Visualization Analysis of the Impact of Rubber Agroforestry Ecosystem on Soil Microbial Community

Rubber agroforestry systems positively impact soil microbial communities. This study employed a bibliometric approach to explore the research status, hotspots, and development trends related to these effects. Using CiteSpace software, we visually analyzed research literature from the Web of Science (WOS) core database, spanning 2004 to 2024. The focus was on the impact of rubber agroforestry ecosystems on soil microbial communities. The results indicate significant attention from Chinese researchers, who have published numerous influential papers in this field. Authors Liu Wenjie have contributed the most papers, although no stable core author group exists. The Chinese Academy of Sciences is the leading research institution in terms of publication volume. While there is close collaboration between different institutions and countries, the intensity of researcher cooperation is low. The most cited literature emphasizes soil nutrients and structure in rubber agroforestry, laying a foundation for soil microorganism studies. Most cited journals are from countries like Netherlands and the United Kingdom. Key research areas include the effects of rubber intercropping on soil microbial communities, agroforestry management, and soil health. Research development can be divided into three stages: the initial stage (2010-2015), the development stage (2015-2020), and the mature stage (2020-2024). Current studies show that rubber intercropping and rubber-based agroforestry systems enhance soil microbial communities, positively impacting soil health. This paper provides a theoretical basis for the sustainable development of rubber agroforestry systems and improved management plans. Future research could explore the effects of species composition on soil microbiological characteristics and develop methods for species interactions. An in-depth study of the soil microbial community’s structure and function, and its relationship with rubber trees, is crucial. Developing effective, rationally designed rubber agroforestry systems and underground soil microbiome technology will promote sustainability and improve plantation productivity.

Synergistic Interactions of Soil and Vegetation in Agroforestry Systems in Mitigating Climate Change in Upper East Region, Ghana

Climate change has been a global pandemic with its adverse impacts affecting environments and livelihoods. This has been largely attributed to anthropogenic activities which generate large amounts of Green House Gases (GHGs), notably carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) among others. In the Upper East of Ghana, climate change manifests in erratic rainfalls, drought, high temperatures, high wind speeds, high intensity rainfall, windstorms, flooding, declining vegetation cover, perennial devastating bushfires etc. Practices such as burning farm residues, use of dung as fuel for cooking, excessive application of nitrogenous fertilizers, and deforestation that are prevalent in the region exacerbate the situation. Although, efforts made by governmental and none-governmental organizations to mitigate climate change through afforestation, agroforestry and promotion of less fuelwood consuming cook stoves, land management practices antagonize these efforts as more CO2 is generated than the carrying capacity of vegetation in the region. Research findings have established the role of trees and soil in carbon sequestration in mitigating climate. However, there is limited knowledge on how the vegetation and soil in agroforestry interplay in mitigation climate change. It is against this background that this review seeks to investigate how vegetation and soil in an agroforestry interact synergistically to sequester carbon and contribute to mitigating climate change in Upper East region of Ghana. In this review, it was discovered soil stored more carbon than vegetation in an agroforestry system and is much effective in mitigating climate change. It was found out that in order to make soil and vegetation in an agroforestry system interact synergistically to effectively mitigate climate change, Climate Smart Agriculture practice which integrates trees, and perennials crops effectively mitigates climate. The review concluded that tillage practices that ensure retention and storage of soil organic carbon (SOC) could be much effective in carbon sequestration in the Savannah zones and could be augmented with vegetation to synergistically mitigate climate change in the Upper East region of Ghana.

A Plan to Extract Gigatons of Atmospheric CO2 through Agroforestry

The UN International Panel Environment Programme (“UNEP”), 2023 Emissions Gap Report urgently presses the global community to adopt a two-pronged approach to reduce atmospheric concentration of CO2—expedite efforts to reduce annual CO2 emissions;and increase investment in large-scale carbon dioxide removal (“CDR”) projects. The Gap Report sets a 2050 target of six-gigatons annual land-based CDR. Our proposed agroforestry project will convert thirty-five-million acres of rangeland in the American Great Plains to silvopasture, combining growing trees and raising livestock. Employing agroforestry interests 61% of Great Plaints farmers/ranchers recently surveyed. The Project plans to annually collect + six-gigatons CO2 equiv. of fallen leaves and store the stable carbon-rich biomass underground for centuries. The purpose of this paper is to describe the framework for formation of a global partnership at the local, regional, and international levels to coordinate public and private financing mechanisms, implement, and operate a large-scale CDR Project that will meaningfully impact the global effort to mitigate climate change.

