Description
Sowing rate: 35-40 kg/ha.
Can be used as a green manure crop in greening and in the AKG programme.
Sand oats (Avena strigosa) are an autumn legume from Mediterranean areas, one of the four cultivated species of the genus Avena.
Abrack oats (Avena sativa) are less favoured by farmers as a main crop because of their significantly higher yield potential, but their high nitrogen content, low C:N ratio and allelopathic ability make them an excellent cover crop. It is currently the most widely grown crop in South American countries, but is also used as a cash crop and as a second crop by farmers in Australia, Scotland and the United States.
Botanical characteristics:
Erect-stalked autumn legume, a more primitive member of the oat family, with seed formation similar to that of the grass family. Height 70-150 cm, leaves flat, rough, 4-8 mm wide and up to 25 cm long. The calyx is open and less compact, weighing around 15 grams per thousand seeds. It is characterised by rapid growth, which, together with its allelopathy, makes it a good weed suppressor, inhibiting the germination of small-seeded weeds when its tissues decompose, and even reducing the population of wheat weeds by 90-95%. It can also be used effectively to control nematodes, but it is important to know which varieties are effective against which nematodes.
It develops best in cool, moderately rainy conditions, is cold tolerant to around 0°C but not frost tolerant, and will die in frosts of minus 7-8°C. It grows well in nutrient-poor soils, with a pH range of 4.5 to 7.5 for chemistry. It prefers sandy and loamy soils, but also thrives in heavy clay soils. It does not tolerate shade but tolerates drought well. Like oats in general, it is very sensitive to herbicide residues in the soil.
As a main crop, it can be sown in early spring at a depth of 1-3 cm. The seed rate is 80-120 kg/ha in our country, but on poorer soils or weedy plots it is advisable to sow the higher rate. Nitrogen demand is 60-80 kg/ha depending on the desired yield. Barley yellow rust virus is largely resistant to the varieties available today and most varieties are also resistant to rust.
Integration into cover crop technology
Sand oats are a useful annual grass for cover crops after harvesting our crops. It has a higher nitrogen content and a lower carbon:nitrogen ratio than other winter cereals, so there is less risk of nitrogen immobilisation when its residues are incorporated. It produces 4-7 t/ha biomass in monoculture but grows faster than other winter cereals, making it a particularly popular cover crop.
Sowing is recommended in the second half of August and the first two weeks of September. In the mix it works well with nitrogen-fixing crops, is a good support crop for vetches and fodder peas, but also combines well with broad beans. You can also add facelias (honeysuckle), testicles and tillage radishes to fill in the soil colour space. The latter is particularly recommended for compacted soils, since sandy oats leave a good soil in the upper layers thanks to their fine roots, but do not reach the deeper layers. Thus, a mixture of sand oats, horse beans, facelia and cultivated radish will fill the 3 to 3 layers above and below the surface. Recommended seed rate per component is 5-15 kg/ha.
If not terminated by winter frosts, it can be killed by rolling, mowing and weed control. If earlier destruction is desired, a combination of herbicide and rolling is advisable at the calving stage, while mechanical termination alone may be sufficient at the later stage (milk ripening).
Its high protein content also makes it suitable for animal feed, which offers an excellent opportunity for utilising cover crops and terminating them naturally. In addition to cattle, sheep are also very fond of it, and sheep are also keen to eat the standing sand oats after malting.
Experience as an administrator
Cereals are less common in cover crop mixtures in Hungary, but the use of sand oats, spring oats and rye for different purposes is something that all cover crop farmers should consider.
Sown after harvest of autumn cereals or rape, before a spring catch crop, sand oats are an excellent mixer. On the one hand, it compensates for the slow growth of the butterfly cover crops recommended in such cases (broad beans, fodder peas, testicles, vetches) and keeps weeds under control until the nitrogen-fixing crops have established. It tolerates drought well, developing a significant amount of green mass during the low rainfall autumn of 2018. It is a particularly good companion plant for buttercups with a creeping habit.
Our tests show that it retains nitrogen from the previous main crop or nitrogen applied to the front of the cover crop well near the surface. Due to the climate in the Carpathian Basin, it freezes during December-January, its stems fall and its straw slowly collapses. Even when fallen, it provides 85-90% ground cover, which lasts until sowing in late March/early April.
The only "con" is the price, which can be two to three times higher than for spring oats. Nevertheless, we recommend trying it, because, true to its name, sand oats are a great mulch, weed suppressor and nitrogen fixing cover crop, even on poorer soils.