Yield, boron uptake and canopy sunlight interception of direct-sown winter rapeseed as affected by boron fertilizer levels in China

Abstract

Boron is a very important micro-element for winter rapeseed, boron deficiency resulted in “flowering without seed setting” for winter rapeseed. Attention should been paid to the effects of boron application levels on yield and its utilization mechanism in main rapeseed production areas of southwestern China. A split-plot field experiment was conducted with five boron application levels (0, 3.75, 7.5, 15, and 30 kg boron ha− 1) and two rapeseed cultivars (Huayouza 9 and Zhongshuang 11). When boron was applied comparing with non-boron supply, seed yield of winter rapeseed increased 17.2–38.5% in 2020-21 and 6.2–38.1% in 2021-22, respectively. The boron uptake in the seed initially increased significantly and then nearly kept steadily, but the accumulation of boron continued to increase in the pericarp and stem with the increase of boron application levels from 0 to 30 kg ha− 1. Boron application level of 7.5–15 kg ha− 1 is important to increase the current direct-sown winter rapeseed yields in field soils with low available boron in Southwest China cropping areas. Seed yield was more significantly affected by boron input than crop canopy sunlight interception for direct-sown winter rapeseed in this region. These results indicated that it is an effective way to maintain soil fertility by returning no-seed rapeseed plant tissues to replenish soil boron in Southwest China and other boron-deficient planting area.