Remember we are talking about growing pasture and grazing animals on it,
solely (without concentrates) for some now, and eventually for most, except
that minerals will always be needed because pasture just can't take up
enough of some, for example, salt and to fertilize with iodine to get
enough in pasture is too expensive.
Tissue testing has had its followers, many of whom have kept quiet about it
for 40 years because they can't be bothered with the old die-hards and the
establishment some of whom are tied to making millions of dollars from soil
testing annually.
Also, few know how to take and read a pasture sample, but then reading a
soil result takes training and questionable theory galore.
Many USA pasture tissue levels are wrong. Look in papers which show USA, UK
and other figures. USA calcium and copper (from memory) and double all
others. It looks like a calculation problem. A lab in Holland sets the
universally agreed standards and monitors labs world-wide. All labs should
belong to it.
Pasture Versus Soil Tests
The first thing to do when pasture farming is to find out the element
levels in pastures.
Trying to work out a complete fertilizer mix from a soil test alone is
impossible and soil testing has very little application in animal
nutrition. Elements in the soil affect each other. By how much, depends on
many factors such as quantity of each, moisture, pH, soil type, texture,
organic content, etc. Pasture tissue figures are actuals in pasture and
what animals eat, so the antagonistic effects in the soil are shown in
results which mean something.
A soil test gives the pH reasonably accurately provided it was taken and
handled correctly, and it doesn=B9t vary much over the years unless lime,
magnesium or excessive acidifying fertilizers are applied, and a few
decimal points change doesn=B9t matter, so checking it every four or five
years is usually enough.
The pH tells you very little about a soil. It doesn=B9t tell you what causes
the pH to be low or high. A pasture sample will tell you what causes the pH
to be high such as high calcium (high molybdenum can indicate high
calcium), or high magnesium. High manganese sometimes indicates a wet soil.
Low cobalt indicates low organic matter, but again not always.
Despite what some laboratories claim, soil tests cannot measure some of the
trace elements accurately. Take one soil sample, mix it thoroughly, divide
it send it to two labs (or even to one under two paddock names) and the
figures can be quite different. Even phosphorus if RPR=B9s are used, or
nitrogen, or even sulphur levels are not measured accurately, and even if
they are, it is not what the plant is taking up or what the animal is
eating.
Good pasture tests are extremely accurate. Take two samples from the same
paddock and see. Do the same with soil samples and you=B9ll feel that you=B9=
ve
been fleeced over the years you=B9ve been taking them, not only in paying fo=
r
an erratic system, but also for using it to determine your main
expenditure, i.e., fertilizer.
There are many statistics which show how much more accurate pasture tissue
analysing is than soil testing. The following is from Dr Don Robinson,
Louisiana State University plot studies for four years on a silt loam soil
with annual ryegrass. The Nitrogen was applied at planting and after each
harvest at 50 lb/acre.
The figures show how tissue levels increased immediately whereas soil took
a while to increase.
lb/acre/yr tons/acre Tissue % P Soil ppm P
0 2.31 0.13 17
20 3.50 0.15 + 15% 18 + 6%
40 4.12 0.19 + 46% 22 + 29%
80 4.30 0.23 + 77% 23 + 35%
160 4.62 0.29 + 123% 38 + 124%
320 4.84 0.39 110
The 320 lb/acre of P is irrelevant because no one would apply that amount.
Other trials have shown that soil P levels take a while to drop after P
application stops, whereas tissue levels drop much sooner so are a more
accurate guide.
On potash, the US=A0Potash & Phosphate Institute wrote that soil levels
decreased after applying K, but tissue levels increased.
Potash & Phosphate Institute (PPI)
655 Engineering Drive, Suite 110
Norcross, GA 30092-2837, USA.
Phone: 770-447-0335; Fax: 770-448-0439
Get There's More Than One Way To Recommend Fertilizer, Fall 1996, No. 7.
Every year there are some producers who are puzzled by the differences in
the amounts of fertilizer recommended for field crops by different sources.
