Abstract:

 Maize-alfalfa intercropping system is a new planting model to solve the problem of single cropping system in the cinnamon soil areas of Liaohe plain. To explore the interspecific competition relationship between maize and alfalfa and over yielding mechanism, and optimize maize-alfalfa intercropping configurations in cinnamon soil areas of Liaohe plain, a two-year (2021−2022) field experiment was conducted in Haifeng farm, Fuxin town, Liaoning province. The experiment was conducted in a completely randomized block design, consisting of five cultivation design, such as intercropping system of 2 rows maize and 2 rows alfalfa (2M2A), and intercropping system of 2 rows maize and 4 rows alfalfa (2M4A), and intercropping system of 4 rows maize and 4 rows alfalfa (4M4A), and sole maize (M), and sole alfalfa (A). Crop yield, dry matter accumulation and distribution of maize, and the competition relationship between maize and alfalfa under different row ratio configuration conditions were studied. The results showed that maize-alfalfa intercropping system had significant effects on maize dry matter accumulation and distribution, crop yields,interspecific competitiveness and productivity. The dry matter accumulation of maize in intercropping system at jointing stage was 2.2%−7.1% higher than that in monoculture, 17.8%−46.8% higher at silking stage and 21.8%−40.3% higher at milk ripening stage. Dry matter partitioning ratio to stem at jointing stage and silking stage and to ear at milk ripening stage increased in all intercropping systems, comparing with that of the sole maize system. The net yield of intercropping maize was significantly increased, with an average increase of 16.3%−26.4% in the two experimental years, but the net yield of intercropping alfalfa was significantly reduced, with an average decrease of 26.8%−48.0% in the two experimental years. The homogenized yield of intercropping maize and intercropping alfalfa was lower than that of monoculture due to the influence of crop area ratio. Maize was more competitive than alfalfa in maize−alfalfa intercropping system(C_MA＞0), and maize was the dominant crop, and alfalfa was the inferior crop. The order of C_MA was 2M2A>2M4A>4M4A. C_MA was significantly negatively correlated with the net yield of alfalfa. The interspecific competitiveness between maize and alfalfa significantly reduced the yield of alfalfa, resulting in changes in productivity of maize-alfalfa intercropping system. Interspecific competitiveness between maize and alfalfa could be regulated by adjusting row ratio configuration and strip width. The net yield of maize and alfalfa of 2M4A was the highest among three intercropping systems due to its C_MA was suitable. The land equivalent ratio of 2M4A was 1.01, which had certain intercropping advantage. It was concluded that 2M4A is suitable for popularization and application in the cinnamon soil areas of Liaohe plain.

Key words: Maize, Alfalfa, Interspecific competitiveness, Yield, Land equivalent ratio