Mitigation effects of agroforestry on crop environmental stress

在泰国Kohn Kaen大学的田野和京都大学的一间塑料屋中，研究了农林间作对作物环境压力的缓解效果。前者在2003-04旱季种植玉米，在2004-05旱季种植花生。这两个季节都可能发生了树木的水力抬升。但对玉米植株的影响没有观察到，可能是由于作物对水分的高需求所致。对于花生树，有人建议，夜间提水可以缓解白天树木和作物之间对水分的竞争。在塑料大棚的试验中，在分根器的一个隔室中种植了马钱树和旱稻，在另一个隔室中只种植了旱稻。在晴天，北侧水稻的光合作用约为南方的20%，但它们仍然存活，尽管南侧的水稻植株在土壤干燥后枯萎。这很可能是在相关的一侧发生了水力抬升，转移到表层根系的水分被释放到土壤中，使这个隔间中树下的水稻植株保持存活。本研究发现，农林复合系统可以缓解作物的环境胁迫。

Mitigation effects of agroforestry on crop environmental stress were examined at fields of Kohn Kaen University in Thailand and in a plastic house in Kyoto University. In the former, maize plants were planted between alleys of mango trees in 2003-04 dry season, and groundnut plants in 2004-05 dry season. It was likely that hydraulic lift by the trees occurred in both seasons. However, its effect on the maize plants was not observed probably because of high water demand of the crops. For groundnut plants, it was suggested that competition for water between the trees and the crop plants in daytime was mitigated by water lifted at night. In the experiment in the plastic house, a markhamia tree and upland rice plants were planted in one compartment of a split-root apparatus, with only upland rice plants planted in other compartment. Photosynthesis of the rice plants in northern side on clear days was about 20% of that in the south, but they remained viable, though rice plants in the south side wilted when soil was dried. It was likely that hydraulic lift occurred in the associated side and that water that had been transferred to the surface roots was released into the soil, enabling the rice plants below the tree in this compartment to remain viable. In this study, it was found that environmental stress of crops would be mitigated by agroforestry system.