Regardless of whether grassland is pasture grazed, a paddock, or simply a strip, it is important to check them regularly. Not only does it help to determine when the land is ready to graze, but it can also act as a guide for deciding when grazed land should have stock removed.
The Three-Leaf Structure
Perennial ryegrass has three leaves on each plant. However, as the fourth leaf is growing, the first leaf generally dies off. This is known as the three-leaf structure.
When managing grassland, the area should be grazed before it progresses to the fourth leaf stage. This is due to the dying material creating shade which can harbour disease and pests. As the plant matures, it will need extra stability to stay upright. This leads to an increase in the amount of lignin, reducing the nutritional value as it is less digestible.
Regrowth is dependent on multiple factors, including circumstances such as the nutrition available to the plant, altitude, daylength and water.
However, there are many factors which need to be considered when planning a grazing system. This can include accessibility, water availability, field boundaries and proximity to farm buildings.
Maintaining Pasture Cover
When ensuring that mature grass has maximum functionality and minimum wastage, it is important to take into consideration different weather conditions. For example, both hot and cold weather can cause plants to become stressed. This not only will reduce its nutritional value but will also make it less palatable.
It is equally as important not to over-graze mature grass, this allowing the grass to rapidly recover. By doing this, weed species will be prevented from infiltrating the pasture and allow the sown species to continue to dominate the area.
Methods for Measuring Pasture
Generally, grass should be 9cm tall pre-grazing and 4cm post-grazing. There are many ways to measure this, including by eye, a sward stick, plate meters, or a pasture meter.
When using a sward stick, the pasture should be walked in the form of a ‘W’, recording the tallest leaves. This process should be carried out around 20-30 times, measuring the average amount of grass available.
Alternatively, plate meters calculate the amount of pasture cover through measuring the compressed height of the sward. This will give a figure for kilos of dry matter per hectare (kg dm/ha).
Despite measuring grass being a useful tool, it is only a small part of the process. Measuring the grass does not give indications towards plant health and which stage of growth it is in. It is also important to understand the soil quality, density, and species.
Common Problems and Solutions
Dominating Weed Species
Weeds are a dominating species which are difficult to eliminate from pastures. However, there are certain solutions which can be carried out to reduce their population.
Solutions such as spraying the area with herbicide and reseeding if necessary, can help reducing the domination of weeds. However, a soil test can also help to determine the nutrient levels and help to tailor a fertiliser plan for the pasture.
However, if weeds have occurred from waterlogged grassland being poached, it is important to evaluate the different options available. It can be helpful to move fields, turn stock in for the winter, or look at the overall drainage of the field.
Grazing Grass at the Incorrect Height
When grass is grazed at the incorrect height, an excess amount of dead matter will reside at the base of the plant. As a result, the plant will rot and not regenerate successfully for the following growing season.
There are solutions to prevent this, such as regularly grazing the area to prevent the dead matter from building up. Additionally, in some cases, it can be helpful to mow the field before grazing where a significant percentage of the grass has grown. Grazing can also be done with animals, such as heifers or dry cows, especially when milk cows have not grazed.
It is also important to reset excessive top grass back to around 4cm. This is because leaving heavy grass over the winter is not always beneficial as it will lead to an early turn out which lacks nutritional value.