Temporal changes in mixing effects on litter decay and nitrogen release in a boreal riparian forest in northeastern China

In riparian forests,litter decay provides essential energy and nutrients for both terrestrial and fluvial ecosystems.Litter mixing effects(LMEs)are crucial in regulating litter decay and nutrient dynamics,yet how LMEs change over time is unclear in riparian forests.In this study,leaf litter of three common species(Alnus sibirica Fisch.ex Turcz,Betula platyphylla Sukaczev,and Betula fruticosa Pall.)were mixed in an equal mass ratio and LMEs were measured for mass and nitrogen(N)remaining in whole litter mixtures over a 3-year period in a boreal riparian forest,northeastern China.LMEs were also assessed for component litter mass and N remaining by separating litter mixtures by species.During the decay of litter mixtures,antagonistic effects on mass and N remaining were dominant after one and two years of decay,whereas only additive effects were observed after three years.LMEs correlated negatively with functional diversity after the first and two years of decay but disappeared after three years.When sorting litter mixtures by species,non-additive LMEs on mass and N remaining decreased over incubation time.Moreover,non-additive LMEs were more frequent for litter of both B.platyphylla and B.fruticosa with lower N concentration than for A.sibirica litter with higher N concentration.These results indicate that incubation time is a key determinant of litter mixing effects during decay and highlight that late-stage litter mixture decay may be predicted from single litter decay dynamics in boreal riparian forests.

Subtropical forest macro-decomposers rapidly transfer litter carbon and nitrogen into soil mineral-associated organic matter

Background:Forest soils in tropical and subtropical areas store a significant amount of carbon.Recent framework to assess soil organic matter(SOM)dynamics under evolving global conditions suggest that dividing bulk SOM into particulate and mineral-associated organic matter(POM vs.MAOM)is a promising method for identifying how SOM contributes to reducing global warming.Soil macrofauna,earthworms,and millipedes have been found to play an important role in facilitating SOM processes.However,how these two co-existing macrofaunae impac the litter decomposition process and directly impact the formation of POM and MAOM remains unclear.Methods:Here,we set up a microcosm experiment,which consisted of 20 microcosms with four treatments earthworm and litter addition(E),millipedes and litter addition(M),earthworm,millipedes,and litter addition(E+M),and control(only litter addition)in five replicates.The soil and litter were sterilized prior to beginning the incubation experiment to remove any existing microbes.After incubating the samples for 42 days,the litte properties(mass,C,and N contents),soil physicochemical properties,as well as the C and N contents,and POM and MAOM^(13)C abundance in the 0–5 and 5–10 cm soil layers were measured.Finally,the relative influences o soil physicochemical and microbial properties on the distribution of C and N in the soil fractions were analyzed Results:The litter mass,C,and N associated with all four treatments significantly decreased after incubation especially under treatment E+M(litter mass:-58.8%,litter C:-57.0%,litter N:-75.1%,respectively),while earthworm biomass significantly decreased under treatment E.Earthworm or millipede addition alone showed no significant effects on the organic carbon(OC)and total nitrogen(TN)content in the POM fraction,but join addition of both significantly increased OC and TN regardless of soil depth.Importantly,all three macrofauna treatments increased the OC and TN content and decreased the^(13)C abundance in the MAOM fraction.More than65%of the total variations in the distribution of OC and TN throughout the two fractions can be explained by a combination of soil physicochemical and microbial properties.Changes in the OC distribution in the 0–5 cm soi layer are likely due to a decrease in soil pH and an increase in arbuscular mycorrhizal fungi(AMF),while those in the 5–10 cm layer are probably caused by increases in soil exchangeable Ca and Mg,in addition to fungi and gram-negative(GN)bacteria.The observed TN distribution changes in the 0–5 cm soil likely resulted from a decrease in soil pH and increases in AMF,GN,and gram-negative(GP)bacteria,while TN distribution changes in the 5–10 cm soil could be explained by increases in exchangeable Mg and GN bacteria.Conclusions:The results indicate that the coexistence of earthworms and millipedes can accelerate the litte decomposition process and store more C in the MAOM fractions.This novel finding helps to unlock the processe by which complex SOM systems serve as C sinks in tropical forests and addresses the importance of soil mac rofauna in maintaining C-neutral atmospheric conditions under global climate change.

