Distribution characteristics of soil organic matter and total nitrogen on the Yajiageng vertical belt,Gongga Mountain around the Dadu River banks

Distribution characteristics of soil organic matter（SOM） and total nitrogen（TN） were studied in different plant communities of the Yajiageng vertical belt in Gongga Mountain around the Dadu River banks. The results show： （1） the contents of SOM and TN of the plant communities gradually decreased with the following order： subalpine coniferous forest （3 027 m）, subalpine meadow （3 873 m）, coniferous broadleaved mixed forest（2 737 m）, subalpine shrub（3 565 m） and treeline（3 564 m）. （2） With soil profile depth increasing, the contents of SOM and TN gradually decreased. For different vegetation types, the contents of SOM and TN in sub-alpine coniferous forest were higher than that of other vegetational types. （3）The ratio of the content of carbon to the content of total nitrogen （Cc/CTN）WaS 13.5-27.6, which was relatively lower than the appropriate Cc/CTN of 25-30, and indicated that the soil in favor of the organic matter decomposed and nutrients released. Cc/CTN in the soil had no correlation with sea level altitude. However, its distribution in the soil x, aried with different vegetation types. （4） Nitrogen in SOM existed mainly in the form of organic nitrogen, and Cc/CTN in the soil was not obvious correlated with SOM and TN.     

Variations in net litter nutrient input associated with tree species influence on soil nutrient contents in a subtropical evergreen broad-leaved forest

The influence of tree species on soils has received much attention,but we know little about either the pattern and underlying mechanisms of net nutrient and carbon inputs under canopy for various tree species or the effects of net nutrient input on soil nutrient contents.To address these issues,we selected three tree species with distinct leaf sizes and arranged litter traps around the target individuals to test what affected net nutrient and carbon inputs under canopy of target individuals,and how net nutrient inputs influenced soil nutrient contents.The results showed that net litter manganese(Mn)and lignin inputs were significantly different among these tree species,as well as soil exchangeable potassium(K),available iron(Fe)and available Mn.The results also revealed that the species with the smallest sized leaves may stimulate more net Mn and lignin inputs than the species with the largest sized leaves.At the same time,net nutrient inputs correlated with soil available Fe,while the ratio of lignin to nitrogen of net litter correlated with total phosphorus contents.These results demonstrated that litter production may be the main factor deciding net nutrient and carbon inputs under different tree species’canopy,which significantly differentiated soil iron’s availability.     

Temporal-spatial dynamics of distribution patterns of microorganism relating to biological soil crusts in the Gurbantunggut Desert

Biological soil crusts serve as an important biological factor contributing to the sand fixation. This study was conducted to investigate the temporal-spatial variability of microorganism in crusts relating to locations, soil layers of sand dunes and seasons. At moss-dominated inter-dune areas, higher soil nutrient and water concentrations were likely to maintain the microbial activities. Bacteria showed the highest capabilities of settlement and growth in inter-dunes in both spring and autumn. Soil water content reached the highest value in soil crusts in the inter-dune areas, especially in spring. Variations of quantities of actinomyces and fungi basically showed the consistent trend in different locations of sand dunes. With the deepening of soil layers, vertical distribution of quantities of each microorganism group showed different characteristics because environmental factors fluctuated in both spring and autumn. Among different microorganism groups, bacteria were predominant, actinomyces the next and fungi the least in both spring and autumn in all soil layers （0-20 cm）. The proportion of bacteria and soil water content were higher in spring than those in autumn in all soil layers （0-20 cm）. No consistent trends were found in actinomyces and fungi. The results showed that the quantities of microorganisms were significantly positive correlated with organic matter content, soil water content, total N, total P, available P, available K, pH, electrical conductivity, total salt content,catalase, urease, phosphatase and alkaline phosphatase.     

