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1.
对科尔沁沙地流动沙丘中林龄为20年左右的樟子松（Pinus sylvestris var. mongolica）和小叶杨（Populus simonii）人工林表层土壤微生物数量、微生物生物量碳和酶活性进行了研究,流动沙丘作为对照。研究表明:樟子松和小叶杨人工林可以显著改善流动沙丘土壤性状,对沙丘土壤微生物活性具有显著的促进作用;土壤微生物数量、微生物生物量碳和酶活性均表现为小叶杨林>樟子松林>流动沙丘。樟子松和小叶杨林地土壤微生物总数分别是对照的50.16倍和72.48倍,三者差异显著;樟子松和小叶杨林地土壤微生物生物量碳分别是对照的23.67倍和33.34倍,林地与对照差异显著;两种林地土壤脱氢酶、过氧化物酶、蛋白酶、脲酶、纤维素酶活性分别是对照的19.00倍和27.54倍、4.78倍和9.89倍、4.05倍和8.67倍、29.93倍和37.46倍、9.66倍和13.42倍,林地与对照差异显著。在科尔沁沙地,人工种植适合当地气候特点的乔木,不仅可以改善流动沙丘土壤性状和微生物活性,而且还能起到固定流动沙丘的目的,樟子松和小叶杨是当地值得推广种植的防风固沙树种。土壤微生物量商（Cmic∶C）是一个衡量林地土壤稳定性和有效性较好的指标,从林地土壤养分有效性、林木稳定性和可持续性等方面综合考虑,樟子松比小叶杨更具优势。 相似文献
2.
YuQiang Li JianPeng Zhang XueYong Zhao TongHui Zhang YuLin Li XinPing Liu YinPing Chen 《寒旱区科学》2016,8(6):495-506
The Horqin Sandy Land of northeastern China was originally a grassland with plenty of water and lush vegetation dominated by palatable grass species along with sparsely scattered woody species. However, it has experienced severe desertification in recent decades due to its fragile ecology together with inappropriate human activities. Currently, the landscape of the Horqin Sandy Land is dominated by irrigated croplands and sand dunes with different degrees of vegetation cover, as the region has become the most important part of the semiarid agro-pastoral ecotone of northern China. In this study, we compared soil physical and chemical properties under different land-use and cover types (irrigated cropland, rainfed cropland, sandy grassland, fixed dunes, and mobile dunes). We found that soil particle size distribution; organic C, total N, and total mineral element, microelement, and available microelement and nutrient contents; pH; CEC; and bulk density differed significantly among the land-use and cover types. In general, soil quality was highest in the cropland, intermediate in the sandy grassland, and lowest in the dunes. The most important soil quality attribute, soil organic carbon (SOC) storage, decreased in the following order: irrigated cropland (5,699 g/m2) > sandy grassland (3,390 g/m2) > rainfed cropland (2,411 g/m2) > fixed dunes (821 g/m2) > mobile dunes (463 g/m2). SOC was significantly positively correlated with a large proportion of the other soil physico-chemical parameters. Our results suggest that the key issue in restoration of the degraded soils will be to increase SOC storage, which would also create a high potential for sequestering soil C in desertified areas of the Horqin Sandy Land. 相似文献
3.
T. Miyasaka T. OkuroH. Zhao X. ZhaoX. Zuo K. Takeuchi 《Journal of Arid Environments》2011,75(11):1155-1163
We examined changes in soil properties, crop biomass, and weed communities in the Horqin Sandy Land of China to elucidate cropland degradation. We studied three local cropland types having periods of cultivation of up to 20 years: maize cropland on lowlands without irrigation (nonirrigated lowland), maize cropland on flat sandy lands with irrigation (irrigated flatland), and bean-centered cropland on sand dunes without irrigation (nonirrigated dunes). Soil properties and crop biomass were more degraded in nonirrigated lowland and nonirrigated dunes than in irrigated flatland. Weed communities in the nonirrigated croplands were the type that become established in drier conditions, whereas wetland weeds were more abundant on irrigated flatland. Trends of change in each indicator did not always occur in parallel and differed statistically among the cropland types. Monitoring these indicators within the context of local land-use systems can provide scientific evidence on which to base local management practices or recommendations for change. 相似文献
4.
