商洛低山丘陵区农林复合生态系统光能竞争与生产力

农林复合系统是改善商洛低山丘陵区脆弱生态环境、促进该区域经济发展的重要举措。以该区具有代表性的核桃(Juglans regia L.)、大豆(秦豆8号)和丹参(Radin salviae Miltiorrhizae)农林复合模式为对象,研究不同农林复合系统对光能分布、农作物生长、生产的影响。研究结果表明,不同复合模式下,大豆、丹参的光合有效辐射、光合速率、生物量及产量均有不同程度的下降,且距树行愈近,影响愈大。叶片水势与大豆、丹参的光合速率、生物量以及产量不相关或负相关,而15—30 cm土壤含水量与大豆的生物量和产量以及丹参的生物量正相关,大豆、丹参的生产量与其光合有效辐射呈显著正相关性,这说明农林复合系统中光能竞争是导致间作大豆、丹参产量下降的主要原因。

Competition for light and crop productivity in an agro-forestry system in the Hilly Region, Shangluo, China

Agroforestry is the most effective way to restore the disturbed lands in the hilly region of Shangluo and to develop the currently poor local economy. In order to study the potential benefits of tree-based intercropping systems, photosynthesis, growth and yield of soybean (Qindou 8) (Glycine max L.) and salvia (Radin salviae Miltiorrhizae) were studied by measuring photosynthetic active radiation (PAR), plant water deficit and soil moisture in a 6-year-old plantation of walnut (Juglans regia L.) grown at a spacing of 5 m 3 m in the hilly region in Shangluo. The effects of tree competition significantly reduced the PAR, the net photosynthetic rate (Pn), growth and yield of individual soybean or salvia plants growing near (within 1m near) tree rows. In 2010, daily plant water deficits were not significantly correlated with the Pn and growth and yield of the both crops. However, the soil moisture (15-30cm depth) was significantly correlated with biomass and yield of the crops. The PAR was highly correlated with growth and yield of the both crops, which indicated that competition for light is one of the key factors impacting crop yield. Possible remediation strategies were suggested that may reduce competitive interactions between the tree and crop species.