Improving Lignin Metabolism, Lodging Resistance and Yield of Brassica Napus L. By Applying Fermented Straw Organic Fertilizer

Abstract

The rational recycling of agricultural waste improves soil productivity, and plays a vital role in crop growth and agricultural sustainability. Still, the mechanism for improving stem strength and rapeseed yield is unclear. To elucidate the complex lodging phenomenon, two different rapeseed varieties, lodging-resistant (Jiayou) and lodging-susceptible (Chuanyou), were selected based on previous experiments and sown in a randomized complete block design with three replications. Four fertilization treatments, local farmers' N practice (150 kg ha−1) (CK);  CK + organic fertilizer (500 kg ha−1) (OF1);  CK + organic fertilizer (800 kg ha−1) (OF2) and CK + organic fertilizer (1100 kg ha−1) (OF3) were used in the field experiment. Our results showed that application of organic fertilizer increased the photosynthetic parameters of rapeseed and the content of soil nutrients (SOC, TN, AP, AK and SOM), and accumulated more lignin by increasing the activities of key enzymes of lignin synthesis (PAl, 4CL, CAD and POD). Organic fertilizer promoted the accumulation of three types of lignin monomers (S,G and S). Correlation analysis showed that G-type and S-type lignin monomers were significantly negatively correlated with lodging rate. soil enzymes (catalase, sucrase, phosphatase, and urease) were upregulated under organic fertilizer application. Furthermore, organic fertilizer application increased the yield of both rapeseed varieties by 4.7, 10.8, and 13.3% under OF1, OF2 and OF3 treatment compared to the CK. In general, the addition of optimum application (800 kg ha−1) of organic fertilizer improved the stem lodging resistance and yield of rapeseed.

Keywords: organic fertilizer, rapeseed, lignin, lodging, soil enzyme activity