科尔沁沙地典型生境下芦苇的生长特征分析 总被引：3，自引：3，他引：0
对科尔沁沙地两类典型生境下芦苇根茎生长及生物量等特性进行了分析研究。结果表明,固定样地芦苇株高、分蘖株数、不定芽数、根茎节数及根茎总长均大于半流动样地。从半流动样地到固定样地,芦苇根茎表现出节间长度缩短,节间直径变粗的趋势。固定样地芦苇叶长、叶宽明显大于半流动样地,并且固定样地芦苇叶间距是半流动样地上的近3倍。与半流动样地相比,固定样地根茎生物量在总生物量中所占比例有所增加,而地上生物量所占比例减小。芦苇根茎生长及生物量分配在两类样地间的变化特征与土壤质地、紧实度以及养分含量等因素有密切的联系,同时也反映了芦苇对不同沙生生境的适应对策。 相似文献
5.
Root distribution plays an important role in both vegetation establishment and restoration of degraded land through influencing soil property and vegetation growth. Root distribution at 0~60 cm depth of A. halodendron was investigated in Horqin Sandy Land. Soil organic carbon (SOC) and nitrogen (SN) concentration as well as carbon and nitrogen in root biomass and necromass were measured. Root length density (RLD) was estimated. Total root biomass, necromass and the RLD at 0~60 cm depth was 172 g/m2, 245 g/m2, and 368 m/m2, respectively. Both biomass and necromass of A. halodendron roots decreased with soil depth, live roots were mainly at 0~20 cm (76% of biomass and 63% of root length), while 73% of the necromass was within 0~30 cm depth. N concentration of roots (biomass and necromass) was about 1.0% and 1.5%, respectively. There were significant differences in SOC concentration between soil layers, but insignificant for SN. Soil C/N ratio decreased with depth (P<0.05). C and N storage for belowground system at 0~60 cm decreased markedly with depth; 41.4% of C and 31.7% of N were allocated to the 0~10 cm layer. Root bio- and necromass together contained similar amount of C to that of the soil itself in the top layer. N stock was dominated by soil nitrogen at all depths, but more so in deeper layers. It is clear that differentiating between soil layers will aid in interpreting A. halodendron efficiency in soil restoration in sandy land. 相似文献
6.
7.
Effects of Pinus sylvestris var. mongolica afforestation on soil phosphorus status of the Keerqin Sandy Lands in China 总被引：2，自引：1，他引：2
Q. Zhao D.H. Zeng D.K. Lee X.Y. He Z.P. Fan Y.H. Jin 《Journal of Arid Environments》2007,69(4):569-582
Few studies have considered the effects of afforestation on soil phosphorus (P) status in semiarid regions such as the Keerqin Sandy Lands in China, though plantations have been widely established on P-deficient sandy soils to control wind-induced desertification. Phosphorus fractions and acid phosphomonoesterase (AP) activities were compared in the rhizosphere and bulk soils (0–5 and 5–20 cm) under Mongolian pine (Pinus sylvestris L. var. mongolica Litv.) plantations of different ages (15, 22, and 30 years old) and in bulk soils under grasslands to understand soil P behavior with Mongolian pine plantation development and to find out major factors controlling soil P cycling. Stand age and rhizosphere processes had similar effects on the soil P fractions. Labile inorganic P and phosphate absorbed on aluminum and iron oxides were not affected by stand age and rhizosphere processes. Rhizosphere effects of Mongolian pine accelerated the mineralization of organic P by increasing microbial and AP activities. Soil P properties in bulk and rhizosphere soils changed similarly with plantation development. In the first 15 years after afforestation, total organic P, calcium phosphate, labile organic P, microbial biomass P (MBP) concentrations, and AP activities were reduced sharply. About 73% of the reduction in total P came from mineralization of organic P and 24% came from solubilization of calcium phosphate. From 15 to 22 years onward, soil total organic P and calcium phosphate decreased gradually and labile organic P, MBP, and AP activities increased greatly, whereas total inorganic P remained constant. The results suggest that soil P pool was depleted with Mongolian pine plantation development, especially in the early stage. As the dominant form of soil P, organic P was the main source of available P and associated biological processes controlled soil P cycling under Mongolian pine plantations. To ensure sustainability of pine plantations, it is imperative that soil fertility is conserved by adding fertilizer, thinning, and protecting litterfall. 相似文献
8.
