Unit 5: Land and Water Use

APES

Soil

renewable resource that can be depleted plant-supporting system
disintegrated rock, organic matter, water, gases, nutrients, microorganisms

Sustainable agriculture

agriculture practice in same way/place far into the future

soil supporting agriculture

Provide nutrients
Have a structure that allows roots to penetrate deeply
Retain water
Livestock

soil effect chart

Soil is teeming with bacteria, algae, fungi, and protists and provides habitat for earthworms, insects, mammals, reptiles, and amphibians
Since soil is composed of interacting living and nonliving matter, it is considered an ecosystem

Parent material

the base geologic material of soil
Lava, volcanic ash, rock, dunes

bedrock

solid rock comprising the Earth’s crust

Weathering

processes that break large rock particles down into smaller ones

Physical (mechanical) weathering

wind and rain; no chemical changes in the parent material

Chemical

parent material is chemically changed

Biological

organisms produce soil through physical or chemical means

Humus

spongy material formed by partial decomposition of organic matter; holds moisture

Soil on Climate

soils form faster in warm, wet climates

Soil on organism

plants and decomposers add organic matter

Soil on Topography

hills and valleys affect exposure to sun, wind, and water

soil on Parent material

Influences properties of resulting soil

Soil on time

soil can take decades to millennia to form

horizon

each layer of soil (up to 6)

soil profile

the cross-section of soil as a whole

weathering & organic matter decrease in lower horizons

Leaching

process whereby dissolved particles move down through horizons, may end up in drinking water

Topsoil

inorganic/organic material most nutritive for plants

Soil horizon charts

Soils color

color indicates its composition and fertility
Black or dark brown soil is rich in organic matter
Pale gray or white soil indicates leaching

soil texture

size of particles
smallest to largest: clay, silt, sand
Loam = soil with an even mixture of the three
Affects how easily air and water travel through the soil
Influences how easy soil is to cultivate

soil structure

“clumpiness" best 4 plants
Repeated tilling compacts soil, decreasing its water-absorbing capabilities

Soil pH

too acidic or basic can kill plants
pH influences the availability of nutrients for plants

Cation exchange

allows plants to gain nutrients
Negatively charged soils hold cations (positively charged ions) of calcium, magnesium, and potassium
Roots donate hydrogen to soil in exchange for these nutrients

Cation exchange capacity

a soil’s ability to hold cations
Cations that don’t leach are more available to plants
A useful measure of soil fertility
Greatest in fine textured or richly organic soils
Decreases with lower pH

regional soil

rainforests the nutrients are in plants, not the soil
leaches minerals and nutrients, reducing their accessibility to roots
Rapid decomposition of leaf litter results in a thin topsoil layer with little humus

Swidden agriculture

traditionally used in tropical areas
cultivation, a plot is left to grow back into forest
Soils are depleted if not enough time is given
Temperate prairies have lower rainfall and less nutrient leaching and are able to build rich topsoil

Soil degradation

decline in soil quality and productivity
Primarily from deforestation, cropland agriculture, overgrazing

Land degradation

a general deterioration of land, decreasing its productivity and biodiversity
Erosion, nutrient depletion, water scarcity, salinization, waterlogging, chemical pollution

Erosion

removal of material from one place to another by wind or water
topsoil—the most valuable layer for plant growth
overfarming

Deposition

arrival of eroded material at a new location

floodplains

deposits nutrient-rich sediment in river valleys and deltas

Desertification

a form of land degradation with more than a 10% loss of productivity

Caused primarily by wind and water erosion, but also by:
Deforestation, soil compaction, and overgrazing
Drought, salinization, water depletion
Climate change

Dust Bowl

massive dust storms from erosion of millions of tons of topsoil in the 1930s

**Conservation districts**

districts that promote soil conservation practices at the county level

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* Operate with federal direction, authorization, and funding and are organized by the states

