Source: Earth PD http://bit.ly/1JPJLLL Farming CC http://bit.ly/1KdyJhL Sheep CC http://bit.ly/1tAz0Jo Hunters PD http://bit.ly/1uGMn5Y Egyptian Ag PD http://bit.ly/1zj337J World Grain GraphCC http://bit.ly/1zFDC3E Rice Field CC http://bit.ly/1LnspI5 Cornfield CC http://bit.ly/1JQkmS9 Latex Tree PD http://bit.ly/1KepE8v Coffee Plant CC http://bit.ly/162WtYk Hens CC http://bit.ly/1yLPf1W Fish Farming CC http://bit.ly/1vfNhMH
Hi. I'm Jensen Morgan. We're going to talk about some great concepts in environmental science. Today's topic is Agriculture Practices. So let's get started. We're going to talk about what agriculture is and how it's changed become what it is today.
Agriculture is the activity of growing crops and raising animals for food and supplies. Thousands of years ago, humans lived by being hunter-gatherers and traveling seasonally. This meant that they would collect whatever plant-based foods they could find and eat whatever animals they could kill.
This period in human history forced populations to be low, because food was sometimes difficult to find. Eventually the practice of growing crops and raising animals-- the practice of agriculture-- took hold and transformed human society. Humans transitioned to having settlements instead of traveling seasonally. The result allowed human populations to grow.
Agriculture then continued for thousands of years, steadily evolving until an explosion of technological advancement in the mid 1900s changed agriculture forever. This was called the Green Revolution. It allowed humans to transition from a resource-based agriculture to demand-based agriculture. Meaning economics drove food production, as opposed to food production being limited by available resources.
Three primary advances allowed food production to skyrocket. Improved breeding methods of crops increased plant survival and yield. Mechanization of farming tools and machines improved farmers' efficiency and cut down on human labor requirements. And chemical fertilizers allowed plants to get whatever nutrients they needed to grow.
The impacts of the Green Revolution are apparent when looking at the increase in grain production from 1950 to 1990. You can ignore the axis labels. What I want you to focus on is the fact the world grain production almost tripled worldwide in only 40 years.
Food production is dependent on four primary factors. Arable land-- which is land suitable for crop growth. Temperature-- certain crops and animals can only survive in certain temperature ranges. Precipitation-- certain crops and animals can only survive with certain amounts of rainfall. And nutrient availability, or the amount of usable nutrients in the soil for plants to consume. These combined factors determine what kinds of kinds of crops can be grown and how well they will grow.
I want to focus in on plant sources of agriculture for a moment. Corn, rice, and wheat are by far the dominant crop grown all over the world. These three crops provide over half of all human calorie needs on the planet.
There are two main categories of plant crops grown. And they also happen to be our key terms for today. Subsistence crops and cash crops.
Subsistence crops are food products needed for human survival. Examples of this are rice and corn.
Cash crops are nonfood products or crops that do not make up primary nutrition needs. Examples are coffee-- a food product not for primary nutrition-- and latex, a nonfood product grown for industrial use and economic gain.
Meat sources are made up of animals that have been domesticated for human use. Only about a dozen large animals have been domesticated for eating. Two prime examples are chickens and sheep. The practice of aquaculture-- or farming fish-- is also an important part of agriculture.
There are a few important facts to know about human meat consumption. The developed world consumes 76% of meat compared to only 24% in the developing world, even though the developing world makes up the majority of the world's population. 90% of the grain grown in the US is used for animal feed, which take 16 pounds of grain to grow one pound of meat.
US citizens eat an average of 120 kilograms of meat per person every year, while their Indian counterparts eat only 4.4 kilograms.
Now let's have a recap. Agriculture is the practice of growing crops and raising animals for food and supplies. Humans transitioned from being hunter-gatherers to being farmers, thousands of years ago. Agriculture has allowed human populations to grow. And in the mid 1900s, the Green Revolution skyrocketed food production worldwide.
There are four key factors that influence food production-- arable land available, temperature, precipitation, and available nutrients in the soil.
Meat sources of food are consumed primarily by the developed world. And plant sources of food are made up of two types-- subsistence crops and cash crops, which brings us back to our key terms for today.
Subsistence crops are food products needed for survival. Cash crops are nonfood products are food crops that do not make up primary nutrition needs.
Well that's all for this tutorial. I hope these concepts have been helpful. I hope to see you next time. Bye.