The Transport and Persistence of Escherichia coli in Leachate from Poultry Litter Amended Soils

Fecal coliform bacteria such as Escherichia coli (E. coli) are one of the main sources of groundwater pollution. An assessment of the transport and Persistence of E. coli in poultry litter amended Decatur silty Clay soil and Hartsells Sandy soil was conducted using soil columns and simulated groundwater leaching. Enumeration of initial E. coli was determined to range from 2.851 × 103 to 3.044 × 103 CFU per gram of soil. These results have been used in a batch study to determine the persistence rate of E. coli in Decatur silty Clay soil and Hartsells Sandy soil. Results prove that E. coli survival growth rate increases for clay soil later than and at a higher rate than sandy soil. The column study has determined that E. coli was transported at a rate of 3.7 × 106 CFU for Decatur silty loam and 6.3 × 106 CFU for Hartsells sandy per gram of soil. Further, linear regression analysis predictions show higher porosity and soil moisture content affect transport, and Hartsells sandy soil has higher transport of E. coli due to its higher porosity and lower volumetric water content.

Litter Productivity and Nutrient Return Characteristics of Three Typical Forest Stands in Golden Mountain

Objective: The paper aims to analyze the dynamic characteristics of litter production and nutrient return of the forest ecosystems in subtropical areas, and provide a theoretical basis for the nutrient cycling study in southwest Hubei Province and carbon sink function of the whole forest ecosystem. Methods: Three typical forest stands (Chinese fir plantation, Cryptomeria fortunei plantation and evergreen and deciduous broad-leaved mixed forest) in Golden Mountain Forest Farm in southwest Hubei Province were investigated and monitored continuously for the litter types and productivity and nutrient return. Results: The annual litter productivity of the three forest stands ranged from 161.77 to 396.26 kg·hm-2;Litters of branches, leaves and reproductive organs accounted for 14.14% - 20.85%, 33.26% - 78.33%, 7.52% - 42.18% of the total, respectively;The litter productivity and total litter productivity of each composition in the three forest stands show unimodal or bimodal changes over months, and the total litter productivity reached the highest value in January, April and October respectively. For different nutrient contents of the three forest stands, the common feature is C > N. The order of nutrient return amount from greatest to least is evergreen and deciduous broad-leaved mixed forest, Cryptomeria fortunei plantation and Chinese fir plantation. For different nutrient return amounts, the common feature is C > N, and the nutrient return amounts are 76.51-180.69 kg·hm-2 and 2.3 - 5.71 kg·hm-2 respectively. Conclusion: The annual litter productivity and nutrient return amount of the evergreen and deciduous broad-leaved mixed forest are the highest among the three forest stands. Therefore, protecting the evergreen and deciduous broad-leaved mixed forest and studying the litter changes of Chinese fir plantation and Cryptomeria fortunei plantation are of far-reaching significance for the development of sustainable forest management in this region and the further improvement of the carbon sequestration function of the whole forest ecosystem.

Effect of Forest Litter on the Regeneration of Larix sibirica: Insight from Aqueous Extract and Litter Coverage

The effect of litter on forest regeneration depends on the characteristics of regional climate and also shows community specificity. The influences of plant litter on seed germination and seedling growth of Larch Siberian forest in the Altai Mountains were investigated through two simulated experiments including litter coverage and litter aqueous extracts. In the litter coverage experiment, three litter coverage methods including above (D), below (S) and in the middle (Z) of litter were set with the litter coverage thickness of 0, 1, 2, and 4 cm, while two aqueous extract obtained methods using the air-dried litter and litter ash after fir were used with the concentration of 10%, 40%, 80% and 100% in the present study. Results showed that: the aqueous extracts obtained using the air-dried litter restrained the seed germination, while the aqueous extracts obtained using litter ash improved the seed germination. Compared with other litter concentration, the influences of 100% concentration reach highest. The seed germination rate, seed germination potential and vital index under the treatment of seeds above the litter coverage were highest, which were significantly higher than other treatments. The above-ground biomass was significantly higher and the inhibition index of below-ground bio-mass was significantly lower under the treatment of seed above the litter with thin litter cover-age (S1) compared to other litter coverage treatments. These results indicated that the litter aqueous extract and the litter coverage had a combined effect on the seed germination and seedling growth of Siberian larch forest. Fire disturbance could promote seed germination by modifying the adverse effects of litter aqueous extracts and litter coverage, and thus plays an important role in the regeneration of Siberian larch in the Altai Mountains.