The amelioration of degraded larch(Larix olgensis)soil depends on the proportion of Aralia elata litter in larch-A.elata agroforestry systems

Research has indicated that introducing Aralia elata into larch plantations forms an agroforestry system which could provide economic benefi ts for local farmers and improve degraded soils.However,the impact of litter mixtures on soil chemical and microbial properties in this agroforestry system are unclear,which limits effi cient management of the agroforestry system.A 365-d incubation experiment examined the eff ect of litter mixtures of diff erent proportions of larch(L)and A.elata(A)on soil chemical and microbial properties.The results show that levels of mineral N,available P,microbial biomass carbon and nitrogen,cumulative C mineralization,and activities of hydrolases and oxidases increased with an increase of A.elata in the litter mixtures.Concentration of total soil carbon,nitrogen,and phosphorous did not change(except for total nitrogen).Compared with larch litter alone,levels of mineral N,available P,microbial biomass carbon and nitrogen,cumulative C mineralization,and the activities of hydrolases and oxidases increased by 7.6–433.5%.Most chemical and microbial properties were positively correlated with mixed litter proportions and the initial levels of N,P,K,Ca,Mg,Mn,Zn and Cu in the litter,while negatively correlated with the initial concentrations of C,Fe and lignin,C/N and lignin/N ratios.The results indicate that A.elata litter can improve degraded larch soil and the degree depends on the proportion of A.elata litter in the litter mixtures.

Expert elicitations of smallholder agroforestry practices in Seychelles:A SWOT-AHP analysis

Agroforestry can leverage the co-benefits of climate change adaptation and mitigation while conserving biodiversity and restoring degraded and deforested lands.The preference of relevant stakeholders regarding agroforestry practices enhances sustainable land management through strategic decision-making in Seychelles and other island states.A suitable approach for assessing stakeholders'preferences of agroforestry is the implementation of the strengths,weaknesses,opportunities,and threats(SWOT)approach in combination with the analytic hierarchy process(AHP)method.The entry point of this study is an extensive literature review process,during which 28 SWOT factors were identified.These SWOT factors were deliberated on during a half-day workshop with agricultural experts who agreed on 20 SWOT factors that reflect the local realities of the Seychelles through a consensus approach.Using the SWOT-AHP approach,focus group discussions were conducted to examine the perceptions of researchers and extension workers about the adoption of agroforestry in Seychelles.The results indicated that the positive aspects of smallholder agroforestry outweigh the negative aspects.For example,increased agricultural production,control runoff and soil erosion receive the highest scores among the strength factors perceived by researchers and extension workers,respectively.The willingness of international organizations to fund agroforestry-related projects and the existence of native tree species on farmlands have the highest scores among the opportunity factors.The lack of education,information,and communication between the government and farmers,and the small land size and crop competition have the highest scores among the weakness factors.Lastly,change in government policies on land use has the highest score among the threat factors by researchers,whereas the most significant threat is climate change and variability for the extension workers.The provision for a 30-year land lease agreement in the National Agroforestry Policy of Seychelles is viewed by both groups as an incentive that could potentially drive the adoption and acceptability of agroforestry.Furthermore,better coordination of various efforts to promote agroforestry and more substantial extension services for farmers,especially the role of technologies for optimal production on small plots of land,can enhance climate resilience in Seychelles and other small island developing states.

