关键词: 豆禾混播, 群落特征, 营养品质, 种间竞争, 组合筛选

Abstract: [Objective] The study aimed to screen high-quality and high-yield mixed sowing combinations suitable for establishing long-term artificial grasslands in the Hohhot region. [Methods] Sowing was carried out on May 8, 2021, at the Dry Farming Experimental Station of the Inner Mongolia Academy of Agricultural and Animal Husbandry Sciences in Wuchuan County. Leguminous forages including Aohan alfalfa （A）, Zhongmu No. 3 （Z）, Zhongmu No. 1 （P）, and gramineous forages including Bromus inermis （W）, Elymus sibiricus （L）, and Elytrigia repens （Y） were selected as the research objects. They were sown separately first, and then mixed-sown in different combinations （AW: Aohan alfalfa + Bromus inermis; AL: Aohan alfalfa + Elymus sibiricus; AY: Aohan alfalfa + Elytrigia repens; ZW: Zhongmu No. 3 + Bromus inermis; ZL: Zhongmu No. 3 + Elymus sibiricus; ZY: Zhongmu No. 3 + Elytrigia repens; PW: Zhongmu No. 1 + Bromus inermis; PL: Zhongmu No. 1 + Elymus sibiricus; PY: Zhongmu No. 1 + Elytrigia repens） to establish artificial grasslands. On August 26, 2022, the height, density, and biomass of the grass population under different treatments were measured; the contents of dry matter, crude protein, crude fat, crude ash, neutral detergent fiber, and acid detergent fiber in the forages of each mixed-sowing combination were detected; the interspecific competition rate and interspecific compatibility were calculated. [Results] The experimental results showed that the characteristics of the vegetation community were better in mixed-sowing than in single-sowing. ①In terms of community characteristics: The forage height performed better in the mixed-sowing combinations ZW and ZL. After mixed-sowing, the height of Z increased by 18.29% compared with that in single-sowing, and the height of W increased by 12.87% compared with that in single-sowing. The density of forages after mixed-sowing ranged from 178.00 to 322.67 plants/m². Compared with the single-sowing of leguminous and gramineous forages, the density increased by 8.99%-35.33% and 11.24%-34.51% respectively, and there were significant differences （P<0.05） in the community density between the ZL combination and other mixed-sowing combinations. The biomass of forages after mixed-sowing ranged from 207.28 to 308.70 g/m². Compared with the single-sowing of leguminous and gramineous forages, the biomass increased by 13.24%-14.35% and 9.36%-12.95% respectively, and there were significant differences （P<0.05） in the community biomass between the ZL and ZW combinations and other mixed-sowing combinations except AW. ②In terms of nutritional quality: The dry matter content of forages in each mixed-sowing combination ranged from 88.67% to 89.38%. The dry matter content of forages in the ZL mixed-sowing combination was the highest, followed by that in the ZW mixed-sowing combination. The crude protein content ranged from 13.15% to 15.78%. The crude protein content of forages in the ZW mixed-sowing combination was the highest, followed by that in the ZL mixed-sowing combination. The crude fat content was between 1.57% and 2.30%. The crude fat content of forages in the AL mixed-sowing combination was the highest, followed by that in the ZL mixed-sowing combination. The crude ash content was between 7.96% and 9.90%. The crude ash content of the ZW mixed-sowing combination was the lowest, and that of the ZL mixed-sowing combination was the second lowest. The neutral detergent fiber content was between 47.45% and 53.01%. The neutral detergent fiber content of the ZL mixed-sowing combination was the lowest, and that of the ZW mixed-sowing combination was the second lowest. The acid detergent fiber content was between 33.70% and 39.43%. The acid detergent fiber content of the ZY mixed-sowing combination was the lowest, and that of the ZW mixed-sowing combination was the second lowest. ③ Interspecific competition rate and interspecific compatibility: Except for the AW and ZY mixed-sowing combinations, the relative yield total of the other different mixed-sowing combinations was greater than 1, ranging from 1 to 1.135, indicating that for all combinations except the AW and ZY mixed-sowing combinations, the interspecific interference was less than the intraspecific interference, and the coexistence of leguminous and gramineous forages in these combinations was good. In addition, except for the AY mixed-sowing combination, the interspecific competition ratio in all treatments was greater than 1, ranging from 1 to 1.754, indicating that the competitiveness of leguminous forages in all combinations except the AY mixed-sowing combination was better than that of gramineous forages. ④ Comprehensive evaluation: Based on the comprehensive evaluation using the grey relational degree and entropy weight-TOPSIS model, the ranking of each mixed-sowing combination from high to low was: ZL > ZW > PL > AL > PW > AY > PY > ZY > AW. [Conclusion] Considering all indicators, the ZL and ZW mixed-sowing combinations performed well in terms of vegetation community characteristics, forage nutritional components, interspecific competition, and community stability. Therefore, ZL and ZW are preliminarily selected as the best mixed-sowing combinations suitable for establishment in the Hohhot region.

Key words: legume-grass mixed sowing, community characteristics, nutritional quality, interspecific competition, combination screening