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Environmental Science > Cereals 2024 Week 9 Lecture Nitrogen Nutrition > Flashcards

Cereals 2024 Week 9 Lecture Nitrogen Nutrition Flashcards

1
Q

Whats the important to get a cereal crop moderate-high yielding

A

Nitrogen uptake

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2
Q

When the crop receives nitrogen what % of N is “efficiency N recovery”
and
“what is the soil N uptake already in the soil?

A
  • Efficiency of fertilizer N recovery = 0.58, 58%

-Soil N uptake = 95kg/ha

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3
Q

Whats the fertiliser N rate (kg/ha) from previous question in terms of formula?

A

Crop N uptake (kg/ha)=
95(kg) + 0.58 = Fert N rate

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4
Q

What is used in Ireland and UK as a basis for fertiliser N Recommendations?

A

Nitrogen Index system for cereals

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5
Q

What does the N index take onto account for each tillage crop? (3)

A

– the previous crop
– manuring history of the field
– soil type

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6
Q

What does the N index scale go from?

A

1-4

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7
Q

Explain Index 1:

A

small release of soil N
The fifth tillage crop following permanent
pasture. For subsequent tillage crops
use the continuous tillage table

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8
Q

Explain Index 2:

A

medium release of soil N
The 3rd or 4th tillage crop following
permanent pasture. If original permanent
pasture was cut only, use index 1

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9
Q

Explain Index 3:

A

large release of soil N
The 1st or 2nd tillage crop following
permanent pasture (see also index 4). If
original permanent pasture was cut only,
use index 2

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10
Q

Explain Index 4:

A

very large release of soil N
The 1st or 2nd tillage crop following very
good permanent pasture which was
grazed only.

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11
Q

In sort of protein do you want in Barley?

A

Moderate

The more N you apply, the higher protein you get so apply a moderate N value

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12
Q

The more N you apply the greater the risk of what?

A

lodging

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13
Q

What does the N Index system for cereals require ?

A

requires that nutrient supply be
matched to crop demand, both in terms of
the quantity applied and the time of
application relative to the crop yield, soil
and climatic conditions

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14
Q

Index:
1
2
3
4
W. Wheat kg/N/Ha?
Winter Cereals

A

1- 210
2-180
3-120
4-80

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15
Q

Index:
1
2
3
4
W. Barley kg/N/Ha?
Winter Cereals

A

1- 180
2-155
3-120
4-80

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16
Q

Index:
1
2
3
4
W. Oats kg/N/Ha?
Winter Cereals

A

1- 145
2- 120
3- 85
4- 45

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17
Q

Index:
1
2
3
4
S.Wheat kg/N/Ha?
Spring Cereals

A

1-160
2-130
3-95
4-60

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18
Q

Index:
1
2
3
4
S.Barley kg/N/Ha?
Spring Cereals

A

1- 135
2- 100
3- 75
4- 40

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19
Q

Index:
1
2
3
4
S.Oats kg/N/Ha?
Spring Cereals

A

1- 110
2- 90
3- 60
4- 30

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20
Q

Increase use of N fertiliser will…

A

Increase yield

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21
Q

If i apply 120-135 kg/ha on malting barley what grain yield will i receive ?

A

7.5 t/ha grain yield

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22
Q

What type of N% is required for high quality malt for making beer?

A

Moderate grain N% is required

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23
Q

To avoid low grain protein in matling barley how much extra should you apply ?

A

20kg/ha

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24
Q

Malting Barley : Effect of +40 kg N on
Grain Protein % - Trends over 3 Years - whats the outcome?

A

10% increase in yields with +40 kg N

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25
Q

Fertiliser Nitrogen use will
increase yield e.g. apply
180-210 kg/ha what extra t/ha grain yield on milling wheat?

A

9 t/ha
grain yield

26
Q

What is required
during grain fill for high
grain protein % for good
breadmaking quality

A

High N uptake

27
Q

What is allowed extra for milling wheat grown on contract?

A

30kg/ha extra in late - N

28
Q

Why is there interest in slurry use on
cereal crops ??

A

High chemical fertiliser prices
* Organic manures becoming a viable option for tillage
farmers
* Attitudes are changing for a cheaper alternative
* Pig manure could replace at least one split of nitrogen
in a crop fertilisation programme
* Pig manure may also reduce P/K and trace element
costs (P/K costs doubled since 2007)

29
Q

What are practical Issues of N? (2)

A

1- Method and timing of application
* Splash Plate, Band Spreader, Trailing Shoe
* Winter/Spring Application
* Growth Stages

2- Efficiency uptake and gaseous losses
* Nitrogen Efficiency
* Ammonia & Nitrous Oxide Emissions
* Leaching

30
Q

Whats the biggest % of N losses?

A

Dont want fallow

31
Q

What sort of trials happened in 2007/2008

A
  • Evaluation of separated liquid pig manure
    (LPM) as a nutrient source for winter wheat
  • Evaluation of separated solid pig manure
    (SPM) as a nutrient source for winter wheat,
  • Measurement of ammonia and nitrous oxide
    emissions from pig manure applied to the
    growing winter wheat crop
32
Q

What are the 3 benefits to separation of pig manure?

