lec 9-10

1.

1 point

why is there fast decrease of som and nutrients in tropics as opposed to temperate zone?

There is no "winter" in the tropics

temperate zone is more abundant with microorganisms

Water availability is very low in the tropics

THIS IS A TRICK QUESTION. both would have equal amounts.

2.

1 point

expansion of non-fertile land at the expense of crops is known as

dessertification

desertability

desertification

desert-formation

3.

1 point

What would not happen if we stopped using pesticides?

loss of food

decrease in population of pests with resistance gene

cleaner ground water

humans more protected from hazardous diseases

4.

1 point

how is soil a critical component of ecosystems?

provides nutrient retention

provides water holding capacity

all plants need it to grow

substrate for microorganisms

5.

1 point

salinization is good in irrigation because it add anions to the soil profile

True

False

6.

1 point

all of soil organic matter which is picked up by wind is known as a ______

hint:8 letters + "-", no caps

7.

1 point

which are ecological negative effects of the green revolution? check all that apply

unsustainable fossil fuel use

unsustainable soil use

negative effects of pesticides

loss of crop production

unsustainable water use

8.

1 point

Humus is....

undecomposed organic matter that has a lot of neg sites to hold down cations.

decomposed organic matter that has a lot of positive sites to hold down anions

undecomposed organic matter that has a lot of positive sites to hold down anions

decomposed organic matter that has a lot of negative sites to hold down cations

9.

1 point

salinization increases with rain

True

False

10.

1 point

Whats is the most common type of water depletion in third world countries?

economical

physical

11.

1 point

Since the green revolution, agriculture has pushed into worse and worse land

True

False

12.

1 point

significance of bacillus thuringiensis

bacteria that is detrimental to crops

used in inserting genes into a plasmid

bacteria that is toxic to many insects

attracts other predators, (enemy of my enemy is my friend)

13.

1 point

how might one reduce desertification? check all that apply

alternating crop rows between heavy and loosely rooted

tilling the land

grow trees or bushes in a way that blocks the wind

irrigate with ground water

stop livestock from overgrazing

crop residue placed on the land as a surface cover during a certain period

move to an environment with no harsh winters (snow, very cold)

14.

1 point

what's good cheap way to decrease population of pests with resistance genes while still maintaining the use of pesticides?

introduce natural predator

refugia

insert bacterium into crops

keep changing pesticides

15.

1 point

what is associated with salinization?

irrigation

both

rain-fed

16.

1 point

where is desertification more likely to occur?

winter dry places

winter wet places

summer dry places

summer wet places

17.

1 point

what is not true about tilling?

There is decreased water loss with tilling

Weeds often are only transplanted if the soil is wet when tilled.

In cracking clay soils, tillage can prematurely close surface cracks and reduce the soils ability to accept high intensity summer storm rainfall, with increased potential for runoff and soil loss

Tillage speeds breakdown of stubble, thus reducing protection from water and wind erosion.

Tillage will bury weed seeds which will prolong seed bank dormancy in some weed species

18.

1 point

Consider the following options as reasons to why the land laser leveling technology adapted from the construction sector is becoming popular in Agriculture now a days. Bring out the one which is not true:

It is an agriculture industry standard in some western countries

It can save the irrigation water

It cuts the cost of agricultural operations

It can increase yield by considerable fraction

19.

1 point

which agriculture systems results in decrease of soil organic matter?

open

closed

20.

1 point

BT cotton is genetically modified in that it produces its own pesticides, the pink bolllworm, and therefore does not require the use of pesticides

True

False

21.

1 point

BT cotton is genetically modified in that it produces its own pesticides, the pink bolllworm, and therefore does not require the use of pesticides

True

False

22.

1 point

You are a farmer. You realize your crops need to be watered. What sort of water source will you use?

rain-fed water

surface water

ground water

purified water

23.

1 point

what is the leading cause of harvest loss?

viruses

animal pests

weeds

pathogens

24.

1 point

whenever fields are harvested and seeds are open and not flat the wind will remove ____ from the soil profile

hint: 5 letters, no caps