environmental aspects of food production page 13.0
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Environmental Environmental Aspects of Food Aspects of Food
ProductionProduction
page 13.0page 13.0
Review:Review: pH scale and 3 soil typespH scale and 3 soil types http://wsd-science9.wikispaces.comhttp://wsd-science9.wikispaces.com
pHpH Use the Use the pinkpink card card
for for acidacid and the and the blueblue card for card for basebase
when identifying when identifying the appropriate the appropriate properties or properties or examples of each.examples of each.
3 soil types3 soil types The vocabulary terms can The vocabulary terms can
be written in your notes, or be written in your notes, or on on 12.012.0 if your small group if your small group instructor is accepting that instructor is accepting that page for extra creditpage for extra credit
Most of the food consumed by Most of the food consumed by humans in the world comes humans in the world comes from plants… from plants…
directly or indirectlydirectly or indirectly
Plants get much of what they Plants get much of what they need to grow from the soil.need to grow from the soil.
- nutrients- nutrients
- waterwater
- air (oxygen for roots)- air (oxygen for roots)
Last week we focused on the Last week we focused on the water and airwater and air that plants that plants receive from the soil and receive from the soil and this this week we will address the week we will address the nutrientsnutrients and farming practicesand farming practices that supply and regulate that supply and regulate nutrient availabilitynutrient availability
Macronutrients = nutrients Macronutrients = nutrients needed in large amountsneeded in large amounts
- nitrogen- nitrogen NN
- phosphorus- phosphorus PP
- potassium- potassium KK
Micronutrients = Micronutrients = nutrients needed nutrients needed in small amountsin small amounts
- sulfur, calcium, sodium, - sulfur, calcium, sodium, magnesium, manganese, magnesium, manganese, zinc, copper, selenium, zinc, copper, selenium, molybdenum, iron molybdenum, iron
(to name a few(to name a few)
MaxiMaximizing food producmizing food production tion means means making suremaking sure thethe plants have everything they plants have everything they need to need to grow.grow.
- plenty of sunlight and - plenty of sunlight and carbon dioxidecarbon dioxide
- water replaced with - water replaced with precipitation or irrigationprecipitation or irrigation
These are mother nature controlled variables…
What does man control?What does man control?
Humans farm the land or soil in order Humans farm the land or soil in order to grow food to survive.to grow food to survive.
These practices can deprive the soil These practices can deprive the soil of the natural nutrients.of the natural nutrients.
Man tries to replace the nutrients to Man tries to replace the nutrients to maximize soil productivity and use maximize soil productivity and use the soil year after year. the soil year after year.
$$$ It is a business for most farmers$$$ It is a business for most farmers
How are soil nutrients lostHow are soil nutrients lost??
- crop removal (harvesting)- crop removal (harvesting)
How are soil nutrients lost?How are soil nutrients lost?
- soil erosion- soil erosion
Fertilizer:Fertilizer: any material added to the soil to any material added to the soil to
supply one or more plant nutrients.supply one or more plant nutrients. Natural Natural FertilizersFertilizerssolid animal wastes, decayed plant matter
ex.manure, compost
Artificial Artificial FertilizersFertilizersnitrogen, phosphorus, potassium, etc.(N, P, K)
Nutrients can be replentished by Nutrients can be replentished by adding adding natural fertilizers.natural fertilizers.
- animal and plant wastes
or Artificial fertilizers:
These both will also build the soil.
Natural FertilizersNatural Fertilizers
Advantages:Advantages:- replace organic matter- natural, safe
Disadvantages:Disadvantages:- may take longer to work or take effect on production- lower crop yields in comparison to artificial fertilizers
Artificial FertilizersArtificial FertilizersAdvantages:
- quickly restores fertility- increases crop yields
Disadvantages:- can be harmful to people and
wildlife- contaminates water- topsoil quality is reduced- topsoil loses ability to hold water- doesn’t replace organic matter
Crop production can be reduced Crop production can be reduced by by competition from other plants competition from other plants
(weeds) and destruction by (weeds) and destruction by other organisms.other organisms.