Exploration and Practice of Rubber Based Agroforestry Complex Systems in China

Agroforestry ecosystems are constructed by simulating natural ecosystems, applying the principles of symbiosis in nature, and organizing multiple plant populations to coexist, while conducting targeted cultivation and structural control scientifically. Rubber agroforestry complex ecosystems aim for sustainable development in terms of industry, ecology, resource utilization, and the livelihoods of producers. Rubber agroforestry complex ecosystems create a complex production structure system that integrates biology, society, and the economy through species combinations. Rubber trees and associated biological components coordinate with each other, mutually promote growth, and yield a variety of products for producers. Cultivation techniques and patterns of rubber agroforestry are essential components of these ecosystems. This study analyzes the production practices of rubber agroforestry complex cultivation, with a focus on the development and characteristics (complexity, systematicity, intensity, and hierarchy) of rubber agroforestry systems using a literature analysis and a survey approach. It explores the types and scales of complex planting, specifications and forms, and major effects of complex cultivation. This study identifies successful rubber agroforestry cultivation patterns and practical techniques, as well as the potential benefits of developing rubber agroforestry cultivation. It also points out the shortcomings in the development of complex planting, including an emphasis on production practices but insufficient theoretical research, a focus on production but inadequate attention to the market, and an emphasis on yield while overlooking the improvement of standards, brands, and added value. There are various complex patterns for young rubber plantations, but relatively fewer for mature plantations. Based on this analysis, this study suggests that future efforts should focus on in-depth research on interspecies and environmental interactions in rubber agroforestry ecosystems, clearly define key roles, accelerate the innovation of development patterns, and strengthen the foundation for development. It recommends promoting and demonstrating successful rubber agroforestry complex patterns and providing technical training, developing product branding for rubber agroforestry patterns, enhancing product value, expanding the application functions of rubber-forest mixed crop products, and establishing a stable and sustainable industry chain. This study provide practical experience and theoretical insights in rubber agroforestry complex systems from China the potential to enrich the knowledge of rubber agroforestry composite systems, provide practical experience to improve the operating income of smallholders, and even promote the sustainable development of rubber plantations.

Diversity and Importance of Benin’s Forests and Agroforestry Systems Woody Species in Mortars and Pestles Manufacture

The disappearance of resources with high genetic potential and great utility for people and the challenge of the conservation and sustainable management of these resources are two opposing facts of which the world is now concerned. In Benin, forests and agroforestry systems complement each other in wood supply for mortar and pestle manufacture. Thus, this study aimed to investigate the diversity of woody species used for mortar and pestle manufacture and to analyze the preferences of manufacturers through an ethnobotanical approach. Based on the snowball sampling method, and interviews with 112 manufacturers from different ethnic groups, we identified 31 tree species. These species belong to 30 genera and 13 plant families. The Fabaceae are more represented with 14 species (i.e. 45% of the total). Ten are frequently used. But there are four species, such as Vitellaria paradoxa C. F. Gaertn., Prosopis africana (Guill. & Perr.) Taub., Terminalia glaucescens Planch. ex Benth. and Pericopsis laxiflora (Benth.) Meeuwen, which are highly preferred by manufacturers respectively. The calculation of the Indexes of Possession of Global Knowledge (IPSG) revealed that the ethnic group Nagot (0.204) possessed more knowledge and is followed by Mahi (0.201) and Fon (0.18) respectively. Forests and agroforestry systems are both supply sites for manufacturers. The non-parametric Wilcoxon test proved that there are no significant differences between the species’ preference for mortars or pestles manufacture (v = 181, p-value = 0.38). Since the trees cutting in agroforestry systems can be destructive to them, provisions such as the promotion of agroforestry in rural areas and the integration of the used species in the reforestations programs must be taken to curb the pressure and contribute to the conservation of the biodiversity.

