthworms and insects. These organisms live on soil organic matter or other soil organisms and perform a number of vital processes in soil. Other organisms are involved in the transformation of inorganic molecules. Very few soil organisms are pests. The role of soil organisms in soil fertility may involve the following: helping soil to form from original parent rock material, contributing to the aggregation of soil particles, enhancing cycling of nutrients, transforming nutrients from one form to another, assisting plants to obtain nutrients from soil, degrading toxic substances in soil, causing disease in plants, minimizing disease in plants, assisting or hindering water penetration into soil RELATED POSTS 9 CONDITIONS FAVOURING IRRIGATION FARMING IN EGYPT 5 CAUSES OF RURAL-RURAL MIGRATION IN KENYA 10 AIMS OF KILOMBERO VALLEY IRRIGATION SCHEME 4 FEATURE...