Abstract:

To explore the mechanism of potassium fertilizer regulating the lodging resistance of oil flax, in field environment, two local oil flax varieties ‘Longya 11’ (V1) and ‘Dingya 23’ (V2) were used as test materials, and the split plot experiment was conducted with four potassium application levels: no potassium (K0, 0 kg/hm ²), low potassium (K1, 30 kg/hm²), medium potassium (K2, 60 kg/hm²) and high potassium (K3, 90 kg/hm²). The effects of different varieties and potassium fertilizer combinations on the plant height, center of gravity height, stem diameter, flexural resistance, lodging resistance index, actual lodging rate, yield and yield components of dry land oil flax and their relationship with plant lodging resistance characteristics were analyzed. The results showed that, the potassium fertilizer application rate of 0~90 kg/hm² could not only promote the growth and development of oil flax, but also improve its lodging resistance, and ultimately increase its yield. After potassium application, the plant height and center of gravity height of the two varieties of oil flax were increased by 4.74% and 8.88% respectively during the whole growth period compared with no potassium application (K0). The stem diameter (green fruit stage) was the largest when the potassium application rate was 60 kg/hm² (K2), increased by 11.79% on average compared with no potassium (K0). The flexural resistance and lodging resistance index of oil flax stalks after applying potassium were 18.32% and 11.50% higher than those without potassium (K0). The actual lodging rate of oil flax under different potassium application levels was: K2<K3<K1<K0, while the yield performance was: K2>K3>K1>K0, and the yield increase rate were 20.69%, 24.93%, and 17.15%, respectively. Correlation analysis showed that the plant height of oil flax and center of gravity height had no significant correlation with the stalk bending resistance, but had a significant and an extremely significant negative correlation with the lodging resistance index (except for the mature period); the flexural resistance and lodging resistance index of oil flax stalks in each growth period were positively correlated with stem diameter, and had a significant and an extremely significant positive correlation with grain yield. In general, under the experimental condition of the study, 60 kg/hm² is the appropriate potassium fertilizer application rate, which could not only increase the yield, but also effectively enhance the lodging resistance of oil flax.

Key words: oil flax, potassium, agronomic traits, lodging, yield