[Optimizing Straw Management to Enhance Carbon and Nitrogen Efficiency and Economic Benefit of Wheat-Maize Double Cropping System].

The optimization of annual straw management can improve the yield, income, and carbon and nitrogen efficiency of wheat-maize double cropping systems. Based on a long-term positioning trial started in 2012, five straw management methods were considered, C100 (100% return), C75 (75% return+25% harvest), C50 (50% return+50% harvest), C25 (25% return+75% harvest), and C0 (100% harvest). We analyzed the effects of farmland carbon and nitrogen inputs and their ratios on crop yield, carbon and nitrogen use efficiency, and economic benefits in wheat and maize anniversaries with different straw managements.

[Study on the optimal extaction of total flavonoids from Tagetes erecta by central composite design-response surface methodology].

Objective: To optimize the process of extracting total flavonoids from Tagetes erecta.

Methods: The influential factors were extraction temperature, ethanol concentration, reflux time and solvent volume fold. The evaluating indicator was the extraction rate of total flavonoids from Tagetes erecta.