A number of factors should be taken into account when you draw up a fodder production plan that includes pastures.
The costs of establishing a pasture are high, so attention to detail, particularly when establishing perennial pasture, will more than compensate for the effort involved.
The species and variety of fodder crops you choose will depend on the soil type on your farm, the availability and efficiency of irrigation, the climate and the purpose for which the pasture is to be planted.
For example, is there a need to plug the autumn quality gap? Is the pasture required to carry beef weaners through winter so that they can be marketed as finished animals the following summer?
- You should also ask yourself for what animal production purposes the pasture will be used.
- Extensive pastures usually require a long recovery period between grazings.
- Some respond better to rotational grazing than others.
- Fertilisation practices should be geared to the pasture’s potential within the constraints of moisture availability (rainfall and/or irrigation) and soil type.
- Once the basic fertility of the soil has been rectified, fertilisation should be based on nutrient removal.
- 1 ton of dry matter (DM) – grass hay or silage – taken off a pasture will remove about 20 kg of nitrogen (N), 15 kg of potassium (K) and 3.5 kg of phosphorus (P).
- Legumes will remove more potassium and phosphorus, but well-nodulated legumes can make a meaningful contribution towards the nitrogen needs of a pasture.
- Up to 85% of the potassium is returned to the pasture via the grazing animal, but in the case of nitrogen, most is lost and only about 30% is used by the plant.
- Intensive pastures, particularly those under irrigation, can cause internal parasite and fungal disease problems.
- An up-to-date dosing programme should be included in the plan, and in the case of sheep and dairy cows there should also be foot rot preventive measures.
- Annual forage crops such as sorghum, millet or cereals should be grown as a supplementary source of feed.
- For example, when perennial pastures are being established or when there is insufficient winter grazing available from irrigated lands, the cereals can be dryland sown.
- These crops are also grown specifically for silage, and sometimes hay, and to fill certain gaps in the fodder flow.
- Establishing pastures should be planned well in advance.
- Take a soil sample and have it analysed in order to correct the basic fertility.
- Separate soil samples should be taken for every variation in soil type and each different crop.
- In the summer rainfall areas, January and February are usually the most suitable months for establishing pasture, because there is less competition from weeds which have to be controlled during the preceding months.
- There is an improved soil moisture status at this time of the year.
- A firm seedbed should be prepared if the pasture is to be irrigated.
- For reasons of economy, plant as early as possible (February/March).
- Use only high-quality seed at the recommended sowing rates.
- About 20% less seed is used if the pasture is planted in rows.
- Use certified seed, which has to comply with certain minimum standards.
- These standards ensure that the germination, purity and genetic stability of each variety within a species are maintained at a prescribed level.
- The use of certified seed protects the farmer from introducing unwanted weed seed and poor germination.
- Prepare a fine, firm, weed-free seedbed.
- Pastures should preferably be sown in narrow rows of 180 mm apart for irrigated and intensive pastures and 1 metre apart for extensive pastures.
- Seed that is broadcast and rolled will also produce a good established pasture, but the individual plants will not be as robust as in a row-planted pasture.
- Plant pastures in rows in the drier areas.
- All pastures will benefit from a good rolling after sowing.
- Small seed in particular should be well rolled, and the soil of some soil types should be rolled before sowing as well.
- Only the larger seeds need to be buried at sowing; small seeds should simply be pressed into the soil.
- Newly established pasture should not be grazed too soon, but should be allowed to develop a good root system.
- Annuals are generally only ready for grazing 6 to 8 weeks after sowing, and perennials after 8 weeks or more.
- Perennial pasture will take up to 2 years to reach full production.
- Heavy grazing after establishment should be prevented.
- If it is necessary to control weeds in a newly established pasture, the first option should be a mower.
- A selective herbicide should only be used if weeds continue to be a problem.
- This article first appeared in Farming SA.