Kigezi highlands currently experiences changes in precipitation and temperature which modify the evaporation and soil moisture storage leading to alterations in runoff and other components of hydrological systems. Ext...Kigezi highlands currently experiences changes in precipitation and temperature which modify the evaporation and soil moisture storage leading to alterations in runoff and other components of hydrological systems. Extreme events, like floods and droughts, are more intense and frequent. Furthermore heavy unpredictable rainfall has become frequent in the area, causing soil erosion and floods that destroy crops. Soil erosion is particularly a pressing challenge due to steep-sided hills leading to deterioration of soil nutrients including soil fertility. The unpredictable rains and droughts are attributed to climate change and variability. Consequently, climate change and variability have caused a significant impact on soil nutrients which have affected the agricultural productivity in the area. This paper presents findings of empirical study which explored the climate variability and soil nutrient status along altitudinal gradient. The paper particularly addresses key questions of: land management practices in the study area, nutrient availability and their effects on productivity of selected crops along altitudinal gradient in changing climate and variability. Independent variables such as topographic sequence along altitudinal gradient were evaluated against dependent variables such as yield harvests of selected grown crops and soil nutrients. Samples for crop yields were collected along transect of 0.5 kilometer using a quadrant of 4 × 4 m<sup>2</sup> along attitudinal gradient. Soil samples were taken from selected plots at 0-20cm soil depth for nutrient analysis. Analysis of physical and chemical soil parameters was carried out on soil samples and these include: soil pH, soil organic content, total nitrogen, available soil phosphorous and exchangeable bases (Ca, Mg, K and Na). The study showed that middle parts of the transects had the highest concentration of most soil nutrients, probably because the middle parts could have been a deposition centre for some organic matter from the upper parts of the hills, and lower lying areas were being affected by floods that affects the decomposition of organic matter which is the main source of nutrients. Similarly, the middle parts of the study were the most fertile due to the high concentration of soil nutrient compositions. This indicates that crop yields were significantly affected by availability of soil nutrients along same gradient, attributable to the severity in soil erosion, nutrients leaching and farming practices.展开更多
Fire has been used to prepare land during tree plantation establishment for many years but uncertainty about how ecosystems respond to prescribed burning makes it difficult to predict the effects of fire on soil nutri...Fire has been used to prepare land during tree plantation establishment for many years but uncertainty about how ecosystems respond to prescribed burning makes it difficult to predict the effects of fire on soil nutrients.The aim of this study was to determine the effect of burning accumulated forest residues(slash)on soil chemical properties and how trees respond.We analyzed 40 burned and unburned sites and compared growth of Eucalyptus grandis W.Hill ex Maiden between sites.Soil pH increased by 39%after fire,suggesting reduced soil acidity and increased liming.Total nitrogen increased by 100%;other nutrients(Ca^2+,Mg^2+and K^+)also increased.Increase in nutrients had a significant effect on the growth of E.grandis;larger and taller trees were associated more with burned than unburned sites.This study provides evidence that burning accumulated slash during land preparation prior to plantation establishment alters soil nutrient status and enhances the growth of E.grandis.展开更多
[Objectives]This study was conducted to investigate the effects of raising chickens under Moringa oleifera forests on soil nutrient changes and selenium absorption by M.oleifera.[Methods]The nutrient contents of the s...[Objectives]This study was conducted to investigate the effects of raising chickens under Moringa oleifera forests on soil nutrient changes and selenium absorption by M.oleifera.[Methods]The nutrient contents of the soil and the selenium contents of different parts of M.oleifera were determined and analyzed.[Results]Raising chickens under the investigated M.oleifera forest improved the soil.Compared with the control,the soil organic matter,hydrolyzable nitrogen,available phosphorus,and available potassium of the plots for underforest chicken raising were significantly improved;the changes were the most significant within the range of 2 m from the chicken houses,respectively,and the values were 1.39,1.38,1.52 and 1.31 times of the control,respectively;soil bulk density decreased,total porosity increased,soil structure and permeability improved,and soil pH values at 2 and 5 m away from the chicken houses were significantly higher than the control by 0.34 and 0.28 unit,respectively;and raising chickens under the forest promoted the absorption and utilization of selenium in M.oleifera,and the selenium contents in stems and leaves of M.oleifera were 1.64 times and 1.51 times of the control,respectively.[Conclusions]This study provides a theoretical basis for the high-value selenium-enriching compound economic model of raising chickens under M.oleifera forests.展开更多
In this study,taking the typical terracing land in Wushan County of Chongqing Municipality for example,we study the distribution of soil nutrients in the terracing land under different land use patterns in Three Gorge...In this study,taking the typical terracing land in Wushan County of Chongqing Municipality for example,we study the distribution of soil nutrients in the terracing land under different land use patterns in Three Gorges Reservoir Area. We conduct field survey and sampling on three different land use patterns( cash crop land,food crop land and abandoned land),and do the indoor experimental analysis of soil nutrient indicators. The results indicate that there is significant or very significant impact on soil nutrients under different land use patterns. The content of soil organic matter declines in sequence from abandoned land,food crop land to cash crop land; the content of soil N declines in sequence from cash crop land,abandoned land to food crop land; the content of soil P declines in sequence from cash crop land,food crop land to abandoned land; the content of soil K declines in sequence from abandoned land,cash crop land to food crop land. The result is in close relation to land use patterns,human cultivation activity,land disturbance and application of fertilizer.展开更多
Based on previous studies,the research methods and influencing factors of spatial variation of soil nutrients are summarized.It is concluded that the spatial variation of soil nutrients is studied generally by geostat...Based on previous studies,the research methods and influencing factors of spatial variation of soil nutrients are summarized.It is concluded that the spatial variation of soil nutrients is studied generally by geostatistics methods,and the spatial distribution of nutrients is visually observed by using Kriging interpolation method.The influencing factors mainly include topography,sampling method,sampling spacing,sampling density and sampling scale.The influence of random sampling and grid sampling on interpolation is analyzed based on the specific conditions of the actual study area.The influence of sampling density and topography on the spatial variation of soil nutrients cannot be ignored,especially on available nutrients.When samples are collected in a large area(under a small and medium scale),the spatial variation of soil nutrients is large,and they have strong spatial autocorrelation;in a small area(namely under a large scale),the spatial variability of soil nutrients is small,and they have obvious spatial autocorrelation.This study can provide intuitive and convenient reference materials for the following researchers.展开更多
Through analyzing the soil organic matters(N,P,K) of farmland cultivated with different years of Panax ginseng,this paper studied the changes in soil nutrients of farmland with different vertical depths and cultivatio...Through analyzing the soil organic matters(N,P,K) of farmland cultivated with different years of Panax ginseng,this paper studied the changes in soil nutrients of farmland with different vertical depths and cultivation years of P.ginseng.Results indicated that the vertical structure was obvious in soil nutrients of farmland with different cultivation years of P.ginseng;in most cases,the soil nutrient content gradually declined with the fibrous roots of P.ginseng spreading downward;the soil electrical conductivity(EC),total nitrogen(TN),total phosphorus(TP),total potassium(TK),available nitrogen,available phosphorus were manifested as surface layer > root layer > bottom layer,while the available potassium was manifested as surface soil and bottom layer > root layer;the soil pH changed in the range of 5.69-6.22,suitable for growth of P.ginseng.It is expected to provide theoretical basis for improvement of soil nutrients of farmland with cultivation of P.ginseng.展开更多
In order to accurately grasp the soil fertility in Three Gorges Reservoir Region after changing mountain slope into terrace field,we take Wushan County for example,and use the spatio-temporal substitution method to an...In order to accurately grasp the soil fertility in Three Gorges Reservoir Region after changing mountain slope into terrace field,we take Wushan County for example,and use the spatio-temporal substitution method to analyze the soil nutrient status and trend about the terrace field changed from mountain slope under different length of implementation.The results show that the soil fertility is generally low in the study area,and according to the soil nutrient grading standards in the second national land survey,the average content of total nitrogen,available potassium,organic matter and available phosphorus reaches Standard III,Standard III,Standard IV and Standard V,respectively,and the spatial heterogeneity of soil nutrients is small.Compared to the sloping land,the terrace field changed from mountain slope has increasing soil nutrients on the whole with the length of farming.The mean of various indicators about soil nutrients in the terrace field changed from mountain slope for 2 years is lower than in the sloping land,and there is the biggest difference in soil fertility,while the mean of various indicators about soil nutrients in the terrace field changed from mountain slope for 14 years shows a linear upward trend,and the difference in soil fertility decreases.展开更多
[Objectives]This study was conducted to clarify the improvement effects of different soil amelioration materials such as lime,green manure and bio-organic fertilizer on acidic tobacco-planting soil.[Methods]The dynami...[Objectives]This study was conducted to clarify the improvement effects of different soil amelioration materials such as lime,green manure and bio-organic fertilizer on acidic tobacco-planting soil.[Methods]The dynamic changes of soil pH,soil nutrients and enzyme activity were studied by applying lime,lime+green fertilizer,and lime+green fertilizer+biological organic fertilizer.[Results]①After the application of amelioration materials,the soil pH and available phosphorus content of tobacco-growing soil showed a stepwise change of first increasing and then decreasing,and became stable at 60 d after tobacco transplanting;the soil organic matter,alkali-hydrolyzable nitrogen and available potassium content showed a gradual change trend of"high-low-high";and the soil invertase and urease activity showed a gradual change trend of"low-high-low".②To 90 d after tobacco transplanting,the application of amelioration materials increased soil pH by 1.29-1.62 units,and increased organic matter content by 15.21%-20.86%,alkali-hydrolyzable nitrogen content by 6.83%-18.17%,available phosphorus content by 54.15%-217.85%,rapidly available potassium content by 11.42%-30.86%,soil invertase activity by 70.09%-18.93%,and soil urease activity by 64.07%-130.47%.③The combination of lime+green manure+alkaline microbial organic fertilizer had the best effect on the improvement of acidic tobacco-growing soil,and the effect of lime+green manure+acid microbial organic fertilizer on acidic soil was the second.[Conclusions]When applying lime,green fertilizer and alkaline bio-organic fertilizer should be applied to achieve sustainable improvement of strongly acidic soil.展开更多
[Objectives]This study was conducted to investigate the effects of milk vetch(Astragalus sinicus)on soil nutrients and microorganisms in paddy fields after returning to the field.[Methods]Three treatments,no fertiliza...[Objectives]This study was conducted to investigate the effects of milk vetch(Astragalus sinicus)on soil nutrients and microorganisms in paddy fields after returning to the field.[Methods]Three treatments,no fertilization,single application of chemical fertilizers and milk vetch return combined with chemical fertilizers,were set up to determine soil nutrient contents and the quantity of microorganisms,respectively.[Results]The return of milk vetch combined with chemical fertilizers could significantly increase the contents of organic matter and total nitrogen in the paddy soil,while the contents of available potassium and available phosphorus decreased.Milk vetch return combined with chemical fertilizers could significantly increase the quantity of soil microorganisms in the paddy field.[Conclusions]The return of milk vetch can be used as a feasible measure to improve soil fertility.展开更多
The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco...The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.展开更多
Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nut...Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.展开更多
Wastewater treated by compound microbial inoculant(CMI)in agricultural irrigation can enrich soil fertility and decompose the possible pollutants.In this study,a greenhouse experiment using tomato as the model crop wa...Wastewater treated by compound microbial inoculant(CMI)in agricultural irrigation can enrich soil fertility and decompose the possible pollutants.In this study,a greenhouse experiment using tomato as the model crop was performed to investigate the effects of treated wastewater irrigation on soil nutrients and enzymes.For this purpose,certain parameters were measured,including soil total nitrogen(N),nitrate N,total phosphorus(P),available potassium(K)and the activities of the enzymes urease,acid phosphatase and catalase in soils irrigated with fresh water,wastewater and CMI-treated wastewater under three amount of irrigation water.The results showed that irrigation with both treated and untreated wastewater significantly increased soil total N,total P,and available K,however the treated wastewater showed higher effects on soil enrichment,especially on available K.The activity of soil urease and acid phosphatase reached highest with treated wastewater irrigation,whereas wastewater irrigation increased the activity of catalase obviously.Soil enzyme and nutrient with fresh water irrigation decreased with increasing water amount;the content of soil urease,nitrate-nitrogen,total N and total P in treated wastewater and wastewater irrigation rose with increasing water amount,but the highest activity of acid phosphatase and the lowest activity of catalase were found in medium irrigation water amount.Under the condition of tomato cultivation,total N,nitrate N and total P were closely correlated with soil urease and catalase;there were significant positive correlation among soil urease,catalase,total N,nitrate N and total P;there existed significantly positive correlation between acid phosphatase and all measured soil nutrient indexes.The results suggested that irrigation with CMI-treated wastewater is a security and effective strategy to agricultural land management.展开更多
Artemisia sacrorum communities with different growth years were selected to analyse soil nutrient characteristics,the variation in soil microbial properties,and their relationships in the loess hilly region.The result...Artemisia sacrorum communities with different growth years were selected to analyse soil nutrient characteristics,the variation in soil microbial properties,and their relationships in the loess hilly region.The results showed that with an increase in the number of growth years,soil microbial biomass carbon and nitrogen contents as well as soil phosphatase and urease activities initially decreased and then increased in the A.sacrorum communities.The soil organic carbon,organic nitrogen,and total nitrogen contents as well as soil respiration rate showed an increasing trend and reached a maximum at age(a)37.The soil available phosphorus content first decreased and then increased,with the lowest level observed at 18 a.By contrast,soil available potassium initially increased and then decreased.Soil microbial biomass carbon had a significant positive correlation with soil organic carbon,total nitrogen and organic nitrogen,while soil respiration had a significant positive correlation with organic nitrogen,soil phosphatase and organic carbon.Soil respiration had a highly significant positive correlation with organic carbon and total nitrogen,while soil phosphatase had a highly significant positive correlation with total nitrogen and organic nitrogen.In the A.sacrorum communities,the soil organic carbon and total nitrogen contents were mainly affected by soil respiration,soil available potassium content was mainly affected by soil urease activity,and soil organic nitrogen content was mainly affected by soil phosphatase activity.These findings indicate that soil basal respiration,urease activity and phosphatase activity were the major microbial factors affecting the characteristics of the soil nutrients in the A.sacrorum communities.In conclusion,the natural restoration process of A.sacrorum communities can enhance soil microbial activity and improve soil quality.展开更多
The effect of soil nutrient content on fruit yield and fruit quality is very important.To explore the effect of soil nutrients on apple quality we investigated 200 fruit samples from 40 orchards in Feng County,Jiangsu...The effect of soil nutrient content on fruit yield and fruit quality is very important.To explore the effect of soil nutrients on apple quality we investigated 200 fruit samples from 40 orchards in Feng County,Jiangsu Province.Soil mineral elements and fruit quality were measured.The effect of soil nutrient content on fruit quality was analyzed by artificial neural network(ANN)model.The results showed that the prediction accuracy was highest(R2=0.851,0.847,0.885,0.678 and 0.746)in mass per fruit(MPF),hardness(HB),soluble solids concentrations(SSC),titratable acid concentration(TA)and solid-acid ratio(SSC/TA),respectively.The sensitivity analysis of the prediction model showed that soil available P,K,Ca and Mg contents had the greatest impact on the quality of apple fruit.Response surface method(RSM)was performed to determine the optimum range of the available P,K,Ca,and Mg contents in orchards In Feng County,which were 10∼20 mg⋅kg^(−1),170∼200 mg⋅kg^(−1),1000∼1500 mg⋅kg^(−1),and 80∼200 mg⋅kg^(−1),respectively.The research also concluded that improving the content of available P and available Ca in orchard soil was crucial to improve apple fruit quality in Feng County,Jiangsu Province.展开更多
Spatial distribution of and interpolation methods for soil nutrients are the basis of soil nutrient management in precision agriculture.For study of application potential and characteristics of algebra hyper-curve neu...Spatial distribution of and interpolation methods for soil nutrients are the basis of soil nutrient management in precision agriculture.For study of application potential and characteristics of algebra hyper-curve neural network(AHCNN)in delineating spatial variability and interpolation of soil properties,956 soil samples were taken from a 50 hectare field with 20 m interval for alkaline hydrolytic nitrogen measurement.The test data set consisted of 100 random samples extracted from the 956 samples,and the training data set extracted from the remaining samples using 20,40,60,80,100 and 120 m grid intervals.Using the AHCNN model,three training plans were designed,including plan AHC1,using spatial coordinates as the only network input,plan AHC2,adding information of four neighboring points as network input,and plan AHC3,adding information of six neighboring points as network input.The interpolation precision of AHCNN method was compared with that of Kriging method.When the number of training samples was big,interpolation precisions of Kriging and AHCNN were similar.When the number of training samples was small,the precisions of both methods deteriorated.Since AHCNN method has no request on data distribution and it is non-linearization of neutron input variables,it is suitable for delineation of spatial distribution of nonlinear soil properties.In addition,AHCNN has an advantage of adaptive self-adjustment of model parameters,which makes it proper for soil nutrient spatial interpolation.After comparison of mean absolute error d,root mean squared error RMSE,and mean relative error%d,and the spatial distribution maps generated from different methods,it can be concluded that using spatial coordinates as the only network input cannot simulate the characteristics of soil nutrient spatial variability well,and the simulation results can be improved greatly after adding neighboring sample points’information and the distance effect as network input.When the number of samples was small,interpolation precision can be improved after properly increasing the number of neighboring sample points.It was also showed that evaluation of interpolation precision using conventional error statistic indexes was defective,and the spatial distribution map should be used as an important evaluation factor.展开更多
Plastic film mulch in agricultural production becomes essential to maintaining crop yields in arid and semiarid areas.However,the presence of residual film in farmland soil has also drawn much attention.In this study,...Plastic film mulch in agricultural production becomes essential to maintaining crop yields in arid and semiarid areas.However,the presence of residual film in farmland soil has also drawn much attention.In this study,three experiments were conducted.The first two experimental designs included 0,450,1350,and 2700 kg ha^(-1) of residual film pieces of approximately 5 cm side length added to field soil(0-20 cm soil depth)for seven years and added to pots for four years.In the third experiment,1350 kg ha^(-1)of the residual film with different side lengths(2-5,5-10,10-15,and 15-20 cm)was added to field soil for six years to explore the effect of residual film fragment size on soil nutrients,soil microorganisms,crop growth and yields.The residual film had little effect on the soil moisture at a field depth of 0-2(or 0-1.8)m.There were no significant effects on organic carbon,total nitrogen,inorganic nitrogen,total phosphorus or available phosphorus in the 0-20 cm soil layer.The presence of residual film decreased the richness and diversity of the bacterial community of the surface soil of the residual film,but it had no significant effect on the microbial community of the non-surface soil.The emergence rates of wheat and lentils occasionally decreased significantly with different amounts of residue fragments added to the field.At 450-2700 kg ha^(-1),the residual film reduced the plant height and stem diameter of maize and significantly reduced the shoot biomass of harvested maize by 11-19%.The average yields of maize and potato over the seven years decreased,but there were almost no significant statistical differences among the treatments.These results provide important data for a comprehensive scientific understanding of the effects of residual film on soil and crops in dryland farming systems.展开更多
Soil chronosequences derived from landslides with certain time series are the great avenue to elevate our understanding on the processes of pedogenesis,nutrient dynamics,and ecosystem evolution.However,the constructio...Soil chronosequences derived from landslides with certain time series are the great avenue to elevate our understanding on the processes of pedogenesis,nutrient dynamics,and ecosystem evolution.However,the construction of reliable soil chronosequence from historical landslides remains intricate.Here,we presented a 22,000-year soil chronosequence from multiple landslides on the upper reach of Minjiang River,western China.The variation in a variety of pedogenesis indices and soil nutrients verified the reliability of the chronosequence.The silica-alumina ratio and silica sesquioxide ratio decreased significantly with soil age.This reflected the enrichment of Al/Fe/Ti oxides but the depletion of Si oxides with the soil development.Meanwhile,the values of the Chemical Index of Weathering and the Chemical Index of Alteration increased significantly with soil age,especially from 5 to 89 years.These variations were attributed to the soil weathering,which led to the destruction of soil minerals with the rapid loss of most of cations(e.g.,K,Na,Ca,and Mg)during the soil development.The concentrations of carbon and nitrogen in topsoil increased with soil age,and the carbon accumulation rate slowed significantly from 5,500 to 22,000 years.The total phosphorus concentrations decreased with soil age,suggesting the gradual loss of soil phosphorus with soil development.The results indicate that the landslide chronosequence established on the upper reach of Minjiang River is reliable and delineates a long-term soil development process,which will provide a great platform for further improvement of biogeochemical theories and understanding sustainable vegetation restoration.展开更多