Preliminary Study on the Effect of Different Ecological Cultivation Modes on the Water Stability of Soil Aggregates in Rubber Based Agroforestry Systems

Rubber trees (Hevea brasiliensis Müll. Arg.) have been commercially cultivated for a century and a half in Asia, particularly in China, and they constitute a common element of plantation ecosystems in tropical regions. Soil health is fundamental to the sustainable development of rubber plantations. The objective of the study is to explore the influence of different complex ecological cultivation modes on the stability of soil aggregates in rubber based agroforestry systems. In this study, the ecological cultivation mode of rubber—Alpinia oxyphylla plantation, the ecological cultivation mode of rubber—Phrynium hainanense plantations, the ecological cultivation mode of rubber—Homalium ceylanicum plantations and monoculture rubber plantations were selected, and the particle size distribution of soil aggregates and their water stability characteristics were analyzed. The soil depth of 0 - 20 cm and 20 - 40 cm was collected for four cultivation modes. Soil was divided into 6 particle levels > 20 cm. soil was divided into 6 particle levels > 5 mm, 2 - 5 mm, 1 - 2 mm, 0.5 - 1 mm, 0.25 - 0.5 mm, and 0.053 - 0.25 mm according to the wet sieve method. The particle size proportion and water stability of soil aggregates were determined by the wet sieve method. The particle size proportion and water stability of soil aggregates under different ecological cultivation modes were analyzed. The results showed that under different ecological cultivation modes in the shallow soil layer (0 - 20 cm), the rubber—Alpinia oxyphylla plantation and the rubber—Phrynium hainanense plantation promoted the development of dominant soil aggregates towards larger size classes, whereas the situation is the opposite for rubber—Homalium ceylanicum plantation. In soil layer (20 - 40 cm), the ecological cultivation mode of rubber—Phrynium hainanense plantation developed the dominant radial level of soil aggregates to the diameter level of large aggregates. Rubber—Alpinia oxyphylla plantation and rubber—Homalium ceylanicum plantation, three indicators, including the water-stable aggregate content R0.25 (>0.25 mm water-stable aggregates), mean weight diameter (MWD), and geometric mean diameter (GMD), were all lower than those in the rubber monoculture mode. However, in the rubber—Phrynium hainanense plantation, the water-stable aggregate content R0.25, mean weight diameter, and geometric mean diameter were higher than in the rubber monoculture mode, although these differences did not reach statistical significance.

Evaluation of Women’s Contribution in Agroforestry Demonstration through Moringa Species Introduction in Western Oromia,Ethiopia

Agroforestry technologies are very keen practices in most small-scale farming systems where gender issues are not well considered in most developing countries.Moringa is a tropical plant that consists of 13 species,while five of them are found in Ethiopia.This study aimed to evaluate the potential and contribution of women in agroforestry demonstrations where Moringa oleifera and Moringa stenopetala are introduced in farmers’fields.Selection of the best performing moringa species and preferred by farmers for further scaling up was also another objective.The activity was conducted in five districts of west and east Wallagga zones.A total of 10 FREG comprising 150 farmers were established.The two moringa species were planted on 100 farmers’fields where 50 women and 50 men were purposively selected and given responsibilities of moringa demonstration.Leaflets and practical training on moringa production,importance and utilization were prepared and given to all concerned bodies.84%of women and only 32%of men effectively demonstrated the moringa species.A total of 200 farmers were interviewed to evaluate and select the best from the two species depending on their growth performance,fresh leaf taste and odor,and survival rate.Based on the above criteria,143(71.5%)farmers preferred Moringa oleifera.In general,the two moringa species were performed well in most places,and its utilization started at household level.Finally,the authors recommend that women are the potential for demonstrating agroforestry technologies,and Moringa oleifera is a more preferred species in western Oromia.

Soil Organic Carbon and Nitrogen Dynamics in Arabica Coffee Agroforestry Systems in the Noun Division, West Cameroon

