| In transitional climate zone, protective turf in the purple hilly area, because of the influence of slope aspect, usually presents poor resistance, unhealthy growth and development, which caused turf structural damage and functional deterioration, and poor community landscape, stability and durability. In order to solve the problems,chose different slope aspects of same hill, formed by building road, as experimental field for sowing cool-season turfgrass. The slope aspects was set as A slope of EN 40°,B slope of WS 33° and C slope of WN 29°, and turfgrass included Festuca arundinacea,Lolium perenne L. and Poa pratensis L., which were mixed according to the ratio of1:1:1. Indexes such as apparent morphology and Chlorophyll content of turfgrass, and density, height and coverage of turf were determined in the young turf period, mature turf period and a year after mature turf. Two years after establishing turf, species and important value of community, community diversity and turf quality were measured.Through the analysis of the effect of different slope aspect on apparent morphology,photosynthetic pigment content, physiological reaction rate of turfgrass, and community structure, and turf quality, the mechanism about effects of slope aspect on growth and development of turfgrass, community stability and turf quality was discussed. The purpose was to provide a theoretical basis for selecting turfgrass species structuring turf bed and maintaining turf in the purple hilly area. The main results were as follows:1.Effect of slope aspect on growth and development of three kinds of turf grassesThere were significant effects on apparent morphology, Chlorophyll content and physiological characteristics of turfgrasses(P<0.05). For F. arundinacea, the biggest root-shoot ratio was 0.92 in the slope A, and the longest root was 10.24 cm in the slope B, yet leaf morphology got maximum in the slope C, with the values of 17.85 cm,0.31 cm, and 5.49 cm2 for leaf length, leaf width and leaf area, respectively. For L.perenne, the highest tiller number per plant of was 4.1 in B slope. Slope aspect had a significant effect on Chlorophyll content of F. arundinacea(P<0.05) and its Chl a, Chl b, Chl(a+b) were higher than that of other species. However, slope aspect only affected Chl a /b of L. perenne and Chl b content of P. Pratensis. The best shade tolerance was L.perenne with the lowest Chla/b value. Slope aspect maximally affected antioxidant enzyme activity and osmotic adjustment substances of P. pratensis, and only had effect on SOD, MDA and PRO of L. perenne, and the content of PRO and SP of F. arinacea.However, antioxidant enzymes activity of F. arundinace all were bigger than that of other species. The highest MDA content of P. pratensis was 10.58 μmol·g-1 in all aspects, but PRO content and SS content got maximum in the slope C, with the value of28.61 μg·g-1 and 24.61 mmol·l-1, respevtively. SP content(29.77 mg·g-1 in A slope, 29.96mg·g-1 in B slope) were bigger than that of C slope and varieties. In a word, F.arundinacea grow well in three slopes, and L. perenne performanced better in shady C slope, but P. pratensis grow poor in all slopes. Therefore, the decreasing order three cool-season turfgrasses was F. arundinacea > L. perenne > P. pratensis in the way of adaptability, and the effect order was C slope > b slope > a slope in the way of slope aspect.2.Effect of slope aspect on the structure and function of turfSlope aspect had significant influence on the height, coverage, density and biomass of turf community in different planting periods(P<0.05). Slope aspect had a significant effect on density of young turf community(P<0.01), and a highly significant effect on total coverage and density of mature turf, including mature turf of planting year,one-year turf and 2-years turf after planting. One year after turf planted, the composition of turf community was relatively stable in the slope C, and height, coverage and density were significant higher than that of other slopes. B slope existed large exposed areas because of the lowest density(23.0 plant·dm-2) and coverage(30.6%). 2-year after turf planted, the coverage and biomass of turf community in the slope B were higher than that in other slopes, and these index in C slope were the lowest. Thus it could be seen,the order of effect on planting period was 2-year turf after planting > mature turf of planting year > one-year turf after planting > young turf, and the sequence of influence on slope aspects was semi-shady slope(WN) > shady slope(EN) > sunny slope(WS).3.Effects of slope aspect on characteristics and diversity of plant communitySlope aspect had no significant effect on composition of plant species and its important value, richness index(DM), Shannon-Wiener diversity index(H) andShimpson advantage index(D)(P>0.05), but significant effect on Pielou index(J)(P<0.05). It mainly displayed that plant species had not difference in three slope aspects,and there were ten families in C slope which was a little more than other aspects. The important value of Arthraxon hispidus got the maximum in all slope aspects, with the value of 30.32, 24.02 and 52.91, respectively, and F.arundinacea took second place. The H index(0.59), D index(0.71), J index(0.91) in A slope were greater than B slope and C slope. Slope aspect had a significant positive correlation with H index(P<0.05), and low positive correlation with DM index, D index and J index. In short, slope aspect had a certain effect on composition of community species, important value of main species and diversity of community plant. therefore, the order of stability on slope aspect was A slope > B slope > C slope.4.Effect of slope aspect on quality of turfSlope aspect significantly affected quality of turf(P<0.01), and had a negative correlation with density of turf, and a low positive correlation with uniform, green period and speed of establishing turf, while it had extremely significant positive correlation with other quality index(P<0.01). The comprehensive score of A slope and B slope, with the value of 2.81 and 2.91 respectively, was significant higher than that of C slope, and the score in B slope was slightly higher than that in A slope. Therefore,density, height, disease resistance, color and turf intensity in B slope were significantly higher than that in other slopes. One-year turf after planting, the dominant community were F.arundinacea communities in all slopes. 2-year turf after planting, A.hispidus community became dominant species, and F. arundinacea, which was the only retained turfgrass, became sub-dominant community and would gradually be eliminated. For one-year turf after planting, the order of overall greening effect on slope aspects was C slope >B slope >A slope, and the order was B slope > A slope > C slope for two-year turf after planting.In summary, slope aspect had influence on adaptability of turfgrass, structure and function of community and turf quality. The adaptability of turfgrass decreased in the following order: F. arundinacea > L. perenne > P. pratensis. The order of effect on planting period was 2-year turf after planting > mature turf of planting year> one-yearturf after planting > young turf. the order of overall stability and greening effects was A slope > B slope > C slope. Therefore, when planting slope protective turf, we should choose appropriate turf species and mixed sowing combination based on the slope aspect, and select corresponding techniques of cultivation and management. Those could ensure healthy growth of turgrass, promote stability of slope protective communities, and improve turf quality, in order to improve ecological benefits and landscape values of turf. |
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