Cereals 2024 Week 9 Lecture Nitrogen Nutrition Flashcards
Whats the important to get a cereal crop moderate-high yielding
Nitrogen uptake
When the crop receives nitrogen what % of N is “efficiency N recovery”
and
“what is the soil N uptake already in the soil?
- Efficiency of fertilizer N recovery = 0.58, 58%
-Soil N uptake = 95kg/ha
Whats the fertiliser N rate (kg/ha) from previous question in terms of formula?
Crop N uptake (kg/ha)=
95(kg) + 0.58 = Fert N rate
What is used in Ireland and UK as a basis for fertiliser N Recommendations?
Nitrogen Index system for cereals
What does the N index take onto account for each tillage crop? (3)
– the previous crop
– manuring history of the field
– soil type
What does the N index scale go from?
1-4
Explain Index 1:
small release of soil N
The fifth tillage crop following permanent
pasture. For subsequent tillage crops
use the continuous tillage table
Explain Index 2:
medium release of soil N
The 3rd or 4th tillage crop following
permanent pasture. If original permanent
pasture was cut only, use index 1
Explain Index 3:
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
Explain Index 4:
very large release of soil N
The 1st or 2nd tillage crop following very
good permanent pasture which was
grazed only.
In sort of protein do you want in Barley?
Moderate
The more N you apply, the higher protein you get so apply a moderate N value
The more N you apply the greater the risk of what?
lodging
What does the N Index system for cereals require ?
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
Index:
1
2
3
4
W. Wheat kg/N/Ha?
Winter Cereals
1- 210
2-180
3-120
4-80
Index:
1
2
3
4
W. Barley kg/N/Ha?
Winter Cereals
1- 180
2-155
3-120
4-80
Index:
1
2
3
4
W. Oats kg/N/Ha?
Winter Cereals
1- 145
2- 120
3- 85
4- 45
Index:
1
2
3
4
S.Wheat kg/N/Ha?
Spring Cereals
1-160
2-130
3-95
4-60
Index:
1
2
3
4
S.Barley kg/N/Ha?
Spring Cereals
1- 135
2- 100
3- 75
4- 40
Index:
1
2
3
4
S.Oats kg/N/Ha?
Spring Cereals
1- 110
2- 90
3- 60
4- 30
Increase use of N fertiliser will…
Increase yield
If i apply 120-135 kg/ha on malting barley what grain yield will i receive ?
7.5 t/ha grain yield
What type of N% is required for high quality malt for making beer?
Moderate grain N% is required
To avoid low grain protein in matling barley how much extra should you apply ?
20kg/ha
Malting Barley : Effect of +40 kg N on
Grain Protein % - Trends over 3 Years - whats the outcome?
10% increase in yields with +40 kg N
Fertiliser Nitrogen use will
increase yield e.g. apply
180-210 kg/ha what extra t/ha grain yield on milling wheat?
9 t/ha
grain yield
What is required
during grain fill for high
grain protein % for good
breadmaking quality
High N uptake
What is allowed extra for milling wheat grown on contract?
30kg/ha extra in late - N
Why is there interest in slurry use on
cereal crops ??
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)
What are practical Issues of N? (2)
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
Whats the biggest % of N losses?
Dont want fallow
What sort of trials happened in 2007/2008
- 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
What are the 3 benefits to separation of pig manure?
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
What’s the DM% of
1- Pig Manure
2- Separated Liquid
3- Separated Solid
1- 2-10%
2- <2%
3- 20-30%
What’s the N% of
1- Pig Manure
2- Separated Liquid
3- Separated Solid
1- 0.42%
2- 0.40%
3- 0.772%
What’s the P% of
1- Pig Manure
2- Separated Liquid
3- Separated Solid
1- 0.08%
2- 0.018%
3- 0.600%
2007 Solid Slurry Trial
Grain Yield (t/ha)
4 treatments
0 t/ha Solid
4t/ha Solid
8t/ha Solid
12t/ha Solid
Whats the problems with N loss?(6)
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
What crop is very prown to lodging?
Barley
-too much nutrient
-too dense, too heavy
Whats the characteristics of a good wheat variety?
Strong strawed
Short strawed
The two biggest sources of GHG
from agriculture are:
Together these are %? of global
GHG emissions
the release of
N20 from soils and the release of
Methane from livestock and
manure
5%
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?
nitrogen
fertilise
50
+ 33%
= 80% plus of all
emissions in crop production
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?
W Oilseed Rape (500 kg CO2e/t)
What is the use efficiency of Nitrogen and Phosphorus use ?
(slide 27)
Nitrogen 65%
Phosphorus 90%
They are the most efficient when it comes to efficiency
Tillage farms emitted how much
tonne/farm GHG equivalent
in 2017 but only what % of this
was from crop production
125 tonne/farm
23%
What % of the Ammonia
emitted on tillage farms was
from non-tillage activity
(cattle)
83%
N Use Efficiency on tillage
farms was what %?
70%
P Use Efficiency was what %
on tillage farms?
91%
Volatilisation : definition in terms of cropping systems
volatised in gaseous form
* NH3; N2O; N2; NO2 and environmental risk associated
with greenhouse gas
How is Volatilisation measured?
Measured using controlled environments / N15
With more efficient N use there is….
less available for N loss in this form
What is the Kyoto Protocol :
Reduction in Gaseous emissions
Name the 2 ways nitrogen is lost from cropping systems :
1- Volatilisation
2- Leaching
Leaching information: how is it lost?
How is nitrate loss measured?
- Leaching : N leached in groundwater
- Currently receiving attention, especially in continental
Europe / Nitrates Directive - Environmental implications
- Nitrate loss measured using lysimeters
How much N losses to fallow on grass based rotation:
Effect of applied N rate on post harvest nitrate
Loss:
1.5 kg/n/ha
Effect of applied N rate on post harvest nitrate
Loss:
Grass based rotation:
on 240 N treatment (kg N/ha)
1.6 kg N/Ha
Effect of applied N rate on post harvest
nitrate Loss:
Continuous cereal: Spring cropping
-Fallow:
-200
-240
-280
(slide 32)
-0.75 kg N/Ha
-0/8 kg/N/Ha
-1.0 kg/n/Ha
-2kg/N/Ha
list 6 GHG:
- Nitrous Oxide (N2O)
- Carbon Dioxide (CO2)
- Methane (CH4)
- Sulphur Hexafluoride (SF6)
- Perfluorocarbons (PFCs) F Gases
- Hydrofluorocarbons (HFCs)
What are the 3 F GHG?
- Sulphur Hexafluoride (SF6)
- Perfluorocarbons (PFCs) F Gases
*Hydrofluorocarbons (HFCs)
F Gases more potent than the 3 naturally occurring
GHG’s
N loss Studies :
Conclusions:
Spring vs Winter
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
What are practices to reduce N losses? (8)
- 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
What are the issues related to reducing nitrate loss in spring cropping ? (5)
- 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