Effect of land use on microbial biomass－C, －N and －P in red soils

Eleven red soils varying in land use and fertility status were used to examine the effect of land useon microbial biomass -C, -N and -P. Microbial biomass-C in the red soils ranged from about 68 rag C/kg to 225 mg C/kg, which is generally lower than that reported from other types of soil, probably because of low or-ganic matter and high acidity in the red soils. Land use had considerable effects on the amounts of soil Cmic.The Cmic was the lowest in eroded fallow land, followed by woodland, tea garden, citrus grove and fallow grassland, and the highest in vegetable and paddy fields. There was significant correlation between Cmic and organic matter content, suggesting that the influence of land use on Cmie is mainly related to the input and ac-cumulation of organic matter. Microbial biomass-N in the soils ranged from 12.1 Nmg/kg to 31.7 Nmg/kg andwas also affected by land use. The change of Nmic with land use was similar to that of Cmic. The microbial C/N ratio ranged from 5.2 to 9.9 and averaged 7.6. The Nmic was significantly correlated with soil total N and available N. Microbial biomass-P in the soils ranged from 4.5 mg P/kg to 52.3 rag P/kg. The microbial C/P ratio was in the range of 4-23. The Pmic was relatively less affected by land use due to differences in fertili-zation practices for various land use systems.     

Extracting change information of land use and soil erosion based on RS & GIS technologystration

Rapid landuse change has taken place in many arid regions of China such as Yulin prefecture over the last decade due to rehabilitation measures. Landuse change and soil erosion dynamics were investigated by the combined use of remote sensing and geographic information systems (GIS). The objectives were to determine landuse transition rates and soil erosion change in Yulin prefecture over 15 years from 1986 to 2000. Significant changes in landuse and soil erosion occurred in the area over the study period. The results show the significant decrease in barren land mainly due to conversion to grassland. Agricultural land increased associated with conversions from grassland and barren land. The area of water erosion and wind erosion declined. The study demonstrates that the integration of satellite remote sensing and GIS is an effective approach for analyzing the direction, rate, and spatial pattern of landuse and soil erosion change.     

Influence of land cover changes on the physical and chemical properties of alpine meadow soil

Taking the alpine cold meadow grassland in the southeastern part of the Qinghai-Tibetan Plateau as an example ,this researcdh deals with the characteristics of apline meadow soil property changes,including soil nutrients,soil physical properties and soil mositure content under differcent land coverage conditions.With the degradation of grassland vegetation and the decline of vegetation coverage ,soil compactness reduces ,gravel content increases and bulk density increases ,The originally dense root-system layer is gradually denuded,making the soil coarse and gravel .The change of the organic matter contents with the vegetation coverage change in the surface soil layer (0-20cm) has shown an obvious cubic polynomial curve process ,The organic matter contents increas rapidly when land coverage is above 60%,contrarily decreases on a large scale when land coverage is below 30%,Between 30%-60% of land coverage the organic matter contents remain stable,The total N and organic matter contents remain stable.The total N and organic matter contents in soil have shown quite similar change regularity ,Following this the mathematic equations are derived to describe such change processes ,Moisture content in soil changes sharply with the vegetation coverage change,Soil moisture content change with the vegetation coverage change,Soil moisture content change with the vegetation coverage change has shown a quadratic parabola process,Results have shown that organic matter conternt and the total N content of the apline meadow soil decrease by 14890 kg/hm^2 and 5505kg/hm^2 respectively as the vegetation coverage reduces from 90% to less than 30%,the heavey changes of soil physical and chemical proerties with grassland degradation have made the recovery of alpine meadow ecological system impossible,The protection of alpine meadow vegetation is of vital importance to the maintenance of the regional soil environment and the regional ecological system.     

Evaluation of soil fertility of the shelter-forest land along the Tarim Desert Highway

To study the changes of soil fertility of the shelter-forest land along the Tarim Desert Highway, soils from the forest land were collected at the layers of 0―10 cm, 10―20 cm, 20―30 cm. Different soil fertility parameters were measured, and quantitative evaluation of soil fertility was performed by the soil integrated fertility index (IFI). The main results show that the construction of the shelter forest along the Tarim Desert Highway improved the soil physical structure, increased soil porosity and enhanced wa- ter-holding capacity. With the increase of plantation time of the shelter forest, soil microbial biomass C, N, P and the activities of six types of enzyme were enhanced, which promoted the accumulation and transformation of soil nutrients of the forest land. Consequently, the soil nutrients in 12-year-old forest land were much higher than in the newer ones and drifting sand. However, soil salt content of the older forest land was higher owing to the drip-irrigation with salt water. Through the comprehensive evalua- tion, we found that soil fertility index in the forest land was enhanced with the forest age, and it had close correlations with the growth indices of the forest trees. In summary, construction of the shelterforest along the Tarim Desert Highway accelerated the improvement of aeolian soil in the forest land, and the soil fertility improved year by year. We conclude that the forest trees grow normally under the stress of the present drip-irrigation with salt water.     