基于Hydrus-1D模型的科尔沁沙地沙丘-草甸相间区土壤水分动态模拟 总被引：1，自引：0，他引：1
土壤水分是干旱半干旱地区生态环境的主要限制性因子,研究科尔沁沙地流动沙丘和草甸地土壤水分动态规律有助于荒漠化地区的生态恢复和保护。以2018年5月25日至10月31日为研究期,利用土壤各项实测参数和气象数据,评价Hydrus-1D模型在科尔沁沙地的适用性,并揭示科尔沁沙丘-草甸相间区土壤水分分布特征,重点分析研究区流动沙丘200 cm剖面和草甸地80 cm剖面土壤水分的动态规律。结果表明:研究区典型土地类型流动沙丘和草甸地土壤水分模拟值和实测值的决定系数均高于0.76,均方根误差0.01~0.02 cm3·cm-3;在土壤剖面上具有明显的分层结构,流动沙丘分为3层,即0~20 cm为干沙层,20~120 cm为活跃层,120~200 cm为稳定层,其中40 cm土壤水分波动性最大;草甸地分为2层,即0~40 cm为活跃层,40~80 cm为稳定层,主要受降雨、蒸散发和地下水位影响;流动沙丘和草甸地降雨与表层土壤水分呈极显著相关,降雨量与地下水位变化仅草甸地呈显著正相关;在整个研究期内,流动沙丘土壤水分储量变化量为12.6 mm,土壤实际蒸发量为105.9 mm,200 cm深层渗漏量为173.9 mm,占总降雨量的59.5%;草甸地土壤水分储量变化量为8 mm,80 cm深层渗漏量为-27.2 mm(地下水补给量),土壤实际蒸发量为67 mm,植被蒸腾量为244 mm,地表径流量为0 mm。 相似文献
9.
科尔沁沙地不同尺度上沙丘景观格局动态变化分析 总被引：11，自引：8，他引：3
研究了科尔沁沙地过去30 a不同尺度上沙丘景观格局及其动态变化。结果表明,大尺度研究区（892.74 km2）从1975—1995年流动沙丘面积、斑块数、景观面积百分比和最大斑块指数逐渐增加;1995—2005年流动和半流动沙丘面积减小,半固定沙丘和固定沙丘面积增加。中尺度（110.42 km2）和小尺度（14.14 km2和14.10 km2）研究区从1975—1985年流动沙丘面积、斑块数增加,1985年后流沙面积减小。通过沙漠化过程指数计算表明,大尺度上沙漠化经历了发展（1975—1995年）—逆转（1995—2005年）的过程,中尺度和小尺度上,沙漠化经历了发展（1975—1985年）—逆转（1985—2005年）的过程。科尔沁沙地不同尺度上景观结构变化具有差异性,显示出景观空间格局变化存在尺度效应;景观格局变化主要受流动沙丘斑块变化的影响,而这一变化的主要原因是人类生产活动引起的。 相似文献
10.
ShaoKun Wang XueYong Zhao XiaoAn Zuo XinPing Liu Hao Qu Wei Mao JianYing Yun 《寒旱区科学》2015,7(1):0074-0080
Cellulose decomposing fungi play an important role in litter decomposition and are decisive in nutrient cycling in sandy
land ecosystems. Thirty-one strains were isolated to select efficient cellulose decomposers, and four efficient cellulose
decomposing fungi (NM3-1, NM3-2, NM3-3, and NM3-4) were screened using a CMC (carboxymethyl cellulose) carbon
source in dune soil of Horqin Sandy Land. They were identified as Asperigillus calidoustus, Fusarium oxysporum,
Fusarium solani, and Hypocrea lixii by rDNA-ITS molecular biological methods. Cloth decomposition rates were 15.71%,
15.89%, 17.29%, and 17.89% by the four efficient decomposers incubated for 30 days, respectively. Screening of efficient
cellulose decomposers can not only increase the dune soil functional microbe bank, but can also accelerate litter decomposition
and available nutrient input in the Horqin Sandy Land. 相似文献
11.