Although most people appreciate that soil testing is inaccurate, it is
perplexing to see recommendations from the same analysis that differ by as
much as several fold.
Wrong fertilizer recommendations waste millions of dollars in New Zealand
each year, mainly though not understanding fertilizing, using soil tests,
sales people=B9s jargon, and not putting enough time and effort into working
out the requirements. The waste is likely to be the same in most countries.
In the USA a soil sample was mixed then divided up and sent to 69 different
laboratories. Fertilizing recommendations made by each lab varied from 0
lbs/acre to 230 lbs/acre for nitrogen, and 0 to 150 for phosphate! A New
Zealand Rukuhia Soil Research Station technician divided a thoroughly mixed
soil into six, and got six different recommendations.
In New Zealand laboratories almost never make recommendations because they
realise that soil and/or pasture analysis can=B9t allow for other factors. A
few examples are -
=80 The farmer=B9s aims, such as maintenance, improving fertility, and even
taxation aims.
=80 Type of livestock. Cattle require more copper than sheep. Dairying loses
more fertility off the farm than beef.
=80 Livestock numbers per hectare. Heavy stocking may need more fertilizer.
=80 Pasture type. Most improved pastures require more.
=80 Rainfall. Low rainfall areas lose less to leaching and grow less grass.
Even with today=B9s knowledge of pasture analysing, on farm fertilizer trial=
s
are best, using a pasture analyses to determine which elements are
deficient, but on-farm trials to finalize the amounts per hectare in the
long term. Meanwhile use local knowledge
Our AgResearch have at last recognized that fertilizer trials are the best
way to be sure that you are not over or under fertilizing and sell farm
trial kits to help do this.
=46ertilizer Trials
These can be the most profitable things you do on your farm. Firstly decide
on which elements to try. Base this on local opinions, successes in other
areas, reading and pasture tissue tests.
A simple trial involves getting a small amount of the fertilizer and
spreading it on a representative part of the paddock, preferably in line
with a fence post and at right angles to a frequently used lane where any
differences can be observed while driving past. Decide on the rates to use
and apply them on a two metre wide strip five metres long. This gives a ten
square metre trial which is one thousandth of a hectare, so the amount to
apply is easily worked out. For example if wanting to apply lime at 2.5
tonnes/ha (1 t/a), 2.5 kg (5.5 lbs) is the amount to apply to ten square
metres (80=B2 x 200=B2). Mark the fence post with a pen, nail, axe, knife or
some other marker.
A thorough trial requires deciding which area and paddocks to use, dividing
them into two or more equal parts (can be two paddocks), applying different
rates on each, measuring and/or counting the grazing days.
Always write down the date and all details and draw a plan of each trial.
Place it in your =B3Bring up Monthly=B2 file to remind you to check the site=
s
monthly.
Accurate measuring is essential for a thorough trial, so use a
PastureGauge. It can soon pay for itself if increased pasture production is
obtained, or money saved on fertilizer.
Whole paddock trials can be done by applying 50% less and 50% more to
similar paddocks and then measuring the yields with a PastureGauge and/or
comparing the number of stock unit grazing days, and by taking pasture
samples six to twelve months later. Remember to record the fertilizer
types, rates, dates and paddocks. Yields are recorded by measuring before
grazing and after grazing, then adding the totals consumed for the year. If
you gross $2,000/ha and you increase pasture yields by 10%, then you have
netted $200, less the cost of the fertilizer.
Collecting Pasture for Tissue Analysing
Pasture tissue analysing is the most accurate way of diagnosing
deficiencies in soils, and pastures and calculating fertilizer and trace
element requirements for soils and animals. Compared with a soil analysis,
it gives a much more accurate assessment of the nutrient and health status
of the soil and plant, and of what the animal is getting and not getting.
Pasture analyses are not affected by P fixation and other soil
complications such as high aluminum, however, soil pH should be measured
every few years in late spring when soil moisture is not too high or too
low. The same soil dry can have a high pH when dry and a lower one when
wet.
