2 14 2012 Natural Resource and Environmental Planning TOPIC 4 SOILS AND SUSTAINABLE AGRICULTURE A Nature of Soil soil is the skin of the earth without it we would not have food SKIN OF THE EARTH DIRT ESSENCE OF SURVIVAL Nature of Soil 1 What is it 2 Why is it important 3 Characteristics 4 Formation 5 Soil Orders and Distribution 1 2 14 2012 1 What is it Skin Contains Minerals Organic matter Water Air Product of parent material Climate controlled Dynamic 2 Why is it important Plant growth Prevent water pollution Food supply Prevent air pollution Supports food web Resist erosion Degrade harmful almost half of the soil makeup is mineral matter the mineral matter comes from weathering rocks the parent material is bedrock in that area mineral content is kind of set by what you are around air changes with grain size there is a natural balance between all of these components climate is really significant in how much we have to do for our soil to be right a soil is dynamic very responsive to changes in the environment the wealth or poverty of nations is directly connected to its ability to grow food ex haiti soil acts as a buffer for water and filtration can filter out harmful contaminants in our air can prevent erosion can hold up things think of it as a sponge so some harmful contaminants can be found in soil that you won t find in other places chemicals Immobilize chemicals wastes and other pollutants 3 Characteristics of Soil Texture Structure Organic matter Soil organisms Aeration Moisture pH Fertility soil scientists describe soil in a way that someone on the other side of the world will know exactly what you are talking about this is really detail orientated they do a very important job and can tell you what your soil is naturally good for and what you can do to amend it its water retention abilities etc texture is important platey blocky etc dust bowl established the soil conservation service this service was set up bc we understood for the first time how important and how vulnerable soil is 2 2 14 2012 in some instances you have completely saturated soil a saturated soil may be good in some instances but can t always be good because no room for oxygen within the pore space ideal is field capacity enough water but still room for air to move wilting point not really water at all Water Content Varies What are ideal conditions Field Capacity ideal water holding situation field capacity Soil Fertility and Yields Nutrients Required Characteristic Organisms found in Soil didn t look at this Yield and essential element concentration Bog Development didn t look at 3 2 14 2012 Nutrient Sources for Crops 4 Soil Formation Climate Parent Material Organisms Topography Time didn t look at the parent material bedrocks and can be a limiting factor organisms important topography best soils on the bottom of the hill weathered material moves from top of the hill to the bottom more water retention usually thicker soils on the bottom flow chart look at in terms of how rocks and minerals contribute to the material of soils we see different grain sizes based on preferentiability we can have contributions to soil that originate in other areas wind is very important in terms of transport we should treat soil as if it were nonrenewable because the rate at which it is used up is going to increase anywhere land is stripped not just farmers it takes 500 years to get a layer of top soil soil is vulnerable and a product of natural processes the rate at which it is used up depleted can exceed to rate at which it is generated 5 Soil Orders sol Latin solum soil USDA 12 Orders US 22 Mollisols Richest agriculturally classification systems we divide all of our soil types into 12 main orders the most significant is the group called the Mollisols the Mollisols are the most productive soils where we see most of our agricultural crops being produced these soils don t do so well once we take the native vegetation away their natural fertility is high 4 2 14 2012 B Soil Conservation and Sustainable Agriculture LEAVE IT UNDISTUR BE D ideal way to manage a soil is to leave it alone leaving soil alone is which of the 4 main conservation methods our ideal method would be to cultivate it while causing the least disturbance to it CULTIVATE AND LEAVE UNDISTUR BE D alabama at the top of no till agriculture minimal invasive operations woohoo go us Soil Conservation and Sustainable Agriculture 1 there are innovative ways to slow water movement Nature of Erosion 2 The Dust Bowl 3 Shelterbelt Program 4 Erosion Today 5 Factors affecting rates 6 Controlling erosion by water 7 NRCS 8 Alternative Agriculture 9 Sustainable Agriculture NRCS voluntary participation 900 000 farmers assisted annually key to success is voluntary participation and grass roots a lot of agents are farmers as well so people are much more willing to listen to him the assistance they get each year include detailed soil analysis on the farm reduce chemicals help with infrastructure that can support sustainable farming 5 2 14 2012 1 Nature of Erosion What is erosion Erodere gnaw out Grand Canyon Geologic by water Natural North Carolina Farm Agricultural practices Accelerated Soil Erosion Soil Erosion by Water Natural vs Accelerated erosion occurs naturally all over the world erosion is naturally capable of carving out immense landscapes such as the grand canyon the picture on the right is caused by man and is the accelerated type caused by poor soil management most erosion occurs on farmed land bc it has been disturbed and its vegetation has been removed the natural process is what wears away our mountains accelerated usually due to us Natural 0 02 mm year Wear mountains Fill basins Accelerated X10 x100 faster Follows disturbance Wind and water on farm land 2 The Dust Bowl the picture shows an average rainfall event it breaks it up and makes it more vulnerable to movement its removing its most fertile layer and moving it down to the bottom the climatic conditions that led to this event the outcomes of the droughts were very different Drought on the Great Plains 1890 1910 1930 huge impacts on the economy because what is left after the dust storm is sand and you can t really farm on that Number of dust storms in March 1936 the drought experienced in the 30 s was nothing new the reason why the effects of it were so catostrophic was because the landscape change the grass was no longer there so huge masses of land were left vulnerable to erosion 6 2 14 2012 Dust Bowl