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.

Core Ideas: Soybean yield with maize as previous crop was ≈10% higher than the average yield. Soybean yield with soybean as previous crop was ≈4% lower than the average yield. Monoculture is explained as producers not valued this impact in short term decisions. Soybean [Glycine max (L.) Merr.] monoculture is the dominant cropping system in the Rio de la Plata region. Despite the benefits of crop rotation, monoculture systems are an actual problem in many soybean and maize (Zea mays L.) production areas worldwide. Soybean monocultures are especially problematic because of their negative impact on soil quality. Regionally, there are only a few reports about soybean monocultures and yield improvement when maize is included in the rotation. We used a producer's database (849 records from 2009 to 2013) to evaluate the effect of maize–soybean rotation on soybean yields. Four frequent annual previous crop sequences where identified: winter fallow–maize, winter crop–maize, winter fallow–soybean, and winter crop–soybean. As all of them are unequally represented, a new database was generated using a bootstrap resampling with 1000 replicates. Each interaction was economically analyzed, generating a variable called the differential gross product (difference in gross product, in US$ ha^–1, with respect to the gross product average). Results indicate that crop rotation with maize has an agronomic and economic advantage. Soybean yield was ≈12% higher than the average when winter crop–maize was the previous crop, whereas it was ≈5% lower than the average when the previous crop was winter crop–soybean. Soybean following maize resulted in a gain in gross product of ≈125 US$ ha^–1. However, the relationship between areas of soybean and maize indicates local producers fail to profitably grow maize or are inadequately assessing the impact of its inclusion into the production system.

Rapeseed (Brassica napus L.) is the second most produced oilseed crop in the world. It provides a high-quality nutrient for pollinating insects, and pollination, in many cases, increases crop yield. Although a large number of species visit rapeseed crops, Apis mellifera (Hymenoptera: Apidae) is the most frequent, abundant, and with the highest pollination potential. Our aim was to evaluate the effect of A.mellifera on the different yield components of Brassica napusL. (cv. Rivette). The hypothesis of the study was that the presence of pollinators would increase rapeseed crop yield and improves maturation uniformity. Four trials were conducted (one in 2013, two in 2015, and one in 2016) in commercial rapeseed crops, using pollinator exclusion tents placed during the flowering period. A randomized complete block design with two treatments and six replications during 2013 and three replications during 2015 and 2016 was used. Treatments consisted of exclusion tents with the addition of an active beehive (WITH) and without a beehive (EXCLUDED). WITH treatments showed greater uniformity on siliques maturation and a lower proportion of flowers at maturity. Rapeseed yield was determined by the site (season and farm) (P < 0.0005) and treatments (WITH or EXCLUDED) (P = 0.0482), with no interaction between them (P = 0.1217). Grain yield in WITH treatments was 14% higher than in EXCLUDED treatments (2089 vs. 1836 kg ha⁻¹). In 12 out of 15 (80%) experimental units, WITH treatment yields were higher than EXCLUDED treatments. Results show that A.mellifera can increase rapeseed yields, despite a high rate of self-fertilization.