Term
| on average planet earth is covered in ___'' of topsoil |
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Definition
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Term
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Definition
| nutrient-rich matter that sustains most of our food and has a critical role in supporting life |
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Term
| we are loosing ___% of topsoil per year |
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Definition
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Term
| We are losing topsoil mostly because of? and also because? |
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Definition
| 1. Agriculture 2. Pollution and Development |
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Term
| The U.s. cropland is eroding ___ times faster than soil replacement |
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Definition
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Term
| This contributes to the increasing numbers of malnourished in Africa |
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Definition
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Term
| soil is more than dirt because? |
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Definition
| It includes a functioning ecosystem; living organisms and dependent on energy flow/nutrient cycling |
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Term
| Soil ecosystems promote these three things? |
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Definition
| 1. breakdown of organic material to humus 2. bioturbation and mixing with organic particles 3. nitrogen fixation |
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Term
| __% of food comes from terrestrial ecosystems |
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Definition
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Term
| what's a critical part of healthy soils is? |
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Definition
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Term
| plant growth reduces this? |
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Definition
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Term
| a limited nutrient supply will? |
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Definition
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Term
| two things that remove nutrients from soil? |
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Definition
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Term
| 3 things that add nutrients to the soil? |
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Definition
| 1. dead plants decomposed 2. Atmospheric nitrogen fixed by bacteria and lightning 3. Weathering of parent rock/deposition of sediments |
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Term
| the pool of nutrients is in a state of? |
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Definition
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Term
| 2 effects of harvesting crops? |
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Definition
| 1. takes nutrients out of system 2. Decreases recycling |
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Term
| Increased erosion can greatly accelerate? |
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Definition
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Term
| With increased losses, agricultural soils over time |
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Definition
| loos productivity unless steps are taken to replenish loss of nutrients |
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Term
| Most common remedy to replenish soil |
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Definition
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Term
| 2 other disturbances that alter the soil ecosystem? |
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Definition
| 1. chemical disturbances 2. Mechanical disturbances |
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Term
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Definition
| poisons such as pesticides that harm soil organisms, reduce decomposition, and decrease nutrient recycling |
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Term
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Definition
| can disrupt the soil profile and the ecosystem pathways, reduces recycling and increase the rate of losses by erosion |
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Term
| dryland soils are especially subject to |
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Definition
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Term
| agriculture is a major contributor to |
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Definition
| the loss in soil productivity |
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Term
| two fastest growing population regions are seeing |
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Definition
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Term
| 2 ways to restore fertility to degraded cropland |
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Definition
| fertilizer (if not too severe) and repair eroded lands (gully reclamation) |
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Term
| How can we prevent further damage to crop land? |
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Definition
| protect existing farmland from ubran sprawl |
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Term
| in PA urban sprawl is taking ____acres per day |
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Definition
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Term
| Soil conservation can be achieved through these three things which reduce wind and water erosion |
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Definition
| terracing, contour farming, and installing windbreaks |
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Term
| 4 Rules of Sustainable Agriculture |
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Definition
| 1. cover the soil with cover crops 2. minimal/no tillage 3. Apply mulch to return nutrients 4. maximize biodiversity by rotating crops |
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Term
| if 80% of farmers reduced their tillage then soil erosion would be reduced |
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Definition
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