nutrient budgeting worksheets -...
TRANSCRIPT
ii Developing a nutrient plan for a dairy farm
Nutrient budgeting worksheets
Developing a nutrient budget for a dairy farm Based on NutriMatch Budgeting Tool designed by DPI Victoria
The following worksheets provide a guide to working through the process of calculating a whole farm
nutrient budget.
Many advisors will be able to assist farmers with calculating nutrient budgets for the farm as a part of the
fertiliser planning process. Often advisors will have spreadsheets or programs that will help crunch the
numbers
Disclaimer
This publication may be of assistance to you but the State of Victoria and its officers do not guarantee that
the publication is without flaws of any kind or is wholly appropriate for your particular purpose and
therefore disclaims all liability for any error, lose or other consequence which may arise from you relying
on any information in this publication
While all reasonable efforts have been made to ensure that the information provided in this manual can be
relied on to the extent indicted, the authors and editors of the work, Dairy Australia and the Department of
Primary Industries Victoria cannot accept responsibility for any inconvenience, material loss or financial
loss resulting from the use of this manual. Dairy Australia acknowledges contributions made by other
organisations and private individuals. Acceptance of these contributions, however, does not endorse or
imply endorsement by the Dairy Australia of any product or services offered by its contributors.
Developing a nutrient plan for a dairy farm iii
Contents
DEVELOPING A NUTRIENT BUDGET FOR A DAIRY FARM ............................................................................................................. II CONTENTS .............................................................................................................................................................................. III INTRODUCTION ........................................................................................................................................................................ 1
NUTRIENT SOURCES ............................................................................................................................................................ 2
1. FERTILISER APPLIED ............................................................................................................................................................. 2 2. NUTRIENTS IMPORTED IN FEED ............................................................................................................................................. 4 WORKSHEET 2 - NUTRIENTS IMPORTED IN FEED ....................................................................................................................... 5 3. EFFLUENT APPLIED .............................................................................................................................................................. 6 WORKSHEET 3 – EFFLUENT APPLIED ........................................................................................................................................ 7
NUTRIENT USES AND LOSSES ........................................................................................................................................... 8
4. NUTRIENTS EXPORTED IN MILK SOLD .................................................................................................................................... 8 WORKSHEET 4 - NUTRIENTS EXPORTED IN MILK SOLD .............................................................................................................. 8 5. DUNG AND URINE ON LANEWAYS AND YARD ........................................................................................................................ 9 WORKSHEET 5 – DUNG AND URINE LOSSES............................................................................................................................... 9 6. WATER RUNOFF ..................................................................................................................................................................10 7. FODDER SOLD OR TAKEN OFF THE MILKING AREA ................................................................................................................11 WORKSHEET 7 - FODDER SOLD OR TAKEN OFF THE MILKING AREA ...........................................................................................11 8. NUTRIENTS EXPORTED IN STOCK .........................................................................................................................................12
Example: Nutrient changes on the milking area .................................................................................................................12 Example: Nutrient losses from runoff block / heifer rearing area (if replacements reared or beef animals run on runoff
block) .................................................................................................................................................................................12 WORKSHEET 8 - NUTRIENTS EXPORTED IN STOCK ....................................................................................................................13
TOTAL NUTRIENT REQUIREMENTS ...............................................................................................................................14
9. MAINTENANCE REQUIREMENTS ...........................................................................................................................................14 WORKSHEET 9 - MAINTENANCE CALCULATIONS .....................................................................................................................15 10. CAPITAL REQUIREMENTS ..................................................................................................................................................16 WORKSHEET 11 - TOTAL NUTRIENT REQUIREMENTS ...............................................................................................................18
Developing a nutrient plan for a dairy farm 1
Introduction Nutrient budgets are a simple tool to allow farmers to monitor and measure the amount of nutrient coming into
and leaving a farm in order to determine if nutrients are in an overall balance, positive or negative state. Just
like a balance sheet in accounting, nutrient budgets give us useful information to help us better manage our
nutrients and make more informed fertiliser decisions.
The following flow diagram helps to explain the important components of a nutrient budget. The numbers in
the diagram correspond to following sections and worksheets which explain the components of calculating a
nutrient budget for the farm
Nutrient budget:
Nutrient Sources 1. Fertiliser applied (last season)
2. Nutrients imported in feed
3. Effluent applied
Nutrient Uses and Losses 4. Nutrients exported in milk sold
5. Dung and urine on laneways and yard
6. Water runoff
7. Fodder sold or taken off milking area
8. Stock exports
Total Nutrient Requirements
9. Maintenance Fertiliser for Soil Factor
10. Capital fertiliser
2 Developing a nutrient plan for a dairy farm
Nutrient Sources
1. Fertiliser applied Fertilisers are described using the NPKS system which gives you the nutrient analysis of a fertiliser in terms of
the percentage of nitrogen (N), phosphorus (P), potassium (K) and sulphur (S) it contains. This allows you to
calculate the amount of each nutrient that is applied when a product is spread, or conversely, the amount of a
fertiliser product required to apply a particular amount of each nutrient. The worksheet on the following page
shows an example of how much of each nutrient is applied when 6.2 tonnes of DAP is spread.
Note Worksheet 1 calculates the nutrients spread over the entire milking area. Other areas which received applications of different
fertilisers must be looked at separately.
Developing a nutrient plan for a dairy farm 3
Worksheet 1 – Nutrients applied in fertiliser
Nutrients applied to your farm in season
........../............
Fertiliser
Type N
%
P
%
K
%
S
%
Fertiliser
Applied tonnes
Conversion
to kg.
Total fert.
applied
(kg)
Total nutrient applied to farm (kg)
Total N Total P Total K Total S Eg. 6200 x 18 = 1116kg N
eg. DAP 18 20 0 1.6 6.2 x 1000 6200 1116 1240 0 99.2 100
Tonnes x 1000 Eg. 6200 x 20 = 1240kg P
Tonnes x 1000 100
Tonnes x 1000
Tonnes x 1000 Eg. 6200 x 1.6 = 99.2kg S
Tonnes x 1000 100
Tonnes x 1000
Tonnes x 1000
Tonnes x 1000
Total nutrient applied to farm (kg)
Divide by effective milking area (ha)
N P K S
Nutrient applied (kg/ha) *Nutrient applications calculated as if applied to the whole farm, not individual paddocks or sections
4 Developing a nutrient plan for a dairy farm
2. Nutrients imported in feed
TABLE 2.1: NUTRIENTS (P, K, S) in milk, grain, fodder and liveweight Nutrient Milk
(%kg milk)
Grain
(kg/tonne DM)
Fodder
(kg/tonne DM)
Liveweight
(kg/1000kg livewt)
Phosphorus 0.1 3kg 3kg 8kg
Potassium 0.14 4kg 17kg 2kg
Sulphur 0.03 2.5kg 2.5kg 2kg
Source: Table 25.5, Soil Analysis Interpretation manual, 1999, Peverill, Sparrow & Reuter
The shaded columns in Table 2.1 show the nutrient content of grain and fodder which allows us to
calculate the nutrients imported onto the farm in bought in feed. For example, it shows that 1 tonne of
grain contains 3kg of phosphorus, 4kg potassium and 2.5kg of sulphur.
The following page takes us through the steps to calculate the kg of phosphorus, potassium and sulphur
imported onto the farm in bought in feed. This information will be used later in calculating the
maintenance requirements for the farm.
Example: If 200 tonnes of grain and 100 tonnes of silage was fed on a 60ha farm:
1. We need to convert this to tonnes of dry matter. Grain is usually about 90% DM so 200 tonnes of grain
wet is only 180 tonnes of grain DM (remember the nutrients are only in the DM, the rest is water).
2. 180 tonnes of grain fed over a milking area of 60ha is 3 tonnes grain/ha. We need to work in common
units and so convert all the information to a per hectare basis.
3. Filling in the boxes on the LHS of the following sheet (for concentrates), if we look at phosphorus:
3 tonnes grain/ha X 3 kg P/tonne of grain = 9 kg P/ha has been imported onto the farm in grain.
4. Continue working down this side of the page and work out potassium and sulphur imported in grain.
5. Now we need to convert the 100 tonnes silage to tonnes of dry matter. Let’s say it was baled silage at
about 50% DM, so 100 tonnes of silage wet is only 50 tonnes of silage DM.
6. 50 tonnes of silage fed over a milking area of 60ha is 0.8 tonnes silage/ha.
7. Now fill in the boxes on the RHS of the following sheet (for fodder).
8. The section at the end of the following page is to add the nutrients imported in both grain and fodder
together to get a total for nutrients imported onto the farm in feed.
Note – It is important to consider if the hay and/or silage was fed out in a sacrifice paddock, or
certain section of the farm (rather than the whole farm), this needs to be taken into account in
calculations.
Developing a nutrient plan for a dairy farm 5
Worksheet 2 - Nutrients imported in feed
Tonnes of feed must be in Tonnes of Dry Matter (DM). If weight is wet weight or as fed, use the following
to convert to dry matter:
Wet Weight X Dry matter % 100 = Tonnes of Dry Matter
Example.
200 tonnes grain X 90 100 = 180 tonnes DM
Concentrates (grains, lupins, pellets)
* Remember to convert to DM (see above)
Grain Tonnes Milking area = Tonne Grain/ha
DM
=
Phosphorus Tonnes Grain/ha X kg P/Tonne = kg P/ha
X 3 = (c1)
Potassium Tonnes Grain/ha X kg K/Tonne = kg K/ha
X 4 = (c2)
Sulphur Tonnes Grain/ha X kg S/Tonne = kg S/ha
X 2.5 = (c3)
Bought in Fodder (Hay and Silage)
(Do not include fodder made on the milking area)
Fodder Tonnes Milking area = Tonne Fodder/ha
DM
=
Phosphorus Tonnes Fodder/ha X kg P/Tonne = kg P/ha
X 3 = (f1)
Potassium Tonnes Fodder/ha X kg K/Tonne = kg K/ha
X 17 = (f2)
Sulphur Tonnes Fodder/ha X kg S/Tonne = kg S/ha
X 2.5 = (f3)
Total Imports in Grain and *Fodder (Add P,K,S in grain and P,K,S in fodder from above.)
Phosphorus Potassium Sulphur
kg/ha kg/ha kg/ha
kg P Concentrate kg P Fodder kg K Concentrate kg K Fodder kg S Concentrate kg S Fodder
(c1) + (f1) (c2) + (f2) (c3) + (f3)
= kg P/ha = kg K/ha = kg S/ha
(Transfer (A) to Worksheet 9) (Transfer (B) to Worksheet 9) (Transfer (C) to Worksheet 9)
*Consider distribution issues. i.e are nutrients spread over the whole farm, feed pad, sacrifice paddock
Guide
Grain DM = 90%
Hay DM = 85%
Pit silage DM= 33%
Baled silage DM = 50%
(A) (B) (C)
6 Developing a nutrient plan for a dairy farm
3. Effluent applied Apart from the potential for off-farm pollution if it is not managed properly, effluent can make a significant
difference to your fertiliser budget. The following table contains the results of analysis of farm effluent in
Gippsland.
Factor Minimum Mean Maximum
PH 6.8 7.5 8.2
Conductivity 1600 3826 9300
Nitrogen (mg/l) 43 505 2100
Phosphorus (mg/l) 13 178 1400
Potassium (mg/l) 67 524 3900
Sulphur (mg/l) 5 132 1300
Calcium (mg/l) 31 213 1500
Magnesium (mg/l) 19 169 1200
Sodium (mg/l) 56 170 170
SAR 0.7 2.4 4.9 Note: 1 mg/litre = 1 kg/megalitre
and 1 megalitre over 1 hectare is equivalent to 100mm of rain or irrigation
If 1 megalitre of the mean effluent was spread over 1 hectare the rates of nutrients spread would be 505
kg/ha of nitrogen, 178 kg of phosphorus and 524 kg of potassium etc.
A key feature of the effluent analyses is the large range of nutrient and salt concentrations in the samples
from different farms. This means that you can’t just take the average concentrations and assume that it is
good enough to work out application rates. If you did this but happened to have the higher nutrient
concentrations, you could be applying 2 to 3 times the rate you expect.
Potassium is often the nutrient of highest concentration in effluent and can also lead to problems such as
grass tetany if soil potassium levels are allowed to rise beyond recommended levels. Therefore application
rates of effluent are usually based on a recommended single application rate of potassium of 60kg/ha or
lower depending on soil potassium levels.
If a 100 hectare farm produces 3.3 megalitres of effluent over a season and it has the nutrient content of the
mean effluent above, the total nutrients in the season’s effluent would be: 1667 kg of Nitrogen, 587 kg of
Phosphorus, 1729 kg of Potassium and 436 kg of sulphur.
If this effluent was applied evenly over the whole farm (which is normally not practical) the application
rates of the nutrients would be insignificant in your total nutrient budget. However if the same effluent
was applied over a smaller (more practical) area of 29 hectares (to achieve a potassium application rate of
60kg/ha), the application rates would be significant. Fertiliser rates for that area would need to be adjusted
to compensate for the nutrients applied in the effluent. A soil test of the area will guide you as to the
overall nutrient requirements. See the table below.
Nutrient Rate if applied
to 100 hectares
(kg/ha)
Fertiliser
equivalent over
100 hectares
(kg/ha)
Rate if applied
to 29 hectares
(kg/ha)
Fertiliser
equivalent over
29 hectares
(kg/ha)
Nitrogen (N) 17 37 (urea) 57 124 (urea)
Phosphorus (P) 6 68 (super) 20 227 (super)
Potassium (K) 17 34 (potash) 60 120 (potash)
Sulphur (S) 4 - 15 -
Developing a nutrient plan for a dairy farm 7
Worksheet 3 – Effluent applied Part A: How much per ha and at what rate?
What are the concentrations of the nutrients from your effluent analysis? (mg/L is the same ratio as kg/megalitre (ML))
Nitrogen (N) kg/ML (mg/L) Potassium (K) kg/ML (mg/L)
Phosphorus (P) kg/ML (mg/L) Sulphur (S) kg/ML (mg/L)
Part B: What nutrients are being applied?
The figures for P, K and S will be used in calculating the maintenance requirements for the part of the farm
where the effluent was applied.
Nutrients in effluent applied
Potassium as the limiting factor
Desired potassium application rate kg/ha (i) (recommended maximum = 60kg/ha, less if soil test levels of potassium are adequate)
Potassium (from analysis) kg/ML (i) (from above)
= ha (ii)
To apply desired application rate of potassium use a rate of
1 megalitre of effluent per (ii) ha’s To convert from ML/ha to an application depth (mm) simply divide 100 by the area (ha). If 1 ML is applied to
1ha it is applied at a depth of 100mm. Therefore 1ML/ha = 100mm application depth.
100 mm (ii) = mm (iii)
To apply desired application rate of potassium use a depth of (iii) mm
kg P/ha (D) kg K/ha (E) kg S/ha (F) (Transfer (D), (E) and (F) to Worksheet 9)
Nitrogen (from analysis) kg/ML (ii) (from above)
= kg/ha N
Phosphorus (from analysis) kg/ML (ii) (from above)
= kg/ha P (D)
Potassium (i) = kg/ha K (E)
Sulphur (from analysis) kg/ML (ii) (from above)
= kg/ha S (F)
8 Developing a nutrient plan for a dairy farm
Nutrient Uses and Losses
4. Nutrients exported in milk sold This page takes us through the steps to calculate the kg of phosphorus, potassium and sulphur exported
from the farm in milk sold. This information will be used later in calculating the maintenance
requirements for the farm.
TABLE 4.1 NUTRIENTS (P, K, S) in milk, grain, fodder and liveweight Nutrient Milk
(%kg milk)
Grain
(kg/tonne DM)
Fodder
(kg/tonne DM)
Liveweight
(kg/1000kg livewt)
Phosphorus 0.1 3kg 3kg 8kg
Potassium 0.14 4kg 17kg 2kg
Sulphur 0.03 2.5kg 2.5kg 2kg
Source: Table 25.5, Soil Analysis Interpretation manual, 1999, Peverill, Sparrow & Reuter
The table above shows that every litre of milk produced contains 0.1% phosphorus, 0.14% potassium and
0.03% sulphur.
Example: If a farm produced 1,100,000 litres of milk from a milking area of 60ha
1. Again, we need to work in common units and so 1,100,000 litres of milk = 1,100,000 kg of milk and
we need to convert the total milk produced on the farm to kg milk/ha. This is done by dividing the
total kg milk by the effective milking area:
1,100,000 kg milk divided by 60ha = 18,333 kg milk/ha.
2. Filling in the boxes as we work through the following sheet, if we look at phosphorus:
18,333 kg milk/ha X 0.1 (P% in milk) divided by 100 = 18.3 kg P/ha has been exported from the
farm in milk sold.
3. Continue working down this page and work out potassium and sulphur exported in milk.
Worksheet 4 - Nutrients exported in milk sold Milk kg/hectare
Total kg Milk Effective Milking Area = kg Milk/ha
ha =
Phosphorus Total exports in milk
kg Milk/ha X P% in Milk 100 = kg P exported/ha
X 0.1 100 = (G) Transfer to Worksheet 9
Potassium
kg Milk/ha X K% in Milk 100 = kg K exported/ha
X 0.14 100 = (H) Transfer to Worksheet 9
Sulphur
kg Milk/ha X S% in Milk 100 = kg S exported/ha
X 0.03 100 = (I) Transfer to Worksheet 9
Developing a nutrient plan for a dairy farm 9
5. Dung and urine on laneways and yard
This is a new calculation from the Phosphorus for Dairy Farms project, to include when working out the
maintenance fertiliser requirements for your farm. It makes an allowance for the nutrients lost in dung and
urine while the cows are walking up the laneways and standing in the dairy yard (as these nutrients are not
being redistributed around the farm as dung and urine in the paddocks are).
You need to know the stocking rate of your farm, which is calculated by dividing the number of cows you
milk by the milking area of your farm. For example, 200 cows on a 60ha farm is a stocking rate of 3.3
cows/ha.
The formulas to work out the loss of phosphorus, potassium and sulphur from dung and urine in the
laneways and dairy yard are below and also on the maintenance calculations worksheet.
Worksheet 5 – Dung and urine losses Phosphorus:
The formula is 0.8kg P x stocking rate (SR). The 0.8kg phosphorus is the figure the researchers have come
up with as an estimate of losses, and you need to multiply it by your stocking rate because of course the
more cows you run per hectare, the greater the loss of phosphorus in laneways and the dairy yard.
Example: For our calculated SR of 3.3 cows/ha, the estimated loss of phosphorus would be
0.8kg P x 3.3 SR = 2.6 kg P/ha (this is already per hectare as your SR is cows/ha).
0.8 kg P x Stocking Rate (cows/ha) = kg P lost /ha
0.8 x = (J) Transfer to WS 9
Potassium:
The formula is 5-8kg K x SR. There is a decision you need to make for this calculation based on how long
your cows spend in the laneways and dairy yard. If the cows don’t have to walk too far and are not waiting
around in the yard for long, then use 5kg K in your calculation. The other extreme would be cows walking
very long distances and standing in the yard for long periods of time each milking. In this case use 8kg K
in your calculation. If the time your cows spend in the laneways and yard is somewhere in-between these
two extremes, then use 6 or 7kg K in your calculation.
Example: Let’s say your cows have up to 1km to walk in the laneways and wait in the yard, on
average, up to 1 hour, so I’ll use 6kg K in the calculation
6kg K x 3.3 SR = 19.8 kg K/ha (you can see the K losses are much higher than P)
5 to 8 kg K x Stocking Rate (cows/ha) = kg K lost /ha
x = (K) Transfer to WS 9
Sulphur:
The formula is 0.8kg S x SR
Example: For our calculated SR of 3.3 cows/ha, the estimated loss of sulphur would be 0.8kg S x 3.3 SR = 2.6 kg S/ha (this is the same as P losses)
0.8 kg S x Stocking Rate (cows/ha) = kg S lost /ha
0.8 x = (L) Transfer to WS 9
10 Developing a nutrient plan for a dairy farm
6. Water runoff Keep phosphorus on the farm - Phosphorus fertiliser does not need to be washed in
Even in dry conditions (eg.summer), phosphorus fertiliser
granules absorb moisture from the soil and air.
As water moves in, phosphorus moves out of the granule and
into the soil, where it locks onto soil particles.
Within a week most of the phosphorus has moved into the soil,
leaving the granule carrier material and a bit of insoluble
phosphorus on the soil surface.
Aim for 7 days (a minimum of 4 days) between fertiliser application and runoff
Aim to apply fertiliser 7 days (at least 4 days) before your next irrigation
Watch the seven-day forecasts and only apply fertiliser if storms that may produce runoff are not
predicted in the next week.
Phosphorus lost in runoff related to fertiliser application and subsequent runoff event
Key factors in keeping nutrients on the farm
Whether your runoff of phosphorus and other nutrients is low or high depends on the following factors:
total water use per season
the percentage of irrigation water coming onto your bays that runs off the farm.
soil type and rainfall characteristics – which influence the percentage of rainfall which runs off the
farm
if you separate fertiliser application from the next irrigation or rainfall runoff event.
Moisture in Air
Soil Moisture Soil Processes
Fertiliser
Granule Phosphorus
moves into
the soil P
1 2 3 4 5 6 7 8 9 1
Days from fertilising
Ph
os
ph
oru
s l
os
t in
ru
no
fff
You control these
nutrient exports
Currently we can't
control these exports
Key messages from graph Large amounts of phosphorus can be lost if a
runoff event occurs the same day as fertiliser
application.
The more time between fertiliser application
and the next runoff event the smaller the
amount of phosphorus lost
The amount of phosphorus lost in runoff from fertiliser application is halved by day 4 and is 1
quarter the amount by day 7.
The timing of application can control
phosphorus losses from fertiliser application.
Developing a nutrient plan for a dairy farm 11
7. Fodder sold or taken off the milking area When fodder that is made on one area is sold or taken away and fed on another area, a significant
quantity of nutrients are exported in the fodder. This section is for fodder grown and harvested on
the home farm and sold or taken off the farm.
This section can also be used to calculate the nutrient removal on an area of the farm where fodder is
frequently harvested, or for a runoff block that is frequently cut for hay or silage and the fodder is
brought to the home farm.
Worksheet 7 - Fodder sold or taken off the milking area
(Hay and Silage)
(Do not include fodder made and fed back on the milking area)
Fodder Tonnes Sold/Off Milking area = Tonne Fodder/ha
=
Phosphorus Tonnes Fodder/ha X kg P/Tonne = kg P/ha
X 3 = (M) Transfer to Worksheet 9
Potassium Tonnes Fodder/ha X kg K/Tonne = kg K/ha
X 17 = (N) Transfer to Worksheet 9
Sulphur Tonnes Fodder/ha X kg S/Tonne = kg S/ha
X 2.5 = (O) Transfer to Worksheet 9
12 Developing a nutrient plan for a dairy farm
8. Nutrients exported in stock TABLE 8.1: NUTRIENTS (P, K, S) in milk, grain, fodder and liveweight
Nutrient Milk
(%kg milk)
Grain
(kg/tonne DM)
Fodder
(kg/tonne DM)
Liveweight
(kg/1000kg livewt)
Phosphorus 0.1 3kg 3kg 8kg
Potassium 0.14 4kg 17kg 2kg
Sulphur 0.03 2.5kg 2.5kg 2kg
Source: Table 25.5, Soil Analysis Interpretation manual, 1999, Peverill, Sparrow & Reuter
Nutrients are removed from the soil & plant & cow nutrient cycle when they are used in building bodies of
growing livestock. For each tonne of liveweight gained, 8 kg of phosphorus, 2 kg potassium and 2 kg of
sulphur are used.
Example: Nutrient changes on the milking area
In a dairy system, say a 200 Friesian cow self-replacing herd, rearing 50 heifer replacements each year.
(assuming 50 replacements come on at 500kgLW and 50 culls leave area at 550 kgLW). As you will see, in this
example the nutrient changes are very low. If you are in a similar situation, nutrient changes due to stock
transfers are probably not worth worrying about in your farm nutrient budget.
Total Liveweight gain / loss
(tonnes)
LW kg/hd Number of
head
Kg Live Weight Gain
Replacements in (Fresian) 500 50 25,000
Culls out (Fresian) 550 50 (-) 27,500
Total kg LW Lost (-) 2,500
Total tonnes LW Lost (-) 2.5
Nutrient Phosphorus Potassium Sulphur
Kg of nutrient /tonne of Liveweight Gain* 8 kg 2 kg 2 kg
kg nutrient total (B) x LW lost (2.5) 20 5 5
kg nutrient per ha kg nutrient totalArea (100 ha) 0.2 0.05 0.05
Example: Nutrient losses from runoff block / heifer rearing area
(if replacements reared or beef animals run on runoff block)
In any one year the farm will be carrying 50 rising 1 year olds and 50 rising 2 year olds. As a Johnes Disease control
measure, all young stock are reared on a runoff block or a separate 25 ha of the farm. If you are doing a nutrient
budget for the runoff block, don’t forget any nutrients brought in or sent off with feed.
Liveweight gain / loss (tonnes) Initial LW
kg/hd
Final LW
kg/hd
Change in
LW kg/hd
Number of
head
Kg Live
Weight
Gain
Rising 1 Year Olds (Fresian) 100 300 200 50 10,000
Rising 2 Year Olds (Fresian) 300 500 200 50 10 000
Total kg LW Gain 20,000
Total tonnes LW Gain 20
Nutrient Phosphorus Potassium Sulphur
kg/tonne LW Gain 8 kg 2 kg 2 kg
kg nutrient total kg/tonne LW Gain t x LW gain 20 160 40 40
kg nutrient per ha kg nutrient totalArea 25 ha 6.4 1.6 1.6
Developing a nutrient plan for a dairy farm 13
Worksheet 8 - Nutrients exported in stock Rising One Year Olds
LW as 1 Year Old LW at Weaning = kg LW gain 1YOs
= (a)
kg LW gain 1YOs (a) X Number 1 YOs = total kg LW gain 1YOs
X = (b)
Rising 2 Year Olds
LW as 2 Years Old LW 1 Years Old = kg LW gain 2YOs
= (c)
kg LW gain 2YOs (c) X Number 2 YOs = total kg LW gain 2YOs
X = (d)
Total Live Weight Gain Heifers
Total kg LW gain 1YOs (b) + Total kg LW gain 2YOs (d) = Total kg LW Gain Heifers
+ = (e)
Total Live Weight Gain t/ha
Total LW Gain Heifers (e) 1000kg Heifer Area ha = t LW Gain/ha
1000kg = (f)
Total nutrient exports in liveweight
Phosphorus t LW Gain/ha (f) X kg P per t LW gain = kg P exported/ha
X 8 = (P) Transfer to WS 9
Potassium t LW Gain/ha (f) X kg K per t LW gain = kg K exported/ha
X 2 = (Q) Transfer to WS 9
Sulphur t LW Gain/ha (f) X kg S per t LW gain = kg S exported/ha
X 2 = (R) Transfer to WS 9
14 Developing a nutrient plan for a dairy farm
Total nutrient requirements
9. Maintenance requirements The maintenance soil factor is the number of kg of nutrient per ha to be applied annually to maintain the
current soil nutrient status. This accounts for losses within the soil structure in the case of phosphorus, and
leaching from the soil in the case of potassium and sulphur. Soils with high P holding capacity will remove
P from the plant available pool more quickly, and will have a higher soils maintenance factor.
Soil Factors - MAINTENANCE The following soil factor (kg/ha) is to account for the nutrients applied that are “held” by the soil in order
to satisfy its requirements over 12 months.
TABLE 9.1: Approximate amount of potassium and sulphur (kg/ha/yr) required to satisfy the soil
retention factor over a range of soil types Soil type PBI Amount K to maintain present soil K levels Amount S to maintain present soil S levels
Sand 0 – 50 25 12
Sandy loam 51 – 100 20 12
Sandy clay loam 101 – 300 15 12
Silty clay loam 101 – 300 15 12
Clay loam 301 – 400 15 12
Clay 401 – 500 10 12
Volcanic clay 501 – 600 10 12
Peat > 600 10 12
Source: Adapted from Accounting for Nutrients Fertiliser Budgeting tool (www.accounting4nutrients.com.au) and Cameron Gourley, DPI, Ellinbank (pers. Com.)
Note: Due to the relatively high mobility of potassium and sulphur combined with minimal research on these 2
elements the potassium and sulphur figures in the above table are estimates based on current research data.
Monitoring soil tests over time will be important to validate potassium and sulphur fertiliser applications levels.
TABLE 9.2: Approximate amount of phosphorus required (kg/ha/yr) to satisfy the soil retention
factor for a range of PBI values and Olsen P levels
PBI Value Current Olsen P Level (mg/kg)
2 to 4 5 to 7 8 to 10 11 to 13 14 to 17 18 to 25 25 to 35
0 to 50 0 3 6 8 9 10 10
50 to 100 0 5 10 15 18 20 20
100 to 200 0 6 13 20 23 25 25
200 to 400 0 7 15 22 26 28 28
400 to 600 0 8 16 24 28 30 30
Over 600 0 10 18 26 31 35 35
Source: Adapted from Burkitt et al. (2002).
Note. Table 9.2 is based on latest research results and is still being reviewed. As always, monitoring soil
tests over time will be important to validate phosphorus fertiliser applications levels.
TABLE 9.3: Approximate amount of phosphorus required (kg/ha/yr) to satisfy the soil retention
factor for a range of PBI values and Colwell P levels
PBI Value Current Colwell P Level (mg/kg)
10 to 15 20 to 30 35 to 40 45 to 55 60 to 80 85 to 115 > 115
0 to 50 1 4 6 8 9 10 10
50 to 100 2 7 10 14 18 20 20
100 to 300 2 8 12 15 20 22 23
300 to 400 2 9 14 18 22 25 25
400 to 600 5 11 17 22 28 31 32
Over 600 5 13 19 24 31 34 35
Source: Adapted from Accounting for Nutrients Fertiliser Budgeting tool (www.accounting4nutrients.com.au)
Developing a nutrient plan for a dairy farm 15
Worksheet 9 - Maintenance Calculations Paddock or area name Soil Type
Phosphorus 1. Milk Worksheet 4 (G) 1. Nuts Imported Worksheet 2 (A)
+ In feed
2. Lanes & dairy Worksheet 5 (J) +
+ 2. Nutrients in Worksheet 3 (D) - only
3. Runoff See sheet 6 applied effluent applies to effluent
+ irrigation paddocks
4. Fodder & Stock Worksheets 7(M)+8(P)
sold
+ - =
Total Nutrients P soil Total Nutrients Maintenance P Out Requirement Imported (kg/ha)
(kg/ha) (kg/ha) (kg/ha)
Potassium 1. Milk Worksheet 4 (H) 1. Nuts Imported_________ Worksheet 2 (B)
+ In feed
2. Lanes & dairy Worksheet 5 (K) +
+ 2. Nutrients in _________ Worksheet 3 (E) - only
3. Fodder & Stock Worksheets 7(N)+8(Q) applied effluent applies to effluent
sold irrigation paddocks
+ - =
Total Nutrients K soil Total Nutrients Maintenance K Out Requirement Imported (kg/ha)
(kg/ha) (kg/ha) (kg/ha)
Sulphur 1. Milk Worksheet 4 (I) 1. Nuts Imported Worksheet 2 (C)
+ In feed
2. Lanes & dairy Worksheet 5 (L) +
+ 2. Nutrients in Worksheet 3 (F) - only
3. Fodder & Stock Worksheets 7(O)+8(R) applied effluent applies to effluent
sold irrigation paddocks
+ - =
Total Nutrients S soil Total Nutrients Maintenance S Out Requirement Imported (kg/ha)
(kg/ha) (kg/ha) (kg/ha)
Transfer (S), (T) and (U) to worksheet 11
From table
9.2or 9.3
Add 1 & 2
(S) Add 1 to 4
From table 9.1 Add 1 & 2
(T) Add 1 to 3
(U) From table 9.1 Add 1 & 2 Add 1 to 3
16 Developing a nutrient plan for a dairy farm
10. Capital Requirements The “capital” fertiliser application is the portion of the total fertiliser application that is over and above
maintenance requirements, and will result in an increase in the soil nutrient status. Determining the
requirement for capital application can only be done with consideration of a recent soil test.
Capital Targets
Pasture growth is limited to the most limiting growth factor, water, sunlight warmth, and macronutrients
phosphorus, sulphur, potassium, etc. Target soil fertility levels for the macronutrients are therefore set for
the most limiting nutrient. There is no point continuing to increase say the sulphur level if the potassium
level is too low, or conversely continuing to increase the potassium level if the phosphorus level is low.
Guidelines for the soil test levels of P, K and S, for Low, Marginal, Moderate and High soil fertility status
can be found in Chapter 8
Capital Soil Factor
The Capital Soil Factor (shown below) gives an indication of the number of kg of nutrient per ha, above
maintenance, required to lift the soil test level by one unit. Capital soil factor is dependent on soil type, the
higher the clay content the higher the capital soil factor.
Soil Factors - CAPITAL The following soil factors are the amount of nutrient (kg/ha) above maintenance required to increase the
soil fertility by 1 unit.
Table 10.1 The approximate amount of capital P (kg/ha) required to raise soil Olsen or Colwell P by
one unit (1 mg/kg) based on the PBI
Soil Type PBI
Amount of P to raise
Olsen P by 1 unit
(kg/ha)
Amount of P to raise
Colwell P by 1 unit
(kg/ha)
Sand 0 to 50 6 2.2
Sandy loam 51 to 100 8 2.3
Sandy clay loam 101 to 300 9 2.5
Silty clay loam 101 to 300 9 2.5
Clay loam 301 to 400 10 2.8
Clay 401 to 500 11 3
Volcanic clay 501 to 600 13 3.2
Peat Over 600 15 3.6
Source: Adapted from Accounting for Nutrients Fertiliser Budgeting tool (www.accounting4nutrients.com.au)
Table 10.2: The estimated amount of capital potassium (kg/ha) required to raise the soil level by one
unit (1 mg/kg)
Soil Type PBI Potassium
(kg K/Unit of K)
Sand 0 - 50 2
Sandy Loam 51 - 100 2
Sandy clay loam 101 - 300 2
Silty clay loam 101 - 300 2
Clay Loam 301 - 400 2
Clay 401 - 500 2
Volcanic clay 501 - 600 2
Peat > 600 2
Source: Adapted from Accounting for Nutrients Fertiliser Budgeting tool (www.accounting4nutrients.com.au) and Cameron Gourley, DPI, Ellinbank (pers. Com.)
Developing a nutrient plan for a dairy farm 17
Worksheet 10 - Capital Calculations Capital P
Target Current = Olsen P Units
Olsen P Olsen P to increase#
Olsen P Units Kg P/Ha to lift Capital P required##
to increase X Olsen P by 1 unit = (above maintenance)
X =
Capital P required Number of years = Capital P Required/ha
to reach target (per year)
= Kg P /ha (V)
Capital K Target Current = K Units
K level K level to increase#
K Units Kg K/Ha to lift Capital K required##
to increase X K level by 1 unit = (above maintenance)
X =
Capital K required Number of years = Capital K Required/ha
to reach target (per year)
= Kg K/ha (W)
Capital S
Current S level
(from soil test)
S Result Interpretation
Level S Test level S Required/ha
Very High >20 0
Adequate 13 - 20 0
Moderate 9 - 12 7.5kg S/ha
Marginal 4 - 8 15kg S/ha
Low <4 30kg S/ha
Source: and Cameron Gourley, DPI, Ellinbank (pers. Com.)
From this soil test level a corresponding
amount of sulphur to apply can be found in
the box below
from above# from table 10.1
from above##
from above# from table 10.2
from above##
Capital S Required/ha
(per year)
Kg S/ha (X)
Transfer (V), (W) and (X) to worksheet 11
18 Developing a nutrient plan for a dairy farm
Worksheet 11 - Total Nutrient Requirements
Total Phosphorus Required Maintenance + Capital = Total kg P / ha/ yr
+
Please Note:
Calculate the rate of fertiliser to apply based on the nutrient application rate.
Consider areas, which require MORE/LESS nutrient, egs. hay/silage, sacrifice paddock, newly sown.
Total Potassium Required Maintenance + Capital = Total kg K / ha/ yr
+ =
Please Note:
Calculate the rate of fertiliser to apply based on the nutrient application rate.
Maximum single application of K suggested is 60 kg K/ha.
Maximum annual application of suggested K is 120 kg K/ha.
Potassium is reasonably mobile in the soil and may be leached, especially in a very wet season and in sandy soils.
It is preferable to apply K after silage/hay is removed to avoid fodder having a high concentration of K. May generate a grass
tetany problem next autumn if feeding this high K fodder to springers/fresh cows.
Total Sulphur Required Maintenance + Capital = Total kg S / ha/ yr
+ =
Please Note:
Calculate the rate of fertiliser to apply based on the nutrient application rate.
Sulphur is very mobile and easily leached, especially in a very wet season.
If nitrogen is being applied in cold wet conditions (late winter/earl spring), consider applying a product containing sulphur.
Reminder: It is important to monitor your soil fertility regularly with soil tests
(S) ( (V)
(X) (U)
(W) (T)