【作者】 孙宗玖；

【导师】 许鹏； 安沙舟；

【作者基本信息】 新疆农业大学 ， 草业科学， 2008， 博士

【摘要】 退化严重的荒漠春秋场已经成为制约新疆北疆季节草地畜牧业发展的瓶颈,其合理利用是实现草地资源可持续发展的关键。研究以天山北坡分布最广泛的蒿类荒漠草地为对象,选择代表性的建群种——伊犁绢蒿,重点探讨其在不同利用方式下的生长节律、可塑性营养物质的变化差异以及蒿类荒漠草地始牧期,以期为荒漠春秋牧场的合理利用、修复及可持续发展提供科学依据。主要研究结果如下:(1)伊犁绢蒿春季3月上、中旬开始返青,4月中旬至6月上旬分枝,6月中旬至8月中、下旬现蕾, 9月上旬开花,9月下旬转入结实期,到10月中、下旬种子成熟,且在年度间存在一定波动性。(2)生长季内伊犁绢蒿的株高、枝条重基本呈近直线生长,且增长速度呈“快—慢—快”的趋势;枝条数及叶片重分别呈“升高—降低—升高”、“双峰”型,根干重变化不明显,均在6.1 g/株左右,而其地上部分和个体总产量均呈“S”型变化,且伊犁绢蒿地上产量是该荒漠草地总产量的主体。因此,在利用上应该避开伊犁绢蒿个体产量低谷期或生长缓慢期,适宜在4月至6月、9月至10月放牧。(3)伊犁绢蒿体内可塑性营养物质以粗蛋白质和蔗糖含量为主。5月4日至11月14日,伊犁绢蒿的可溶性碳水化合物、蔗糖呈现“升高—降低—再升高—再降低”特征,且在根、茎、叶中存在不同步性;叶中淀粉呈“单峰”曲线,茎中呈“下降—上升—再下降”趋势,根中变化规律不明显;叶中粗蛋白质呈“单峰”曲线,根中基本不变,茎中呈下降趋势;根中可塑性营养物质均在10月17日前完成贮存。(4)放牧对伊犁绢蒿的现蕾期、开花期、结实期具有一定的推迟作用,一般为10~15 d,且显著降低植株高度,但禁牧放牧地、连续放牧地间差异不显著;种子繁殖方面,连续放牧地上不能产生成熟种子,而多年封育地在结实能力、实生苗出现时间及数量上早于围栏休牧地,但在千粒重上两者相反。(5)三种利用方式间伊犁绢蒿叶、枝条重差异显著,且多年封育地>连续放牧地≈禁牧放牧地;根重上则差异不显著,但在增长趋势上存在一定差异,禁牧放牧地和连续放牧地呈现“下降—上升—下降—上升”趋势;枝条数在生长前期(8月24日以前)差异显著,且均呈“升高—降低—升高”趋势。多年封育能够增强伊犁绢蒿个体的生长潜力,促进草群盖度的增加,而短期禁牧后再进行连续放牧对其个体的影响不大。根颈破碎度间差异显著(p<0.01),可以将其作为判断蒿类荒漠草地放牧强度的一个有效指标。(6)三种利用方式间伊犁绢蒿体内可塑性营养物质含量差异显著(p<0.01)。可溶性碳水化合物及蔗糖含量均呈“上升—降低”趋势,并以多年封育地最高,连续放牧地最低;淀粉含量变化较复杂,叶中呈“单峰”曲线,茎中呈“双峰”曲线,且多年封育地明显高于其他两种利用方式;根中淀粉含量表现为多年封育地>连续放牧地>禁牧放牧地;叶中粗蛋白质含量呈下降趋势,根中粗蛋白质含量呈“降低—升高—再降低”特征,而茎中粗蛋白质含量变化较大;并以连续放牧地上根中粗蛋白质含量最高,茎中最低,叶中位于两者之间。(7)放牧强度处理前,伊犁绢蒿的高度、盖度、密度差异不显著(p>0.05),仅在地上干草产量存在极显著差异(p<0.01),且极度放牧>重度放牧>中度放牧≈轻度放牧;恢复后,极度放牧下伊犁绢蒿已经全部死亡,而其他放牧强度间,除在春季盖度恢复效果间有显著差异外,伊犁绢蒿的再生高度、密度、盖度差异不显著,但均以轻度放牧和中度放牧下恢复效果好。结合当前畜牧业发展情况及不同放牧强度间伊犁绢蒿粗蛋白质、粗脂肪含量测定结果轻度放牧>中度放牧>重度放牧>极度放牧,认为伊犁绢蒿荒漠春秋场以中度放牧为宜。(8)同一放牧强度下,不同放牧始期间伊犁绢蒿盖度、密度差异不显著(p>0.05),仅在高度和地上干草产量上存在一定的差异。恢复后,极度放牧下伊犁绢蒿全部死亡;其他放牧强度下,春季不同放牧始期间伊犁绢蒿再生高度以4月1日、4月15日恢复最好,且差异极显著(p<0.01);盖度均以4月15日恢复最快,密度变化不显著。而秋季再生高度、盖度、密度在不同放牧始期间差异不显著(p>0.05),但9月15日至10月1日伊犁绢蒿的恢复效果较好。结合粗蛋白质、粗脂肪含量表现出下降趋势,认为春季4月15日前后,秋季9月15日至10月1日作为伊犁绢蒿荒漠草地始牧期,最有利于该草地的可持续利用。更多还原

