【摘要】 在宁夏黄土高原丘陵区中度退化苜蓿草地，以不补播草地为对照，研究补播多年生黑麦草、无芒雀麦、披碱草、鸭茅、苇状羊茅、羊草对苜蓿光合生理、荧光特性、形态特征、群落生物量及牧草营养品质的影响。结果表明：与不补播相比，补播禾草提高了苜蓿叶片光合速率、气孔导度、相对叶绿素含量、最大光能转换效率、电子传递体、单位面积吸收光能，其中补播苇状羊茅处理的苜蓿光合速率最高；补播禾草处理的苜蓿株高和叶面积系数增高，蒸腾速率降低(P<0.05);补播对退化苜蓿草地群落密度增幅、盖度增幅、地上生物量、营养成分贡献率、单位面积粗蛋白产量均有促进作用，补播无芒雀麦处理牧草单位面积粗蛋白产量最高，达115.37 g/m~2;相关分析表明，苜蓿光合因子与苜蓿株高、地上总生物量相关性较高，苜蓿中性洗涤纤维与蒸腾速率、气孔导度相关性较高；冗余分析表明，土壤全氮、全磷显著影响苜蓿株高、群落密度和地上总生物量，苜蓿光合速率受土壤全钾影响显著。综上，补播禾草可以有效改善退化苜蓿草地的光合生理和荧光特性，提高群落地上生物量和营养成分；从补播后牧草单位面积粗蛋白产量看，无芒雀麦是改良黄土高原丘陵区退耕苜蓿草地最合适的补播草种。更多还原

【Abstract】 The experiment was carried out on the moderately degraded alfalfa grassland in the hilly area of the Ningxia Loess Plateau, we studied the effects of reseeding Festuca arundinacea, Leymus chinensis, Dactylis glomerata, Elymus dahuricus, Bromus inermis, and Lolium perenne on the photosynthetic physiology, fluorescence characteristics, morphological characteristics, community biomass and forage nutrient quality of alfalfa. The results showed that the photosynthetic rate, stomatal conductance, relative chlorophyll content, maximum light energy conversion efficiency, electron transporter, and light energy absorption per unit area of alfalfa leaves were increased by reseeding grass compared with no reseeding grass, the photosynthetic rate of alfalfa was the highest in reseeding Festuca arundinacea. The plant height and leaf area coefficient of alfalfa increased and the transpiration rate decreased in the treatment of reseeding grass(P<0.05). Reseeding promoted the increase of community density, coverage, aboveground biomass, contribution rate of nutrient components and crude protein yield per unit area of degraded alfalfa grassland. The yield of crude protein per unit area of forage treated with reseeding Bromus inermis treatment was the highest(115.37 g/m~2). The correlation analysis showed that there was a high correlation between alfalfa photosynthetic factors and alfalfa plant height and total aboveground biomass, and there was a high correlation between alfalfa neutral detergent fiber and transpiration rate and stomatal conductance. The redundancy analysis showed that soil total nitrogen and total phosphorus significantly affected alfalfa plant height, community density and total aboveground forage biomass, and the photosynthetic rate of alfalfa was significantly affected by soil total potassium. In conclusion, reseeding can effectively improve the photosynthetic physiology and fluorescence characteristics of alfalfa, and improve the aboveground biomass and nutrient composition of grass community. According to the crude protein yield per unit area of forage after reseeding, Bromus inermis was the most suitable reseeding species for improving rehabilitated alfalfa grassland in hilly region of Loess Plateau.更多还原