Lecture 3 - Tropical Cropping Systems

Question 1

cropping system

Answer 1

refers to growing a combination of crops in space and time

Question 2

an ideal cropping system should…..

Answer 2

use natural resources efficiently, provide stable and high returns, and does not damage the environment

Question 3

commonly practiced cropping systems

Answer 3

crop rotation, intercropping, mixed cropping, relay cropping

Question 4

crop rotations in cool temperate systems (like Canada)

Answer 4

1 crop per season (rotate different crops each year)
occasional double crop/winter crop
winter is part of cropping system as pest management

Question 5

common example of western Canada cereal based cropping system (4 yrs)

Answer 5

Yr 1: pulses
Yr 2: cereal
Yr 3: cereal
Yr 4: oilseed

Question 6

benefits of crop rotation

Answer 6

diversification of production
positive effects on next crop
source of N and organic matter
breaks cycle of pests

Question 7

what needs to be considered abut effects of 1 crop on another

Answer 7

will residual herbicides/chemicals affect subsequent crop
are there shared diseases
is the previous crop greedy/ take up a lot of moisture and nutrients

Question 8

what does cropping intensity mean

Answer 8

number of crops per year

Question 9

what is the cropping intensity in cooler and warmer climates

Answer 9

one in cooler temps
2 in warmer temps
3 if it is hot and irrigation is used

Question 10

how is cropping intensity sometimes expressed

Answer 10

as a decimal meaning average intensity for area

Question 11

what are some ways 2 or more crops are grown on the same field in a year

Answer 11

sequential cropping
relay intercropping
full intercropping

Question 12

sequential cropping

Answer 12

one crop after the other

Question 13

relay intercropping

Answer 13

2nd crop seeded before 1st crop is finished

Question 14

full intercropping

Answer 14

2 or more crops grown at the same time

Question 15

methods of intercropping

Answer 15

broadcasting seed of both crops (mixed intercropping)
main crop planted in rows, other crop broadcasted
main crop and intercrop planted in rows (row intercropping)
second crop planted before 1st crop matures (relay intercropping)

Question 16

economic benefits of intercropping

Answer 16

greater yield
insurance against crop failure or unstable market
financial stability
lower inputs
improvement of forage quality

Question 17

agronomic benefits of intercropping

Answer 17

organic matter increases
improve soil fertility
reduction of pests/disease
restore biodiversity

Question 18

environmental benefits of intercropping

Answer 18

promotion of biodiversity
soil conservation through ground cover
carbon sequestration

Question 19

limitations of intercropping

Answer 19

extra work in planting, crop management, and harvest
complex interactions between intercropped plants
mechanization

Question 20

what are some of the hypotheses for why there are reduced pests in intercropping

Answer 20

1: disruptive crop hypothesis
2: natural enemies hypothesis
3: trap crop hypothesis

Question 21

disruptive crop hypothesis

Answer 21

2nd plant disrupts ability of pest to attack host crop efficiently

Question 22

natural enemies hypthesis

Answer 22

more predators and parasites in intercrop

Question 23

trap crop hypothesis

Answer 23

2nd plant species attracts pest, keeping it away from more vulnerable crop

Question 24

alley cropping

Answer 24

crops planted in alleys between hedge rows of woody species

Question 25

effects of trees on crops

Answer 25

shield smaller, shade-tolerant crops
stabilize temps
permanent reservoirs for parasitoid and predators
decompose organic matter
supply nutrients and mulch via leaf litter

Question 26

example of alley cropping

Answer 26

rubber trees and rice. Rice is planted in the water ways between trees until the canopy closes

Question 27

when is there no advantage to plant competition

Answer 27

if both plant species are aggressively pursuing resources in the same niche

Question 28

what does plant competition or compatibility depend on

Answer 28

crops species or cultivar
density
arrangement
timing of planting each crop

Question 29

interspecific

Answer 29

between different species

Question 30

intraspecific

Answer 30

between members of the same species

Question 31

when is competitive production an advantage

Answer 31

if the interspecific competition is less than the intraspecific competition due to different use of resources

Question 32

benefits of facilitation in intercrops

Answer 32

one species modifies environment for benefit of second species and improves soil resources and pest management

Question 33

how would you calculate intercrop advantage

Answer 33

LER (Land Equivalent Ratio)

Question 34

LER (Land Equivalent Ratio)

Answer 34

amount of monoculture land needed to produce same yield as intercrop (basically if it worth intercropping)

Question 35

LER equation

Answer 35

I1/M1 + I2/M2
I - grown as intercrop
M - grown as monocrop

Question 36

what does it mean if LER> 1

Answer 36

intercrop is more efficient

Question 37

what does it mean if LER < 1

Answer 37

monoculture is more efficient