Lightweight Surface Litter Detection Algorithm Based on Improved YOLOv5s

In response to the problem of the high cost and low efficiency of traditional water surface litter cleanup through manpower,a lightweight water surface litter detection algorithm based on improved YOLOv5s is proposed to provide core technical support for real-time water surface litter detection by water surface litter cleanup vessels.The method reduces network parameters by introducing the deep separable convolution GhostConv in the lightweight network GhostNet to substitute the ordinary convolution in the original YOLOv5s feature extraction and fusion network;introducing the C3Ghost module to substitute the C3 module in the original backbone and neck networks to further reduce computational effort.Using a Convolutional Block Attention Mechanism(CBAM)module in the backbone network to strengthen the network’s ability to extract significant target features from images.Finally,the loss function is optimized using the Focal-EIoU loss func-tion to improve the convergence speed and model accuracy.The experimental results illustrate that the improved algorithm outperforms the original Yolov5s in all aspects of the homemade water surface litter dataset and has certain advantages over some current mainstream algorithms in terms of model size,detection accuracy,and speed,which can deal with the problems of real-time detection of water surface litter in real life.

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.

Ecological stoichiometric comparison of plant-litter-soil system in mixed-species and monoculture plantations of Robinia pseudoacacia,Amygdalus davidiana,and Armeniaca sibirica in the Loess Hilly Region of China

We examined how afforestation patterns impact carbon(C),nitrogen(N),and phosphorus(P)stoichiometry in the plant-litter-soil system.Plant leaf,branch,stem,and root,litter,and soil samples were collected from mixedspecies plantations of Robinia pseudoacacia with Amygdalus davidiana(RPAD),R.pseudoacacia with Armeniaca sibirica(RPAS),and monocultures of R.pseudoacacia(RP),A.davidiana(AD),and A.sibirica(AS)in the Loess Hilly Region.The results showed that in mixed-species plantations,R.pseudoacacia had lower leaf N and P concentrations than in monocultures,while both A.davidiana and A.sibirica had higher leaf N and P concentrations.Soil P limited tree growth in both afforestation models.Mixing R.pseudoacacia with A.davidiana or A.sibirica reduced N-limitation during litter decomposition.Average soil total N and P concentrations were higher in RPAS than in RPAD,and both were higher than the corresponding monocultures.The average soil C:N ratio was the smallest in RPAS,while the average soil C:P ratio was larger in RPAS than in RP.A positive correlation between N and P concentrations,and between C:N and C:P ratios,was found in litter and all plant organs of mono-and mixedstands.Alternatively,for N concentration and C:N ratio,the correlations between plant(i.e.,leaf,branch,root)and litter and between plant and soil were inverse between plantation types.RPAD has an increased litter decomposition rate to release N and P,while RPAS has a faster rate of soil N mineralization.RPAD was the best plantation(mixed)to improve biogeochemical cycling,as soil nutrient restrictions,particularly for P-limitation,on trees growth were alleviated.This study thus provides insights into suitable tree selection and management by revealing C:N:P stoichiometry in the plant-litter-soil system under different afforestation patterns.

去除凋落物和草毡层对寒温带典型森林土壤活性有机碳的短期影响

[目的]探究去除凋落物和草毡层对寒温带森林土壤活性有机碳的影响,为我国寒温带森林土壤碳循环的研究提供科学参考。[方法]以大兴安岭北部3种典型森林(白桦林、樟子松林和兴安落叶松林)为研究对象,在3种林型中设置对照、去除凋落物、去除草毡层以及去除凋落物和草毡层4种处理,于2021年9月对各处理不同土层(0—10 cm和10—20 cm)土壤进行取样,研究其土壤活性有机碳组分及其影响因子。[结果]在0—10 cm土层,与对照相比,去除凋落物后土壤可溶性有机碳和易氧化有机碳含量在白桦林和樟子松林中无显著变化,而在兴安落叶松林中显著降低了25.49%和39.40%;土壤微生物量碳含量在白桦林和兴安落叶松林中显著降低了19.26%和18.86%,而在樟子松林中无显著变化。去除草毡层后土壤可溶性有机碳和易氧化有机碳含量在白桦林和樟子松林中显著降低了16.08%,60.69%和17.38%,17.33%,而在兴安落叶松林中的变化不显著;土壤微生物量碳含量在3种林型中显著降低了19.47%~42.02%。同时去除凋落物和草毡层后3种林型土壤微生物量碳和易氧化有机碳含量极显著降低了22.03%~27.01%和52.22%~57.01%;土壤可溶性有机碳含量降低了11.25%~22.18%,其中白桦林和樟子松林达显著水平;在10—20 cm土层,不同去除处理对3种林型土壤可溶性有机碳和微生物量碳含量均无显著影响,白桦林和樟子松林土壤易氧化有机碳含量分别在去除草毡层以及同时去除凋落物和草毡层后显著降低,而兴安落叶松林土壤易氧化有机碳含量无明显变化。3种林型土壤活性有机碳各组分与土壤总有机碳、全氮、含水量呈显著正相关,与土壤pH则呈显著负相关。[结论]去除凋落物和草毡层降低了土壤活性有机碳含量,凋落物和草毡层的存在有利于土壤活性有机碳的形成与累积。

