Effect of potassium rate on yield, potassium uptake and canopy radiation interception of direct-seeded winter canola

Rui Wang1, 2, 3*, Ahui Liu1, 3, Xiaolei Chen1, 3, Yanhua Wu1, 3, and Wenli Peng3, 4
Direct seeded canola (Brassica napus L.) has become increasingly popular in China’s key canola-producing regions. The studies on the K response of direct-seeded canola performance are limited. This research aimed to investigate the K utilization efficiency and canopy radiation interception rate of direct seeded winter canola at various K application rates. Two seasons field trials were done with five K levels (0, 75, 150, 225, and 300 kg K2O ha-1) utilizing two key local cultivars (Huayouza no. 9 and Zhongshuang no. 11) in Southwest China. Canola yield rose by 17.9%-82.6% in 2017-2018 and 21.1%-73.6% in 2018-2019 when K was applied, compared to K-unfertilized. Canola yield go up rapidly at first and then gradually when K ingestion grew, demonstrating the phenomena of K luxury consumption. As K levels rose, internal utilization efficiency, agronomic efficiency, and physiological efficiency all decreased. In canola pod development and maturation period, 150 kg K2O ha-1 intercepted the most solar radiation (73.8%), while K-unfertilized treatment intercepted the least (61.6%) on average. The K supply rates had a significant effect on canopy radiation interception and K absorption in winter canola. When K application exceeded a specific rate, luxury consumption occurred. Canola’s luxury K consumption was mostly stored in the pericarp and plant stem.
Keywords: Brassica napus, potassium fertilizer rates, potassium uptake, winter canola, yield.
1Tongren University, College of Agroforestry Engineering and Planning, Tongren, Guizhou 554300, China.
2Provincial Key Laboratory of Biodiversity Conservation and Utilization in Fanjing Mountain Area of Guizhou, Tongren, Guizhou 554300, China.
3Tongren University, Physiological and Ecological Research Center for Agroforestry Complex Planting System in Southwest Mountain Area, Tongren, Guizhou 554300, China.
4Tongren University, Tongren University Library, Tongren, Guizhou 554300, China.
*Corresponding author (ngywr@gztrc.edu.cn).