微生物量碳是土壤有机碳的重要组成部分,是判别退化系统生态修复的重要指标之一。为了探明生物土壤结皮对土壤微生物量碳的影响,以腾格里沙漠东南缘的人工固沙区不同生物土壤结皮覆盖的沙丘土壤为研究对象,根据固沙年限的不同将样地分为4个不同的区进行采样(1956、1964、1981年和1987年固沙区),并以流沙区为对照。与流沙区相比较,54龄、46龄、29龄和23龄固沙区的真藓结皮和藻结皮的存在均可显著提高其下土壤微生物量碳（P<0.05）,且固沙年限与结皮下土壤微生物量碳存在正相关关系;真藓结皮和藻结皮对其下土壤微生物量碳的影响仅限于0~20 cm的土层,随着土层的加深,其影响逐渐减弱,到20~30 cm土层与对照相比已无显著差异（P>0.05）。因此,对生物土壤结皮的干扰可能会造成土壤微生物量碳的损失。 相似文献
12.
科尔沁沙地是中国半干旱地区沙漠化发展的典型地区和沙漠化防治的重点区域。本研究以科尔沁沙地为研究区域,以沙漠化逆转不同阶段的沙地为研究对象,通过野外调查和室内分析,采用空间代替时间的方法,在区域尺度上探讨了土壤有机碳对沙漠化过程的响应规律,并结合气候、植被和地形因子阐释了该区域土壤有机碳空间变异的主导因素。结果表明:(1)土壤有机碳含量随沙漠化程度的加剧表现出疏林草地(未沙漠化)>固定沙地(轻度沙漠化)>半固定沙地(中度沙漠化)>半流动沙地(重度沙漠化)>流动沙地(极重度沙漠化)。(2)固定沙地、半固定沙地、半流动沙地和流动沙地土壤有机碳密度分别比疏林草地降低了29.1%、49.3%、62.9%和84.1%。(3)随着沙漠化的发展,土壤质地发生粗化现象,即中、细砂粒含量明显增加,而土壤细颗粒(极细砂和黏粉粒)含量明显下降。(4)科尔沁沙地沙漠化过程中,土壤黏粉粒的损失是土壤粗化、有机碳含量下降的主要原因,而pH的变化受沙漠化影响较小。(5)气候因子是导致SOC含量受经纬度影响的主要因素,而地形因子的影响次之。 相似文献
13.
科尔沁沙地坨甸相间地区土壤水分空间分布特性分析 总被引：3，自引：1，他引：3
固定沙丘、半固定沙丘、流动沙丘、甸子地等不同地貌的相间分布是科尔沁沙地的主要地貌特征之一。在这种特殊的坨甸相间地貌中，土壤水分的空间分布必定有其特殊性。在科尔沁沙地坨甸相间地区的各种地貌类型区进行了土壤层及植被根系层水分状况的实地调查及室内实验。基于实验结果分析出沙地固定沙丘、半固定沙丘、流动沙丘、甸子地不同地貌类型的土壤水分的空间变异特性，并结合四种不同地貌类型区的土壤水分空间分布特征，按照表层、中间层和底层进一步对比分析了不同地貌土壤水分的变化和分布，这对于了解科尔沁沙地土壤水分的变化规律及其与地貌类型的关系，具有一定的意义。 相似文献
14.
