We estimated the effect of three crop strategies on soil health based on 63 functional genes in long-term fields.The keystone microbial phylotypes support the agroecosystem sustainability.Rotation management thrives k...We estimated the effect of three crop strategies on soil health based on 63 functional genes in long-term fields.The keystone microbial phylotypes support the agroecosystem sustainability.Rotation management thrives keystone phylotypes and soil functions.Rotation with soybean is beneficial for the subsequent crops.Given the often-independent study of microbial diversity and function,the comprehensive impact of various cropping patterns on both aspects,as well as the interconnections between them,remains unclear.This gap constrains us from evaluating the impact of soil microbiome shifts on soil health across varying agricultural management regimes.Here,we examined the associations between microbial diversity and soil multifunctionality in three long-term cropping patterns:continuous soybean cropping,soybeancorn rotation,and continuous corn cropping.We targeted 63 functional genes associated with carbon,nitrogen,phosphorus and sulfur cycling to assess soil multifunctionality.Our study demonstrated that the biodiversity and interactions of keystone phylotypes had significant positive associations with multiple soil functional genes,such as organic carbon degradation and fixation,nitrogen fixation and phosphorus solubilization.The analysis of retrieved complete genome revealed that the keystone bacteria identified in our study harbored these functional genes.Moreover,these keystone phylotypes showed associations with the dissipation of herbicide residues.Above all,we revealed that rotation of soybean with corn cropping enhanced a greater diversity of keystone phylotypes and thus fueled soil functions.Collectively,our results highlighted the importance of rotation with soybean in maintaining soil health,which could give a mechanism-based guidance for a sustainable agroecosystem.展开更多
To better understand the effects of ground-level ozone(O_(3))on nutrients and stoichiometry in different plant organs,urban tree species Celtis sinensis,Cyclocarya paliu-rus,Quercus acutissima,and Quercus nuttallii we...To better understand the effects of ground-level ozone(O_(3))on nutrients and stoichiometry in different plant organs,urban tree species Celtis sinensis,Cyclocarya paliu-rus,Quercus acutissima,and Quercus nuttallii were sub-jected to a constant exposure to charcoal-filtered air(CF),nonfiltered air(NF),or NF+40,60,or 80 nmol O_(3)mol^(-1)(NF40,NF60,and NF80)starting early in the summer of the growing season.At the end of summer,net CO_(2)assimila-tion rate(A),stomatal conductance(gs),leaf mass per area(LMA),and/or leaf greenness(SPAD)either were not sig-nificantly affected by elevated O_(3)or were even higher in some cases during the summer compared with the CF or NF controls.LMA was significantly lower in autumn only after the highest O_(3)exposures.Compared to NF,NF40 caused a large increase in gs across species in late summer and more K and Mn in stems.At the end of the growing season,nutri-ent status and stoichiometric ratios in different organs were variously altered under O_(3)stress;many changes were large and often species-specific.Across O_(3)treatments,LMA was primarily associated with C and Mg levels in leaves and Ca levels in leaves and stems.NF40 enriched K,P,Fe,and Mn in stems,relative to NF,and NF60 enhanced Ca in leaves relative to CF and NF40.Moreover,NF resulted in a higher Ca/Mg ratio in leaves of Q.acutissima only,relative to the other O_(3)regimes.Interestingly,across species,O_(3)stress led to different nutrient modifications in different organs(stems+branches vs leaves).Thus,ambient and/or elevated O_(3)exposures can alter the dynamics and distribution of nutrients and disrupt stoichiometry in different organs in a species-specific manner.Changes in stoichiometry reflect an important defense mechanism in plants under O_(3),and O_(3)pollution adds more risk to ecological stoichiometries in urban areas.展开更多
The responses of ecosystem nitrogen (N) and phosphorus (P) to drought are an important component of globalchange studies. However, previous studies were more often based on site-specific experiments, introducing a sig...The responses of ecosystem nitrogen (N) and phosphorus (P) to drought are an important component of globalchange studies. However, previous studies were more often based on site-specific experiments, introducing a significantuncertainty to synthesis and site comparisons. We investigated the responses of vegetation and soil nutrientsto drought using a network experiment of temperate grasslands in Northern China. Drought treatment (66%reduction in growing season precipitation) was imposed by erecting rainout shelters, respectively, at the driest,intermediate, and wettest sites. We found that vegetation nutrient concentrations increased but soil nutrient concentrationsdecreased along the aridity gradient. Differential responses were observed under experimentaldrought among the three grassland sites. Specifically, the experimental drought did not change vegetation andsoil nutrient status at the driest site, while strongly reduced vegetation but increased soil nutrient concentrationsat the site with intermediate precipitation. On the contrary, experimental drought increased vegetation N concentrationsbut did not change vegetation P and soil nutrient concentrations at the wettest site. In general, the differentialeffects of drought on ecosystem nutrients were observed between manipulative and observationalexperiments as well as between sites. Our research findings suggest that conducting large-scale, consistent, andcontrolled network experiments is essential to accurately evaluate the effects of global climate change on terrestrialecosystem bio-geochemistry.展开更多
The environmental problems in the Bohai Sea have become more serious in the last decade. High nutrient concentration contributes much to it. A Sino-German cooperation program has been carried out to improve the unders...The environmental problems in the Bohai Sea have become more serious in the last decade. High nutrient concentration contributes much to it. A Sino-German cooperation program has been carried out to improve the understanding of the ecosystem by observations and modelling. A three-dimensional ecosystem model, coupled with a physical transport model, is adopted in this study. The simulation for the year 1982 is validated by the data collected in 1982/1983. The simulated annual mean nutrient concentrations are in good agreement with observations. The nutrient concentrations in the Bohai Sea, which are crucial to the algal growth, are high in winter and low in summer. There are depletion from spring to summer and elevation from autumn to winter for nutrients. The nutrients’ depletion is a response to the consumption of the phytoplankton bloom in spring. Internal recycle and external compensation affect the nutrient cycle. Their contributions to the nutrient budgets are discussed based on the simulated results. Production and respiration are the most important sink and source of nutrients. The process of photosynthesis consumes 152 kilotons-P and 831.1 kilotons-N while respiration releases 94.5 kilotons-P and 516.6 kilotons-N in the same period. The remineralization of the detritus pool is an important source of nutrient regene- ration. It can compensate 23 percent of the nutrient consumed by the production process. The inputs of phosphates and nitrogen from rivers are 0.55 and 52.7 kilotons respectively. The net nutrient budget is -3.05 kilotons-P and 31.6 kilotons-N.展开更多
Litterfall is the largest source of nutrients to for-est soils of tropical rainforests.However,variability in lit-terfall production,nutrient remobilization,and changes in leaf nutrient concentration with climate seas...Litterfall is the largest source of nutrients to for-est soils of tropical rainforests.However,variability in lit-terfall production,nutrient remobilization,and changes in leaf nutrient concentration with climate seasonality remain largely unknown for the central Amazon.This study meas-ured litterfall production,leaf nutrient remobilization,and leaf area index on a forest plateau in the central Amazon.Litterfall was measured at monthly intervals during 2014,while nitrogen,phosphorus,potassium,calcium and mag-nesium concentrations of leaf litter and canopy leaves were measured in the dry and rainy seasons,and remobilization rates determined.Leaf area index was also recorded in the dry and rainy seasons.Monthly litterfall varied from 33.2(in the rainy season)to 87.6 g m^(-2) in the dry season,while leaf area index increased slightly in the rainy season.Climatic seasonality had no effect on concentrations of nitrogen,calcium,and magnesium,whereas phosphorous and potassium responded to rainfall seasonality oppositely.While phosphorous increased,potassium decreased during the dry season.Over seasons,nitrogen,potassium,and phosphorous decreased in leaf litter;calcium increased in leaf litter,while magnesium remained unaffected with leaf aging.Regardless,the five nutrients had similar remobilization rates over the year.The absence of climate seasonality on nutrient remobilization suggests that the current length of the dry season does not alter nutrient remobilization rates but this may change as dry periods become more prolonged in the future due to climate change.展开更多
In recent years,interest in the larvae of black soldier fly(BSF)(Hermetia illucens)as a sustainable protein resource for livestock feed has increased considerably.However,knowledge on the nutritional and physiological...In recent years,interest in the larvae of black soldier fly(BSF)(Hermetia illucens)as a sustainable protein resource for livestock feed has increased considerably.However,knowledge on the nutritional and physiological aspects of this insect,especially compared to other conventional farmed animals is scarce.This review presents a critical comparison of data on the growth potential and efficiency of the BSF larvae(BSFL)compared to conventional monogastric livestock species.Advantages of BSFL over other monogastric livestock species includes their high growth rate and their ability to convert low-grade organic waste into high-quality protein and fat-rich biomass suitable for use in animal feed.Calculations using literature data suggest that BSFL are more efficient than broilers,pigs and fish in terms of conversion of substrate protein into body mass,but less efficient than broilers and fish in utilization of substrate gross energy to gain body mass.BSFL growth efficiency varies greatly depending on the nutrient quality of their dietary substrates.This might be associated with the function of their gastrointestinal tract,including the activity of digestive enzymes,the substrate particle characteristics,and their intestinal microbial community.The conceived advantage of BSFL having an environmental footprint better than conventional livestock is only true if BSFL is produced on low-grade organic waste and its protein would directly be used for human consumption.Therefore,their potential role as a new species to better close nutrient cycles in agro-ecological systems needs to be reconsidered,and we conclude that BSFL is a complementary livestock species efficiently utilizing organic waste that cannot be utilized by other livestock.In addition,we provide comparative insight into morpho-functional aspects of the gut,characterization of digestive enzymes,gut microbiota and fiber digestion.Finally,current knowledge on the nutritional utilization and requirements of BSFL in terms of macro-and micronutrients is reviewed and found to be rather limited.In addition,the research methods to determine nutritional requirements of conventional livestock are not applicable for BSFL.Thus,there is a great need for research on the nutrient requirements of BSFL.展开更多
Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The ...Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The wetland zone covered with Picea glehnii pure stand. The riparian zone was deciduous broad-leaved stand dominated by Alnus hirsuta and Salix spp., while the mixture of deciduous broadleaf and evergreen conifer dominated by Betula platyphylla, Quercus crispula and Abies sachalinensis distributed on the upland zone. Annual litterfall averaged 1444, 5122, and 4123 kg.hm^-2·a^-1 in the wetland, riparian and upland zones, respectively. Litterfall production peaked in September-October, and foliage litter contributed the greatest amount （73.4%-87.6 %） of the annual total litterfall. Concentrations of nutrients analyzed in foliage litter of the dominant species showed a similar seasonal variation over the year except for N in P glehnii and A. hirsuta. The nutrient fluxes for all elements analyzed were greatest on riparian zone and lowest in wetland zone. Nutrient fluxes via litterfall followed the decreasing sequence： N （11-129 kg.hm-2.aq） 〉 Ca （9-69） 〉 K （5-20） 〉 Mg （3-15） 〉 P （0.4-4.7） for all stands. Significant differences were found in litterfall production and nutrient fluxes among the different landscape components. There existed significant differences in soil chemistry between the different landscape zones. The consistently low soil C：N ratios at the riparian zone might be due to the higher-quality litter inputs （largely N-fixing alder）.展开更多
Coffee cultivation by using shade trees is simple of agroforestry, this system could get better ecosystem service and sustainable agricultural. The aims of this research are to study the possibility of some species of...Coffee cultivation by using shade trees is simple of agroforestry, this system could get better ecosystem service and sustainable agricultural. The aims of this research are to study the possibility of some species of industrial woods as shade trees of Coffea canephora. The research was conducted in Jember, Indonesia （45 m asl., D rainfall type according to Schmidt and Ferguson）, and arranged in split plot design. The main plots were （A） coffee-T, grandis （3 m × 2.5 m ×12 m）, （B） coffee-P, falcataria single row （2.5 m ×6 m）, （C） coffee-P, falcataria double rows （3 m× 2.5 m × 12 m）, （D） coffee-P, falcataria vat. Solomon （3 m× 2.5 m × 12 m）, （E） coffee-M, azedarach （3 m ×5 m ×22.5 m）, （F） coffee-H, macrophyllus （3 m ×5 m ×12.5 m）, and （G） coffee-Leucaena sp. （3 m × 2.5 m） as control. The sub plots were coffee clones, i.e., BP 534, BP 409, BP 936, dan BP 939. Among those timber trees, Leucaena was planted as the alternative shade trees. The result showed that in comparison with control, all of coffee agroforestry system improved carbon sequestration. Total C-stock on （B） was highest, i.e., 1,007 percent to control while the lowest one was （A） 317.44% to control. During one year observation, litter weight of H. macrophyllus was heaviest followed by T. grandis. The lightest litter was obtained from M. azedarach. Based on its mineral contents, litters of T. grandis potentially supplied back nutrients that equaled to total Urea, SP-36, KC1, Dolomite, and Kieserite as much as 574.14 g; P. falcataria 287.57 g, P. falcataria var. Solomon 453.59 g, M. azedarach 450.84 g, H. macrophyllus 877.56 g, and Leucaena 445.12 g per tree per year. Because of heavily fallen leaves of M. azedarach during dry season and conversely too dense shading of H. macrophyllus, bean yield at 4 and 5 years old by using both species were consistently lower than that under T. grandis, P. falcataria and control. At those ages, effect of clone on cherry yield was still not consistent but there was a tendency that BP 939 was most productive, while BP 534 was the less. Its outturn was not influenced by agroforestry system but by clones. The agroforestry pattern influence physical bean characters, more dense of shading, more single bean and empty bean. That bean abnormality also genetically, on BP 939 percentage of round and empty bean was highest while on BP 936 was lowest. It was concluded that coffee agroforestry improve ecology service, but M. azedarach and H. macrophyllus were not appropriate to be used as coffee shade trees. P. falcataria is recommended as an alternative shade tree beside Leucaena sp.展开更多
Biomass production and nutrient （N, P, K, Ca and Mg） accumulation, distribution and cycling were quantified in young, mature and over-mature （10-, 22-, and 34-year old） Chinese fir [Cunninghamia lanceolate （Lamb....Biomass production and nutrient （N, P, K, Ca and Mg） accumulation, distribution and cycling were quantified in young, mature and over-mature （10-, 22-, and 34-year old） Chinese fir [Cunninghamia lanceolate （Lamb.） Hook] plantations in southern China. Total stand biomass of young, mature and over-mature stands was 38, 104 and 138 t ha-1 respectively. Biomass production increased significantly with age. Stem wood represented the highest percentage of stand biomass, accounting for 41, 55 and 63 % in the young, mature and over-mature plan- tations respectively. Nutrients concentration was highest in live needles and branches, and lowest in stem wood. The plantations accumulated more N, followed by K, Ca, Mg, and P. Nutrient return amount, nutrient utilization effi- ciency, nutrient turnover time, the ratio of nutrient return and uptake increased with stand age, which implies that young Chinese fir deplete soil nutrients to maintain growth, and efficiently utilize nutrients to decrease dependence on soil nutrients as they age. Harvesting young Chinese fir plantations would therefore lead to high nutrient loss, but prolonging the rotation length could improve soil recovery, and help sustain productivity in the long-term. Improved nutrient return through litterfall as stands get older may also be beneficial to nutrient pool recovery.展开更多
An experiment was conducted in a red soil derived from Quaternary red clay in the Ecological ExperimentStation of Red Soil, the Chinese Academy of Sciences, located in Yingtan (28° 15′ 30″ N, 116° 55′ 30...An experiment was conducted in a red soil derived from Quaternary red clay in the Ecological ExperimentStation of Red Soil, the Chinese Academy of Sciences, located in Yingtan (28° 15′ 30″ N, 116° 55′ 30″E), Jiangxi Province. The results show that the major ways of nutrient loss are leaching and nitrogenvolatilization. Rationalizing crop distribution, stimulating nutrient recycling, and improving internal nutrientflow are effective measures to decrease nutrient loss and to promote nutrient utilization efficiency. Theimportant ways of regulating nutrient cycling and balance in the agroecosystem of the red soil are to establishoptimal eco-agricultural models, practice balanced fertilization and combine the cropping system with thelivestock system.展开更多
In this paper, the biomass productivity and nutrient cycling in an agroforestry system of coconut (Cocus nucifera) interplanted with pineapple (Ananas comosus) had been studied. The result showed that the biomass prod...In this paper, the biomass productivity and nutrient cycling in an agroforestry system of coconut (Cocus nucifera) interplanted with pineapple (Ananas comosus) had been studied. The result showed that the biomass productivity of this ecosystem was 47 460 kg...hm2...a?1, which was 4.3 times as much as that of pure coconut plantation. In the biological cycling of N, P. K elements, the total annual retention was 559.470 kg...hm?2, the annual return was 410.745 kg...hm?2, the annual uptake was 970.475 kg...hm?2, respectively. The average circulation rate in three nutrient elements (N, P, K) was 42.32%, which was 27.53% more than that in pure coconut stands. Coconut interplanted with pineapple was proved to be one of optimum cultural patterns, which had the higher biomass productivity, and better usage efficiency of environment resources in tropical areas.展开更多
The nutrient cycling model NuCM is one of the most detailed models for simulating processes that influence nutrient cycling in forest ecosystems. A field study was conducted at Tieshanping, a Masson pine (Pinus masson...The nutrient cycling model NuCM is one of the most detailed models for simulating processes that influence nutrient cycling in forest ecosystems. A field study was conducted at Tieshanping, a Masson pine (Pinus massoniana Lamb.) forest site, in Chongqing, China, to monitor the impacts of acidic precipitation on nutrient cycling. NuCM simulations were compared with observed data from the study site. The model produced an approximate fit with the observed data. It simulated the mean annual soil solution concentrations in the two simulation years, whereas it sometimes failed to reproduce seasonal variation. Even though some of the parameters required by model running were measured in the field, some others were still highly uncertain and the uncertainties were analyzed. Some of the uncertain parameters necessary for model running should be measured and calibrated to produce a better fit between modeled results and field data.展开更多
At a global scale, tree growth in alpine treeline ecotones is limited by low temperatures. At a local scale, however, tree growth at its upper limit depends on multiple interactions of influencing factors and mechanis...At a global scale, tree growth in alpine treeline ecotones is limited by low temperatures. At a local scale, however, tree growth at its upper limit depends on multiple interactions of influencing factors and mechanisms. The aim of our research was to understand local scale effects of soil properties and nutrient cycling on tree growth limitation, and their interactions with other abiotic and biotic factors in a near-natural Himalayan treeline ecotone. Soil samples of different soil horizons, litter, decomposition layers, and foliage samples of standing biomass were collected in four altitudinal zones along three slopes, and were analysed for exchangeable cations and nutrient concentrations, respectively. Additionally, soil and air temperature, soil moisture, precipitation, and tree physiognomy patterns were evaluated. Both soil nutrients and foliar macronutrient concentrations of nitrogen(N), magnesium(Mg), potassium(K), and foliar phosphorus(P) decrease significantly with elevation. Foliar manganese(Mn) concentrations, bycontrast, are extraordinarily high at high elevation sites. Potential constraining factors on tree growth were identified using multivariate statistical approaches. We propose that tree growth, treeline position and vegetation composition are affected by nutrient limitation, which in turn, is governed by low soil temperatures and influenced by soil moisture conditions.展开更多
Background:In contrast with the negligible contribution of the forest understorey to the total aboveground phytobiomass of a forest,its share in annual litter production and nutrient cycling may be more important.Whet...Background:In contrast with the negligible contribution of the forest understorey to the total aboveground phytobiomass of a forest,its share in annual litter production and nutrient cycling may be more important.Whether and how this functional role of the understorey differs across forest types and depends upon overstorey characteristics remains to be investigated.Methods:We sampled 209 plots of the FunDivEUROPE Exploratory Platform,a network of study plots covering local gradients of tree diversity spread over six contrasting forest types in Europe.To estimate the relative contribution of the understorey to carbon and nutrient cycling,we sampled non-lignified aboveground understorey biomass and overstorey leaf litterfall in all plots.Understorey samples were analysed for C,N and P concentrations,overstorey leaf litterfall for C and N concentrations.We additionally quantified a set of overstorey attributes,including species richness,proportion of evergreen species,light availability(representing crown density)and litter quality,and investigated whether they drive the understorey’s contribution to carbon and nutrient cycling.Results and conclusions:Overstorey litter production and nutrient stocks in litterfall clearly exceeded the contribution of the understorey for all forest types,and the share of the understorey was higher in forests at the extremes of the climatic gradient.In most of the investigated forest types,it was mainly light availability that determined the contribution of the understorey to yearly carbon and nutrient cycling.Overstorey species richness did not affect the contribution of the understorey to carbon and nutrient cycling in any of the investigated forest types.展开更多
Shifts in tree species and their mycorrhizal associations driven by global change play key roles in biogeochemical cycles. In this paper, we proposed a framework of the mycorrhizal-associated nutrient economy(MANE), a...Shifts in tree species and their mycorrhizal associations driven by global change play key roles in biogeochemical cycles. In this paper, we proposed a framework of the mycorrhizal-associated nutrient economy(MANE), and tested it using nutrient addition experiments conducted in two tropical rainforests. We selected two tropical rainforests dominated by arbuscular mycorrhizal(AM) and ectomycorrhizal(ECM) trees, and established eighteen20 m×20 m plots in each rainforest. Six nitrogen(N) and phosphorus(P) addition treatments were randomly distributed in each rainforest with three replicates. We examined the differences in soil carbon(C) and nutrient cycling, plant and litter productivity between the two rainforests and their responses to 10-year inorganic N and P additions. We also quantified the P pools of plants, roots, litter, soil and microbes in the two rainforests. Overall,distinct MANE frameworks were applicable for tropical rainforests, in which soil C, N and P were cycled primarily in an inorganic form in the AM-dominated rainforest, whereas they were cycled in an organic form in the ECMdominated rainforest. Notably, the effects of mycorrhizal types on soil P cycling were stronger than those on C and N cycling. The intensified N and P deposition benefited the growth of AM-dominated rainforests instead of ECMdominated rainforests. Our findings underpin the key role of mycorrhizal types in regulating biogeochemical processes, and have important implications for predicting the ecological consequences of global changes.展开更多
The stoichiometry of carbon,nitrogen and phosphorous in plants can reflect the interactions between plants and their environment.The interplay between plant nutrients,climatic factors,and soil properties and the under...The stoichiometry of carbon,nitrogen and phosphorous in plants can reflect the interactions between plants and their environment.The interplay between plant nutrients,climatic factors,and soil properties and the underlying regulatory mechanisms are pillars of ecology but remain underexplored.In this study of plant C-N-P stoichiometry and nutrient resorption in Castanopsis hystrix groves in three cities(Guangzhou,Zhongshan,and Lechang)that represent an urban-rural gradient in Guangdong Province,South China,we explored potential relationships among NO_(2) concentrations,diameter at breast height(DBH),and resident human population.Mean annual temperature,mean annual precipitation,insolation duration per year,and the human resident population differed significantly among the three cities.Soil C-N-P was always highest in suburban Lechang,and the concentration of NO_(2) was highest in urban Guanghzou(55.33±0.67μg m^(-3))and positively correlated with the resident population and leaf N:P.Our findings suggest that C-N-P stoichiometry of C.hystrix was better explained by NO_(2)than by soil C-N-P stoichiometry and that nutrient resorption was better explained by leaf nutrients and DBH than by NO_(2) and soil stoichiometry.Our study supports the hypothesis that rapid urbanization influences NO_(2) concentrations and microclimate,which may jointly change the stoichiometry of plant nutrients in the forest ecosystems.展开更多
The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest which is the most common forest type in the Three Gorge Reservoir areas in China,...The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest which is the most common forest type in the Three Gorge Reservoir areas in China, were systematically analyzed. The results showed that N, P and K accumulated in the plant pool and in the litter pool, while total N, P, and K were deficient in the soil pool and in the forest systems. Contents of N in the soil of depth 20—40 cm were the key factor limiting growth of trees. The biological outside cycling coefficients were 878, 725 and 117 times of inside cycling coefficients of N, P and K, respectively. 3392, 1026 and 1588 kg of N, P and K return to the litter pool from branches, leaves and throughfall per year, but, 1431, 132 and 1048 kg of N, P and K return to the soil from litter pool per year respectively. It is clear that 58% of N, 87% of P, and 34% of K are lost by surface runoff per year. 549%, 130%, and 834% of N, P and K withdraw from leaves to branches, 499%, 199% and 730% of N, P and K withdraw from branches to trunks per year, respectively.展开更多
In Uruguay, <em>Pinus taeda</em> is usually planted a few months after harvest of the former turn, therefore;decomposing residues represents a nutrient source for the new plantation. The aim of this study ...In Uruguay, <em>Pinus taeda</em> is usually planted a few months after harvest of the former turn, therefore;decomposing residues represents a nutrient source for the new plantation. The aim of this study was to determine the biomass and nutrient extraction off site, following the harvest of a <em>P. taeda</em> plantation. Residue decomposition patterns, and nutrient release were also examined. The site will be referred as S1, corresponding to the clear cut of a 22-year-old <em>P. taeda</em> plantation. Before the clear cut 10 trees were harvested, and logs, branches, twigs, and needles separately weighed. Additionally, forest litter at harvest time was quantified in three different areas. To assess decomposition, mesh bags with residues were allocated in three areas over the forest litter, and samples were taken periodically for 26 months. The remaining biomass, N, P K, Ca, and Mg contents were determined in the different fractions, calculating decompositon rates. Most of the harvested biomass was removed in logs, but the proportion of nutrients exported was considerably lower. Needles showed the highest biomass loss and only 39.1% remained after 26 months, while branches presented high rates in the first two months after cut, but slower thereafter, and at the end of the study more than two thirds of the woody residues remained. Potassium was rapidly released from the residues, while Ca, and Mg, were slowly released, and there was evidence of N and P immobilization in the early stages of decomposition. It was concluded that, although a lower proportion of nutrients were exported, compared to biomass, in the long term, nutrient export with logs could be significant for the sustainability of this production system. While K release from residues did not depend on biomass decay, the slow decomposition, and release of the other nutrients, indicates that this process could have been delayed by nutrient scarcity.展开更多
Background:Nitrogen(N)deposition affects forest stoichiometric flexibility through changing soil nutrient availability to influence plant uptake.However,the effect of N deposition on the flexibility of carbon(C),N,and...Background:Nitrogen(N)deposition affects forest stoichiometric flexibility through changing soil nutrient availability to influence plant uptake.However,the effect of N deposition on the flexibility of carbon(C),N,and phosphorus(P)in forest plant-soil-microbe systems remains unclear.Methods:We conducted a meta-analysis based on 751 pairs of observations to evaluate the responses of plant,soil and microbial biomass C,N and P nutrients and stoichiometry to N addition in different N intensity(050,50–100,>100 kg·ha^(-1)·year^(-1)of N),duration(0–5,>5 year),method(understory,canopy),and matter(ammonium N,nitrate N,organic N,mixed N).Results:N addition significantly increased plant N:P(leaf:14.98%,root:13.29%),plant C:P(leaf:6.8%,root:25.44%),soil N:P(13.94%),soil C:P(10.86%),microbial biomass N:P(23.58%),microbial biomass C:P(12.62%),but reduced plant C:N(leaf:6.49%,root:9.02%).Furthermore,plant C:N:P stoichiometry changed significantly under short-term N inputs,while soil and microorganisms changed drastically under high N addition.Canopy N addition primarily affected plant C:N:P stoichiometry through altering plant N content,while understory N inputs altered more by influencing soil C and P content.Organic N significantly influenced plant and soil C:N and C:P,while ammonia N changed plant N:P.Plant C:P and soil C:N were strongly correlated with mean annual precipitation(MAT),and the C:N:P stoichiometric flexibility in soil and plant under N addition connected with soil depth.Besides,N addition decoupled the correlations between soil microorganisms and the plant.Conclusions:N addition significantly increased the C:P and N:P in soil,plant,and microbial biomass,reducing plant C:N,and aggravated forest P limitations.Significantly,these impacts were contingent on climate types,soil layers,and N input forms.The findings enhance our comprehension of the plant-soil system nutrient cycling mechanisms in forest ecosystems and plant strategy responses to N deposition.展开更多
Soil health is an important component of“One Health”.Soils provide habitat to diverse and abundant organisms.Understanding microbial diversity and functions is essential for building healthy soils towards sustainabl...Soil health is an important component of“One Health”.Soils provide habitat to diverse and abundant organisms.Understanding microbial diversity and functions is essential for building healthy soils towards sustainable agriculture.Arbuscular mycorrhizal fungi(AMF)form potentially symbiotic associations with approximately 80%of land plant species that are well recognized for carbon flux and nutrient cycling.In addition to disentangling the signaling pathways and regulatory mechanisms between the two partners,recent advances in hyphosphere research highlight some emerging roles of AMF and associated microbes in the delivery of soil functions.This paper reviews the contribution of AMF to soil health in agroecosystems,with a major focus on recent progress in the contribution of hyphosphere microbiome to nutrient cycling,carbon sequestration,and soil aggregation.The hyphosphere microbiome and fungal stimulants open avenues for developing new fertilizer formulas to promote AMF benefits.In practice,developing AMF-friendly management strategies will have long-term positive effects on sustainable agriculture aiming at simultaneously providing food security,increasing resource use efficiency,and maintaining environment integrity.展开更多
基金financially supported by Zhejiang Provincial Key Research and Development Program of China(Grant No.2023C02004)the National Natural Science Foundation of China(Grant Nos.42225705 and 42177006)China Agriculture Research System of MOF and MARA(Grant No.CARS-04).
文摘We estimated the effect of three crop strategies on soil health based on 63 functional genes in long-term fields.The keystone microbial phylotypes support the agroecosystem sustainability.Rotation management thrives keystone phylotypes and soil functions.Rotation with soybean is beneficial for the subsequent crops.Given the often-independent study of microbial diversity and function,the comprehensive impact of various cropping patterns on both aspects,as well as the interconnections between them,remains unclear.This gap constrains us from evaluating the impact of soil microbiome shifts on soil health across varying agricultural management regimes.Here,we examined the associations between microbial diversity and soil multifunctionality in three long-term cropping patterns:continuous soybean cropping,soybeancorn rotation,and continuous corn cropping.We targeted 63 functional genes associated with carbon,nitrogen,phosphorus and sulfur cycling to assess soil multifunctionality.Our study demonstrated that the biodiversity and interactions of keystone phylotypes had significant positive associations with multiple soil functional genes,such as organic carbon degradation and fixation,nitrogen fixation and phosphorus solubilization.The analysis of retrieved complete genome revealed that the keystone bacteria identified in our study harbored these functional genes.Moreover,these keystone phylotypes showed associations with the dissipation of herbicide residues.Above all,we revealed that rotation of soybean with corn cropping enhanced a greater diversity of keystone phylotypes and thus fueled soil functions.Collectively,our results highlighted the importance of rotation with soybean in maintaining soil health,which could give a mechanism-based guidance for a sustainable agroecosystem.
基金supported by the National Natural Science Foundation of China(NSFC)(No.42107299).
文摘To better understand the effects of ground-level ozone(O_(3))on nutrients and stoichiometry in different plant organs,urban tree species Celtis sinensis,Cyclocarya paliu-rus,Quercus acutissima,and Quercus nuttallii were sub-jected to a constant exposure to charcoal-filtered air(CF),nonfiltered air(NF),or NF+40,60,or 80 nmol O_(3)mol^(-1)(NF40,NF60,and NF80)starting early in the summer of the growing season.At the end of summer,net CO_(2)assimila-tion rate(A),stomatal conductance(gs),leaf mass per area(LMA),and/or leaf greenness(SPAD)either were not sig-nificantly affected by elevated O_(3)or were even higher in some cases during the summer compared with the CF or NF controls.LMA was significantly lower in autumn only after the highest O_(3)exposures.Compared to NF,NF40 caused a large increase in gs across species in late summer and more K and Mn in stems.At the end of the growing season,nutri-ent status and stoichiometric ratios in different organs were variously altered under O_(3)stress;many changes were large and often species-specific.Across O_(3)treatments,LMA was primarily associated with C and Mg levels in leaves and Ca levels in leaves and stems.NF40 enriched K,P,Fe,and Mn in stems,relative to NF,and NF60 enhanced Ca in leaves relative to CF and NF40.Moreover,NF resulted in a higher Ca/Mg ratio in leaves of Q.acutissima only,relative to the other O_(3)regimes.Interestingly,across species,O_(3)stress led to different nutrient modifications in different organs(stems+branches vs leaves).Thus,ambient and/or elevated O_(3)exposures can alter the dynamics and distribution of nutrients and disrupt stoichiometry in different organs in a species-specific manner.Changes in stoichiometry reflect an important defense mechanism in plants under O_(3),and O_(3)pollution adds more risk to ecological stoichiometries in urban areas.
基金the National Key Research and Development Program of China(2019YFE0117000)the National Natural Science Foundation of China(32171549 and 31971465)and the Youth Innovation Promotion Association CAS(2020199).
文摘The responses of ecosystem nitrogen (N) and phosphorus (P) to drought are an important component of globalchange studies. However, previous studies were more often based on site-specific experiments, introducing a significantuncertainty to synthesis and site comparisons. We investigated the responses of vegetation and soil nutrientsto drought using a network experiment of temperate grasslands in Northern China. Drought treatment (66%reduction in growing season precipitation) was imposed by erecting rainout shelters, respectively, at the driest,intermediate, and wettest sites. We found that vegetation nutrient concentrations increased but soil nutrient concentrationsdecreased along the aridity gradient. Differential responses were observed under experimentaldrought among the three grassland sites. Specifically, the experimental drought did not change vegetation andsoil nutrient status at the driest site, while strongly reduced vegetation but increased soil nutrient concentrationsat the site with intermediate precipitation. On the contrary, experimental drought increased vegetation N concentrationsbut did not change vegetation P and soil nutrient concentrations at the wettest site. In general, the differentialeffects of drought on ecosystem nutrients were observed between manipulative and observationalexperiments as well as between sites. Our research findings suggest that conducting large-scale, consistent, andcontrolled network experiments is essential to accurately evaluate the effects of global climate change on terrestrialecosystem bio-geochemistry.
基金supported by the National Natural Science Foundation of China with Grant(No.G497901001)the Major State Basic Research Program with Grant(No.G1999043703)
文摘The environmental problems in the Bohai Sea have become more serious in the last decade. High nutrient concentration contributes much to it. A Sino-German cooperation program has been carried out to improve the understanding of the ecosystem by observations and modelling. A three-dimensional ecosystem model, coupled with a physical transport model, is adopted in this study. The simulation for the year 1982 is validated by the data collected in 1982/1983. The simulated annual mean nutrient concentrations are in good agreement with observations. The nutrient concentrations in the Bohai Sea, which are crucial to the algal growth, are high in winter and low in summer. There are depletion from spring to summer and elevation from autumn to winter for nutrients. The nutrients’ depletion is a response to the consumption of the phytoplankton bloom in spring. Internal recycle and external compensation affect the nutrient cycle. Their contributions to the nutrient budgets are discussed based on the simulated results. Production and respiration are the most important sink and source of nutrients. The process of photosynthesis consumes 152 kilotons-P and 831.1 kilotons-N while respiration releases 94.5 kilotons-P and 516.6 kilotons-N in the same period. The remineralization of the detritus pool is an important source of nutrient regene- ration. It can compensate 23 percent of the nutrient consumed by the production process. The inputs of phosphates and nitrogen from rivers are 0.55 and 52.7 kilotons respectively. The net nutrient budget is -3.05 kilotons-P and 31.6 kilotons-N.
基金supported by the Ministerio da Ciencia,Tecnologia e Inovacoes (MCTI-INPA),Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq,grant number:303913/2021-5)Fundagao de Amparo a Pesquisa do Estado do Amazonas (FAPEAM)Coordenagao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES code 0001).
文摘Litterfall is the largest source of nutrients to for-est soils of tropical rainforests.However,variability in lit-terfall production,nutrient remobilization,and changes in leaf nutrient concentration with climate seasonality remain largely unknown for the central Amazon.This study meas-ured litterfall production,leaf nutrient remobilization,and leaf area index on a forest plateau in the central Amazon.Litterfall was measured at monthly intervals during 2014,while nitrogen,phosphorus,potassium,calcium and mag-nesium concentrations of leaf litter and canopy leaves were measured in the dry and rainy seasons,and remobilization rates determined.Leaf area index was also recorded in the dry and rainy seasons.Monthly litterfall varied from 33.2(in the rainy season)to 87.6 g m^(-2) in the dry season,while leaf area index increased slightly in the rainy season.Climatic seasonality had no effect on concentrations of nitrogen,calcium,and magnesium,whereas phosphorous and potassium responded to rainfall seasonality oppositely.While phosphorous increased,potassium decreased during the dry season.Over seasons,nitrogen,potassium,and phosphorous decreased in leaf litter;calcium increased in leaf litter,while magnesium remained unaffected with leaf aging.Regardless,the five nutrients had similar remobilization rates over the year.The absence of climate seasonality on nutrient remobilization suggests that the current length of the dry season does not alter nutrient remobilization rates but this may change as dry periods become more prolonged in the future due to climate change.
基金funded by the institutional budget of FBN Dummerstorfpartly supported by the Leibniz ScienceCampus Phosphorus Research Rostock.
文摘In recent years,interest in the larvae of black soldier fly(BSF)(Hermetia illucens)as a sustainable protein resource for livestock feed has increased considerably.However,knowledge on the nutritional and physiological aspects of this insect,especially compared to other conventional farmed animals is scarce.This review presents a critical comparison of data on the growth potential and efficiency of the BSF larvae(BSFL)compared to conventional monogastric livestock species.Advantages of BSFL over other monogastric livestock species includes their high growth rate and their ability to convert low-grade organic waste into high-quality protein and fat-rich biomass suitable for use in animal feed.Calculations using literature data suggest that BSFL are more efficient than broilers,pigs and fish in terms of conversion of substrate protein into body mass,but less efficient than broilers and fish in utilization of substrate gross energy to gain body mass.BSFL growth efficiency varies greatly depending on the nutrient quality of their dietary substrates.This might be associated with the function of their gastrointestinal tract,including the activity of digestive enzymes,the substrate particle characteristics,and their intestinal microbial community.The conceived advantage of BSFL having an environmental footprint better than conventional livestock is only true if BSFL is produced on low-grade organic waste and its protein would directly be used for human consumption.Therefore,their potential role as a new species to better close nutrient cycles in agro-ecological systems needs to be reconsidered,and we conclude that BSFL is a complementary livestock species efficiently utilizing organic waste that cannot be utilized by other livestock.In addition,we provide comparative insight into morpho-functional aspects of the gut,characterization of digestive enzymes,gut microbiota and fiber digestion.Finally,current knowledge on the nutritional utilization and requirements of BSFL in terms of macro-and micronutrients is reviewed and found to be rather limited.In addition,the research methods to determine nutritional requirements of conventional livestock are not applicable for BSFL.Thus,there is a great need for research on the nutrient requirements of BSFL.
基金The project was supported by Japanese Society for Promotion of Sciences (15P03118).
文摘Within a forested watershed at the Uryu Experimental Forest of Hokkaido University in northern Hokkaido, overstory litterfall and related nutrient fluxes were measured at different landscape zones over two years. The wetland zone covered with Picea glehnii pure stand. The riparian zone was deciduous broad-leaved stand dominated by Alnus hirsuta and Salix spp., while the mixture of deciduous broadleaf and evergreen conifer dominated by Betula platyphylla, Quercus crispula and Abies sachalinensis distributed on the upland zone. Annual litterfall averaged 1444, 5122, and 4123 kg.hm^-2·a^-1 in the wetland, riparian and upland zones, respectively. Litterfall production peaked in September-October, and foliage litter contributed the greatest amount （73.4%-87.6 %） of the annual total litterfall. Concentrations of nutrients analyzed in foliage litter of the dominant species showed a similar seasonal variation over the year except for N in P glehnii and A. hirsuta. The nutrient fluxes for all elements analyzed were greatest on riparian zone and lowest in wetland zone. Nutrient fluxes via litterfall followed the decreasing sequence： N （11-129 kg.hm-2.aq） 〉 Ca （9-69） 〉 K （5-20） 〉 Mg （3-15） 〉 P （0.4-4.7） for all stands. Significant differences were found in litterfall production and nutrient fluxes among the different landscape components. There existed significant differences in soil chemistry between the different landscape zones. The consistently low soil C：N ratios at the riparian zone might be due to the higher-quality litter inputs （largely N-fixing alder）.
文摘Coffee cultivation by using shade trees is simple of agroforestry, this system could get better ecosystem service and sustainable agricultural. The aims of this research are to study the possibility of some species of industrial woods as shade trees of Coffea canephora. The research was conducted in Jember, Indonesia （45 m asl., D rainfall type according to Schmidt and Ferguson）, and arranged in split plot design. The main plots were （A） coffee-T, grandis （3 m × 2.5 m ×12 m）, （B） coffee-P, falcataria single row （2.5 m ×6 m）, （C） coffee-P, falcataria double rows （3 m× 2.5 m × 12 m）, （D） coffee-P, falcataria vat. Solomon （3 m× 2.5 m × 12 m）, （E） coffee-M, azedarach （3 m ×5 m ×22.5 m）, （F） coffee-H, macrophyllus （3 m ×5 m ×12.5 m）, and （G） coffee-Leucaena sp. （3 m × 2.5 m） as control. The sub plots were coffee clones, i.e., BP 534, BP 409, BP 936, dan BP 939. Among those timber trees, Leucaena was planted as the alternative shade trees. The result showed that in comparison with control, all of coffee agroforestry system improved carbon sequestration. Total C-stock on （B） was highest, i.e., 1,007 percent to control while the lowest one was （A） 317.44% to control. During one year observation, litter weight of H. macrophyllus was heaviest followed by T. grandis. The lightest litter was obtained from M. azedarach. Based on its mineral contents, litters of T. grandis potentially supplied back nutrients that equaled to total Urea, SP-36, KC1, Dolomite, and Kieserite as much as 574.14 g; P. falcataria 287.57 g, P. falcataria var. Solomon 453.59 g, M. azedarach 450.84 g, H. macrophyllus 877.56 g, and Leucaena 445.12 g per tree per year. Because of heavily fallen leaves of M. azedarach during dry season and conversely too dense shading of H. macrophyllus, bean yield at 4 and 5 years old by using both species were consistently lower than that under T. grandis, P. falcataria and control. At those ages, effect of clone on cherry yield was still not consistent but there was a tendency that BP 939 was most productive, while BP 534 was the less. Its outturn was not influenced by agroforestry system but by clones. The agroforestry pattern influence physical bean characters, more dense of shading, more single bean and empty bean. That bean abnormality also genetically, on BP 939 percentage of round and empty bean was highest while on BP 936 was lowest. It was concluded that coffee agroforestry improve ecology service, but M. azedarach and H. macrophyllus were not appropriate to be used as coffee shade trees. P. falcataria is recommended as an alternative shade tree beside Leucaena sp.
基金supported by the Forestry Public Benefit Research Projects of National Forestry Administration under Grant No.201304303National Natural Science Foundation of China under Grant No.31370619+1 种基金Science and Technology Project of the Fujian Province under Grant No.2014N0002China Postdoctoral Science Foundation under Grant No.132300148
文摘Biomass production and nutrient （N, P, K, Ca and Mg） accumulation, distribution and cycling were quantified in young, mature and over-mature （10-, 22-, and 34-year old） Chinese fir [Cunninghamia lanceolate （Lamb.） Hook] plantations in southern China. Total stand biomass of young, mature and over-mature stands was 38, 104 and 138 t ha-1 respectively. Biomass production increased significantly with age. Stem wood represented the highest percentage of stand biomass, accounting for 41, 55 and 63 % in the young, mature and over-mature plan- tations respectively. Nutrients concentration was highest in live needles and branches, and lowest in stem wood. The plantations accumulated more N, followed by K, Ca, Mg, and P. Nutrient return amount, nutrient utilization effi- ciency, nutrient turnover time, the ratio of nutrient return and uptake increased with stand age, which implies that young Chinese fir deplete soil nutrients to maintain growth, and efficiently utilize nutrients to decrease dependence on soil nutrients as they age. Harvesting young Chinese fir plantations would therefore lead to high nutrient loss, but prolonging the rotation length could improve soil recovery, and help sustain productivity in the long-term. Improved nutrient return through litterfall as stands get older may also be beneficial to nutrient pool recovery.
文摘An experiment was conducted in a red soil derived from Quaternary red clay in the Ecological ExperimentStation of Red Soil, the Chinese Academy of Sciences, located in Yingtan (28° 15′ 30″ N, 116° 55′ 30″E), Jiangxi Province. The results show that the major ways of nutrient loss are leaching and nitrogenvolatilization. Rationalizing crop distribution, stimulating nutrient recycling, and improving internal nutrientflow are effective measures to decrease nutrient loss and to promote nutrient utilization efficiency. Theimportant ways of regulating nutrient cycling and balance in the agroecosystem of the red soil are to establishoptimal eco-agricultural models, practice balanced fertilization and combine the cropping system with thelivestock system.
文摘In this paper, the biomass productivity and nutrient cycling in an agroforestry system of coconut (Cocus nucifera) interplanted with pineapple (Ananas comosus) had been studied. The result showed that the biomass productivity of this ecosystem was 47 460 kg...hm2...a?1, which was 4.3 times as much as that of pure coconut plantation. In the biological cycling of N, P. K elements, the total annual retention was 559.470 kg...hm?2, the annual return was 410.745 kg...hm?2, the annual uptake was 970.475 kg...hm?2, respectively. The average circulation rate in three nutrient elements (N, P, K) was 42.32%, which was 27.53% more than that in pure coconut stands. Coconut interplanted with pineapple was proved to be one of optimum cultural patterns, which had the higher biomass productivity, and better usage efficiency of environment resources in tropical areas.
基金the Chinese-Norwegian Cooperation Project Integrated Monitoring Program on Acidification of Chinese Terrestrial Systems (IMPACTS)the Chinese Academy of Forestry (No.CAFYBB200700X)
文摘The nutrient cycling model NuCM is one of the most detailed models for simulating processes that influence nutrient cycling in forest ecosystems. A field study was conducted at Tieshanping, a Masson pine (Pinus massoniana Lamb.) forest site, in Chongqing, China, to monitor the impacts of acidic precipitation on nutrient cycling. NuCM simulations were compared with observed data from the study site. The model produced an approximate fit with the observed data. It simulated the mean annual soil solution concentrations in the two simulation years, whereas it sometimes failed to reproduce seasonal variation. Even though some of the parameters required by model running were measured in the field, some others were still highly uncertain and the uncertainties were analyzed. Some of the uncertain parameters necessary for model running should be measured and calibrated to produce a better fit between modeled results and field data.
文摘At a global scale, tree growth in alpine treeline ecotones is limited by low temperatures. At a local scale, however, tree growth at its upper limit depends on multiple interactions of influencing factors and mechanisms. The aim of our research was to understand local scale effects of soil properties and nutrient cycling on tree growth limitation, and their interactions with other abiotic and biotic factors in a near-natural Himalayan treeline ecotone. Soil samples of different soil horizons, litter, decomposition layers, and foliage samples of standing biomass were collected in four altitudinal zones along three slopes, and were analysed for exchangeable cations and nutrient concentrations, respectively. Additionally, soil and air temperature, soil moisture, precipitation, and tree physiognomy patterns were evaluated. Both soil nutrients and foliar macronutrient concentrations of nitrogen(N), magnesium(Mg), potassium(K), and foliar phosphorus(P) decrease significantly with elevation. Foliar manganese(Mn) concentrations, bycontrast, are extraordinarily high at high elevation sites. Potential constraining factors on tree growth were identified using multivariate statistical approaches. We propose that tree growth, treeline position and vegetation composition are affected by nutrient limitation, which in turn, is governed by low soil temperatures and influenced by soil moisture conditions.
基金the framework of the FunDivEUROPE project and has received funding from the European Union Seventh Framework Programme(FP7/2007–2013)under grant agreement n°265171.Dries Landuyt was supported by a postdoctoral fellowship of the Research Foundation-Flanders(FWO).Kris Verheyen was supported by the ERC Consolidator Grant 614839 that is linked with the project PASTFORWARD.
文摘Background:In contrast with the negligible contribution of the forest understorey to the total aboveground phytobiomass of a forest,its share in annual litter production and nutrient cycling may be more important.Whether and how this functional role of the understorey differs across forest types and depends upon overstorey characteristics remains to be investigated.Methods:We sampled 209 plots of the FunDivEUROPE Exploratory Platform,a network of study plots covering local gradients of tree diversity spread over six contrasting forest types in Europe.To estimate the relative contribution of the understorey to carbon and nutrient cycling,we sampled non-lignified aboveground understorey biomass and overstorey leaf litterfall in all plots.Understorey samples were analysed for C,N and P concentrations,overstorey leaf litterfall for C and N concentrations.We additionally quantified a set of overstorey attributes,including species richness,proportion of evergreen species,light availability(representing crown density)and litter quality,and investigated whether they drive the understorey’s contribution to carbon and nutrient cycling.Results and conclusions:Overstorey litter production and nutrient stocks in litterfall clearly exceeded the contribution of the understorey for all forest types,and the share of the understorey was higher in forests at the extremes of the climatic gradient.In most of the investigated forest types,it was mainly light availability that determined the contribution of the understorey to yearly carbon and nutrient cycling.Overstorey species richness did not affect the contribution of the understorey to carbon and nutrient cycling in any of the investigated forest types.
基金supported by the National Natural Science Foundation of China(No.31988102)National Key Research and Development Program of China(No.2017YFC0503906)。
文摘Shifts in tree species and their mycorrhizal associations driven by global change play key roles in biogeochemical cycles. In this paper, we proposed a framework of the mycorrhizal-associated nutrient economy(MANE), and tested it using nutrient addition experiments conducted in two tropical rainforests. We selected two tropical rainforests dominated by arbuscular mycorrhizal(AM) and ectomycorrhizal(ECM) trees, and established eighteen20 m×20 m plots in each rainforest. Six nitrogen(N) and phosphorus(P) addition treatments were randomly distributed in each rainforest with three replicates. We examined the differences in soil carbon(C) and nutrient cycling, plant and litter productivity between the two rainforests and their responses to 10-year inorganic N and P additions. We also quantified the P pools of plants, roots, litter, soil and microbes in the two rainforests. Overall,distinct MANE frameworks were applicable for tropical rainforests, in which soil C, N and P were cycled primarily in an inorganic form in the AM-dominated rainforest, whereas they were cycled in an organic form in the ECMdominated rainforest. Notably, the effects of mycorrhizal types on soil P cycling were stronger than those on C and N cycling. The intensified N and P deposition benefited the growth of AM-dominated rainforests instead of ECMdominated rainforests. Our findings underpin the key role of mycorrhizal types in regulating biogeochemical processes, and have important implications for predicting the ecological consequences of global changes.
基金The work was supported by the National Key Research and Development Program of China(2017YFC0505606)National Natural Science Foundation of China(31570594,31600449)Forestry Science and Technology Innovation Project of Guangdong Province(2021-2023).
文摘The stoichiometry of carbon,nitrogen and phosphorous in plants can reflect the interactions between plants and their environment.The interplay between plant nutrients,climatic factors,and soil properties and the underlying regulatory mechanisms are pillars of ecology but remain underexplored.In this study of plant C-N-P stoichiometry and nutrient resorption in Castanopsis hystrix groves in three cities(Guangzhou,Zhongshan,and Lechang)that represent an urban-rural gradient in Guangdong Province,South China,we explored potential relationships among NO_(2) concentrations,diameter at breast height(DBH),and resident human population.Mean annual temperature,mean annual precipitation,insolation duration per year,and the human resident population differed significantly among the three cities.Soil C-N-P was always highest in suburban Lechang,and the concentration of NO_(2) was highest in urban Guanghzou(55.33±0.67μg m^(-3))and positively correlated with the resident population and leaf N:P.Our findings suggest that C-N-P stoichiometry of C.hystrix was better explained by NO_(2)than by soil C-N-P stoichiometry and that nutrient resorption was better explained by leaf nutrients and DBH than by NO_(2) and soil stoichiometry.Our study supports the hypothesis that rapid urbanization influences NO_(2) concentrations and microclimate,which may jointly change the stoichiometry of plant nutrients in the forest ecosystems.
文摘The cycling characteristics of nitrogen(N), phosphorus(P) and potassium(K) of the Quercus acutissima and Pinus massoniana mixed forest which is the most common forest type in the Three Gorge Reservoir areas in China, were systematically analyzed. The results showed that N, P and K accumulated in the plant pool and in the litter pool, while total N, P, and K were deficient in the soil pool and in the forest systems. Contents of N in the soil of depth 20—40 cm were the key factor limiting growth of trees. The biological outside cycling coefficients were 878, 725 and 117 times of inside cycling coefficients of N, P and K, respectively. 3392, 1026 and 1588 kg of N, P and K return to the litter pool from branches, leaves and throughfall per year, but, 1431, 132 and 1048 kg of N, P and K return to the soil from litter pool per year respectively. It is clear that 58% of N, 87% of P, and 34% of K are lost by surface runoff per year. 549%, 130%, and 834% of N, P and K withdraw from leaves to branches, 499%, 199% and 730% of N, P and K withdraw from branches to trunks per year, respectively.
文摘In Uruguay, <em>Pinus taeda</em> is usually planted a few months after harvest of the former turn, therefore;decomposing residues represents a nutrient source for the new plantation. The aim of this study was to determine the biomass and nutrient extraction off site, following the harvest of a <em>P. taeda</em> plantation. Residue decomposition patterns, and nutrient release were also examined. The site will be referred as S1, corresponding to the clear cut of a 22-year-old <em>P. taeda</em> plantation. Before the clear cut 10 trees were harvested, and logs, branches, twigs, and needles separately weighed. Additionally, forest litter at harvest time was quantified in three different areas. To assess decomposition, mesh bags with residues were allocated in three areas over the forest litter, and samples were taken periodically for 26 months. The remaining biomass, N, P K, Ca, and Mg contents were determined in the different fractions, calculating decompositon rates. Most of the harvested biomass was removed in logs, but the proportion of nutrients exported was considerably lower. Needles showed the highest biomass loss and only 39.1% remained after 26 months, while branches presented high rates in the first two months after cut, but slower thereafter, and at the end of the study more than two thirds of the woody residues remained. Potassium was rapidly released from the residues, while Ca, and Mg, were slowly released, and there was evidence of N and P immobilization in the early stages of decomposition. It was concluded that, although a lower proportion of nutrients were exported, compared to biomass, in the long term, nutrient export with logs could be significant for the sustainability of this production system. While K release from residues did not depend on biomass decay, the slow decomposition, and release of the other nutrients, indicates that this process could have been delayed by nutrient scarcity.
基金supported by the National Natural Science Foundation of China(Nos.31800369,32271686,U1904204)the State Scholarship Fund of Chinathe Innovation Scientists and Technicians Troop Construction Projects of Henan Province(No.182101510005)。
文摘Background:Nitrogen(N)deposition affects forest stoichiometric flexibility through changing soil nutrient availability to influence plant uptake.However,the effect of N deposition on the flexibility of carbon(C),N,and phosphorus(P)in forest plant-soil-microbe systems remains unclear.Methods:We conducted a meta-analysis based on 751 pairs of observations to evaluate the responses of plant,soil and microbial biomass C,N and P nutrients and stoichiometry to N addition in different N intensity(050,50–100,>100 kg·ha^(-1)·year^(-1)of N),duration(0–5,>5 year),method(understory,canopy),and matter(ammonium N,nitrate N,organic N,mixed N).Results:N addition significantly increased plant N:P(leaf:14.98%,root:13.29%),plant C:P(leaf:6.8%,root:25.44%),soil N:P(13.94%),soil C:P(10.86%),microbial biomass N:P(23.58%),microbial biomass C:P(12.62%),but reduced plant C:N(leaf:6.49%,root:9.02%).Furthermore,plant C:N:P stoichiometry changed significantly under short-term N inputs,while soil and microorganisms changed drastically under high N addition.Canopy N addition primarily affected plant C:N:P stoichiometry through altering plant N content,while understory N inputs altered more by influencing soil C and P content.Organic N significantly influenced plant and soil C:N and C:P,while ammonia N changed plant N:P.Plant C:P and soil C:N were strongly correlated with mean annual precipitation(MAT),and the C:N:P stoichiometric flexibility in soil and plant under N addition connected with soil depth.Besides,N addition decoupled the correlations between soil microorganisms and the plant.Conclusions:N addition significantly increased the C:P and N:P in soil,plant,and microbial biomass,reducing plant C:N,and aggravated forest P limitations.Significantly,these impacts were contingent on climate types,soil layers,and N input forms.The findings enhance our comprehension of the plant-soil system nutrient cycling mechanisms in forest ecosystems and plant strategy responses to N deposition.
基金financially funded by the National Natural Science Foundation of China(Nos.U23A2054 and 42377128)the National Key R&D Program of China(No.2022YFD1901300)。
文摘Soil health is an important component of“One Health”.Soils provide habitat to diverse and abundant organisms.Understanding microbial diversity and functions is essential for building healthy soils towards sustainable agriculture.Arbuscular mycorrhizal fungi(AMF)form potentially symbiotic associations with approximately 80%of land plant species that are well recognized for carbon flux and nutrient cycling.In addition to disentangling the signaling pathways and regulatory mechanisms between the two partners,recent advances in hyphosphere research highlight some emerging roles of AMF and associated microbes in the delivery of soil functions.This paper reviews the contribution of AMF to soil health in agroecosystems,with a major focus on recent progress in the contribution of hyphosphere microbiome to nutrient cycling,carbon sequestration,and soil aggregation.The hyphosphere microbiome and fungal stimulants open avenues for developing new fertilizer formulas to promote AMF benefits.In practice,developing AMF-friendly management strategies will have long-term positive effects on sustainable agriculture aiming at simultaneously providing food security,increasing resource use efficiency,and maintaining environment integrity.