Response of soil nutrients to different cropping systems in the oasis of arid land

In the process of transformation of tropic rain forest and semi-arid grassland to farmland, the soil degradation usually occurs. But the transformation of arid desert to oasis is likely to differ from that of tropic rain forest and semi-arid grassland. Taking an alluvial plain oasis as a study case, the oasis soil properties during the process of the transformation of different cropping systems have been investigated and evaluated. Selected cropping systems consist of saline tolerance crop （STC）, food crop （FC）, melon and vegetables （MV）, Economic plants-cotton （EP-C） economic plants-grape （EP-G）, Economic plants-Hop （EP-H）. Surface soil （0-20 cm） samples were collected in 1982, 1999 and 2003. Soil, organic matter （OM）, and available N （AN）, available P （AP） and available K （AK） were determined for each soil sample. SPSS statistical software was used to analyze the soil property data. The transformation of cropping systems in the Sangong River watershed was affected directly by the policy, law and market. The soil OM contents experienced a decline during 1982- 1999, then a rise during 1999-2003. AN, AP and AK contents increased significantly with cultivated time. Soil OM tends to decrease during the conversion from STC and FC to cotton but increase during the conversion from the cotton to the grape. The soil OM was increased gradually with the cultivation time, so the oasis soil presented carbon sink, which indicates that human activities was reasonable and favorable for improvement of the oasis-ecosystem.     

Ecosystem valuation and the conservation of wild lands in visorous economic resions： A case study in Jiuduansha Wetland, Shanshai

As the loss of wild lands to satisfy traditional economic development has become a global environmental problem in recent decades, using ecosystem valuation to estimate the total economic value （TEV） of an ecosystem has become popular. The main purpose of the ecosystem valuation is to strengthen the importance of ecosystems, and bring the ecosystem services into the traditional cost-benefit analyses of land use strategy. Some studies have illustrated that in remote areas, wilderness can produce more value if it is conserved, rather than converted to traditional agricultural or industrial uses. The same situation does not seem to exist in vigorous economic regions. Thus, a case study was conducted on the Jiuduansha Wetland in Shanghai using three approaches： the direct market valuation, the replacement valuation and the contingent valuation. The net present TEVs of three land use scenarios over one hundred years were evaluated. The results proved that simply based on ecosystem valuation, when compared with the other two scenarios of ＂conservation＂ and ＂selective use＂, ＂partial conversion into terrene （dry land）＂ of Jiuduansha might be the optimal scenario for the well-being of the people in Shanghai. Land price was identified as the most important factor. This situation is likely due to the scarcity of land available for traditional economic development in Shanghai. Thus, we speculated that the fate of the wilderness to ＂be destroyed＂ in vigorous economic regions could not be changed simply based on ecosystem valuation. However, the variety of interest by local residents in wilderness might enhance the TEVs of scenarios such as ＂conservation＂ and ＂selective use＂, and affect the valuation results. Since some important benefits of natural ecosystems remain unknown and others are underestimated, we suggested that any land use decisions regarding the Jiuduansha Wetland should be conservative and cautious as converting wetlands into terrene is an irreversible process.     

Biomass Fraction of Phosphate-Accumulating Organisms Grown in Anoxic and Aerobic Stages under Optimum Nitrate Concentration