Effect of nitrogen amendments on microbial biomass, above-ground biomass and nematode population in the Negev Desert soil 总被引：1，自引：0，他引：1
Nitrogen amendments (0, 25, 50 and 100 kg NH4NO3/ha) were used to study the responses of primary production, microbial biomass and nematode population in desert soil. The study was conducted in the Israeli Negev Desert, a region characterized by low and randomly distributed rainfall. Over a 1-year study period, nitrogen amendments resulted in a significant (p<0·01) increase in soil microbial biomass. Soil microbial biomass also increased concomitantly with the increase in soil organic matter. The number of free-living nematodes in the soil increased with the increase in soil moisture, ranging from 43,000 individuals per square metre at the end of the summer to 351,000 individuals per square metre during the rainy season. No significant correlation was found between the nitrogen treatments and the nematode population, whereas a significant positive correlation was found between the nitrogen amendments and the above-ground biomass (r2=0·94, p<0·03). The nitrate proportion of the total soluble nitrogen in the soil also increased with the increase in soil moisture. This study provides baseline data for nitrogen amendments on soil microbial status, as well as insights into the importance of nitrogen in fertility in arid environments. 相似文献
15.
Changes in intensity of wind erosion at different stages of degradation development in grasslands of Inner Mongolia, China 总被引：14，自引：1，他引：14
F.-R. Li L.-F. Kang H. Zhang L.-Y. Zhao Y. Shirato I. Taniyama 《Journal of Arid Environments》2005,62(4):567-585
Overgrazing by increasing numbers of livestock in the Horqin Sandy Land of Inner Mongolia, China, has led to extensive degradation of the region's sandy steppes. Degraded grasslands are generally classified into four main types: fixed (least degradation), semi-fixed (light degradation), semi-shifting (moderate degradation) and shifting (severe degradation) sandy lands, representing four stages of degradation development. An experiment was conducted in the Horqin Sandy Land to investigate changes in intensity of wind erosion at different stages of degradation development in sandy grasslands and determine the extent to which surface wind erosion was affected by surface-related soil and vegetation factors through their effects on surface roughness length and wind regimes. Daily wind erosion rate was monitored at four sites of degraded grassland over an erosive period from 1 April to 10 June in 2001. Soil and vegetation properties for these sites were also measured twice: one in mid-April prior to the establishment of vegetation and again in mid-June after the establishment of vegetation. Relationships between surface roughness length and soil and vegetation variables were examined at each of the two stages of vegetation development. This study shows striking differences in the intensity of surface wind erosion among sites. The daily wind erosion rate in the fixed sandy land was, on average, only about 1/5 of the rate in the semi-fixed sandy land, 1/14 of the rate in the semi-shifting sandy land and 1/47 of the rate in the shifting sandy land suggesting a much higher resistance of the fixed sandy land to wind erosion compared to other sites. Differences in rate of wind erosion between sites were attributed to between-site differences in soil and vegetation properties that exerted significant effects on wind regimes by altering surface roughness length. At the pre-establishment stage of vegetation, surface roughness length was determined by a combination of litter amount on the ground, soil surface hardness and soil moisture content, with litter amount explaining the greatest proportion of the variation. At the post-establishment stage of vegetation, the development of the surface roughness effects was mainly governed by vegetation characteristics (vegetation cover in particular), while the effects of soil surface hardness and soil moisture on surface roughness length are likely to be masked by vegetation effects. The findings suggest that better management practices of restoring vegetation in degraded grasslands are required to reduce soil erosion losses and achieve a sustainable livestock production in the Horqin Sandy Land, an ecologically fragile sandy land ecosystem. 相似文献
16.
