August and September Sowing Strategies for Rapeseed Planting
In Germany, the optimal sowing period for most locations is during the last decade of August, extending to the first decade of September due to the warmer climate of recent years. This timeline provides ideal conditions for the growth and development of rapeseed crops.
The choice of rapeseed variety plays a significant role in determining the optimal harvest time. A table offers a guide for the optimal sowing window for a large selection of rapeseed varieties, taking into account the delay in straw ripening that ultimately influences the harvest schedule.
One factor that can contribute to a delay in straw maturity is strong Phoma resistance, found in certain varieties. It's worth noting that an expression level four in straw ripening delay means that the stand has reached optimal swathing suitability when the grain reaches maturity.
Winter rape has been entering the generative development phases earlier in the past three decades, on average 15 to 17 days earlier. This trend is important to consider when planning the sowing and harvesting schedule.
To potentially counteract infestation by wireworms and the small cabbage fly in autumn, a slightly later sowing can be beneficial. Lower sowing rates are recommended for early sowing into a well-prepared, fine-crumbly seedbed or under rather dry conditions.
The period between flowering and harvest has increased by about 17 days on average, a factor to consider when planning the harvest schedule. Hybrid varieties perform well in conditions with weather-related uncertainties in autumn development or a late start to vegetation in spring.
Hybrid varieties now dominate the winter rape portfolio and deliver stable market performance with top scores for oil yield. Their faster juvenile development compared to line varieties contributes to their higher late sowing tolerance. Additionally, the genetically anchored pod shatter resistance and kernel robustness provide the breeding prerequisites for a wide harvest window.
Lower plant densities in rapeseed counteract premature stem elongation. About 40 to 50 seeds per square meter should be used for the sowing of line and hybrid varieties up to the third decade of August.
A good oil content requires sufficient water supply, optimal lighting at daytime temperatures of up to 25°C, and nighttime temperatures in the range of up to 10°C during the fruit and grain formation phase. Under these conditions, the rapeseed root can grow up to 10 cm deep per week.
Hybrid varieties can regenerate quickly and benefit from higher (late) frost tolerance. Given the ongoing drought and wet phases that alternate or very variable temperatures, hybrid varieties can show their strengths.
In summary, understanding the optimal sowing period, variety selection, and growth conditions is crucial for successful rapeseed cultivation in Germany. Embracing hybrid varieties and their advantages can help farmers adapt to the changing climate and ensure a bountiful harvest.