The effects of nitrate concentration on the capability of phosphorus uptake in the main anoxic stage were investigated.Meanwhile, the biomass fractions — heterotrophs, phosphateaccumulating organisms（ PAOs）,and nitrifying organisms in a pilot-scale enhanced biological phosphorus removal（ EBPR） system— were both experimentally and theoretically evaluated（ from the mass balance calculations of organic matter, nitrogen and phosphorus）,under optimum nitrate concentration in the main anoxic stage,in which the influent chemical oxygen demand（ COD）concentration was stabilized at（ 290 ± 10） mg·L^- 1and the influent total phosphorus（ TP） concentration was stabilized at（ 7. 0 ± 0. 5）mg · L^- 1. In long term operations,the process exhibited high performance in removing organic matter, nitrogen, and phosphorus. Approximately 46. 41% of organic matter,57. 21% of nitrogen,and 48. 14% of phosphorus were removed from the influent in the form of carbon dioxide,nitrogen gas,and polyphosphate,respectively. XH（ heterotrophs）,XPAO（ PAOs）,and XAUT（ autotrophs） were regarded as the major organisms responsible for biomass production. The yield fractions of XHgrowth in the first anoxic,the second anoxic,and the aerobic stages were 10. 24%,19. 11%,and 19. 71%,respectively; the yield fractions of XPAO growth in the second anoxic and the aerobic stages were 24. 34% and19. 86%,respectively; the yield fraction of XAUTgrowth in the aerobic stage was 6. 74%. These results showed that XHand XPAOformed the major community. Moreover,a higher amount of XPAOgrowth on stored poly-hydroxyalkanoates（ PHAs） under the anoxic condition was seen in this EBPR system for municipal wastewater treatment.     

不同林地清理方式下生物炭和氮添加对桉树红锥混交林土壤养分的影响

【目的】阐明不同林地清理方式下(火烧清理和人工清理)生物炭和氮添加对桉树红锥混交林土壤养分的影响,为人工林的经营管理提供参考。【方法】在火烧清理和人工清理林地的桉树红锥混交林中,设置生物炭和氮添加的控制实验,研究生物炭和氮添加对土壤有机碳(SOC)、全氮(TN)、全磷(TP)、全钾(TK)、有效磷(AP)和有效钾(AK)含量的影响。【结果】不同林地清理方式下,生物炭和氮添加对林地土壤养分的影响存在差异:与对照相比,人工清理林地时,添加生物炭显著增加了20～40cm土层的AP含量;氮添加极显著增加了0～10cm土层的SOC、TP、AP含量和C∶N;10～20cm土层的SOC、AK含量,20～40cm土层的AP和AK含量也显著增加;而0～10cm土层的N∶P则极显著降低。林地清理方式为火烧清理时,生物炭添加极显著增加0～10cm土层的TP含量,而0～10cm、10～20cm土层的SOC和AK含量,0～10cm土层的C∶N,10～20cm的AP∶TP、C∶P以及0～10cm、10～20cm、20～40cm土层的AK∶TK显著降低,0～10cm土层的AP含量、AP∶TP、C∶P和N∶P更是极显著降低。氮添加显著降低10～20cm土层的N∶P以及0～10cm土层的AP∶TP,0～10cm土层的AP含量以及10～20cm的TN含量下降达到极显著水平。【结论】人工清理林地条件下,实施生物炭和氮添加有利于提高桉树红锥混交林的土壤养分。     

黄土高原大南沟小流域土壤养分空间分异特征?

本文利用地统计学空间插值分析了陕西安塞县大南沟流域内土壤有机质、全氮、全磷、碱解氮、速效磷、速效钾6种土壤养分的空间分布特征.结果表明:流域内土壤养分含量普遍较低,质量分数平均值分别是:有机质0.964%,全氮0.506g·kg-1,全磷0.609g·kg-1,碱解氮41.295mg·kg-1,速效磷2.009mg·kg-1,速效钾138.506mg·kg-1.各养分空间分布模型:全磷符合指数模型,速效磷和碱解氮符合球状模型,速效钾符合高斯模型,其变程由大到小依次是全磷(870m)、速效磷(724m)、速效钾(207m)、碱解氮(105m).各养分空间分布由高到低总体表现为林地、果园、荒草地、退耕地、农地,坡下部高于坡上部.由于氮素易于淋溶损失,且受人工施肥影响严重,在分布上有连片特征;磷素受母质控制,存在状态稳定,所以空间变异较小;速效钾也易淋溶损失,且与植被类型有较强关系.研究为优化大南沟流域的土地利用模式,从根本上遏制以水土流失为代表的生态环境退化提供科学依据.     

