Poor pasture management and overgrazing can seriously damage a farm’s profit margins. Here are some tips to ensure optimal pasture and veld production.
Good management is essential to improve the quality and quantity of pastures. But before you can decide on a strategy, it’s essential to know what your resources are and what you want to do with it, says Dr Wayne Truter, a forage specialist at the University of Pretoria.
Your management strategy depends on whether you use natural pasture – known as veld or rangeland – or planted pastures.
If you decide to plant a pasture, take the following into consideration:
To determine which species to use, whether your soil is suitable for good grass production and the fertiliser requirements of the soil, Truter suggests that a soil analysis be done by an accredited laboratory. Acidic soil, for example, is unsuitable for some species.
SELECTING THE SPECIES
There are more than 9 000 natural grass species. Some are more adapted to certain regions than others.
For example, sub-tropical species like kikuyu, Eragrostis and certain cultivars of temperate legumes – such as lucerne – are generally better adapted to warmer regions. Temperate species, including tall fescue and annual rye grass, prefer cooler climates. Water requirements and water use efficiency are also different for each species.
A third consideration is what you want to use the pasture for. Different animals have different feeding requirements and grazing habits. Sheep and horses, for example, are selective grazers and prefer short grass. Cattle are bulk grazers and prefer grasses that are taller.
There are a number of grazing methods to choose from, including:
continuous/season-long grazing – a number of animals are put out on a pasture and left to graze in that area for as long as the pasture will support them;
rotational grazing – the pasture is fenced into several smaller camps and animals are moved from time to time, depending on pasture availability, to allow the area to rest.
It is generally advised that animals be put into a camp when the grass is 25cm to 50cm tall, depending on the species grazed, and rotated when the grass is down to 8cm.
An advantage of this system is that some of the divisions can be harvested for hay, and fertilisation and/or irrigation practices can be more efficient;
strip grazing – animals are given just enough pasture to meet a day’s requirements. The fence is moved once or twice daily to provide fresh grass.
This is the most labour-intensive method, but results in the highest quality feed, the least waste and the least damage to a pasture, if used at the correct time of the year with sufficient rest afterwards;
forward grazing/leader-follower system – this is similar to rotational grazing. Two groups of animals are put out to pasture.
The first group uses the highest quality vegetation components, followed by the second group that grazes on the grass left by the first group. For example, lactating dairy cows and calves have a high nutritional requirement and should therefore be allowed to graze first, followed by dry cows and bulls;
mob grazing – large numbers of animals are allowed to graze until all the grass is eaten. This approach is often used to clean up pastures having a lot of coarse, mature plants (this is a form of strip grazing in the non-active growing months);
and mixed grazing – different types of animals are allowed to graze at the same time. Sheep and cattle make excellent grazing partners because they eat different plants. Sheep and horses shouldn’t be allowed to graze together because both prefer short grass.
The aim of a fodder flow programme is to match the production capabilities of the farm with the animals’ requirements to obtain the greatest margin over feed costs.
Production potential refers to the carrying capacity of the farm, not the farmer’s target income. The size of the herd should be determined by the capacity of the property. It’s important to estimate how much fodder can be produced annually for the use of the herd and, if economically viable, to supplement the forage resource available with other high-value crops or grains.
Annual rainfall, soil quality and species composition of the area play an important role in determining the carrying capacity of a farm.
The geographic region plays an important role in determining the best time to plant pastures. There are two planting seasons for pastures; namely spring and autumn. Truter says February and March are the best time to plant sub-tropical pastures.
Pastures should be planted on level areas to ease management. Ensure seed beds are cleared of all stones and existing vegetation to ensure good seed-to-soil contact.
Seed used in irrigated and intensive pastures should preferably be sown in narrow rows, about 180mm apart, while seeds used in extensive pastures can be sown a metre apart.
All pastures will benefit from a good rolling after sowing. Rolling is a mechanical action using equipment such as a Cambridge roller, to ensure seed-to- soil contact. Some grass types need to be rolled before sowing. Large seed should be buried, while small seed should simply be pressed into the soil.
Truter also advises farmers to use only the best-quality seed, accredited by the South African National Seed Organisation (SANSOR): “Good-quality seed has a high germination potential; if a farmer uses poor-quality seed, the quality of his or her pasture will be poor. This, in turn, will have a negative impact on the animal production system.”
Newly established pasture should not be grazed too soon, but allowed to develop a good root system first. Perennial or annual grass is generally ready for grazing six to eight weeks after sowing.
To get the most from a rangeland or veld, a veld condition survey should be conducted before animals graze the area. Follow-up surveys should be conducted every two to three years; and an effective grazing management system should then be implemented.
According to Truter, it is possible to improve the quality and quantity of your veld by using fertiliser. This, however, is extremely expensive. He recommends that farmers rather reinforce poor-quality veld through inter seeding higher quality grasses, adapted to the local environment, once the survey has been conducted. A mixture of grass and legumes is usually recommended in the high-input systems generally used in the dairy industry.
Because soil-to-seed contact is crucial for germination, it’s recommended that inter seeding takes place in the growing season, especially when pasture production potential declines.
In the long run, if good management strategies for pastures are not adhered to, farmers will pay the cost. “Overgrazing can render a natural pasture unproductive for up to five years and can also have a negative impact on its carrying capacity. As a result, farmers will need more hectares to feed the same number of animals as in the past,” warns Truter.
He concludes that good management is essential to protect the country’s rich biodiversity, and that planted pastures can be used to relieve the pressure from over-exploited natural rangelands.
Enquiries: Dr. Wayne Truter Email: firstname.lastname@example.org