Agroforestry systems (AFSs) offer viable solutions to climate change because of the below-ground biomass (BGB) that is maintained by the soil. Therefore, spatially explicit estimation of their BGB is crucial to account for emission reduction efforts. A study to assess soil organic carbon (SOC) and nitrogen dynamics in Arabica coffee agroforests was conducted in two subdivisions (Foumbot and Kouoptamo) of the Noun Division in western Cameroon. The methodological approach involved the collection of 150 soil samples taken at different depths: 0 - 10, 10 - 20 and 20 - 30 cm. Depending on the depth, the SOC stock is 27.93 ± 1.13 tC/ha at 10 cm depth, 22.37 ± 1.47 tC/ha at 20 cm and 20.79 ± 0.31 tC/ha at 30 cm. According to the age classes of the Arabica coffee systems (ACA), the C/N ratio in our study area averaged 26.94 ± 13.60 for the (5 - 20) year old systems in Foumbot and 60.64 ± 48.80 for the (20 - 35) year old systems in Kouoptamo. Depending on the depth, at 10 cm this ratio is higher in Kouoptamo than in Foumbot with a maximum value of 57 and 38 respectively for the two subdivisions. In view of the results obtained, it would be important to analyse the types of microorganisms responsible for the decomposition of organic matter which is linked to soil organic carbon.

豫东沙土农区杨树-农作物复合生态系统中温室气体排放的研究

为了探讨农林复合系统农田土壤温室气体排放的贡献率,在豫东沙区杨树—农作物复合生态系统中选取了2种典型的防护林网密度——大网格BT(防护林间距1000 m×1000 m)、小网格ST(防护林间距200 m×200 m),并用周边5~10年生的人工纯林地作对照,采用静态箱—气相色谱法对不同防护林网密度的杨树—农作物复合生态系统中土壤温室气体(CO_(2)、N_(2)O、CH_(4))季节排放通量进行田间原位测定。结果表明:豫东农区农田土壤是CO_(2)、N_(2)O的排放源、CH_(4)的吸收汇。不同农林复合模式对土壤温室气体的排放或吸收的强度都有不同的特征,大网格、小网格、林地土壤CO_(2)日排放通量均在7月达到最大值,分别为1163.17、1005.91、923.53 mg/(m^(2)·h);大网格的土壤N_(2)O日排放通量在7月达到最大值,小网格和林地则在8月达到最大值,土壤N_(2)O排放通量为4.29~313.28μg/(m^(2)·h);3种模式下土壤CH_(4)的吸收峰值均在7月达到最大值,其中大网格的吸收峰值最大,为4.41 mg/(m^(2)·h)。不同农林复合经营模式通过影响土壤、空气温度和湿度等来影响农田土壤温室气体排放,其中增温干燥强化了土壤CO_(2)和N_(2)O排放源的特征,但同时也增加了土壤作为大气CH_(4)吸收汇的功能,大网格、小网格、林地的全球增温潜势(GWP)分别为1.50×10^(5)、1.03×10^(5)、0.885×10^(5)kg C/hm^(2),单位面积GWP值以林地的最小、大网格的最大。总的来看,适当增加防护林网密度有利于减少农林系统的增温潜能。

不同类型橡胶园间作对竹芋生产力、经济效益和净温室气体排放的影响

【目的】构建和发展橡胶农林复合模式提高综合产出和生态效益,为保障海南省天然橡胶种植业可持续发展提供参考。【方法】以淀粉作物竹芋(Maranta arundinacea L.)为对象,在幼龄常规胶园(6龄)、幼龄(6龄)和成龄(20龄)的全周期胶园中进行间作,从光照、土壤养分、生产力、经济效益和温室气体排放方面,综合分析竹芋在不同类型胶园中的适宜性。【结果】幼龄常规胶园间作的光照条件最差,间作竹芋产量仅4750 kg/hm^(2),而幼龄和成龄全周期胶园中间作区域的光照条件较好,产量分别为27470和11190 kg/hm^(2),不同处理之间存在显著差异(P<0.05)。不同间作处理竹芋的生物量亦呈相同趋势。不同处理竹芋的营养成分(淀粉、粗蛋白和可溶性糖)总体上无显著变化。幼龄和成龄全周期胶园间作竹芋的经济效益分别为86185和9285元/hm^(2),而在幼龄常规胶园中间作则为-21415元/hm^(2)。从净温室气体排放方面看,仅幼龄全周期胶园间作竹芋处理为温室气体的汇(368 kg/hm^(2)),而其他两种处理则为温室气体的源。【结论】幼龄的全周期胶园间作竹芋具有最佳的生产力和经济效益,同时能兼顾一定的生态效益,是海南省适宜的橡胶农林复合模式。