**Crop rotation**

* **growing different crops from one year to the next** 
* **Returns nutrients to soil** 
* **Prevents erosion, reduces pests**
* **Like crop rotation, no-till farmers may alternate wheat or corn with nitrogen-fixing soybeans**

**Contour farming**

**plowing furrows sideways across a hillside perpendicular to its slope**

* Sides of furrows trap water and prevent erosion

**Terracing**

* **cutting level platforms into steep hillsides**
* **The steps of this “staircase” hold water**

**Intercropping**

*  **planting different crops in alternating bands or mixed arrangements**
* **Increases ground cover, preventing erosion**
* **Decreases pests and disease**
* **Replenishes soil**

**Shelterbelts** **(windbreaks)**

* **rows of trees planted along edges of fields to slow the wind**
* **Can be combined with intercropping**

**Conservation tillage**

*  **strategies that reduce the amount of tilling relative to conventional farming**
* **Leaves at least 30% of crop residues in the field**
* **No-till farming disturbs the soil even less**

**Overgrazing**

* **occurs when too many animals eat too much of the plant cover** 
* **Impedes plant regrowth**

**Irrigation**

* **artificially providing water to support agriculture**
* **Unproductive regions become productive farmland**
* **Can grow water-intensive crops like rice and cotton**

**Waterlogging**

**experienced by overirrigated soils when the water table rises to cover and suffocates roots**

**Salinization**

* **the buildup of salts in surface soil layers**
* **Worse in arid areas**
* **Evaporation pulls salts up from lower soil horizons**

**Fertilizers**

* **substances containing essential nutrients**
* **Plants require nitrogen, phosphorus, and potassium and remove them from the soil, possibly limiting growth**

**Inorganic fertilizers**

* **mined or synthetically manufactured mineral supplements**

**Organic fertilizers**

*  **the remains or wastes of organisms**
* **Manure, crop residues, fresh vegetation**

compost

* **mixture produced when decomposers break down organic matter**

Wetlands

swamps, marshes, bogs, river floodplains

**No-till** farming

l**eaving crop residue atop the fields**

* **Benefits the soil**
* **Saves time and money**

**Cover crops**

* **= crops planted to hold soil in place between the times that main food crops are growing**

**Agriculture**

*  **practice of raising crops and livestock for human use and consumption**  

**Cropland**

*  **land used to raise plants for human use** 

**Rangeland** or **pasture**

* **and used for grazing livestock** 
* Land devoted to agriculture covers 38% of Earth’s land

**Soil** 

**a complex plant-supporting system** 

* **Consists of disintegrated rock, organic matter, water, gases, nutrients, and microorganisms**  
* **It is a renewable resource that can be depleted**

**Sustainable agriculture**

**agriculture we can practice in the same way and same place far into the future**

**Traditional agriculture**

*  **biologically powered form of agriculture that uses human and animal muscle power**
* **Hand tools, simple machines**

**Subsistence agriculture**

*  **form of agriculture in which families produce only enough food for themselves**

**Polyculture**

**different crops are planted in one field**

**Industrialized agriculture**

**form of agriculture that uses large-scale mechanization and fossil fuels to boost yields**

* **Also uses pesticides, irrigation, and fertilizers**

**Monoculture**

**uniform planting of a single crop**

**Green Revolution**

* **new technology, crop varieties, and farming practices were introduced to developing countries**
* **Increased yields and decreased starvation**
* **Degraded the integrity of the soil**

*Swidden* agriculture

traditionally used in tropical areas

* After cultivation, a plot is left to grow back into forest
* Soils are depleted if not enough time is given

**Soil degradation**

* **a decline in soil quality and productivity**
* **Primarily from deforestation, cropland agriculture, overgrazing**

