关键词: 旱坡地, “作物-植物篱”系统, 能结构, 能效率

Abstract:

Aims Energy flow characteristics of alley cropping have been rarely studied, although alley cropping is common in Sichuan in order to control soil erosion and promote productivity. Our aims are to understand growth pattern and production mechanization of crops, determine effects of hedgerows on main crops in order to realize positive interactions, promote the level and structure of energy inputs, optimize and establish an environment-friendly farming system and realize sustainable agriculture on hillsides.

Methods We recorded labor input, fertilizer, pesticides, farming activities and leaf fall on the soil surface in trial plots for two years. After harvesting, we separated plant parts to determine economic yield and biological yield, calculated energy of the different parts according to a conversion ratio of energy and studied energy structure and energy efficiency of alley cropping by statistical analysis.

Important findings In comparison with the traditional agricultural system on hillsides, there were differences between hedgerows and crop in shape and spatial distribution of crown and roots, such that light, heat, water and soil were utilized continuously in time and in space, resulting in enhanced efficiency of light utilization, efficiency of input labor energy utilization and total output energy per unit area on steeper hillsides. Moreover, input of inorganic energy of alley cropping was reduced significantly and use of chemical fertilizer and pesticide could be reduced, resulting in environmental protection. Quantity and structure change of output and input energy of alley cropping was affected mainly by the type of hedgerow subsystem. Total energy input (including organic energy) of hedgerow system with fruit trees was increased, which was useful for improving input energy structure and ecosystem and enhancing intensive agricultural development. A hedgerow system of shrubs and herbs could reduce input labor energy, decreasing input energy and input energy consumption greatly and resulting in increased efficiency of input labor energy utilization and biomass and energy output/input ratio of the main crops. Alley cropping conserved water and soil, thereby playing an important role in agricultural reform in the vast mountainous and hilly area of Sichuan.

Key words: hillside, alley cropping, energy structure, energy efficiency