沿江典型区域杨树大径材人工林复合经营技术研究

本文对杨树大径材培育周期内的5个典型复合经营模式生长和经济效益进行分析,选择出适宜长江沿江典型区域种植的杨树大径材复合经营模式。结果表明:参试林农复合经营模式下杨树的胸径、树高、单位面积蓄积量分别比纯林增加15.31%(YM)~20.92%(YYD)、9.52%(YM)~11.31%(YY)、45.66%(YM)~61.38%(YYD)。采用间作模式的6年生杨树复合经营总收益均大于杨树纯林,杨树间作模式的总产值为杨树纯林的2.78(YM)~4.47倍(YYD)。采用多作物间作模式总收益及总产值明显高于单作物间作模式。其中套种6年杨树-油菜-黄豆(YYD)模式累计总收益(11 905元/667m^(2))最高,杨树-小麦-黄豆(YMD)累计总收益(11 599元/667m^(2))次之。5个模式下6年生杨树木材收益由高到低依次为:YYD(7 244元/667m^(2))>YMD(7 197元/667m^(2))>YY(7 106.5元/667m^(2))>YM(6 539.6元/667m^(2))>YC(4 408.48元/667 m^(2))。杨树-油菜-黄豆(YYD)是促进大径材杨树生长、材积和经济效益最高的优选模式。此研究旨在为长江沿江典型区域杨树的大径材培育和复合经营策略提供参考。

农林交错带植被覆盖度与地表温度的相关性分析

以内蒙古赤峰市喀喇沁旗为研究区,基于2000—2019年8期Landsat影像,利用空间分析、线性回归和空间自相关3种方法,在4类土地覆被上分析植被覆盖度(FVC)与地表温度(LST)的时空变化及其相关性。结果表明:(1)近19 a来,喀喇沁旗FVC呈西南向东北递减的趋势,而LST空间分布与FVC相反,呈西南低东北高的趋势;(2)FVC与LST整体表现为负相关,在空间相关性与线性回归中,农田的相关性强于林地,而空间自相关中林地强于农田;(3)与农田、建筑、草地相比,林地的FVC能有效降低LST,FVC≥0.75时,对LST影响最明显。

紫色土区不同农林复合模式土壤入渗特征及影响因素

[目的]为探究紫色土区不同农林复合模式土壤入渗特征及其影响因素。[方法]通过野外调查和室内试验,分析紫色土区无作物(CK)、花生(HS)、花椒(HJ)、花生+花椒(HS+HJ)4种农林复合模式下土壤物理性质与入渗过程变化特征,评价了3种土壤入渗模型(Kostiakov、Horton、Philip)的适用性。[结果](1)HJ模式下土壤总孔隙度与CK、HS+HJ模式差异不显著,但显著高于HS模式(p<0.05);CK和HS模式的土壤抗剪强度差异不显著,但均显著高于HJ模式和HS+HJ模式(p<0.05);各模式下土壤容重、含水率、温度、斥水性、紧实度、土壤硬度差异均显著(p<0.05)。(2)4种模式土壤水分入渗过程差异较大,CK和HS下土壤水分入渗在20 min左右进入稳渗阶段,而HJ和HS+HJ模式下土壤入渗分别在70,80 min左右进入稳渗阶段。HS+HJ模式的土壤稳定入渗率分别比CK、HS、HJ模式高出162%,140%,82%(p<0.05)。(3)与Horton和Philip模型相比,Kostiakov模型拟合入渗过程的效果最佳(决定系数R^(2)=0.933~0.991);Horton模型拟合效果相对较差(R^(2)=0.849~0.979)。(4)相关性与多元线性回归分析发现,土壤总孔隙度与土壤抗剪强度是影响土壤入渗的关键因素。[结论]研究结果为紫色土区农林复合模式的优化选择提供科学依据。

Impact of cattle density on the structure and natural regeneration of a turkey oak stand on an agrosilvopastoral farm in central Italy

