The Role of Cultivated Plants in the Living World

Crop Science 1

Fall 2004

Who are Plant Scientists?

• The first plant scientists were those who:– Observed how plants grew– Developed ideas about the process and how to

improve it– Tested those ideas– Came to conclusions

What if there were no Plants?

• Without animals plants would survive and/or flourish

• Without plants all animals would die

• Without humans most farmed plants would become extinct

Plants as a Food Source

• Plants – autotrophic use sun energy to create food

• Animals – heterotrophic depend upon plants for their food

• Photosynthesis – Carbon dioxide (air) + water (roots) = carbohydrates

• Photosynthesis occurs in leaves and other green parts (chloroplasts)

Cultivation

• Definition: the growing or tending of crops• Cultivation came into use about 18,000 years ago

(10,000 years after modern humans)• 18,000 years ago – Egypt - Cereals (Wheat,

Barley)• 6,000 years ago – Europe – Cereals• 5,000 years ago – Mexico – Corn• 3,500 years ago – South America – Potatoes • 3,500 years ago - Far East - Rice

Feeding the World’s Population

• Cereal Crops

• Roots and Tubers

• Oil Crops

• Sugar

• Fruit Crops

• Vegetable Crops

Cereal Crops

• Wheat• Maize (Corn)• Rice• Barley• Oats• Sorghum• Rye• Millet• Over ½ the world’s food

supply comes from these

Roots and Tubers

• Potatoes• Sweet Potatoes• Cassavas

Oil Crops

• Soybeans• Corn• Peanuts• Palm• Coconut• Sunflowers• Olive• Safflower

Sugar

• Sugar Cane• Sugar Beets

Fruit Crops

• Bananas• Oranges• Apples• Pears• Etc.

Vegetable Crops

• Lettuce• Carrots• Broccoli• Asparagus• Etc.

Table 1-1

RankCalories

Produced per Unit Area

Protein Produced per

Unit Area

1 Sugar Cane Soybeans2 Potato Potato3 Sugar Beets Corn4 Corn Peanuts5 Rice Sorghum6 Sorghum Peas7 Sweet Potato Beans8 Barley Rice9 Peanuts Barley10 Winter Wheat Winter Wheat

Some Important Food Crops Ranked According to Calorie and Protein Production per

Unit of Land Area

Energy Transformation

• 22 pounds of grain to produce 2.2 pounds of beef• Bushel of grain = protein requirement for 23

people– If fed to chickens energy for 2 and protein requirement

for 8 people

• Animals consume grain that is not edible to humans and produce protein of a higher quality and provide necessary minerals and vitamins

Past and Present

• 1970’s brink of famine, ecological disaster• 1980’s reversal of projection• Reversal was achieved by:

– Agricultural research available to developing countries

– New Cultivars – cultivated varieties (wheat, corn, rice)

• By 2009, food consumption in nearly ½ of the developing countries will not meet nutritional standards

Non-Food Benefits

• Wood and wood products– Building material, fuel, landscape, paper, etc.

• Textiles from fiber-producing crops– Clothing, rope, twine, burlap and etc.

• Drugs and medicines– Aspirin from willow trees, codeine from

poppies, tobacco

Non-Food Benefits

• Industrial– Latex from rubber tree– Pitch, turpentine and resin from pine trees

• Aesthetic– Perfumes and spices

• Environmental– Erosion control– Oxygen

Challenges for the Future

• New challenges more social than production

• Starvation Exists – social, political reasons

• Increased GMO’s (genetically modified organisms)– Round-up Ready, Flavr Savr, Rice w/vitamin A

Lab Assignment

• Divide into Groups of 3-4• Using the internet research:

– World Food Supply – 1800-2010– World Population – 1800-2010– U.S. Corn Yield – 1700-2010– Average U.S. Farm Size – 1700-2010– Average World Farm Size – 1700-2010– Top 25 Commodities in U.S. 2000– Pick 3 California Counties – top 10 commodities

• Email clintcowden@westhillscollege.com