Pasture Persistence

Question 1

Define pasture persistence

Answer 1

the continued yield and performance of a pasture over time

Question 2

Define poor pasture persistence

Answer 2

when a desirable species is replaced by a weedy, undesirable species

Question 3

What are the 8 Factors Affecting Pasture Persistence

Answer 3

Summer dry conditions, high temperature, soil fertility, pests and diseases, grazing management, pugging, genetics, endophytes

Question 4

How many factors affecting pasture persistence need to combine to cause severe damage?

Answer 4

2-3

Question 5

Explain the gradual deterioration of pasture components

Answer 5

Total DM production drops over time and the composition changes where weed species which are not as nutritious increase, whilst the sown species decreases. But overtime this all decreases.

Question 6

Name 3 uncontrollable factors which may affect pasture persistence

Answer 6

Temperature, rainfall, soil type

Question 7

Name 3 controllable factors that can affect pasture persistence

Answer 7

species choice, soil fertility, grazing management

Question 8

What are the 4 areas which policies can be made in to enhance pasture persistence?

Answer 8

livestock type, stocking rate, calving and lambing date, supplement use, summer crops

Question 9

What is the main factor to consider when choosing species to maintain pasture persistence

Answer 9

Match the species to the environmental conditions

Question 10

How can soil fertility be managed for optimal fertility/nutrient requirements of the pasture species?

Answer 10

Do soil testing, ensure N, P K, S and soil pH is adequate

Question 11

How can summer crops improve pasture persistence in dry climates?

Answer 11

Takes the pressure of the pasture platofrm whilst providing high ME feed to compensate for reduced summer pasture growth to maintain residuals and allow healthy leaf canopy to be formed without damaging growing points.

Question 12

How can supplements be used to promote pasture persistence ?

Answer 12

Have an advantage over crops as you can store them for a long period of time. It is also good for feed budgetting as the quantity is known before feeding.

Question 13

How can pasture establishment increase pasture persistence?

Answer 13

If conditions are created to allow for a healthy pasture to establish within the first month after sowing then persistence is increased.

Question 14

What are the 4 focus points for grazing management to maximise pasture persistence?

Answer 14

Before, during and after a dry period, as well as during wet conditions

Question 15

How high should pasture covers be before a dry period and why?

Answer 15

1000-2500kgDM/ha - maximise net accumulation and resilience

Question 16

What is the main aim of grazing management before the dry period

Answer 16

Have a high population of healthy, well grown plants

Question 17

What is the relationship between tiller size and tiller number?

Answer 17

If tiller numbers go down, leaf size increases. If leaf size goes down, tiller numbers increase.

Question 18

Explain the seasonal cycle of white clover

Answer 18

Old stolons die in mid-spring, with stolon growth and clover recovery in late spring. In the summer, stolons produce alot of shoots, want to minimize the shading of the ryegrass to get more PAR.

Question 19

How is ryegrass persistence impacted during dry periods?

Answer 19

Long periods of soil moisture stress, evapotranspiration and temperatures

Question 20

What are the implications of overgrazing in extended dry spells?

Answer 20

Killing ryegrass plants, allows weed species to come in.

Question 21

Explain on-off grazing and when it should be used

Answer 21

On-off grazing occurs when animals are removed as soon as the residual is reached, being moved to a feed pad or sacrifice paddock. Sacrificing animal intake short-term for long-term pasture persistence. Do this during dry-periods.

Question 22

What other methods can be used to improve pasture persistence during a dry-period?

Answer 22

Supplements and decreasing feed demand through selling stock or once-a-day milking dependent on the price of milk/meat.

Question 23

Why is it important not to graze too soon after the dry-period has ended?

Answer 23

Pasture needs time to recover and accumualte the buffer of herbage until it can be grazed again

Question 24

When should ryegrass be grazed?

Answer 24

At the 2-3 leaf stage, when the majority of the tillers have reached this 2.5 tiller stage.

Question 25

How much can pugging damage reduce dry matter by?

Answer 25

Up to 35%

Question 26

What are two grazing strategies which can be used in wet conditions?

Answer 26

On-off grazing and restoring pastures

Question 27

Explain the process of restoring pugged pastures

Answer 27

under sowing with Italian or hybrid ryegrasses, localised broadcasting or oversowing with species to minimize bare areas and weed takeover.

Question 28

What is the cost of pastoral weeds to the NZ economy?

Answer 28

$1.2 billion per year

Question 29

What did Harris say will lead to adequate weed control / increase pasture persistence?

Answer 29

knowledge of the weed flora, habitat preferences and competitive characteristics of desirable species can allow seed mixtures to be sown to minimize this.

Question 30

How much did grazing increase when drought area pasture mixes were changed from perennial ryegrass to cocksfoot, tall fescue and phalaris?

Answer 30

112% more grazing

Question 31

What impact does lax grazing have on ryegrass tiller density and how does this impact pasture persistence?

Answer 31

Decreases tiller density, increased ability for weeds such as dock to invade pasture.

Question 32

List 7 of the factors causing gaps in pasture

Answer 32

pugging/trampling, drought, shading, lack of fertlity, undergrazing/over grazing, insect attack, waterlogging

Question 33

What did Boswell and Crawford find to be the best grazing heights for maximum pasture density?

Answer 33

grazing to 3cm rather than 6cm , grazing below this reduced tiller density, especially in dry conditions