A pasture analysis is like a video recording of the nutrient status of the
plant over a month, while a soil analysis is like a photograph - a
recording of the instant. A soil analysis can't measure some elements at
all, and items as important as sulphur and phosphorus are not measured
accurately. Tissue analysing was first done in 1920 and progressive fruit
growers have used this system since then and pasture farmers more recently.
Pasture element levels should be measured before applying fertilizer to
avoid causing toxicities and to apply deficient items which could be
adversely affecting the uptake of other elements and animal health.
Most advisory people will recommend soil sampling rather than pasture
sampling simply because they=B9ve never bothered to learn how to sample and
use tissue figures, although this is changing. Plenty of results I see show
that many people don't know how to collect samples without polluting them.
An example is that, if iron levels are above 300 ppm in perennial
ryegrass/clover pasture samples, soil contamination has occurred, so the
cobalt, manganese and some other figures will be artificially high,
depending on the soil levels and the amount of soil in the sample.
In the 1950s New Zealand Ag scientist Ken McNaught studied the benefits of
tissue testing and wrote that measuring pasture is far more reliable than
soil. Winchmore, Woodlands and many other New Zealand research centre=B9s
comparative figures confirm this, as do on farm ones.
Pasture analyses measure 15 elements in percentages and parts per million.
Many of these can't be measured accurately in soils. Scientists are still
trying to develop an accurate sulphur soil measuring system. Elements which
can be measured accurately in soils can change with the seasons, with rain,
pugging, earthworm activity, temperature, organic levels, availability,
etc. Organic phosphorus and that from raw rock phosphates can't be measured
by soil tests (Olsen P), whereas pasture element levels and changes are
consistent and easily measured. More and more are learning that soil
testing has very little application in animal nutrition, whereas tissue
testing does, so more are using this system. Analyzing feed is common.
Pasture is feed, soil is not. Using soil analyses for complete fertilizing
has let many people down.
In pastures, some tissue levels change with growth rates and seasons, but
the changes have been well documented, both in New Zealand and overseas
over decades, so allowances can be made for the time of the year and the
pasture condition. The cost for a comprehensive test of 15 elements is
about $100, and can return many times that in pasture and animal health.
Pasture Versus Soil Tests
The first thing to do when pasture farming is to find out the element
levels in pastures.
Trying to work out a complete fertilizer mix from a soil test alone is
impossible and soil testing has very little application in animal
nutrition. Elements in the soil affect each other. By how much, depends on
many factors such as quantity of each, moisture, pH, soil type, texture,
organic content, etc. Pasture tissue figures are actuals in pasture and
what animals eat, so the antagonistic effects in the soil are shown in
results which mean something.
A soil test gives the pH reasonably accurately provided it was taken and
handled correctly, and it doesn=B9t vary much over the years unless lime,
magnesium or excessive acidifying fertilizers are applied, and a few
decimal points change doesn=B9t matter, so checking it every four or five
years is usually enough.
The pH tells you very little about a soil. It doesn=B9t tell you what causes
the pH to be low or high. A pasture sample will tell you what causes the pH
to be high such as high calcium (high molybdenum can indicate high
calcium), or high magnesium. High manganese sometimes indicates a wet soil.
Low cobalt indicates low organic matter, but again not always.
Despite what some laboratories claim, soil tests cannot measure some of the
trace elements accurately. Take one soil sample, mix it thoroughly, divide
it send it to two labs (or even to one under two paddock names) and the
figures can be quite different. Even phosphorus if RPR=B9s are used, or
nitrogen, or even sulphur levels are not measured accurately, and even if
they are, it is not what the plant is taking up or what the animal is
eating.
Good pasture tests are extremely accurate. Take two samples from the same
paddock and see. Do the same with soil samples and you=B9ll feel that you=B9=
ve
been fleeced over the years you=B9ve been taking them, not only in paying fo=
r
an erratic system, but also for using it to determine your main
expenditure, i.e., fertilizer.
There are many statistics which show how much more accurate pasture tissue
analysing is than soil testing. The following is from Dr Don Robinson,
Louisiana State University plot studies for four years on a silt loam soil
with annual ryegrass. The Nitrogen was applied at planting and after each
harvest at 50 lb/acre.