不同固沙区结皮中微生物生物量和数量的比较研究 总被引：30，自引：16，他引：14
沙地生态系统是温带干旱区、半干旱区的重要草地类型, 沙地的稳定性是生态系统健康的重要条件。在中国科学院沙坡头沙漠试验研究站, 笔者对不同程度固沙区结皮和流动沙丘表层中的微生物生物量和数量进行了比较研究。结果表明: 自然和人工植被固沙区结皮及流沙表层的微生物数量分布不同, 细菌数量比真菌和放线菌数量多数百倍, 在所有微生物类群中, 细菌数量最大, 微生物总数的变化取决于好气性细菌数量的多少, 但生物量却与之不同。在不同程度固沙区结皮中, 微生物生物量大小依次排列为: 自然植被区>1956年人工植被区>1964年人工植被区>1982年人工植被区>流沙区, 微生物生物量在自然植被固沙区中最多, 分别是1956年、1964年、1982年人工植被固沙区和流沙区的2.63、4.17、9.25和44.29倍, 表明微生物生物量随人工植被的栽植年代增加而增大, 在流动沙丘中最小, 而菌丝生物量方面是1956年人工植被固沙区已与自然植被固沙区十分接近。微生物生物量和数量与沙丘固定程度、人工植被栽植年代、结皮厚度、苔藓种类等均呈正相关, 人工植被栽植年代越长, 结皮越厚、微生物生物量和数量也越大。在不同年代人工植被固沙区结皮中, 微生物生物量和数量与相对稳定的自然植被固沙区相比, 仍未达到稳定状态。 相似文献
17.
Ecological patterns and processes in dune ecosystems have been a research focus in recent years, however information on how dune stabilization influences vegetation and soil at different spatial scales... 相似文献
18.
科尔沁沙地奈曼旗固沙造林沙丘土壤微生物区系的变化 总被引：12，自引：2，他引：10
在科尔沁沙地西南部的流动沙丘上固沙造林,不同造林时间和不同造林树种的沙丘土壤中细菌、放线菌和真菌等类群和生理群的微生物生长情况不同、林地土壤中微生物都比流动沙丘中繁殖旺盛。造林时间长的沙丘又比造林时间短的沙丘土壤微生物增殖量大。有林木生长的沙丘上层土壤也比下层土壤微生物的数量大,沙丘结皮层中尤为明显。 相似文献
19.
科尔沁沙地两种固沙灌木林地土壤理化性质和酶活性比较 总被引：1，自引：1，他引：0
小叶锦鸡儿(Caragana microphylla)和差不嘎蒿(Artemisia halodendron)是科尔沁沙地典型的固沙灌木,它们在退化沙地的恢复过程中起着重要的作用。本研究对这两种灌木林地表层土壤理化性质和酶活性进行了比较。结果表明:小叶锦鸡儿比差不嘎蒿对沙丘土壤理化性质和酶活性的改善作用较大。其中,小叶锦鸡儿林地土壤黏粉粒含量比差不嘎蒿高3倍左右,土壤含水量是差不嘎蒿的1.31倍,土壤有机碳和全氮分别是差不嘎蒿的1.35和1.36倍,土壤过氧化物酶和脲酶活性分别是差不嘎蒿林地土壤的2和3倍。科尔沁沙地流动沙丘中种植小叶锦鸡儿和差不嘎蒿后,两种灌木均能改善沙丘土壤理化性质和酶活性,但是其改善能力存在一定差异,总体来说,在退化沙地土壤肥力和生物活性的恢复方面,小叶锦鸡儿的优势高于差不嘎蒿。 相似文献
20.
科尔沁沙质草甸土壤微生物数量的垂直分布及季节动态 总被引：5，自引：0，他引：5
通过对中国农牧交错带科尔沁沙质草甸土壤微生物数量的垂直分布及其季节动态的研究分析表明:(1)微生物总数、细菌和放线菌数量均表现出与降雨量同步的季节动态,即6月份较5月份有所减少,7月份增至最多,7月份以后微生物数量逐渐下降,真菌则表现出从5月份到8月份一直增加,9月份开始回落;(2)土壤微生物具有明显的垂直分布差异.细菌和放线菌的垂直分布表现出随土壤深度增加逐渐减少的趋势,真菌数量表层最高,20 cm以下变化不够规律;(3)土壤微生物的层化比率均大于2(5月份放线菌除外);(4)不同土壤生态因子对微生物的影响不同,相同因子对不同微生物类群的影响也不相同.细菌受水分影响较大,真菌与地温的变化趋势相近,放线菌与水热条件的共同作用有关.土壤养分(有机碳和全氮)与微生物数量呈显著的正相关. 相似文献