On an agrosilvopastoral farm in central Italy where Maremmana cattle graze in Turkey oak forests,we evaluated the impact of different livestock densities on stand structure,tree diversity and natural regeneration in four types of grazed areas based on the grazing regime adopted:calf-grazed,high-intensity-grazed,low-intensity-grazed,ungrazed control.For each area,we set up three permanent circular plots(radius of 15 m)to survey the structural and dasometric characteristics of the overstorey,understorey,and regeneration layer.The results showed that grazing negatively affected the complexity of the forest structure and its potential to regenerate and maintain a high level of biodiversity.The differences in stand structure observed between the grazing areas were closely related to livestock density.The most sensitive components of the system were the understorey and the regeneration layers.Contrarily,the current grazing management did not affect the dominant tree structure or its composition.Our findings identified medium-term monitoring and regeneration management as the two significant aspects to consider when assessing sustainable livestock.New forests can be established by excluding graz-ing for about 20–25 years.

Parkland trees on smallholder farms ameliorate soil physical-chemical properties in the semi-arid area of Tigray,Ethiopia

Proposed agroforestry options should begin with the species that farmers are most familiar with,which would be the native multipurpose trees that have evolved under smallholder farms and socioeconomic conditions.The African birch(Anogeissus leiocarpa(DC.)Guill.&Perr.)and pink jacaranda(Stereospermum kunthianum Cham.)trees are the dominant species in the agroforestry parkland system in the drylands of Tigray,Ethiopia.Smallholder farmers highly value these trees for their multifunctional uses including timber,firewood,charcoal,medicine,etc.These trees also could improve soil fertility.However,the amount of soil physical and chemical properties enhanced by the two species must be determined to maintain the sustainable conservation of the species in the parklands and to scale up to similar agroecological systems.Hence,we selected twelve isolated trees,six from each species that had similar dendrometric characteristics and were growing in similar environmental conditions.We divided the canopy cover of each tree into three radial distances:mid-canopy,canopy edge,and canopy gap(control).At each distance,we took soil samples from three different depths.We collected 216 soil samples(half disturbed and the other half undisturbed)from each canopy position and soil depth.Bulk density(BD),soil moisture content(SMC),soil organic carbon(SOC),total nitrogen(TN),available phosphorus(AP),available potassium(AK),p H,electrical conductivity(EC),and cation exchange capacity(CEC)were analysed.Results revealed that soil physical and chemical properties significantly improved except for soil texture and EC under both species,CEC under A.leiocarpus,and soil p H under S.kunthianum,all the studied soils were improved under both species canopy as compared with canopy gap.SMC,TN,AP,and AK under canopy of these trees were respectively 24.1%,11.1%,55.0%,and 9.3% higher than those soils under control.The two parkland agroforestry species significantly enhanced soil fertility near the canopy of topsoil through improving soil physical and chemical properties.These two species were recommended in the drylands with similar agro-ecological systems.

杨树人工林复合经营模式对土壤N_(2)O与CO_(2)排放的影响

为探讨杨树人工林复合经营模式对土壤温室气体排放的影响,基于11年生“南林-895杨”(Populus×euramericana‘Nanlin-895’)人工林,设置纯林、林下种植麦冬(Ophiopogon japonicas)和林下养鸡3种复合经营模式,采用静态箱-气相色谱法每月测定土壤N_(2)O和CO_(2)排放通量,同时测定土壤温湿度,分析复合经营模式对土壤N_(2)O和CO_(2)排放和产量的影响及与相关影响因子的关系。结果表明:不同复合经营模式林下土壤温、湿度存在显著差异;不同杨树复合经营模式间,土壤N_(2)O和CO_(2)排放速率动态变化与年累积排放量存在显著差异,杨树林下种植麦冬的土壤N_(2)O年累积排放量最高,为233.47 mg·m^(-2)·a^(-1),而林下养鸡的土壤CO_(2)年累积排放量最高,达2328.87 g·m^(-2)·a^(-1)。总体来看,不同复合经营模式林地土壤温室气体(N_(2)O和CO_(2))年累积排放量为林下养鸡>林下种植麦冬>杨树纯林;土壤温、湿度对土壤CO_(2)和N_(2)O排放速率有显著影响,其中,土壤CO_(2)排放速率与土壤温度之间呈显著线型相关,而与土壤湿度呈现抛物线型关系;土壤N_(2)O排放速率与土壤温、湿度的关系均可用抛物线型关系来描述。综上所述,不同杨树复合经营模式改变了林地土壤的温、湿度,进而对温室气体排放产生了显著的影响。从1年的研究结果看,种植麦冬和养鸡的杨树人工林林地土壤温室气体的年累积排放量高于纯林,表明林农复合经营增加了土壤温室气体的排放。