The figures show how tissue levels increased immediately whereas soil took
a while to increase.
lb/acre/yr tons/acre Tissue % P Soil ppm P
0 2.31 0.13 17
20 3.50 0.15 + 15% 18 + 6%
40 4.12 0.19 + 46% 22 + 29%
80 4.30 0.23 + 77% 23 + 35%
160 4.62 0.29 + 123% 38 + 124%
320 4.84 0.39 110
The 320 lb/acre of P is irrelevant because no one would apply that amount.
Other trials have shown that soil P levels take a while to drop after P
application stops, whereas tissue levels drop much sooner so are a more
accurate guide.
On potash, the US=A0Potash & Phosphate Institute wrote that soil levels
decreased after applying K, but tissue levels increased.
Potash & Phosphate Institute (PPI)
655 Engineering Drive, Suite 110
Norcross, GA 30092-2837, USA.
Phone: 770-447-0335; Fax: 770-448-0439
Get There's More Than One Way To Recommend Fertilizer, Fall 1996, No. 7.
Every year there are some producers who are puzzled by the differences in
the amounts of fertilizer recommended for field crops by different sources.
Although most people appreciate that soil testing is inaccurate, it is
perplexing to see recommendations from the same analysis that differ by as
much as several fold.
Wrong fertilizer recommendations waste millions of dollars in New Zealand
each year, mainly though not understanding fertilizing, using soil tests,
sales people=B9s jargon, and not putting enough time and effort into working
out the requirements. The waste is likely to be the same in most countries.
In the USA a soil sample was mixed then divided up and sent to 69 different
laboratories. Fertilizing recommendations made by each lab varied from 0
lbs/acre to 230 lbs/acre for nitrogen, and 0 to 150 for phosphate! A New
Zealand Rukuhia Soil Research Station technician divided a thoroughly mixed
soil into six, and got six different recommendations.
In New Zealand laboratories almost never make recommendations because they
realise that soil and/or pasture analysis can=B9t allow for other factors. A
few examples are -
=80 The farmer=B9s aims, such as maintenance, improving fertility, and even
taxation aims.
=80 Type of livestock. Cattle require more copper than sheep. Dairying loses
more fertility off the farm than beef.
=80 Livestock numbers per hectare. Heavy stocking may need more fertilizer.
=80 Pasture type. Most improved pastures require more.
=80 Rainfall. Low rainfall areas lose less to leaching and grow less grass.
Even with today=B9s knowledge of pasture analysing, on farm fertilizer trial=
s
are best, using a pasture analyses to determine which elements are
deficient, but on-farm trials to finalize the amounts per hectare in the
long term. Meanwhile use local knowledge
Our AgResearch have at last recognized that fertilizer trials are the best
way to be sure that you are not over or under fertilizing and sell farm
trial kits to help do this.
=46ertilizer Trials
These can be the most profitable things you do on your farm. Firstly decide
on which elements to try. Base this on local opinions, successes in other
areas, reading and pasture tissue tests.
A simple trial involves getting a small amount of the fertilizer and
spreading it on a representative part of the paddock, preferably in line
with a fence post and at right angles to a frequently used lane where any
differences can be observed while driving past. Decide on the rates to use
and apply them on a two metre wide strip five metres long. This gives a ten
square metre trial which is one thousandth of a hectare, so the amount to
apply is easily worked out. For example if wanting to apply lime at 2.5
tonnes/ha (1 t/a), 2.5 kg (5.5 lbs) is the amount to apply to ten square
metres (80=B2 x 200=B2). Mark the fence post with a pen, nail, axe, knife or
some other marker.
A thorough trial requires deciding which area and paddocks to use, dividing
them into two or more equal parts (can be two paddocks), applying different
rates on each, measuring and/or counting the grazing days.
Always write down the date and all details and draw a plan of each trial.
Place it in your =B3Bring up Monthly=B2 file to remind you to check the site=
s
monthly.