A

1- Reduce manure dry matter
* Easily absorbed into soil surface
* Reduced risk of scorch
2- Reduce manure P level
* Higher application levels without reaching P limit
3- Increased manure uniformity

33
Q

What’s the DM% of
1- Pig Manure
2- Separated Liquid
3- Separated Solid

A

1- 2-10%
2- <2%
3- 20-30%

34
Q

What’s the N% of
1- Pig Manure
2- Separated Liquid
3- Separated Solid

A

1- 0.42%
2- 0.40%
3- 0.772%

35
Q

What’s the P% of
1- Pig Manure
2- Separated Liquid
3- Separated Solid

A

1- 0.08%
2- 0.018%
3- 0.600%

36
Q

2007 Solid Slurry Trial
Grain Yield (t/ha)

4 treatments

A

0 t/ha Solid
4t/ha Solid
8t/ha Solid
12t/ha Solid

37
Q

Whats the problems with N loss?(6)

A

1* Economic loss to production
2* Environmental implications of nitrate:
– Eutrophication of waterways: depletion of O2
– Overgrowth of plants on waterways
3* Health implications of nitrate:
– Inconclusive evidence of cause of Blue Baby syndrome/
stomach cancers. Evidence suggests no risk from Nitrate
4* Gaseous losses: NH3; N2O; N2; NO2-
5* N2O is a greenhouse gas, 300 times more potent than
methane
6* Implications of Kyoto Protocol

38
Q

What crop is very prown to lodging?

A

Barley
-too much nutrient
-too dense, too heavy

39
Q

Whats the characteristics of a good wheat variety?

A

Strong strawed
Short strawed

40
Q

The two biggest sources of GHG
from agriculture are:

Together these are %? of global
GHG emissions

A

the release of
N20 from soils and the release of
Methane from livestock and
manure

5%

41
Q

In crop production what is the most important
part of the carbon footprint
What % does fertiliser production account for?
What % does fertiliser induced emissions account for?

A

nitrogen
fertilise

50
+ 33%
= 80% plus of all
emissions in crop production

42
Q

W Oilseed Rape (500 kg CO2e/t)

Sp Malting Barley (220 kg CO2e/t)

Winter Wheat (300 kg CO2e/t)

What one has the most fertiliser induced field emissions?

A

W Oilseed Rape (500 kg CO2e/t)

43
Q

What is the use efficiency of Nitrogen and Phosphorus use ?
(slide 27)

A

Nitrogen 65%

Phosphorus 90%

They are the most efficient when it comes to efficiency

44
Q

Tillage farms emitted how much
tonne/farm GHG equivalent
in 2017 but only what % of this
was from crop production

A

125 tonne/farm

23%

45
Q

What % of the Ammonia
emitted on tillage farms was
from non-tillage activity
(cattle)

A

83%

46
Q

N Use Efficiency on tillage
farms was what %?

A

70%

47
Q

P Use Efficiency was what %
on tillage farms?

A

91%

48
Q

Volatilisation : definition in terms of cropping systems

A

volatised in gaseous form
* NH3; N2O; N2; NO2 and environmental risk associated
with greenhouse gas

49
Q

How is Volatilisation measured?

A

Measured using controlled environments / N15

50
Q

With more efficient N use there is….

A

less available for N loss in this form

51
Q

What is the Kyoto Protocol :

A

Reduction in Gaseous emissions

52
Q

Name the 2 ways nitrogen is lost from cropping systems :

A

1- Volatilisation
2- Leaching

53
Q

Leaching information: how is it lost?
How is nitrate loss measured?

A
  • Leaching : N leached in groundwater
  • Currently receiving attention, especially in continental
    Europe / Nitrates Directive
  • Environmental implications
  • Nitrate loss measured using lysimeters
54
Q

How much N losses to fallow on grass based rotation:
Effect of applied N rate on post harvest nitrate
Loss:

A

1.5 kg/n/ha

55
Q

Effect of applied N rate on post harvest nitrate
Loss:
Grass based rotation:
on 240 N treatment (kg N/ha)

A

1.6 kg N/Ha

56
Q

Effect of applied N rate on post harvest
nitrate Loss:
Continuous cereal: Spring cropping
-Fallow:
-200
-240
-280
(slide 32)

A

-0.75 kg N/Ha

-0/8 kg/N/Ha

-1.0 kg/n/Ha

-2kg/N/Ha

57
Q

list 6 GHG:

A
  • Nitrous Oxide (N2O)
  • Carbon Dioxide (CO2)
  • Methane (CH4)
  • Sulphur Hexafluoride (SF6)
  • Perfluorocarbons (PFCs) F Gases
  • Hydrofluorocarbons (HFCs)
58
Q

What are the 3 F GHG?

A
  • Sulphur Hexafluoride (SF6)
  • Perfluorocarbons (PFCs) F Gases
    *Hydrofluorocarbons (HFCs)

F Gases more potent than the 3 naturally occurring
GHG’s

59
Q

N loss Studies :
Conclusions:
Spring vs Winter

A

Winter cropping
* Acts as cover crop
* Mops up autumn mineralised N
* Well developed root structure to trap N

vs

Spring cropping:
* Lower N requirement
* Poor root structure then poor trapping and recovery
* Over winter fallow
* Winter ploughing can lead to flush of mineralisation

60
Q

What are practices to reduce N losses? (8)

A
  • Continuous winter cereal production where possible
  • Avoid rotation cropping : build up of soil organic N level
  • Where rotations practiced:
  • Harvest as early as possible: Including Sugar beet and
    Potatoes !
  • Controlled by variety selection, planting date etc.
  • Establish winter crop soon after harvest
  • Reduce applied N rate to take mineralised N into account
  • Where late harvest, leave until spring : mineralisation flush
61
Q

What are the issues related to reducing nitrate loss in spring cropping ? (5)

A
  • Avoid winter ploughing
  • Establish cover crop to avoid winter fallow
    – Dedicated cover crops are problematic: subsequent establishment ,
    moisture retention etc
  • Consider autumn cultivation which germinates weeds and
    volunteer seeds these act as cover crop
  • Constraints reduce recovery: increase N not taken into crop
    – Compaction
    – Disease: Take all; early season disease
    – Deficiency of other inputs : P, K, Lime etc
  • When deciding the N Application rates take crop
    requirements over season into consideration

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