Grassland management targets to improve sward quality and animal performance
Once the basic building blocks of soil fertility, infrastructure and grazing management are in place, the next step to getting more from grass is to develop grass measurement and budgeting skills. Philip Creighton, Grassland Science Research Officer explains that this needn't be complicated.
Main Messages
- Grass measurement and budgeting does not have to be complicated or expensive
- Sward sticks, rising plate meters and the quadrant and shears are common methods
- Measurement carried out on a regular basis can be used to aid management decisions
Introduction
To try and manage any business without knowing what the current and projected future basic inputs may be would not be accepted by the majority and sheep farming and grassland management should be no different. Once the basic building blocks of soil fertility, infrastructure and grazing management are in place the next step to getting more from grass is to develop grass measurement and budgeting skills.
Grass measurement to aid grazing management
Grass measurement and budgeting does not have to be complicated or expensive as is often the perception. There are a number of methods that can be used to measure grass supply on farms. The use of sward sticks, rising plate meters and the quadrant and shears method are all commonly used methods. Whichever method you use is irrelevant, the important thing is that some form of measurement is carried out on a regular basis which can then be used to aid management decisions.
Teagasc has developed an online grassland management decision support tool Pasturebase Ireland. Pasturebase Ireland enables the farmer to keep track of grass growth per paddock, the number of grazings per paddock and the quantity of grass being consumed at each grazing. This immediately highlights poor-performing paddocks and deficiencies in grazing management. This programme allows you to input grassland measurements and information on stock numbers. Using this information grassland management advice is generated based on your current grass supply and demand status to aid decision making on your farm. Table 1 shows an example of grassland management guidelines developed through grazing trials on the Research Demonstration farm in Athenry.
These guidelines can be used to more accurately manage grass during the main grazing season to improve the management, utilisation and quality of swards offered.
The Grass Wedge
A tool which can be used to aid the management and measurement of grass is the ‘Grass wedge’ concept. The idea of the grass wedge is that once a week the farm is walked and an assessment of the quantity of grass available on each paddock is made be it in terms of kg DM/ha or sward height. Paddocks are then arranged from highest to lowest as shown in Figure 1. A line is then drawn from the point on the graph representing the target pre grazing yield down as far as the point on the graph representing the target post grazing yield. If paddocks are above the line you are in surplus or below the line you are in deficit. Where there is too much grass available the quality can deteriorate rapidly and on the other end of the scale if we continue to graze swards too tightly for a prolonged period in an effort to improve quality, growth rates can be reduced and we can run short of grass. 
The idea of the wedge is that we can recognise in advance what is coming down the line and take corrective action. Three words to remember when dealing with grassland systems are Monitor, Manage and Control. The use of the Grass wedge allows us to monitor what is happening thus allowing us to manage the system to control the desired outcome. Examples of actions which might be taken include removing heavy paddocks as baled silage to reduce supply or increasing fertiliser use where we see a period of deficit emerging.