Environmental Environmental Aspects of Food Aspects of Food

ProductionProduction

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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: