石漠化地区单播与混播牧草光合差异研究

Study on Photosynthetic Differences between Monoculture and Mixed Sowing Forage Grass in Rocky Desertification Area

利用英国Lcpro+便携式测定系统研究了石漠化地区多年生黑麦草和白三叶的单播与混播群落光合日变化特征差异。结果表明:混播牧草由于其种间竞争与互补优势提高了其混播组合的净光合速率及水分利用效率。多年生黑麦草(净光合速率5.09±3.42μmol CO2·m-2·s-1、水分利用效率1.29±0.84μmol CO2·mmol-1 H2O)-白三叶(7.53±3.65μmol CO2·m-2·s-1、水分利用效率1.68±0.67μmol CO2·mmol-1 H2 O)混播草地群落的净光合速率及水分利用效率高于多年生黑麦草(净光合速率4.82±2.79μmol CO2·m-2·s-1、水分利用效率1.22±0.95μmol CO2·mmol-1 H2 O)、白三叶(净光合速率6.97±3.26μmol CO2·m-2·s-1、水分利用效率1.52±0.65μmol CO2·mmol-1 H2 O)的单播草地群落。混播处理的多年生黑麦草蒸腾速率(4.24±2.43 mmol H2O·m-2·s-1)高于单播(4.22±2.43mmol H2O·m-2·s-1)处理,白三叶混播处理的蒸腾速率(4.55±1.98 mmol H2O·m-2·s-1)则低于单播(4.64±1.98mmol H2O·m-2·s-1)处理。本研究对维持混播草地群落的稳定性,探寻种间竞争机理,优化牧草种植模式,科学发展喀斯特草地畜牧业具有一定的理论与现实意义。

The British Lcpro + portable measurement system was used to study the diurnal change difference of photosynthesis between monoculture and mixed sowing community of Lolium perenne and Trifolium repens in the rocky desertification area.The results show that the mixed sowing forage grass has improved its mixed seeding combination of net photosynthetic rate and water use efficiency because of its interspecific competition and complementary advantages.The net photosynthetic rate and the water use efficiency of mixed sowing Lolium perenne(net photosynthetic rat 5.09±3.42μmol CO2·m-2·s-1,water use efficiency 1.29±0.84μmol CO2·mmol-1H2O)-Trifolium repens(net photosynthetic rat 7.53±3.65μmol CO2·m-2·s-1,water use efficiency 1.68±0.67μmol CO2·mmol-1H2O)are higher than monoculture Lolium perenne(net photosynthetic rat 4.82±2.79μmol CO2·m-2·s-1,water use efficiency1.22±0.95μmol CO2·mmol-1H2O)-Trifolium repens(net photosynthetic rat 6.97±3.26μmol CO2·m-2·s-1,water use efficiency 1.52±0.65μmol CO2·mmol-1H2O).The transpiration rate of mixture sowing Lolium perenne(4.24±2.43 mmol H2O·m-2·s-1)is higher than monoculture sowing(4.22±2.43 mmol H2O·m-2·s-1)Lolium perenne,while the transpiration rate of mixture sowing Trifolium repens(4.55±1.98 mmol H2O·m-2·s-1)is lower than monoculture sowing(4.64±1.98 mmol H2O·m-2·s-1).The research has a certain theoretical and practical significance to maintain the stability of the mixed sowing grassland communities,explore the interspecific competition mechanism,optimize the planting patterns of forage grass,and develop the karst grassland animal husbandry scientifically.