How do international agreement constraints affect marine litter management strategies?A research based on differential game

Based on differential game theory,the decision-making problem of two homogeneous countries facing transboundary marine litter governance is studied.On the basis of assuming that the input of marine litter is an exogenous variable,the focus is on reducing the accumulation of marine litter through cleanup and transfer processing by both parties.Considering the constant and increasing input of marine litter,in the framework of international agreement constraints,the analysis of the game behavior of the players in the marine litter governance under the open-loop strategy(in the case of agreement constraints)and the Markov strategy(in the case of no agreement constraints)was compared and analyzed.The research results show that when the direct pollution cost of marine litter is high enough,both sides of the game adopt an open-loop strategy that complies with the constraints of the agreement,which can reduce the accumulation of marine litter and improve the environmental quality.However,when there is a high initial accumulation of marine litter,the Markov strategy without protocol constraints will be better than the open-loop strategy.In the case that marine litter does not need to be transferred,there will be no difference between the two sides of the game adopting the Markov strategy and adopting the open-loop strategy on the equilibrium growth path.

Effectiveness of Combined Biochar and Lignite with Poultry Litter on Soil Carbon Sequestration and Soil Health

Healthy soils are important to ensure satisfactory crop growth and yield. Poultry litter (PL), as an organic fertilizer, has proven to supply the soil with essential macro and micronutrients, enhance soil fertility, and improve crop productivity. Integrating this treatment has the potential to improve soil physical and biological properties by increasing soil carbon, C. However, rapid decomposition and mineralization of PL, particularly in the hot and humid southeastern U.S., resulted in losing C and reduced its effect on soil health. Biochar and lignite have been proposed to stabilize and mitigate C loss through application of fresh manure. However, their combined effects with PL on C sequestration and soil health components are limited. A field experiment was conducted on Leeper silty clay loam soil from 2017 to 2020 to evaluate the combined effect on soil properties when applying biochar and lignite with PL to cotton (Gossypium hirsutum L.). The experimental design was a randomized complete block involving nine treatments replicated three times. Treatments included PL and inorganic nitrogen, N, fertilizer with or without biochar and lignite, and an unfertilized control. Application rates were 6.7 Mgkg⋅ha−1 for PL, 6.7 Mgkg⋅ha−1 for biochar and lignite and 134 kg⋅ha−1 for inorganic N fertilizer. Integration of PL and inorganic fertilizer with biochar and lignite, resulted in greater soil infiltration, aggregate stability, plant available water, reduced bulk density and penetration resistance as compared to the sole applications of PL and inorganic fertilizer.

