5.13-5.17

• Urban Runoff: Environental Consequences

  • Decreased infiltration
  • No groundwater recharge
  • Rain washes pollutants into storm drains and into local surface waters
  • Fertilizers, oil/gas, and sediments
• Pollutants and Effects of Urban Runoff

  • Salt
  • Plant and insect death that can't tolerate saltiness
  • Sediments
  • Turbidity kills organisms and decreases photosynthesis
  • Fertilizer
  • Eutrophication
  • Pesticide
  • Kills NON-TARGET species
  • Oil and Gasoline
  • Suffocate fish and kill aquatic insects
• Reducing Urban Runoff: Solution 1

  • Permable Pavement
  • Especially designed to allow stormwater to infiltrate and recharge groundwater
  • Decreased runoff, decreasing pollutants carried into storm drains and into local surface water
  • Decreases likehood of flooding during heavy rainfall
  • Drawback is that it's more costly than traditional pavement
• Reducing Urban Runoff: Solution 2

  • Rain Gardens
  • Gardens planted in urban areas, especially surrounding a storm drain
  • The goal is for the garden to soak up most rain
  • Decreases runoff by allowing it to soak into garden soil surrounding storm drain
• Reducing Urban Runoff: Solution 2

  • Rain Gardens
  • Decreases likehood of flooding during heavy rainfall
  • Creates habitats for pollinators, aesthetic for passers, and stores CO2
• Reducing Urban Runoff: Solution 3

  • Public Transit
  • More cars on the road = more pollutants on streets to runoff into storm drains and local waters (ex. motor oil, gasoline, and antifreeze
  • Using a bus reduces cars on the road
  • More cars = more lanes and parking lots (impervious surfaces) and more storm water runoff
• Reducing Urban Runoff: Solution 3

  • Public Transit
  • Public transit reduces lanes, allowing for more space
  • Public transit decreases urban runoff, pollutants on the road, CO2 emissions, and even more traffic
• Reducing Urban Runoff: Solution 4

  • Building Up, Not Out
  • Building vertically decreases impervious surfaces by maximizing space and reducing land use in urban areas
  • Combined with "green roof" or rooftop gardens to further decrease runoff
• Reducing Urban Runoff: Solution 4

  • Building Up, Not Out
  • Green roof also sequesters CO2 and filters air pollutants out
  • Plants absorb NO2, particulate matter, and other pollutants into stomata and store in tissue or soil
  • Cleans air and decreases urban runoff
• Integrated Pest Management (IPM) Basics

  • Using a variety of pest control methods that minimize environmental disruption and pesticide use
• IPM

  • Requires researching and monitoring pests and targeting methods to specific pest life cycles
  • Must first identify pest
• What are three types of IPM (Integrated Pest Management)?

  Biocontrol, crop rotation, and intercropping
• IPM: Biocontrol

  • Introducing a natural predator, parasite, or competitor to control the pest population
  • Can include actually purchasing and spreading the control organisms in fields
  • Or building homes for them/planting habitats; they need to attract them
• Examples of Biocontrol

  • Ladybugs for aphids
  • Spiders for many pests insects
  • Parasitic wasps for caterpillars
• Crop Rotation

  • Many pests prefer one specific crop or crop family. They lay eggs in the soil, so when larvae hatch, they have preferred food source
  • Rotating crops (planting a different crop each season) can prevent pests from becoming established since it disrupts their preferred food choice

  
• Crop rotation disrupts weed growth since different crops can be planted at different times preventing bare soil from being taken over by weeds
• Intercropping

  • Often referred to as a "push-pull" system

  
• Intercropping Push-Pull

  • Push Plant: A plant that emits volatile chemicals that natural repel pest away from crop
  • Pull Plant: A plant that emits chemicals that attracts moths/pests to lay eggs in them instead of crop

  These 2 plants ensure pests stay away from the crop; pull plants can attract pest predators

