Soil P IndexWhat the P Index means 0Deficient Production will be limited. Requires slurry/manure and/or P fertiliser. 1 Optimum Extensive Extensive grazing. Continue with usual slurry & fertiliser policy. 2 Optimum Intensive Intensive grazing & silage fields & arable. Continue with usual slurry & fertiliser policy. 3High No yield response to added P. Redistribute slurry to more suitable fields. Use a zero- P fertiliser. Apply P to arable crop needs only. 4 +Excessive No yield response to added P. Redistribute slurry to more suitable fields. Use a zero- P fertiliser. Apply P to arable crop needs only. Increasing Soil P
Speeds up reactions (catalyst) Controls water movement (translocation) Controls water loss Involved in nutrient and sugar transport.
Soil K IndexWhat the K Index means 0Deficient Production will be limited. Requires slurry and/or high K fertiliser. 1Low Inadequate for production, especially silage. Use slurry and/or high K fertiliser. 2- 2+ Optimum High Grazing, silage & arable fields. Continue with usual slurry and fertiliser policy. 3High No yield response to added potash. Avoid slurry applications unless low P levels. Redistribute slurry to more suitable fields. 4 & above Excessive No yield response to added potash. Avoid slurry applications unless low P levels. Redistribute slurry to more suitable fields. Increasing Soil K
During rapid vegetative growth, the rapid uptake of nitrogen as negatively charged nitrate ions (NO3-) is normally balanced by a similar uptake of positively charged potash ions (K+) which maintains the electrical neutrality of the plant Water mobility Tugor pressure
Soil - summary Valuable source of nutrients Sample every 4 years Use analysis to determine the amount of nutrients in the soil The higher the soil nutrient reserves (Index), the lower the need for additional nutrients
Organic manures are a valuable source of nutrients Use at the right time, rate, place and with the right equipment Chemical fertiliser is expensive and should only be used as a top up.
Why manage nutrients? 1. Potential to reduce fertiliser costs 2. Protect the environment 3. Meet Nitrates Directive requirements
3000 gal/acre Cattle slurry= £31/acre 100 cow dairy herd = £4,200/yr 50 suckler herd= £1,300/yr Total slurry in NI= £23m The value of slurry
2. Protect the environment Nutrient loss – phosphates and nitrates Slurry & fertiliser runoff Leaching through the soil Soil particle loss Causes nutrient enrichment (eutrophication)
If sowing chemical P fertiliser ◦ Soil Analysis ◦ P recommendation for the crop ◦ Type and quantity of all fertiliser containing P applied If sowing chemical N fertiliser on crops other than grass ◦ Soil N supply index
Step 1 - Soil analysis Step 2 - What does the soil analysis mean? Step 3 - Estimate Nitrogen requirements Step 4 - What nutrients does the crop require? Step 5 - How many nutrients can be supplied by organic manures? Step 6 - Which chemical fertiliser can supply the remaining nutrients required
Mr AN Other Somewhere Report generated on: 07 March 2008 Date Received: 29 February 2009 pHTextureLime RequirementPhosphorusPotassiumMagnesium Lab No./ Reference Arable t/ha (t/acre) Grass t/ha (t/acre) mg/l (index) mg/l (index) mg/l (index) 400-2008 Soil 1-19-60 Field 4 6.1SZL (Sandy silt loam) 4.00 (2.00) 0.00 (0.00) 20.0 (2) 216 (2+) 102 (3) Farm Survey & Field Number pHTextureLime requirement for arable & Grass Available amounts of nutrients (Index) Step 1 - Soil Analysis Laboratory Report
Not included in soil analysis Estimated after considering, rainfall, soil type and previous cropping Soil Nitrogen Supply Index – the higher the index, the lower the requirement
(1) N Kg/ha (2) P 2 O 5 (2+) K 2 0 Crop requirement (Based on crop type & soil analysis) 1405040 Available nutrients in 33m3 dairy cow slurry 3540104 Chemical fertiliser requirement 105100 Getting the balance right – Spring Barley
Determine N, P 2 O 5 and K 2 O required by crops; Calculate the amount of nutrients supplied by organic manures Select the correct chemical fertiliser and application rate Retain information required for record keeping
1. N, P, K In = N, P, K Out 2. Nutrient sources soil, slurry/ manure and fertiliser 3. Make best use of nutrient sources Save money Protect the environment Meet Nitrates Directive Requirements 4. How? Soil sampling and analysis is the starting point Estimate crop needs Use slurry/manure effectively Only use fertiliser to top-up any outstanding crop needs 5. Help Crop Nutrient Recommendation Calculator Nitrates Guidance RB209 Codes of Good Agricultural Practice