基于转录组测序分析猪子宫内膜妊娠中的关键非编码RNA及其调控通路

【目的】探究调控具有不同产仔数的川乡黑猪和藏猪的猪子宫内膜妊娠过程的相关miRNA、lncRNA及靶基因,进一步揭示影响不同品种猪子宫内膜妊娠相关非编码RNA富集的信号通路。【方法】对平均产仔数为11.35和6.70的川乡黑猪和藏猪第2、5胎次的子宫内膜进行分离,提取RNA,质检合格后进行转录组测序,测序数据经过拼接、比对到miRNA和lncRNA并预测其靶基因,进行GO和KEGG富集分析筛选到调控川乡黑猪和藏猪不同产仔数的候选基因以及信号富集通路。【结果】不同胎次的川乡黑猪和藏猪之间存在多个miRNA、lncRNA及靶基因的差异表达,其中第2胎次具有1571个miRNA和2042个lncRNA差异表达,第5胎次具有1042个miRNA和2096个lncRNA差异表达。进一步根据靶基因的GO和KEGG富集分析发现川乡黑猪在促性腺激素释放激素(GnRH)分泌、ECM受体互作以及Wnt信号通路等的富集程度高于藏猪。同时发现川乡黑猪相比藏猪有醛固酮调节钠重吸收、谷胱甘肽代谢、果糖和甘露糖代谢等过程的富集。此外,已鉴定的关键候选调控基因包括FSHR(Follicle stimulating hormone receptor)、DBX1(Developing brain homeobox 1)、ARID2(AT-rich interaction domain 2)、TNC(Tenascin C)、NT5C2(Neuropilin 2)、LAMC3(Laminin subunit gamma 3)、MADD(MAP kinase activating death domain)等。【结论】高产仔数的川乡黑猪相比低产仔数的藏猪在子宫内膜妊娠过程中有更高的促性腺激素释放激素(GnRH)分泌、ECM受体互作以及Wnt信号通路富集(GO分析结果),同时也有代谢途径的参与(KEGG分析结果)。涉及到的关键调控基因主要有FSHR、DBX1等。本研究为探究非编码RNA在猪子宫内膜妊娠过程中的功能及其分子调控机制提供了新的思路。

凋落物处理对华山松人工林土壤呼吸的影响

【目的】通过探讨凋落物添加和去除处理对土壤呼吸速率的影响,为人工林土壤碳库管理提供理论依据。【方法】以神农架林区华山松人工林为研究对象,2021年4月—2022年3月通过设置对照(CK)、凋落物去除(LR)和凋落物添加(LA)3种处理,采用Li-8100A土壤碳通量测量系统测定土壤呼吸速率和土壤温湿度,研究土壤呼吸速率对凋落物处理的响应规律。【结果】1)3种处理间的土壤温度和土壤含水量均无显著差异(P>0.05),土壤呼吸速率与土壤温度的变化趋势一致,最大值均出现在7月,最小值均出现在2月;2)3种处理下土壤呼吸速率的年平均值为LA(2.17μmol·m^(-2)·S^(-1))>CK(1.69μmol·m^(-2)·S^(-1))>LR(1.25μmol·m^(-2)·S^(-1)),与对照相比,凋落物去除使土壤呼吸速率年均降低了26.02%,凋落物添加使土壤呼吸速率年均提高了29.48%;3)不同凋落物处理的土壤呼吸速率与土壤温度均呈极显著正相关(P<0.01),土壤温度分别解释了3种处理下土壤呼吸速率97.31%、99.18%和95.37%的变异。而土壤呼吸速率与土壤含水量相关性不显著(P>0.05),华山松人工林土壤呼吸速率的主要影响因子是土壤温度;4)土壤呼吸温度敏感性指数(Q10)为CK(2.98)>LR(2.91)>LA(2.88),凋落物去除和添加处理均降低了土壤呼吸温度敏感性。【结论】凋落物输入量的改变对土壤呼吸速率具有重要影响,且不同处理方式对土壤呼吸影响程度不一致。

凋落物输入变化对黄河三角洲柽柳人工林土壤有机碳及其组分的影响

为探究凋落物输入变化对土壤有机碳库的影响,明确凋落物对森林生态系统土壤碳循环的作用,以黄河三角洲滨海盐碱地柽柳人工林为研究对象,通过设置添加凋落物(LA)、去除凋落物(LR)和对照(CK)3种处理方法,分析凋落物不同输入变化对土壤理化性质、土壤有机碳及其组分的影响。结果表明:凋落物添加和去除处理影响土壤理化性质的变化,与对照相比,添加凋落物降低了土壤密度和含盐量,增加了土壤含水量和养分(全氮、全磷、全钾),而去除凋落物则相反。3种处理对土壤有机碳(SOC)及其储量以及活性有机碳组分的影响一致,均表现为LA处理影响最大,LR处理影响最小,其中LA处理比CK增加了SOC质量分数及储量,但增加不显著;LR处理则显著降低了SOC质量分数及其储量,土层深度(d)0<d≤10 cm土层,LR处理比CK处理的SOC质量分数及其储量分别显著降低了34.93%、12.66%,10 cm<d≤20 cm土层,LR处理比CK处理的SOC质量分数及其储量分别显著降低了24.27%、16.13%。LA处理的土壤SOC及可溶性有机碳(DOC)、易氧化有机碳(EOC)、微生物量碳(MBC)质量分数均出现明显的表聚现象,而LR处理影响则不显著,且DOC和MBC则出现随土层深度增加而增大的趋势。土壤惰性有机碳(ROC)质量分数在不同土层间存在差异,0<d≤10 cm土层,各处理表现为LA>CK>LR,10 cm<d≤20 cm土层,各处理则表现为CK>LA>LR,而在CK和LR处理出现随土层增加而增加的趋势,偏于向土层下方积累。土壤密度(BD)与SOC及其各组分呈负相关,而土壤含水量(WC)、全氮、全磷与SOC及EOC、MBC、DOC质量分数呈极显著正相关(P<0.01)。因此,不同处理方式及不同土层深度的土壤密度、全氮质量分数和土壤含水量是影响SOC及组分变化的主要环境因子。

东北槭属植物凋落叶对东北槭生长的影响及其化感作用初探

为解决东北槭小苗生长缓慢成材周期长,寻求促进其生长的途径,采用温室培养的方法,以一年生东北槭小苗为受体,通过高生长量、叶长、叶宽、冠幅、地上鲜重、地下鲜重及叶绿素含量、POD活性的测定,研究茶条槭、元宝槭凋落叶及假色槭和东北槭混合凋落叶粉碎物对东北槭小苗生长的影响。结果表明,茶条槭凋落叶对东北槭表现出了“低促高抑”的化感作用,当添加量最大120g/10kg时,小苗受到抑制。元宝槭凋落叶添加量最大时各指标促进作用显著,东北槭高生长量增加了1倍。混合凋落叶对东北槭生长无明显作用。

微生物发酵床养猪垫料研制番茄育苗基质的效果分析

为了实现废弃资源的资源化利用,使用微生物发酵床养猪垫料研制番茄育苗基质,选取使用1年的微生物发酵床养猪垫料,提取其浸提液并稀释成不同浓度,以番茄种子萌发情况为指标,筛选基质中垫料适宜添加量,并通过穴盘育苗试验确定基础基质配方,进一步优化N、P、K用量,最终确定番茄育苗基质配方。结果表明:利用微生物发酵床养猪垫料研制番茄育苗基质的配方为垫料︰椰糠=3︰7(体积比),N用量0.3 kg·m^(−3)、P用量0.2 kg·m^(−3)、K用量0.1 kg·m^(−3);用该基质进行番茄育苗,出苗率达98%,幼苗的株高、茎粗、根长均显著优于市售草炭基质(对照);所繁育的幼苗移栽田间种植,其田间番茄苗的株高和挂果数均显著优于对照。番茄育苗基质的研制可实现微生物发酵床养猪垫料的资源化利用。

不同温度下4种速生树种凋落叶的浸泡分解特性

[目的]了解树种和温度对速生树种凋落叶浸泡后分解特性的影响,以预测气候变化背景下速生树种的生态功能响应。[方法]以4种南方常见速生树种(松树、杉木、桉树、红锥)凋落叶为研究对象,分别在常温、20℃、35℃下浸泡22 d,并比较了4种凋落叶浸泡液的总磷、总氮、腐殖酸、单宁酸、COD含量和浊度、电导率、pH等。[结果]温度显著影响4种速生树种凋落叶浸泡液浊度的变化(P<0.05)。浸泡22 d,桉树凋落叶分解对浸泡液单宁酸含量、腐殖酸含量、pH等指标的影响大于其他树种。其中,桉树凋落叶浸泡液单宁酸含量为1407.84 mg·L^(-1),分别是松树、杉木、红锥的12、14、4倍;腐殖酸溶出量为871.40 mg·L^(-1),分别是松树、杉木、红锥的15、14、12倍;pH值保持在4.35~4.46之间,低于其他树种。[结论]松树、杉木、桉树和红锥凋落叶浸泡液浊度主要受温度影响,其余指标的变化均随树种不同而各有差异。常温比恒温条件更能促进桉树凋落叶浸泡液单宁酸的溶出,进而导致浸泡液pH值降低。

