关键词: 生物炭, 菜籽饼, 玉米, 白菜, 产量, 光合特性, 品质

Abstract: Nitrogen reduction combined with organic materials is an important measure to achieve or even increase crop yield retention at the background of fertilizer reduction. We conducted a pot experiment to explore the effects of nitrogen reduction combined with organic materials on yield, photosynthetic characteristics, and product quality of agricultural products of maize-cabbage rotation system in yellow soil area of Guizhou. There were five treatments, including no fertilizer (CK), conventional fertilizer (CF), nitrogen reduction (20%, the same below) combined with biochar (RF+B), nitrogen reduction combined with rapeseed cake (RF+O), and nitrogen reduction combined with both biochar and rapeseed cake (RF+BO). Leaf photosynthetic characteristics were measured in maize (seedling stage, jointing stage, heading stage, and mature stage) and cabbage (seedling stage, growing stage and harvest stage). The biological characters, yield and quality indices were investigated in the harvest period. Compared with CF, RF+BO significantly enhanced the yield of corn and cabbage by 9.7% and 39.2%, respectively, while RF+O had no effect, and RF+B did not affet maize yield. RF+BO improved the biological properties of maize and cabbage, including the 100-kernel weight of maize, and plant height, maximum leaf length and total biomass of cabbage. Furthermore, the green holding period and high photosynthetic duration of maize and cabbage were prolonged, among which, maize leaf SPAD was increased respectively by 42.7%, 11.0%, 12.8%, and 30.3% at seedling, jointing, heading, and mature stages, the cabbage leaf SPAD was increased by 13.5%, 9.2%, and 30.3% in seedling, growing and harvest stages, respectively. The net photosynthetic rate (P_n) of maize was increased by 11.1%, 10.9%, and 119.8% in seedling, jointing, and mature stages, while that of cabbage was increased by 12.7% and 14.6% in growing and harvest stages, respectively. The stomatal conductance (g_s) of maize was increased by 58.3% and 41.7% in jointing and harvest stages, while that of cabbage was increased by 10%, 64.7%, and 19.2% in seedling, growing, and harvest stages, respectively. The transpiration rate (T_r) of maize was increased by 55.0%, 10.6%, 14.0%, and 143.9% in seedling, jointing, heading, and mature stages, respectively, while that of cabbage was increased by 26.1% in growing stage. The nutritional quality of maize and cabbage was significantly improved. The contents of reducing sugar, starch, and crude protein in maize were increased by 16.2%, 3.5% and 20.3%. The contents of Vc, amino acid, and reducing sugar in cabbage were increased by 26.3%, 21.0% and 27.8%, separately. In conclusion, 20% nitrogen reduction combined with biochar and rapeseed cake had positive effects on crop growth, yield increase, green retention period, high photosynthetic duration, and agricultural product quality improvement in Guizhou yellow soil maize-cabbage rotation system, the overall effect of which was the best. Nitrogen reduction combined with single organic material overally did not affect crop yield, photosynthetic characteristics, and quality.

Key words: biochar, rapeseed cake, corn, cabbage, yield, photosynthetic characteristic, quality