兰州市南北两山土壤养分空间分布及其影响因子

分析了兰州南北两山土壤有机质、全氮及全磷的空间分布特征并重点探讨了植被类型与坡向、海拔、坡度等环境因子对土壤有机质、全氮、全磷空间分布的影响.研究结果表明:兰州南北两山土壤有机质和全氮空间分布变异非常显著,空间变异系数分别为55.946%,49.597%,而全磷空间分布差异不显著,空间变异系数仅为8.935%.植被类型对土壤有机质、全氮质量分数有重要影响,其中对土壤有机质质量分数的影响达到显著水平.土壤全磷质量分数不受植被类型影响,仅取决于土壤黄土母质.阴坡土壤有机质、全氮、全磷质量分数均高于阳坡的,其中有机质、全氮质量分数差异达到了显著水平;海拔与土壤有机质、全氮、全磷质量分数均呈极显著的正相关性;坡度与土壤有机质、全氮、全磷质量分数呈负相关性,但相关性不显著.     

不同林龄马尾松人工林针叶功能性状及其与土壤养分的关系

【目的】植物功能性状将植物与环境的结构、过程与功能有机联系起来,反映了植物对环境的适应机制。探究马尾松叶功能性状对林龄和土壤养分的响应,揭示马尾松人工林对喀斯特环境的适应策略,为喀斯特地区更好地营造马尾松人工林提供科学依据。【方法】以黔西北地区14、26、33年生马尾松人工林群落为研究对象,用空间代替时间的方法来分析不同林龄对马尾松叶功能性状和土壤养分的影响。【结果】8个叶功能性状中变异系数最小的是有机碳(OC)含量,最大的是比叶面积(SLA),除SLA和叶面积(LA)外,其他叶功能性状均属弱变异;随着林龄的增长,马尾松叶功能性状值(除叶干物质含量外)均呈增长的趋势,各叶功能性状之间存在一定的相关性;土壤全磷含量和土壤有机碳含量是影响不同林龄马尾松叶功能性状的主要土壤因子。【结论】不同林龄马尾松叶功能性状的差异表明马尾松针叶具有较强的可塑性,可以通过性状的耦合协调或组合来适应环境。植物功能性状对土壤理化性质的响应是一个长期的过程,需加强长期监测。     

南京城市土壤pH和养分的空间分布

采用GIS与地统计学相结合的方法，对南京市城市表层土壤pH、全钾、全磷、速效磷、有机质和全氮的空间分布进行了研究。结果表明，南京市城市土壤pH、全钾的变异函数的理论模型均符合线性有基台模型，可以用克立格（Kriging）插值分析。全磷、速效磷、有机质和全氮经对数处理后，仍然没有合适的拟合模型，采用逆距离加权（IDW）插值进行了分析。土壤pH、全钾有较强的空间相关性，说明它们受成土母质和地形等影响较大，全磷、速效磷、有机质和全氮空间变异性很大，主要受城市人类活动及土地利用方式的影响。     

江西省茶叶主产地茶园土壤生态化学计量特征

为了探讨茶园土壤碳、氮、磷含量及生态化学计量特征及其对环境因子的响应,在江西省茶叶主产县不同海拔、种植年限的茶园采集0~20 cm土壤样品,用于测定土壤SOC、TN、TP含量并计算化学计量比。结果表明：(1)茶园土壤SOC、TN含量均值分别为13.84 g/kg、1.37 g/kg,均高于全国土壤平均水平,达到Ⅰ级茶园肥力指标,而土壤TP含量均值为0.47 g/kg,低于全国土壤平均水平,达到Ⅱ级茶园肥力指标。(2)土壤C：N、C：P、N：P均值分别为10.97、32.61、3.49,均低于全国土壤平均水平,表明茶园土壤P具有较高的有效性,而土壤N相对缺乏。(3)随着海拔的增加,土壤SOC含量、C：N、C：P均表现出先减少后增加的趋势,土壤TN含量、TP含量、N：P则变化规律不明显。(4)随着种植年限的增加,土壤SOC含量、TN含量、C：P均表现出增加的趋势,土壤N：P呈现先增加后减少的趋势,土壤C：N呈现先减少后增加的趋势,而土壤TP含量变化规律不明显。建议在茶园经营过程中适当施加氮肥以维持氮磷元素平衡。     

