| Grassland
New tools for optimising grass production
This article focuses on the latest research and highlight emerging technologies that are being developed to help
farmers optimise the quantity and quality of their grass crops.
here is growing pressure on UK
farmers to use more home
grown forage and reduce the
use of more expensive imports,
such as soymeal, in order to
become more economically
and environmentally sustainable. Currently, the
average UK grass yield is 7.3 t/ha dry matter
(DM). This is considerably lower than the
potential yield, which is calculated to be over
20 t/ha DM, for lowland England. It is clear that
there is a great opportunity to increase the yield
(and quality) of grass crops to reduce the cost
of purchasing alternative feedstuffs and
improve sustainability.
It is estimated that within the UK, over 3
million hectares of the total land area is
predominantly grazed by livestock and
approximately 700,000 hectares of grassland is
used to produce silage. Managing grassland
and forage crops calls for the same level of
precision as arable crops. However, very few
precision farming technologies have been
transferred from arable to grassland and forage
crops.
Precision farming technologies have the
potential to help farmers increase production
efficiencies through several mechanisms:
• Regular monitoring of grass yield and
quality to optimise grazing performance /silage
harvest.
• Yield mapping to identify fields or part-fields
that are underperforming and require different
management.
• Identify the crop husbandry and
management changes required to improve
yield and/or quality.
• Enable variable rate appl ication of inputs,
such as seed, fertiliser and crop protection
products.
This article summarises four current research
projects that aim to develop precision farming
technologies for grass crops.
Review of tools for measuring grass growth
It is recognised that relatively few producers
measure and record grass growth or set
pasture cover targets for various times of the
year. This results in many farmers not
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understanding the maximum potential from
their grassland or livestock growth rates. To
help farmers better understand grassland
potential AHDB Beef & Lamb are funding ADAS
UK Ltd to review available tools for measuring
and managing grassland as well working with a
small group of farmers to develop a blueprint
for managing grass for beef cattle.
There are a number of hardware tools
available to measure grass growth or pasture
cover. Traditionally visual assessment, rising
plate meters or electronic probes are used.
These methods are relatively skilled, timeconsuming processes that can quickly become
monotonous when done with the frequency
required to result in effective management
decisions. The frequency of pasture
assessment required is farm specific, but
during the peak growing season is
recommended to be at least every 7-10 days1.
The review is based on current tools used in
grazing systems and includes those from the
United Kingdom, Republic of Ireland, mainland
Europe, Australia and New Zealand and covers
tools such as the sward stick, GrassOmeter or
Automatic Pasture Reader for measuring grass
and online or APP based tools for managing
the grazing wedge (e.g. FARMAX or
farmGRAZE).
Grass Sense - Tractor mounted sensors
An Innovate UK project involving Yara, ADAS
UK Ltd, Precision Decisions and ForFarmers is
investigating how to develop the tractor
mounted Yara N sensor to estimate grass
biomass and N content from the spectral
reflectance of grass crops. The N-Sensor will
work across different:
• Grass species and varieties;
• Clover contents;
• Amounts of lodging;
• Farm systems (with and without history of
manure);
• Cutting/grazing strategies; and,
• Grass growth class.
Results to-date have been very promising
and indicate that the sensor can sense
differences in grass biomass and N content in
different parts of a field. Ultimately it is
anticipated that the sensor could provide a
precise method of calculating the N fertiliser
required on a field by field, and metre by metre
basis. Precision application of N fertiliser could
help optimise N fertiliser inputs and increase
grassland productivity.
Satellite technologies
Current technologies for measuring grass
yield are either labour intensive or not well
developed. An Innovate UK funded project
aims to develop novel satellite sensing
technology that will provide an inexpensive
method of remotely sensing grass yield and
quality. ADAS UK Ltd and Precision Decisions
are developing techniques to exploit optical
and radar remote sensing technologies to
estimate grass yield and quality. An allied
AHDB funded project will investigate the
potential for developing existing grass growth
models to make use of remote sensing
information acquired by satellites.
Review of the Fertiliser Manual (RB209)
New tools for measuring grass growth can
only be fully exploited if the guidance for
targeting crop inputs is up to date. The
Fertiliser Manual (RB209) provides best
practice information on the application of
mineral fertilisers, manures and slurries to
arable crops and grassland. AHDB are funding
a consortium led by ADAS UK Ltd to provide an
independent review of the Fertiliser Manual in
order to bring the latest nutrient management
research to farmers.
The project involves reviewing crop nutrition
research carried out since 2009 with a view to
publishing a new “AHDB Nutrient Management
Guide (RB209)” by June 2017. The review has
assessed recent data on grassland and forage
crop productivity and has proposed a new
format for grassland nitrogen recommendations
for silage and grazing situations, based on N
application sequences linked to contrasting
levels of grass dry matter yield.
Authors:
Pete Berry, Alice Willett & Paul Newell-Price
For further information, contact Alice Willett
on [email protected] or 01954 267666
July 2016 | Farming Monthly | 27