The Importance of Soil

our most overlooked natural resource is literally underfoot soil is a living dynamic system it's the place with the Earth's geosphere hydrosphere atmosphere and biosphere interact soil is the mix of minerals organic materials moisture and air that makes a home for billions of animals plants and fungal species without soil we would not exist healthy soil is the foundation for our food system it purifies the water that we drink and it is critical in its role in the regulation of greenhouse gases because it's our major store of carbon there are 70,000 different kinds of soil on earth these are the product of the original parent material the climate of the area the amount of organic matter that's in the soil and the environmental conditions under which the soil is actually being produced we can't grow soil by its texture this is a sandy soil it has no water holding capacity water just goes straight through it it holds no nutrients a loamy soil has a lot more organic matter in it it's perfect for growing plants and a clay soil is exactly what you think it is it has a lot of clay in it it's very sticky plant roots have a hard time growing in it lighter colored soils like sandy soils have low fertility and they're very poor for a plants to grow in on the other hand darker colored clothes have a lot of organic matter in them this organic matter holds a lot of nutrients for the plants to grow normally it would be nitrogen and phosphorus but also indicates the better carbon holding to be in the oil healthy soil is teeming with the diversity of organisms from the microscopic to the macroscopic these organisms move from the organic layer in the top of the soil down to the soil areas below and back up again in fact you'll find more organisms in the tablespoon of soil than there are people on planet earth this community of organisms performs a vital function dead and decaying plant and animal materials fall onto the soil where decomposes such as pill bugs and worms speed up the process these animals break down complex molecules in their guts and release carbon and nutrients such as nitrogen the minerals smaller soil decomposes such as fungi bacteria and archaea continue this process soil microbes tend to make up the bulk of the organic matter below the surface there's actually more microbes per kilogram of soil than there are anything else and those microbes are extraordinarily important for soil carbon sequestration trees and other plants rely on these nutrients as they play a role in their carbon cycle plants remove carbon dioxide from the atmosphere during photosynthesis carbon is fixed in the form of carbohydrates in turn these carbohydrates arrive at our table and many forms sometimes they become other animals first we read products of the soil and weave we're products of the soil another irreplaceable function of soil is an excess of water filter gravity draws water down through the layers of the soil until it meets an impenetrable layer where it gathers as groundwater as water trickles through contaminants are trapped in tiny openings in the soil bacteria and other microorganisms in the ground filter water by removing carbon dioxide and soluble substances and pathogens this is particularly true in wetlands for a complex mixture of soil and soil organisms and microbes help filter water through percolation and metabolism soil is an absolutely marvelous system it works really well all by itself in its own particular time scale unless you abuse it we use soil as a holding facility for solid waste as a filter for our waste water from our cities towns and agriculture and is a dumping ground for toxic waste our soil is being blown off and washed down streams and rivers precious topsoil is pouring off the continent and the depths of the ocean at a rate that is almost impossible to replace why because making soil is an exceedingly slow process plants play a role in the weathering of rock into soil their strong roots can enter fissures in rock wedging the rock part and breaking off tiny chips fungi can grow into the spaces or pores in rocks that are impossible for risk enter the fungi release acids and enzymes that are capable of solubilizing the rock burrowing animals are a natural disturbance during their activities animals will bring soil from the lower layers back up to the surface and take organic material back down to the lower soil layers on the other hand agricultural tilling construction mining and quarrying are all unnatural disturbances they bring rocks up to the surface where they are an expert topsoil the resulting material is extraordinarily hard to restore back to any level of normal functioning water is also a soil builder it penetrates into the fissures of the rock when the water freezes it expands wedging the rock apart when the ice thaws it leaves behind a slightly larger fissure that allows more water to seep in freeze and expand once more as this freeze and thaw cycle continues tiny chips of rock continually break off these tiny chips continue to be weathered into smaller and smaller pieces by erosion chemical reactions at some point they become small enough that organic material can actually cling to these particles it may take thousands of years to build and rebuild even the thinnest layer of soil archeologists have determined that the collapse of a number of ancient civilizations including the Mayans in Central America may have been due to the mismanagement of their soils and if that is the case then soil science truly is the key to our future you

Channel: chicagobotanicgarden

Views: 52,445

Rating: 4.4909091 out of 5

Keywords: Soil Science (Field Of Study), Chicago Botanic Garden (Tourist Attraction), conservation science, plant science, Ecology (Field Of Study)

Id: qMFo5fxE8Bs

Length: 6min 40sec (400 seconds)

Published: Thu Aug 22 2013