Rapeseed‐to‐Wheat Yield Ratio in Different Production Environments and Effects on Subsequent Summer Crops Yields

Abstract

Core Ideas The rapeseed/wheat yield ratio was 0.55 and was independent of soil conservation. Soybean after rapeseed yielded 11% more than after wheat. Maize after rapeseed yielded 17% more than after wheat. A more diverse cropping sequence enhances both production levels and profitability. Winter crop production in eastern Argentina and western Uruguay has been limited to wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), forming a double annual cropping system with soybean [Glycine max (L.) Merr.] and maize (Zea mays L.) during summer seasons. Currently, double annual cropping system covers less than 30% of the area. Past studies suggests that the rapeseed (Brassica napus L.)/wheat yield ratio ranges from 40 to 60%, and the inclusion of rapeseed in the system could improve grain yield of the following crops. The objectives of this study were to: (i) quantify the rapeseed/wheat yield ratio under different cropping systems; (ii) quantify the differential yield of summer crops compared with wheat and rapeseed while keeping a similar harvest date for winter crops and planting date for summer crops, respectively; and (iii) assess the economic result of the evaluated cropping systems. Rapeseed and wheat crops were sown in a long‐term rotation trial where different cropping systems were evaluated. Experiments were conducted for two seasons (2014 and 2015) and in each summer season after the winter crop harvest, soybean (2014–2015) and maize (2015–2016) were sown. No yield differences were detected for wheat and rapeseed as a result of the previous cropping systems, and the rapeseed/wheat yield ratio was about 55%. Higher summer crop yields were obtained after rapeseed compared with wheat (11 and 17% for soybean and maize, respectively). Producers may be able to enhance both production levels and profitability by adopting a more diverse cropping sequence.