**Land degradation**

* **a general deterioration of land, decreasing its productivity and biodiversity**
* **Erosion, nutrient depletion, water scarcity, salinization, waterlogging, chemical pollution**

erosion

**removal of material from one place to another by wind or water**

**Deposition**

*  **arrival of eroded material at a new location**
* Flowing water deposits nutrient-rich sediment in river valleys and deltas
* Floodplains are excellent for farming

**Desertification**

* **a form of land degradation with  more than a 10% loss of productivity** 

**Undernutrition**

*  **people receive fewer calories than their minimum requirements** 
* **Due to economics, politics, conflict, and inefficiencies in distribution**

Most undernourished live in developing nations

**Food security**

*  **guarantee of an adequate, safe, nutritious, and reliable food supply**

**Monoculture**

*  **large expanses of a single crop**
* **More efficient, increases output**
* **Devastates biodiversity**
* **Plants are more susceptible to disease and pests**

**Sustainable agriculture**

* **agriculture that does not deplete soils faster than they form. It does not**
* **reduce the amount of healthy soil**
* **pollute water**
* **decrease genetic diversity**

**Biofuels**

* **fuels derived from organic materials**
* **Replace petroleum in engines**

**Ethanol**

* **a biofuel derived from corn**

\
* Food prices increased 
* Farmers sold corn for ethanol, not food
* Farmers planted biofuels, not food crops
* Riots erupted in many nations

**Feedlots**

* ***factory farms*****, also called** ***concentrated animal feeding operations,*** **or** ***CAFOs*****) = huge warehouses or pens that deliver food to animals living at extremely high densities**
* **Increases production**

**Seed banks**

*  **institutions that preserve seed types as living museums of genetic diversity**

**Pollination**

*  **male plant sex cells fertilize female sex cells**
* **By wind or animals** 

**Pest**

* **any organism that damages valuable crops** 

**Weed**

any plant that competes with crops

**Pesticides**

*  **poisons that target pest organisms**

**Biological control (biocontrol)**

* **strategy that uses a pest’s predators or parasites to control the pest**

***Bacillus thuringiensis*** **(Bt)**

* ***soil bacterium that kills many caterpillars and some fly and beetle larvae***

**Integrated pest management (IPM)**

*  **use of a mix of techniques to suppress pests:**
* **Pest population monitoring** 
* **Biocontrol and mechanical pest removal**
* **Chemicals, if necessary**
* **Crop rotation and alternative tillage methods**
* **Use of transgenic crops**

**Organic agriculture**

 food-growing practices that use no synthetic fertilizers or pesticides but rely on biological approaches such as composting and biocontrol

Criteria

**Biotechnology** 

*  **the application of biological science to create products derived from organisms** 
* **Seeks to scale up the technological aspects of agriculture**

**Genetic engineering**

* **direct manipulation of genetic material through adding, deleting, modifying DNA**

**Recombinant DNA**

* **DNA patched together from multiple organisms**
* Biotechnology has created medicines, cleaned up pollution, and dissolved blood clots

**Precautionary principle**

* **idea that one shouldn’t undertake a new action until the effects of that action are understood**

**Farmers’ markets**

* **provide meats and fresh fruits and vegetables from local producers**

**Community-supported agriculture (CSA)** 

* Consumers pay farmers in advance so farmers get guaranteed income
* Consumers get fresh locally grown food

**Life-cycle analysis**

**analysis of all inputs across all stages of production, transportation, sale, and use**

*Factory fishing*

* *huge vessels use powerful technologies to capture fish in huge volumes* 

*Driftnets*

*  *transparent nylon mesh nets that drift with the current*
* *Used for herring, sardines, mackerel, sharks, shrimp*

*Longline* *fishing*

*  *extremely long (up to 80 km or* \n *50 mi) lines with several thousand baited hooks*
* *Used for tuna and swordfish* 

*Trawling*

* *using cone shaped nets with weights at the bottom and floats at the top to catch pellagic fish*

*Bottom trawling*

* *using weighted nets that drag across the seafloor to catch groundfish or scallops*