- Modern farmers use pesticides to - Modern farmers use pesticides to help with these problemshelp with these problems
Pesticides:Pesticides:
Pesticides: Pesticides: chemicals that are used chemicals that are used to control, repel or eliminate to control, repel or eliminate destructive organisms (weeds, destructive organisms (weeds, insects, insects, bacteria, fungi, etc.).bacteria, fungi, etc.).
Herbicide - Herbicide - used to kill plants.used to kill plants.
Insecticide –Insecticide – used to kill insects.used to kill insects.
Fungicide –Fungicide – used to kill fungi.used to kill fungi.
Advantages of pesticides:Advantages of pesticides:- quick fix to problems with weeds, insects, etc.
- controls problems thus reducing work
- reduce damage done to crops, resulting in higher yields and lower food costs to consumers
Disadvantages of pesticides:Disadvantages of pesticides:
- expensive $$$$$$$$$$$$
- makes soils prone to erosion
- harmful to humans, livestock, and other organisms and surrounding ecosystems
- pests build up resistance due to overuse
- not target specific
Protecting the soil:
- It is most effective to try and retain as many soil nutrients as possible, and build the soil
-This requires a process to till crop residue back into the soil
Protecting the soil:Protecting the soil:A. rotate cropsA. rotate crops
-Why? You want to replenish nutrients
-How? Plant legumes after crops that use a lot of nitrogen… like corn
Notice the nodules on these roots
+=
- helps conserve and replenish soil nutrients
- increased diversity over years
- reduces long-term problems with pests
Crop rotation advantages:
- requires planning
- some crops are less valuable than others
corn=$Beans=$
Crop rotation disadvantages:Crop rotation disadvantages:
B. Reduce erosion:B. Reduce erosion:
How? 1. Practice contour farming.How? 1. Practice contour farming.
- work across a hill instead of - work across a hill instead of up and down the hillup and down the hill
Contour farming advantages:Contour farming advantages:
- reduces soil erosion!- reduces soil erosion!
- reduces the need for - reduces the need for expensive expensive fertilizersfertilizers
- helps to keep waterways - helps to keep waterways cleanercleaner
Contour farming disadvantages:Contour farming disadvantages:
- more difficult to accomplish - more difficult to accomplish with big equipmentwith big equipment
- takes more time and fuel- takes more time and fuel
Other ways of Reducing erosion Other ways of Reducing erosion to conserve soil:to conserve soil:
2. Keep soil covered!. Keep soil covered!
- vegetation (cover crops- vegetation (cover crops))- crop residues – - crop residues –
tilling these residues is a wonderful soil building example
Reducing erosion to conserve soil:3. Slow down water and wind moving
across the soil surface.
- shelter belts and windbreaks
Reducing erosion to conserve soil:
4. Practice 4. Practice strip strip cropping.cropping.
5. Protect areas where water wants to flow with permanent grass cover…
**This is also a wonderful soil **This is also a wonderful soil building method**building method**
Reducing erosion to conserve soil:
6. Take extra care on steep slopes
- terracing- terracing
Another wonderful soil building method
Reducing erosion to conserve soil:
Why else reduce erosion?Why else reduce erosion? These practices that reduce erosion can These practices that reduce erosion can
also also build soilbuild soil.. Tilling the ‘humus’Tilling the ‘humus’ or leftover crop waste or leftover crop waste Growing grassGrowing grass to prevent erosion will result in to prevent erosion will result in
a nice circle of life that builds the soil.a nice circle of life that builds the soil. TerracingTerracing could even ‘catch’ soil from above could even ‘catch’ soil from above
that may be washing down to increase the that may be washing down to increase the level of soil where the farming is occurringlevel of soil where the farming is occurring
Food production in the Space age:Modern farm machines use onboard computers and global positioning satellites to monitor crop yields.
- satellite monitoring
Food production in the Space age:
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