Cereals Lecture Week 7 2024 Crop Nutrition Part 1 P and K
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What are the major elements in cereal crops? (4)
N, P, K, S
What are the minor elements in cereal crops? (4)
Zn, Cu, Mn, Mg B
Factors in Crop Production that all feed into yield quality:
Rotation Climatic factors Soil factors Nutrient supply Husbandry Variety Disease, Pest, Weed control Growth Regulation Harvest Technique Post- harvest handling
In modern intensive crop production systems the main source of key nutrients for crop growth is from…
soluble synthetic fertilisers
Crop Nutrition 1-Whats the aim in crop production: 2- Is crops nutrient value all the same or does it differ?
1* the aim in crop production is to have the key nutrients availiable to the crop that will optimise production and at the same time will not cause pollution 2* crops will differ in their nutrient requirements e.g. high P requirement for root crops
1- The two biggest sources of GHG from agriculture are : 3- Together what % do they make up of global GHG emissions?
1- The release of N20 from soils 2- The release of Methane from livestock and manure 3- 5%
In crop production what is the most important part of the carbon footprint?
Nitrogen fertiliser
% of GHG emissions in Crop Production 2 Main segments:
1-Fertiliser- Induced Emissions 33% 2-Fertiliser Production 50%
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%
Example of Carbon Footprints in Crops Based on per tonne of production 1- Highest - lowest of 3
W Oilseed Rape (500 kg CO2e/t) Winter Wheat (300 kg CO2e/t) Sp Malting Barley (220 kg CO2e/t)
Fate Of Applied Fertiliser N in Cereals 4 things can happen:
N immobilised into the Soil OM% 31% Denitrification 4% Leaching 6% Crop Uptake 59%
Up to what% of the applied fertiliser N is not taken up by the cereal crop in the year of application
40%
Major Elements (4)
Nitrogen - N Phosporus - P Potassium - K Sulphur - S
Minor Elements (6)
Zinc Zn Copper Cu Manganese Mn Magnesium Mg Boron B Sodium Na
Sulphur – ‘major’ / minor nutrient: • When is it applied? • how much kg/ha? -What does it have a role as?
– An important element and routinely applied in recent decades – 5-10 (20) kg/ha – Also a role as a foliar applied nutrient to reduce fungal disease
Managanse • What is its requirment linked to? -High PH soils have… -What happens in Oats?
-requirement is linked to soil pH – High Ph soils have higher Mn reqt, also varies with crop – ‘grey speck’ in Oats
Zinc -Whats it linked to? -What sort of resonse does it get from foliar Zn application?
– linked to soil type and also soil Zn levels – High yield response to foliar Zn application when a severe deficiency
Copper What is it most noticeable in?
High soil OM/Peat soils
Magnesium -Whats it linked to? -When can there be a deficiency? -What crop is most prone?
• linked to weather conditions – Transient deficiency in dry spring weather – Barley most prone , also late-season benefits (Epson salts)
P and K fertilisation -Whats the index system based on? -What’s the aim of crop production? -Is there recent evidence of some sort of leaching?
1-* The index system based on soil testing, nutrient balance calculations 2-* the aim in crop production is to have P and K availiable to the crop that will optimise production and at the same time will not cause pollution 3-* there is recent evidence of P leaching from soils – from very light free draining soils – on soils which have been artificially (tile) drained
1- What does soil testing give the results of? 2- What are the P and K indexes correlated to? 3- In the soil test, the water and readily soluble reserves are measured using what? 4- In Ireland, what test do we use? In Britain what test do they use?
1* In soil testing as well as giving the soil test result in mg/kg the result for each nutrient is shown using an index on a scale of 1 to 4 2* the P and K index’s are correlated with crop response 3* in the soil test the water- and readily-soluble reserves are measured using extraction process 4– in Ireland Teagasc use Morgans P and K tests – in Britain Olsens P and exchangable K tests