【Abstract】 Severe degradation of sagebrush desert in spring and autumn have became the bottleneck that restricted development of seasonal stock raising in North area of Xinjiang. Reasonable utilization of sagebrush desert was the key for sustaining development of grassland resource in Xinjiang. In order to reasonable utilize, renovate and develop continuely sagebrush desert of spring-autumn, study on growth rhythm, change and difference on flexibility nutrition substance of Seriphidium transiliense under different utilizing model and beginning grazing-period of sagebrush desert were discussed, which widely distributed in Northern Slope of Tianshan Mountains.The main results were the flowing:(1) Seriphidium transiliense was begin to return green between the beginning of March and middle of March, tillering period was between the middle of April and the beginning of June, buding period was between the middle of June and middle-last of Augest, ablooming period was at the beginning of September, seed was appeared after the last of September, and seed maturity was between the middle of October and last of October. Phenophase of S. transiliense had certainly fluctuation at different years.(2) Height and tiller weight of S. transiliense were linearity increased during whole growth season, and emerged in a‘rapid-slow-rapid’shape on rate of growth. Curved shapes of the tiller quantity and the leaf biomass had“increase-reduce-increase”and“double growth peaks”respectively. The root biomass had no distinct difference, aboutindividual plant was 6.1g, the whole yield and aboveground biomass of S. transiliense emerged in“S”shape and aboveground biomass of S. transiliense was mainly part of whole yield in desert pasture. Hence desert pasture of S. transiliense was suitable for grazing from April to June in spring, from September to October in fall during whole growing season, which could avoided period of low-vale or slow-growth in individual.(3) The crude protein and sucrose were the dominating nutrition substance of S. transiliense. The seasonal changes of soluble carbohydrate and sucrose contents of S. transiliense emerged in an‘up-down-up-down’trend between 4th May and 14th November and appeared on different in roots, stems and leaves. Starch of leaves appeared‘single peaks’, stems appeared‘down-up-down’trend and no rule in root. The crude protein of leaves appeared‘single peaks’, no changes in roots and the trend of bellowing in stem.The contents of flexibility nutrition substance had finished storage in roots before 17th October.(4) Grazing had certainly effect on delaying phenophase on budding, blooming and seeding, about 10~15d. Grazing could obviously reduced height of plant, and had no difference on forbidding grazing and continuous grazing. Seed-ability, seeding appear period and quantity of S. transiliense on perennial enclosure pasture were higher than that of forbidding grazing pasture, but 1000-grain weight was on the contrary, and maturity of seed could not producted in continuous grazing pasture.(5) Leaves and tiller weight of S. transiliense had obvious discrepancy among three utilizing model, and the order of weight was perennial enclosure pasture>continuous grazing pasture≈forbidding grazing pasture. Root weight had no discrepancy among three utilizing model, and trend of growth had certainly difference, curved shapes on forbidding grazing pasture and continuous grazing pasture was“descend -increase-descend-increase”. The tiller quantity had obvious discrepancy among three utilizing model in prophase of growth (before 24th August), and appeared‘up-down-up’. Perennial enclosure could stimulate individual growth potential of S. transiliense, added the coverage of community, and forbidding grazing had no effect on S. transiliense individual. The cracking degree of root-stem had obvious discrepancy (p<0.01), and as could be evaluated grazing intension of Artemisia sagebrush desert.(6) The contents of flexibility nutrimental substance had significiant differnce in S. transiliense among three utilizing model (p<0.01). Soluble carbohydrate and sucrose contents emerged in an‘up-down’trend, and the highest at perennial enclosure pasture, the lowest at continuous grazing pasture. The changes of starch contents had more complex, respectively appeared‘single peak’,‘double peaks’at leaves and stems of S. transiliense, and the highest at perennial enclosure pasture. The order of starch contents of roots was perennial enclosure pasture> continuous grazing pasture>forbidding grazing pasture. Crude protein contents of leaves and roots appeared‘descending’,‘descend -increase-descend’respectively, more varieties at stems, and the highest contrnts of roots, the lowest of leaves and the middle of stems was at continuous grazing pasture.(7) Coverage, height and density of S. transiliense had no discrepancy before simulating grazing intensity (p>0.05), had significiant difference among aboveground yield (p<0.01) and the order was‘super grazing>high grazing>middle grazing≈light grazing’. After resuming, S. transiliense had all died at super grazing. Except coverage in spring, there was no difference on regrowth height, density, coverage of S. transiliense among high grazing, middle grazing and light grazing, but effect of renewing was best at middle grazing and light grazing. According to currently development of stockbreeding and crude protein and crude fat contents of S. transiliense appeared‘light grazing>middle grazing>high grazing>super grazing, middle grazing was suitable to the spring- autumn desert pasture of S. transiliense. (8) Coverage and density of S. transiliense had no discrepancy among different beginning grazing-period at the same grazing intensity (p>0.05), had significiant difference among aboveground yield and heigh. After resuming, S. transiliense had all died at super grazing. In spring, regrowth height of S. transiliense had significant difference (p<0.01), and that of between 1st April and 15th April was best, Coverage of resuming was quicker on 15th April, density had no discrepancy (p>0.05). In autumn, regrowth height, coverage and density of S. transiliense had no significant difference (p>0.05) among different beginning grazing-period, but effect of renewing was better between 15th September and 1st October. According to crude protein, crude fat contents of S. transiliense appeared the trend of descending and grazing intensity, the Beginning grazing-period was at 5th April in spring, from 15th September to 1st October under middle grazing, which was propitious to the continuely development of S. transiliense sagebrush desert.更多还原