Accurate measuring is essential for a thorough trial, so use a
PastureGauge. It can soon pay for itself if increased pasture production is
obtained, or money saved on fertilizer.
Whole paddock trials can be done by applying 50% less and 50% more to
similar paddocks and then measuring the yields with a PastureGauge and/or
comparing the number of stock unit grazing days, and by taking pasture
samples six to twelve months later. Remember to record the fertilizer
types, rates, dates and paddocks. Yields are recorded by measuring before
grazing and after grazing, then adding the totals consumed for the year. If
you gross $2,000/ha and you increase pasture yields by 10%, then you have
netted $200, less the cost of the fertilizer.
Reading Pasture Samples
When studying a pasture analysis, firstly check weather it is for sheep or
cattle. Then look at the date because element levels vary with the weather
and seasons. Relate it to the weather at the time, because winters can
extend into spring, when springs are late, and springs can extend into
summer, or continuous rain over a period can grow grass like that normally
grown in spring.
The next thing to look at is the iron content, because, if it is high
(above 200 ppm) then it indicates that the pasture sample has been
over-polluted with soil (it is hard to get 100% clean samples), which means
that the cobalt level will be higher than is the actual case, and manganese
could also be higher.
Next look at the nitrogen figure, which indicates the speed of growth of
the pasture. 4.5% indicates good growth, higher indicates faster growth,
which could mean that some elements will be deficient and too much N was
applied, so beware of nitrate toxicity. Very low N figures indicate slow
growth, so P and some other elements will be higher than normal, if
everything else is equal. However, the slow growth could be as a result of
low P levels in the first place
Areas which don=B9t fertilize can make mineral feeding suggestions from the
herbage results.
When reading the samples, one must realise that P is the most important
growth element, so 10% difference in pasture sample P levels is a lot.
The first P applied to soils is used by the soil microbes, so heavy capital
dressings are important to feed the grass. Once the microbes have increased
thanks to the P, they start improving the soil, which then grows more
grass, so it takes time. Steady continuous P supply as is achieved with
RPR, as long as there is acidity and moisture, I believe is good for
everything in the soil, i.e., microbes, earthworms, pasture rooting,
pasture growth, and animal health.
Check your farm and others, for improved pastures (especially clovers and
legumes) where subsoil has been brought up in ditch cleanings, and where
plants are growing in ditches or refilled trenches where pipes or cables
have been laid.
Correct Sampling Essential
Decide why you are sampling. If to plan fertilizer applications for the
farm then sample at least one average paddock. If to diagnose visual
deficiencies (poor areas), sample only affected areas. Initially get a
pasture analysis from each different soil type on the farm, and in
subsequent years test different paddocks, in case there are localized
deficiencies.
Aim for 80% grass and 20% clover, or all clover or all grass, and always
let the consultant know the proportions and pasture species. Take about 40
representative samples from across one paddock. Never collect and mix
samples from around the farm because various soil types and management
variations can hide deficiencies.
Pasture analyses measure some elements in parts per million (ppm), so
cleanliness and accuracy are essential. Don't sample paddocks which have
been fertilized or limed within two months or grazed within two weeks
(there could be urine still on some). Ensure there are no mud splashes or
mud dragged onto leaves by hooves. Collect complete leaves of green growing
pasture (not just leaf tips) and avoid above dung and urine patches,
gateways, dust affected (near roads), soiled or areas affected by anything
different. Don't collect leaves that are damaged in any way from frost,
wind, insects, etc. Samples can be taken after a frost has thawed.
It is essential to have clean hands, to not touch soil, galvanized gates or
wire and to collect the samples in clean paper bags. Don't use plastic bags
because they can give off minerals and cause pasture sweating, leading to
incorrect results.
=46irstly wash the hand you'll be using, but not in dirty or a mineralized
water trough, after which don't touch anything with that hand except the
pasture you're collecting. Throw away the first few handfuls you pick to
Ndutralise your hand with the pasture.