  
• Intercropping Benefits: Part 1

  • Reduces death and mutation of non-target species
  • Atrazine leads to intersex frogs
  • DDT leads to eagle death from egg thinning
  • Glyphosate leads to bee die-offs
• Intercropping Benefits: Part 2

  • Reduces effects on human consumers of produce
  • Many pesticides are carcinogens (cancer-causing)
  • Reduces contamination of surface and groundwater by agricultural runoff with pesticides
• Intercropping Drawbacks

  • More time-consuming and costly than just crop dusting pesticide
  • Researching specific pests and planting numerous species of crops
• Soil Conservation

  • Agricultural techniques that minimize erosion (US is losing soil 10 times faster than it forms)
• Soil conservation prevents the loss of?

  Nutrients in topsoil, soil moisture, decomposers in topsoil, organic matterthat traps soil moisture
• Contour Plowing

  • Plowing parallel to natural slopes of the land instead of down slopes prevents water runoff and soil erosion
  • Curved furrows

  
• Terrancing

  • A method of cultivating crops on the sides of mountains or hills by planting on graduated terrances cut into slope
  • A series of "steps" or terrances
  • Catches water and prevents it from running off and eroding the soil

  
• Perennial Crops

  • The cultivation of crop species that live longer than 2 years without the need of replanting each year
  • Longer, more established roots and prevention of bare soil between harvest
• Windbreaks

  • Using trees or other plants to block the force of the wind from eroding topsoil
  • Can be used as a source of firewood or fruit (income)
  • Can provide habitat for pollinators and other species

  
• No-Tilling Farming

  • Leaving leftover crop remains in soil instead of tilling under
  • Adds organic matter to soil (nutrients, soil cover, moisture)
  • Prevents erosion from loosened soil

  
• Strip Cropping

  • Another name for intercropping
  • Alternating rows of dense crops (hay, wheat) with rows of less dense crops (corn, soy, cotton) to prevent runoff from eroding soil from less dense rows of crops

  
• Improving Soil Fertility

  • Restoring nutrient levels in the soil (Nitrogen, Phosphorus, Calcium and Magnesium)
• Improving Soil Fertility: Crop Rotation

  • Replating same crops continuously depletes soil of the same nutrients
  • Crop rotation can allow soil to recover from nitrogen-demanding crops like corn
  • Peas/beans (legumes) nitrogen-fixing bacteria in their root nodules that can return nitrogen to the soil
• Green Manure

  • Green manure is leftover plant matter from a cover crop -- a crop planted in the offseason between harvest and replanting of main crop

  
• Green Manure: Examples

  • Cover crops roots stabilize soil limiting topsoil erosion
  • Remains of cover crops (green manure) left on the field breakdown to release nutrients into the soil
• Limestone

  • Addition of limestone releases calcium carbonate -- a base -- which neutralizes acidic soil
  • Calcium is a needed plant nutrient
  • High H+ ion concentration, which displaces + charged nutrients from soil (leeching them out)
  • Makes toxic metals (aluminum) more soluble in soil

  
• Rotational Grazing

  • Regular rotation of livestock to prevent overgrazing

  
• • Overgrazing can kill plants, compact soil, and lead to erosion of topsoil
  • Rotational grazing can actually promote pasture growth as it is clipped down to half length, which is the fastest growth.

  
• Aquaculture

  • Raising fish or other aquatic species in cages/enclosures underwater

  
• Aquaculture: Benefits

  • Requires only a small amount of water, space, and fuel as opposed to wild populations
  • Reduces risk of fishery collapse (90% population decline in a fishery)
  • Doesn't take up any land space (compared to beef, pork, chicken)
  • Can be done efficiently where waste can be used by sea floor invertebrates
• Aquaculture: Drawbacks

  • High density produces high concentration of waste (e. coli and eutrophication)
• Aquaculture: Drawbacks

  • High density increases disease risk, which can be transmitted to wild population as well
  • May introduce non-native species or GMOs to local ecosystem if captive fish escape
  • Fish are fed antibiotics which can contaminate water via their waste