“黑麦草-水稻”草田轮作系统的根际效应 Ⅱ.冬种黑麦草对土壤物理化学性状的影响

研究了冬种黑麦草对土壤物理化学性状的影响．结果表明,冬种黑麦草使土壤容质量下降９．４％,而对照区仅下降４．０％;冬种黑麦草使土壤有机质质量分数提高了６６％,而对照区降低了１４％;冬种黑麦草使土壤的全Ｎ,全Ｐ和有效Ｎ,有效Ｐ的质量分数分别提高了２６％,３２％,６７％和３３％,而对照区下降了１３％,４％,２０％和１３％;冬种黑麦草使土壤的全Ｋ和有效Ｋ质量分数提高了１４％和７８％,对照区也提高了１０％和１０％;种草区虽然土壤养分的增加与施肥有关,但有效Ｎ和Ｋ的增加显然还受到根际效应的影响,其证据是：在种草区,尽管土壤中的Ｎ通过收获黑麦草产生了较大的净输出（２８．０ｇ／ｍ２）,但土壤Ｎ含量仍然有不寻常的增加,说明可能存在着不明Ｎ源．２种养分有效含量的增幅比全量的增幅更大．从收获的黑麦草中发现土壤有Ｎ的净输出,可能是由于冬种黑麦草有不明来源的Ｎ素积累．     

修建后的临汾汾河公园土壤养分评价

以临汾市新建的湿地汾河公园为研究对象,通过对30个样点的园林土壤进行养分分析,以3个农田样点为对照,从有机质、碱解氮、速效磷和速效钾四个土壤养分指标分析土壤养分含量状况,对其园林土壤质量作出客观评价.结果表明汾河公园的建造显著降低了汾河沿岸的土壤的有机质、碱解氮、速效磷和速效钾的含量,现有机质和速效钾含量处于B级,属于中等水平,而碱解氮和速效磷含量仍为C级,处于匮乏的状态.人为调控土壤肥力有利于公园植被恢复及生态环境的平衡发展.     

天童植被演替过程中环境因子对土壤动物群落的影响

天童常绿阔叶林演替过程中,凋落物质量的变化是影响土壤动物群落的主要因子.凋落物层土壤动物群落总密度与凋落物C/N之间存在显著负相关（r=-0.681, P<0.001）,与总磷含量存在显著正相关(r=0.762, P<0.001), 但类群总数与各养分含量之间均无明显相关性;0~15cm土层中土壤动物群落总密度与土壤有机质（r=0.457, P<0.05）、总氮（r=0.463, P<0.05）和总磷（r=0.564, P<0.01）间均存在显著正相关,类群总数与总氮（r=0.528, P<0.01）和总磷(r=0.632, P<0.001)显著正相关.主要土壤动物类群密度与各养分含量之间的相关性不同：凋落物中螨和跳虫与凋落物总氮、总磷含量呈极显著正相关, 而土层中的跳虫却与土壤各养分含量间表现出不明显的负相关,螨与土壤总氮、总磷含量呈显著正相关;膜翅类与凋落物和土壤总磷含量均呈显著正相关;凋落物层综合类、土层线虫、线蚓和鞘翅类分别与凋落物和土壤各养分含量间呈显著正相关.     

烤烟总糖、蛋白质及施木克值与土壤养分的关系分析

该文分析了云南省保山烟区195份烤烟样品总糖、蛋白质及施木克值与土壤养分的关系.结果表明:①5县区烟叶平均总糖质量分数变异系数在10％以内,变幅以施甸县最大.蛋白质质量分数接近优质烟叶标准,平均质量分数以施甸(9.28％)最高,昌宁(8.19％)较低;②保山烟区烤烟总糖质量分数与速效钾、有效铜、有效锌和有效硼质量分数呈极显著正相关;蛋白质质量分数与碱解氮、速效磷、有效铁、有效锰和有效硫质量分数呈极显著正相关;施木克值与pH值、速效磷和有效硫质量分数呈显著负相关,与碱解氮、有效铁和有效锰质量分数呈极显著负相关;③该地区属于北回归线区域火山灰土壤特色优质烟区,土壤呈中性微酸,有机质质量分数丰富,总体供氮水平较高,速效磷质量分数中等,速效钾质量分数中等偏上,多数烟区中微量元素质量分数丰富;④最后构建了保山烟区烤烟总糖、蛋白质及施木克值与土壤养分指标间的双重筛选逐步回归分析方程.