Environmental Science Agriculture and Food Production 2

Question 1

The Ogallala Aquifer, which underlies the U.S. Great Plains, is a critical concern for agriculture because:

Accepted Answer

It is being depleted by irrigation much faster than it is naturally recharged

Answer

The Ogallala is a fossil aquifer recharged over thousands of years; current irrigation withdrawals vastly exceed recharge rates, threatening the agricultural productivity of 8 Great Plains states.

Question 2

Terracing as an agricultural technique on steep slopes primarily serves to:

Accepted Answer

Create level planting areas that reduce runoff velocity and soil erosion

Answer

Terraces cut horizontal steps into hillsides, converting steep, erosion-prone slopes into level or nearly level planting areas that hold water and soil.

Question 3

In terms of water use efficiency, which of the following irrigation methods uses water most efficiently?

Accepted Answer

Drip (micro) irrigation

Answer

Drip irrigation delivers water directly to the root zone through emitters, minimizing evaporation and runoff; typical efficiency is 85-95% compared to 60-80% for sprinklers and 25-60% for flood irrigation.

Question 4

Genetically modified (GM) crops engineered with Bt toxin produce an insecticide that:

Accepted Answer

Is derived from a naturally occurring soil bacterium and is toxic to specific insect larvae

Answer

Bt toxin is derived from Bacillus thuringiensis, a naturally occurring soil bacterium; its crystal proteins are highly selective, primarily toxic to Lepidoptera (caterpillars) or Coleoptera (beetles) larvae, not to mammals or most non-target organisms.

Question 5

Salinization of agricultural soils is primarily caused by:

Accepted Answer

Irrigation with saline water or waterlogging that allows dissolved salts to accumulate as water evaporates

Answer

When irrigation water evaporates or transpires, it leaves behind dissolved salts; in waterlogged conditions without adequate drainage, salts accumulate in the root zone to toxic levels.

Environmental Science Practice Test

Environmental Science Practice Test

Environmental Science Agriculture and Food Production 2