Effects of Forest Types on Soil Available Nutrients and Carbon Contents in Coastal Areas,China

Clarifying the soil nutrient dynamics caused by forest type variations in the coastal region helps scientifically to apply fertilizer to forest plantations and enhance the carbon(C)sink capacity.Pure forests of Ligustrum and Metasequoia,as well as their mixed forests,in a coastal region of China were investigated by collecting 0-20 and 20-40 cm soil samples and analyzing their differences in bulk density,water content,pH,soil organic matter(SOM),ammonium(NH_(4)^(+)-N),nitrate(NO_(3)^(-)-N)and total nitrogen(TN),available phosphorus(AP)and potassium(AK),microbial biomass C(MBC)and N(MBN),and enzyme activity.The results demonstrated that different forest types had no significant(p≥0.05)effect on 0-20 cm soil bulk density,water content,pH,NH_(4)^(+)-N,and SOM.However,the surface soil NO_(3)^(-)-N,TN,AP,and AK contents as well as enzyme activity changed significantly(p<0.05),in which the soil AK content of the ligustrum×metasequoia mixed forest was 47.5%and 65.5%higher than that of the ligustrum and metasequoia pure forest,respectively.The mixed forest soil had the highest MBN content,which was significantly(p<0.05)25.1%higher than that in the pure metasequoia forest.Meanwhile,soil phosphatase activities in ligustrum and metasequoia pure forests were significantly(p<0.05)lower than those in the mixed forests by 17.4%and 43.1%,respectively.However,soil NO_(3)^(-)-N and AP contents in the metasequoia pure forest were significantly(p<0.05)higher than those in the ligustrum pure forest and mixed forests.Soil MBC content and reductase NO_(3)^(-)-N activity were significantly(p<0.05)higher in ligustrum pure forest than in metasequoia pure forest and mixed forests.In addition,the results of two-way ANOVA showed that there were no significant(p≥0.05)differences in nutrient contents(e.g.,NH_(4)^(+)-N,AP,AK,and SOM)in different soil layers(0-20 and 20-40 cm)within the same forest type,except for NO_(3)^(-)-N.However,forest types had a significant(p<0.05)impact on NO_(3)^(-)-N and AP contents in 20-40 cm soil layer.Combining the two factors of forest stand and soil layer,there was a significant(p<0.05)interaction effect for their soil NH_(4)^(+)-N,NO_(3)^(-)-N,AP,and AK contents.In conclusion,significant(p<0.05)differences were observed in nutrient contents in 0-20 cm soil layer from different forest types,with soil fertility indices inmixed forests generally higher than in pure forests.Therefore,establishing mixed forests in coastal saline region is recommended to retain soil fertility and to enhance the C sink capacity of forestry.

农林废弃物衍生生物炭吸附水中污染物的研究进展

近年来,水中污染物对人类健康的影响引起了人们广泛关注,以农林废弃物等为原料制备的生物炭是一种高效低成本吸附剂,已被用于去除水中污染物。为进一步提高生物炭的吸附性能,有必要对生物炭进行功能化改性。关于改性生物炭吸附去除水中污染物的报道较多,这些研究探索了各种生物炭功能化改性方法,表明不同改性生物炭对不同污染物具有不同的吸附行为和机制。综述了近5年来改性生物炭吸附去除水中污染物的方法,并对改性生物炭吸附剂在未来废水处理中的发展方向进行展望。