【作者】 徐丽君；

【导师】 孙启忠；

【作者基本信息】 中国农业科学院 ， 草业科学， 2009， 博士

【摘要】 2007-2008年在内蒙古林西县,以敖汉苜蓿、Rangelander、阿尔冈金、金皇后4个紫花苜蓿(Medicago sativa L.)品种为材料,从植物产量构成要素、根系形态特性、生理生化特性、土壤特性等方面对4种紫花苜蓿人工草地健康状况进行评价,结果表明:(1)筛选出适宜评价紫花苜蓿人工草地健康的39个指标,分别为株高、分枝数、叶片重、叶面积、叶面积指数、叶倾角、越冬率、生长速度、产草量、根颈直径、根颈收缩、根颈芽、单位根系总长度、总表面积、根瘤数、根系生物量、钙、脯氨酸、丙二醛、过氧化氢酶、光合速率、蒸腾速率、水分利用效率、气孔导度、叶绿素、土壤含水量、土壤pH、土壤紧实度、土壤呼吸速率、土壤全氮、全磷、全钾、有机质、土壤有机氮、土壤有机碳、微生物碳、微生物氮、微生物商、Nbio/Norg和微生物数量。(2)采用的AHP层次分析与模糊综合评价相结合的评价方法,对4种紫花苜蓿人工草地健康状况评价表明,Rangelander人工草地的差异性健康系数为1.36,阿尔冈金1.34,金皇后为1.16, 3种紫花苜蓿人工草地均好于本土品种敖汉苜蓿人工草地。用生态承载力的方法进行验证,得到了与模糊评价相类似的结果。(3)4个紫花苜蓿品种产量构成要素随着生长年限的延长,产量构成要素表现出一定的规律性,即生长3、4年,各项指标达到一高峰,之后,随着生长年限的延长呈递减的变化趋势。生长2年处于生长阶段,生长5、6年的产量构成要素变化规律表现为下降趋势,尤其是株高、分枝数、叶片重量等下降明显。(4)不同生长年限的4个紫花苜蓿品种根系形态的各项指标随着生长年限的延长呈递增趋势。阿尔冈金、Rangelander、金皇后和敖汉苜蓿根系腐烂面积百分比分别为7.09%、8.11%、8.45%和15.49%,根据根系腐烂分级标准,阿尔冈金、Rangelander和金皇后3种紫花苜蓿品种根系处于轻度伤害水平,敖汉苜蓿根系处于中度伤害水平。(5)生长年限相同的不同紫花苜蓿品种植物营养含量差异不显著(P>0.05)。4个紫花苜蓿品种的Pn、Tr和WUE日变化最大值出现的时间分别为11:00~13:00、9:00~11:00和15:00左右。各项生理适应性指标的变化规律与品种及其生长年限有关,以生长3、4年的4个紫花苜蓿品种能较好的抵御外界的胁迫环境。阿尔冈金脯氨酸含量、CAT活性均较高,丙二醛、电导率比较低,具有较高抵御外界不良环境的能力,金皇后与阿尔冈金的变化规律相反,抵御外界不良环境的能力较弱,敖汉苜蓿与Rangelander介于二者中间。(6)土壤含水量变化呈双峰型,分别在15cm和70cm处出现最大值,在30cm处出现最小值;土壤紧实度随着种植年限的延长,呈上升趋势;土壤pH总体上差异不显著;土壤呼吸速率日变化不明显,仅有微小波动,最大值出现在4:00左右;土壤养分总体是随着生长年限的延长呈“上升——下降”的变化趋势,养分存在“表聚”现象。(7)4种紫花苜蓿人工草地微生物生物学指标表现出:起初较低(生长2年),在3年达到高峰后,逐渐下降(生长4、5年居中)的单峰型规律,如蛋白酶与脲酶总体变化表现为先增后降、生长3年活性较高的趋势;土壤健康指数显示,生长6年的敖汉苜蓿和Rangelander与生长4年的阿尔冈金和金皇后人工草地微生物处于较好的生存环境。更多还原

【Abstract】 Health conditions of four types of cultivated alfalfa (Medicago sativa L.) grassland were evaluated in Linxi of Inner Mongolia in 2007 and 2008 from yield components and the morphological characteristics of root system, physiological and biochemical properties, soil properties, M. sativa cv. Aohan, M. sativa cv. Rangelander, M. sativa cv. Algonquin and M. sativa cv. Golden queen as materials. The results showed as below:(1) 39 indicators were selected to evaluate health conditions of cultivated alfalfa grassland, which were height, branches, leaf weight, leaf area, leaf area index, leaf angle, over-wintering rate, growth rate, yield, crown diameter, crown systolic, crown buds, total root length, total root surface area, nodules, root biomass, Ca, proline, MDA, CAT, Pn, Tr , WUE, Gs, chlorophyⅡ, soil water content, soil pH, soil compaction, soil respiration, soil total nitrogen, soil total potassium, soil total phosphorus, soil organic nitrogen, soil organic carbon, soil organic, microbial biomass carbon, microbial biomass nitrogen, microbial quotient,Nbio/Norgand microbial amount.(2) Fuzzy comprehensive evaluation(FCE) and analytical hierarchy process(AHP) were integrated to evaluate health conditions of cultivated alfalfa grassland. The results showed that deferent health coefficients on cultivated grassland of Rangelander,Algonquin and Golden queen were 1.36, 1.34 and 1.16 respectively, which were better than cultivated grassland of native cultivar Aohan. The results from the method of ecological carrying capacity were similar to FCE.(3) Yield components of four alfalfa cultivars presented regularity with increasing years of growing. All the indicators reached the peak after growing for three or four years, then showed descending trend with growing years’increasing. The first two years were growing period. Yield components of the 5t h or 6t h year showed the descending trend, especially height, branches and leaf weight.(4) All the indicators of root system showed the tendency of increase with growing years’increasing. The percentage of root rot area of Algonquin,Golden queen, Rangelander and Aohan was respectively 7.09%, 8.11%, 8.45% and 15.49%. According to the grade criteria of root rot, the root system of Algonquin,Golden queen and Rangelander located at the level of slight injury, while Aohan located at the level of moderate injury.(5) The difference of nutrients content of four alfalfa cultivars with different growing years was not significant (P>0.05). The time that the maximum value of diurnal variation of Pn, Tr and WUE appeared was 11: 00 ~13:00, 9:00~11:00 and 15:00 respectively. Variation laws of physiological adaptive indicators were related to cultivars and growing years. Four alfalfa cultivars with three or four years’growing have good resistance to environmental stresses. In four alfalfa cultivars, Algonquin had strong resistance to environmental stresses with high praline content and CAT activity, low MDA content and electric conductivity. On the contrary Golden queen showed different variation laws and had weak resistance to environmental stresses. Aohan is between Algonquin and Golden queen.(6) The variation of soil water content showed a double peak curve with the maximum values at 15cm and 17cm respectively, the minimum value at 30cm. Soil compaction showed the trend of increase with the planting years’increasing. The difference of soil pH was generally not significant. Soil respiration rate had slight fluctuation with the maximum value at 4:00am. Soil nutrients show the ascend-drop trend with growing years’increasing and accumulated in the surface.(7) Microorganism biological indicators of four cultivated alfalfa grassland showed the single peak curve which were low at the first two growing years, then highest at the 3 th year, lastly dropped, such as protease and urease. The activity of soil invertase was not related to growing years and cultivars. On the grasslands of Aohan and Rangelander with six years’growing and the grasslands of Algonquin and Golden queen with four years’growing, microorganism lived in a favorable environment.更多还原