Increasing grassland yield through overseeding and reseeding
Over the course of harvesting grassland, the sward inevitably becomes damaged. Over the summer months, the sward also dries out in places. Patches form, enabling low-yielding grasses and weeds to spread. The consequence: losses in yield and quality. Between August and September is a good time to improve grassland and fill in gaps. There is less competition from the old sward at this time, so new grasses have a better chance of getting established. Depending on the type of damage to the grassland, it will need to be partially or completely oversown, or even reseeded to increase the yield in spring.
Maintaining or re-establishing grassland
Over the course of the year, restorative measures are carried out on medium to high-intensity grassland to maintain a dense sward with as few weeds as possible. As such, localised overseeding is carried out once or more times a year. Smaller, existing gaps are filled in as a preventive measure. This enables weed infestation to be reduced and the stem density of valuable grasses to be increased.
In addition to localised overseeding, less damaged fields can also be completely overseeded to achieve a stronger sward with valuable, high-yielding grasses. The overriding aim is to increase the proportion of German ryegrass. This method also requires prior cultivation (e.g. harrowing, mulching, mowing). The sward itself, however, is not disturbed. This ensures that the sward is evenly developed. If the grassland is heavily infested with weeds, selective weed control is carried out beforehand. Without overseeding, a secondary weed infestation (by, for example, common chichweed, shepherd’s purse, annual meadowgrass and rough-stalk meadowgrass) can often develop. If weeds persistently penetrate the gaps in the grassland, it will need to be completely replenished multiple times.
On heavily damaged grassland with a weed infestation of over 50%, overseeding is usually insufficient, and complete reseeding is required. This should ideally be carried out in autumn. Due to the high likelihood of rainfall, the newly seeded grassland has a better chance of germinating. The first growth then appears in spring, promising a healthy yield and a high quality potential. In contrast to overseeding as a grassland maintenance measure, which is introduced as part of production-specific routines, reseeding is usually a last resort when regeneration and maintenance has been unsuccessful, or the land is being converted from arable to grassland. Reseeding requires more intensive cultivation and is associated with a longer period of forage loss during the growing season.
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Seed and crop selection: German ryegrass, cocksfoot, meadow fescue
Grassland can be overseeded or reseeded during the growing season from March to September depending on the location. In early autumn, after a second harvest, the weather conditions are usually ideal for overseeding — the soil moisture and dew formation is just right. There is also minimal competition from the existing sward. Overseeding before mid-September allows the newly sown crop enough time to develop and be as strong as possible going into winter. Overseeding requires soil temperatures of at least 10°C and some rainfall to promote germination of the grass seed. If the damage is minimal (covering up to 30% of the acreage), a seed quantity of 10–15 kg/ha is required, and if the damage is extensive, 20–30 kg/ha. In contrast, the seeding rate for localised overseeding is 5–10 kg/ha. With reseeding, the seed quantity varies between 35–100 kg/ha depending on the physical situation and local conditions.
In terms of crop selection, special overseeding and regenerative blends are used for overseeding. These blends exclusively contain fast-germinating, fast-growing grass varieties to fill in the gaps as quickly as possible. On the other hand, a wider range of varieties is used for reseeding. Overall, the grass varieties are selected in relation to the local conditions and farming intensity. To reduce risks, farmers often apply a blend containing different types of grasses from different maturity groups. In addition, aspects such as disease resistance, endurance, yield and feed quality are taken into consideration. Grasses with above-average germination rates are especially preferred for overseeding. These include German ryegrass, cocksfoot and meadow fescue, among others. The best growing conditions for German ryegrass, one of the most prominent cultivated grasses, are on fresh, loamy/clayey soils on lowlands or in a maritime climate. Cocksfoot, on the other hand, grows heavily in masses, sprouts early, achieves good feed values and prefers the growing conditions of nutrient-rich mineral soils and boggy soils in fresh, moderately damp locations. In contrast, meadow fescue is one of the most prominent forage grasses with high feed values, although it is not particularly competitive in intensive grassland that is cut four or more times in a season. Meadow fescue prefers the growing conditions of fresh, moist mineral soils and boggy soils.
Grassland farming with 365FarmNet
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AgroPressure by Michelin is a free component that can be used to calculate the optimum tyre pressure for avoiding soil compaction.