APES Ch.9

• What is agriculture?


  The practice of raising crops and livestock for human use and consumption
• What is cropland?


  Land used to raise crops for human use
• What is rangeland also known as?


  Pasture
• What fraction of land on Earth is used to produce food and fiber?

  More than 1 out of every 3 acres
• How did agriculture contribute to the development of modern societies?

  It allowed human cultures to shift from hunter-gatherers to permanent settlements with farming
• How may farming have begun according to the study material?

  As the seeds of wild fruits, grains, and nuts were unintentionally planted near human encampments
• What does archaeological evidence suggest about the invention of agriculture?

  It was invented independently in many different cultures, each specializing in a different local crop

  
• What is traditional agriculture?

  Biologically powered agriculture, using human and animal muscle power
• What is subsistence agriculture?

  Families produce only enough food for themselves
• What is intensive agriculture?

  It produces excess food to sell and uses animals, irrigation, and fertilizer, but not fossil fuels
• What characterizes industrial agriculture?

  It uses large-scale mechanization and fossil fuels to boost yields
• How do higher rates of irrigation, synthetic fertilizers, and chemical pesticides affect crop yields?

  They reduce crop pests and weed competition, further increasing yields
• What are monocultures?

  Uniform planting of a single crop
• What are the advantages and disadvantages of monocultures?

  Higher yields and profitability, but they destroy soil nutrients and pollute groundwater
• What is polyculture?

  Mixed crops in the same field
• What was the Green Revolution?

  An introduction of new technology, crop varieties, and farming practices to the developing world starting in 1950
• What were the effects of the Green Revolution?

  It increased yields and reduced starvation but degraded soil, water supplies, and pollinators
• What is soil?

  A system consisting of disintegrated rock, organic matter, water, gases, nutrients, and microorganisms
• How is soil derived?

  From rock, but shaped by microorganisms through biological activity
• What are the main components of soil composition?

  50% mineral matter, 5% organic matter, and 45% pore space
• Why do plants need soil?

  To provide nutrients for growth, structure for rooting, and a medium to hold water and nutrients for absorption

  
• What role do mycorrhizae play in soil?

  They form mutualistic relationships with plant roots, increasing water and nutrient absorption
• What is primary succession in relation to soil formation?

  It begins the process of soil formation as water, air, and living organisms break down parent material
• What is parent material?

  The base geologic material in a particular location
• What are examples of parent material?

  Hardened lava, volcanic ash, sediment deposited by glaciers, wind-blown dunes, and bedrock
• What is weathering?

  The physical, chemical, or biological processes that break down rocks to form soil
• What are the types of weathering?

  Physical, chemical, and biological weathering
• What causes physical weathering?

  Wind, rain, freezing, and thawing
• What is chemical weathering?

  It occurs as water or gases chemically alter rock
• What is biological weathering?

  It involves living things such as lichens producing acid or tree roots rubbing against rock
• What is humus?

  A dark, spongy, crumbly mass of material formed by partial decomposition that is very productive for plant material
• What factors influence weathering and organic matter accumulation?

  Climate, organisms, topography, parent material, and time
• How does climate affect soil formation?

  Warm, moist climates accelerate most weathering processes and increase the rate at which soil forms
• How do organisms influence soil formation?

  Plants and decomposers add organic material
• How does topography affect soil formation?

  Hills and valleys affect exposure to sun, wind, water, and influence soil movement
• How does parent material influence soil formation?

  The composition of parent material influences soil formation
• How long can soil formation take?

  It can take centuries, decades, or millennia
• Is soil renewable?

  Yes, but at a very slow rate
• What is a soil profile?

  The cross-section of soil as a whole
• What is a horizon in soil science?

  Each layer of soil