2010–2020年塔里木盆地南部荒漠草地凋落物回收量月动态数据集

中国科学院新疆策勒荒漠草地生态系统国家野外科学观测研究站(以下简称“策勒站”)地处塔里木盆地南缘,南依昆仑山,北临我国最大的塔克拉玛干沙漠。具有植被群落简单,土壤有机质积累缓慢等特点。凋落物是该区域重要的养分来源。基于对策勒站荒漠植物群落的长期定位观测,通过对不同植物凋落物器官(枝、叶、果)分组,本文整理统计得到2010–2020年塔里木盆地南部荒漠草地凋落物的回收量月动态数据,同时记载了观测场群落以及土壤养分的年度变化情况。数据的产生严格遵照CERN生物观测规范执行,数据的审核及质量控制由台站与分中心质控人员共同完成。本数据集以期为深入研究塔里木盆地南部荒漠草地凋落物动态变化提供基础数据,为了解和评估极端干旱荒漠生态系统养分循环过程提供理论支撑。

滇中地区主要森林凋落物有效截留量及其影响因素

[目的]研究滇中地区主要森林类型凋落物有效截留量差异及其影响因素,为该地未来植被恢复和森林管理提供科学支撑。[方法]利用样方调查法、烘干法和浸泡法分析了昆明市双河—磨南德水源林自然保护区内的地带性次生常绿阔叶林(SF)、针阔混交林(TF)、旱冬瓜林(ACF)、华山松林(PA)、成熟云南松林(OPY)、幼龄云南松林(YPY)、银荆林(AD)7种主要森林类型凋落物未分解层(OL)和半分解层(OF)的有效截留量及其影响因素。[结果](1) 7种森林类型凋落物厚度为2.06~7.57 cm,其中OL层1.10~4.30 cm, OF层0.83~3.93 cm,凋落物层厚度排序为TF>ACF>PA>OPY>SF>AD>YPY,凋落物蓄积量为4.75~17.45 t/hm^(2),其中OL层占比为32.02%~62.48%,OF层占比为37.52%~67.98%,凋落物层蓄积量排序为TF>PA>SF>OPY>ACF>AD>YPY。(2)凋落物最大持水率为115.3%~170.7%,初始吸水速率为3.65~5.62 g/(g·h),凋落物持水率和浸水时间的关系可用对数函数y=aln(x)+b表示,吸水速率与浸水时间可用幂函数y=kt~n表示。(3)凋落物最大持水量为7.05~32.19 t/hm^(2),排序为PA>TF>SF>OPY>ACF>AD>YPY,有效截留量为5.45~25.34 t/hm^(2),以TF最高(25.34t/hm^(2)),PA(24.99 t/hm^(2))和SF(24.62 t/hm^(2))次之,YPY最低(5.45t/hm^(2)),影响有效截留量的场地特征主要为蓄积量、自然含水率、分解强度以及厚度,影响有效截留量的水动力过程主要是最大失水量、前6.0 h平均吸水速率和前2.0 h平均吸水速率。[结论]滇中地区未来植树造林应以针阔混交林为主,注重对地带性次生常绿阔叶林的保育,采取辅助自然更新的措施促进人工纯林向混交林演化,同时减少踩踏、收集凋落物等人类活动的干扰,从而增加森林生态系统凋落物的水源涵养能力。

绒毛皂荚特定森林环境育苗技术组合与常规育苗对比试验

[目的]提高绒毛皂荚场地发芽率,加速种群回归。[方法]在特定的森林环境进行育苗技术组合试验,并以苗圃常规育苗为对照,研究不破坏林地环境的小铲破土和地表播种+死地被物多种覆盖方式技术组合对发芽率与苗木生长的影响。[结果]小铲破土播种或地表播种加4种不同死地被物覆盖方式技术组合的场地发芽率分别为(A_(1))61.67%、(A_(2))55.56%、(A_(3))61.11%、(A_(4))57.22%,均高于常规育苗(CK)的35.03%;A_(1)小铲破土播种后,盖1 cm厚表层有机土+3 cm厚粗腐殖质+未分解的枯枝落叶组合和A_(3)种子直播土壤地表后,盖3 cm厚的粗腐殖质+未分解枯枝落叶同为最佳组合;常规育苗的苗木成苗率(成苗数与发芽数之比×100%)与苗木生长量略高于其他处理;但从成苗数的绝对数比较,CK小于A_(1)、A_(2)、A_(3)、A_(4)处理的106、85、95和88株。[结论]特定的森林环境母树下小铲破土或地表播种后+林地死地被物覆盖组合育苗是提高场地发芽率和成苗数的有效方法。