Hold the bag under your arm, break the grass off with your clean hand and
remove old dead grass and soiled material with the hand which is holding
the bag. Clovers usually break off at ground level and their stems have a
foot which will have soil on it, so break these off and discard them. Using
clippers is difficult with only two hands and frequently causes soil
contamination. With a helper clippers can speed things, but avoid using
rusty or dirty ones. Soil, weeds, dead herbage and other forms of pollution
such as perspiration can distort the results. Some people have to wear thin
plastic gloves to avoid sodium pollution from perspiring hands. After
washing your hand, don=B9t wipe your brow or anywhere with you collecting
hand.
Plants have varying levels of some elements in different parts. For example
leaf tips have more P, but less Ca, so if only the tips of leaves were
collected P could be inaccurately high and Ca inaccurately low. Aim for 150
mm (6=B2) long leaves. If sampling 75 mm (3=B2) pasture, only leaf tips can =
be
collected, so inform the consultant to allow for this in the reading of the
figures.
At seeding, many leaf levels decrease as the elements move to the seed,
because the leaves have finished their job and are ready to die. Element
levels also vary with the weather and season, but these trends are known
and allowed for. The N level indicates the speed of growth. The lower the
slower, the higher the faster. Slow growing pasture has higher P and Mg
levels than fast growing pasture.
Collect about half a kilogramme (1 lb), or 1,800 cubic centimetres - 120 mm
(5=B2) x 120 mm x 120 mm which is two heaped double handfuls of pasture. On
each bag record your name and address, the paddock number or name. Leave
the bag open until dispatching. Tightly packed pasture will heat and
deteriorate. Refrigerating helps preserve it, but never freeze it.
The above may seem a lot of work, however, the profit in farming is not
high, so if you can get more animal profit from better pastures, which is
not hard, it=B9ll be worth while. Pasture farming saves a lot of work, but
has its own jobs which should not be skimped.
If your lab isn't geared to analyze the 15 essential elements (Nitrogen N,
Phosphorus P, Potassium K, Sulphur S, Calcium Ca, Magnesium Mg, Sodium Na,
Iron Fe, Manganese Mn, Zinc Zn, Copper Cu, Boron B, Molybdenum Mo, Cobalt
Co, Selenium Se) you can send samples to Hill Laboratories, 1 Clyde St,
Private Bag 3205, Hamilton. Ph 07-858-2000.
Sending Samples from Outside New Zealand
Air-dry the samples in clean trays or paper in a warm, dry dust-free
environment for a few days, or in an oven at about 80=B0 C (180=B0 F) for 12
hours with the fan going (if it has one), or in a microwave in short 2 or 3
minute bursts on high, then at the lowest setting (defrost) to avoid
charring. Any charred pasture must be discarded. Never freeze the sample.
Post by airmail (NOT=A0Airfreight) to Hill Laboratories, Private Bag 3205,
Hamilton. Ph 07-858-2000. Quarantine Permit # 32629. This permit number
must be with the address to allow pasture through agriculture pest and
health controls.
Include your name and address, and payment to Hill Laboratories Ltd for
NZ$100 (US check for US$70, or equivalent) and ask them to analyse for
Basic elements and molybdenum, cobalt and selenium, and to send the results
to Vaughan Jones. Send us payment for NZ$90 (US$65 or equivalent) with the
number of hectares or acres to be fertilized, dollars/hectare or acre to be
spent on fertilizer, type of livestock, annual rainfall figures or
irrigation details, soil type (clay, loam, peat, pumice, sandy) and pH,
quantities and types of fertilizers and limes applied over the last three
years, pasture species and details, e.g., 80% grass (type) 20% clover
(type), or 100% grass (type), or 100% clover (type).
We will enter the analysis onto our computer, send you the chart, and work
out a suggested fertilizer mix and post it airmail or Email (if you have
it) via jonesv@wave.co.nz
Vaughan Jones, 71 Newcastle Rd, Hamilton 2001, New Zealand.
Best wishes,
Vaughan Jones
(retired dairy & beef farmer, consultant)
Hamilton
New Zealand
jonesv@wave.co.nz