Environmental Aspects of Food Production page 13.0

Review: pH scale and 3 soil types  pH  Use the pink card for acid and the blue card for base when identifying the appropriate properties or examples of each.  3 soil types  The vocabulary terms can be written in your notes, or on 12.0 if your small group instructor is accepting that page for extra credit

Most of the food consumed by humans in the world comes from plants… directly or indirectly

Plants get much of what they need to grow from the soil. - nutrients water - water - air (oxygen for roots) Last week we focused on the water and air that plants receive from the soil and this week we will address the nutrients and farming practices that supply and regulate nutrient availability

Macronutrients = nutrients needed in large amounts - nitrogenN - phosphorusP - potassiumK

Micronutrients = nutrients needed in small amounts - sulfur, calcium, sodium, magnesium, manganese, zinc, copper, selenium, molybdenum, iron (to name a few (to name a few)

Maximizing food production means making sure the plants have everything they need to grow. - plenty of sunlight and carbon dioxide - water replaced with precipitation or irrigation These are mother nature controlled variables…

What does man control?  Humans farm the land or soil in order to grow food to survive.  These practices can deprive the soil of the natural nutrients.  Man tries to replace the nutrients to maximize soil productivity and use the soil year after year.  $$$ It is a business for most farmers

How are soil nutrients lost ? - crop removal (harvesting)

How are soil nutrients lost? - soil erosion

Fertilizer: any material added to the soil to supply one or more plant nutrients. Natural Fertilizers solid animal wastes, decayed plant matter ex.manure, compost Artificial Fertilizers nitrogen, phosphorus, potassium, etc. (N, P, K)

Nutrients can be replentished by adding natural fertilizers. - animal and plant wastes

or Artificial fertilizers: These both will also build the soil.

Natural Fertilizers Advantages: - replace organic matter - natural, safe Disadvantages: - may take longer to work or take effect on production - lower crop yields in comparison to artificial fertilizers

Artificial Fertilizers Advantages: - 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 by competition from other plants (weeds) and destruction by other organisms. - Modern farmers use pesticides to help with these problems Pesticides:

Pesticides: chemicals that are used to control, repel or eliminate destructive organisms (weeds, insects, bacteria, fungi, etc.).  Herbicide - used to kill plants.  Insecticide – used to kill insects.  Fungicide – used to kill fungi.

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: - 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: A. 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:

B. Reduce erosion: How? 1. Practice contour farming. - work across a hill instead of up and down the hill

Contour farming advantages: - reduces soil erosion! - reduces the need for expensive fertilizers - helps to keep waterways cleaner

Contour farming disadvantages: - more difficult to accomplish with big equipment - takes more time and fuel

Other ways of Reducing erosion to conserve soil:. Keep soil covered! 2. Keep soil covered! - vegetation (cover crops) - 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 strip cropping.

5. Protect areas where water wants to flow with permanent grass cover … **This is also a wonderful soil building method** Reducing erosion to conserve soil:

6. Take extra care on steep slopes - terracing Another wonderful soil building method Reducing erosion to conserve soil:

Why else reduce erosion?  These practices that reduce erosion can also build soil. Tilling the ‘humus’ or leftover crop waste Tilling the ‘humus’ or leftover crop waste Growing grass to prevent erosion will result in a nice circle of life that builds the soil. Growing grass to prevent erosion will result in a nice circle of life that builds the soil. Terracing could even ‘catch’ soil from above that may be washing down to increase the level of soil where the farming is occurring Terracing could even ‘catch’ soil from above that may be washing down to increase the level 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: