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Trevor Craig

Energy Science 110

Crop Intensification, Forests, & Biomass Energy Today, 12

10/2/11

This lecture was about the green revolution and biomass, primarily being wood, usage

throughout the world. When we grow plants and harvest them we take a little of the earths

nutrients. Coffee yields 2000 kg/ha and has 293 kg/ha of potassium within them from the soil,

after prolong use of the same crop the soil begins to be deficient of the nutrients which the crop

needs. This is the biggest problem for nitrogen, potassium, and phosphorous.

Not all of the ground in the world can be used for planting crops, where we can plant

crops is limited by many things like, drought, mineral stress, shallow depth, water excess, and

permafrost, leaving only about 11% of the worlds land to be able to be used for crop growing

without serious limitations. Increasing the percentage of land without major limitations was one

of the ideas of the green revolution.

During the green revolution we saw an increase of crop yields, between the years 1960s

and 1980s. One of the major reasons we have seen crops increase is because of the use of

fertilizer, especially the fertilizer nitrogen. In 1960 the amount of nitrogen we were using was

about 2 million tons, and then in 1980 it was 20 million tons, and finally in 1990 it was at 40

million tons of nitrogen. Nitrogen helps crops grow but only to a certain point, crops seem to be

helped when using nitrogen up to 200 kg N/ha, then they start to level out in growth or actually

decrease. With this increase in agriculture yield during the green revolution there was also an

increase in meat production between the years 1950 and 2000, where it increased 5 fold.

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Depending on how we grow the plants determines how much nutrition is used and how

much is left in the soil. Slash and burn technique supplies food for approximately 40 million

people but is not a very effective or ecofriendly technique. The most used cropping system is

irrigated continuous lowland using only 24 million ha. and providing food for 1800 million

people, where slash and burn technique used 1,035 million ha. and provided for 40 million

people.

Trees are extremely important to society and have been used as a primary source of fuel

and building materials for over 5000 years. Today 40% of the world often uses biomass to heat

their homes and cook their meals. The use of biomass as our primary fuel source has gone down

to almost 0 but with rising oil prices we could use more biomass for energy, like we used to, to

help offset the rising price of oil.

Per capita-Per unit of population; per person.

Fertilizer- Any of a large number of natural and synthetic materials, including manure and

nitrogen, phosphorus, and potassium compounds, spread on or worked into soil to increase its

capacity to support plant growth.