It is important to understand the research trends and hotspots of global soil nutrient migration and control. Based on the core collection of WOS (Web of Science), citespace knowledge map analysis tool was used to ana...It is important to understand the research trends and hotspots of global soil nutrient migration and control. Based on the core collection of WOS (Web of Science), citespace knowledge map analysis tool was used to analyze the number of publications, cooperation networks, disciplines, research hotspots and frontier trends on nutrient migration in soil. The results showed that: the number of publications on the study of soil nutrient migration showed a good growth from 1990 to 2021. 173 countries had cooperative relationships. The number of articles published in the United States and China was significantly higher than that in other countries, while Chinese Academy of Sciences was the institution with the largest number of publications. It was a comprehensive system that permeates with agriculture, environmental science, botany and other disciplines. The research of nutrient migration in soil mainly focused on the measures of microbial community in different land types to promote nutrient transformation, improve soil fertility and reduce nutrient loss. In the future, the research trends will be the management measures of soil nutrient loss, the relationship between the change of soil nutrient and plant community diversity, and the remediation of agricultural contaminated soil. Through the above analysis, there was an overall understanding of soil nutrient migration. The research on nutrient migration may continue to increase in the future. It is suggested that Chinese research institutions, teams and universities need to strengthen international cooperation, and speed up their integration with the international community.展开更多
Qilian Mountains in Northwest China is a significant ecological security barrier due to its distinctive geographic setting,which has significant biological resource and gene pool.In order to assess the soil quality an...Qilian Mountains in Northwest China is a significant ecological security barrier due to its distinctive geographic setting,which has significant biological resource and gene pool.In order to assess the soil quality and ecosystem health in this area,we identified the structural characteristics and functional groups of soil microbial communities.This study focused on Amidongsuo,a typical watershed of the Qilian Mountains,and researched the vertical distribution and dominant populations of soil microorganisms in different habitats,and the relationship between soil microorganisms and environmental factors.Soil microorganisms from three grassland plots,five shrubland plots,and five forest plots in Amidongsuo were studied using high-throughput sequencing.The Venn diagram showed that the types of bacteria were fewer than those of fungi in Amidongsuo.Soil bacteria Acidobacteriota,Proteobacteria,and Methylomirabilota as well as fungi Basidiomycota,Ascomycota,and Mortierellomycota played dominant roles in Amidongsuo,according to the LEfSe(linear discriminant analysis(LDA)effect size)and community structure analyses.According to the ANOSIM(analysis of similarities)result,for both bacteria and fungi,R values of grassland and shrubland were small(R^(2)=0.045 and R^(2)=0.256,respectively),indicating little difference between these two ecosystems.RDA(redundancy analysis)showed a closer relationship between soil nutrients and fungi,and a gradually decreasing correlation between soil nutrients and microorganisms with increasing soil depth.Bacteria were mainly affected by pH,nitrogen(N),and potassium(K),while fungi were mainly affected by K.Overall,fungi had more effect on soil quality than bacteria.Therefore,adjustment of soil K content might improve the soil environment of Amidongsuo in the Qilian Mountains.展开更多
[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragran...[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragrant pear in the orchard were collected and returned to the field for a period of 150 d for indoor mixed culture.[Results]Different ages of Korla fragrant pear branches have different effects on soil nutrient content during the simulated return to field decomposition process.Compared with the control in the same period,the treatment of returning to field reached a significant level(P<0.05).Compared with the control,the average values of organic matter,total nitrogen and available phosphorus content in treatment 1 and treatment 2 increased by 2.16 times and 1.93 times,61%and 59%,5.88 times and 6.88 times,respectively;compared with the control,the average increase performance of the alkaline hydrolysis nitrogen content of the two treatments was basically the same,and the treatment 2 was the best;compared with the control,the average total phosphorus content of treatment 1 and treatment 2 increased but not significantly.[Conclusions]The contents of soil organic matter,nitrogen and phosphorus were all increased during the decomposition of pear branches,and the overall improvement effect of 10-year-old trees was better than that of 5-year-old trees.Returning the pruned branches to the field can provide a reliable theoretical basis for solving the problem of organic fertilizer shortage in orchards,and also can ensure technical support for improving soil fertility and improving the rhizosphere micro-environment of pear trees.展开更多
文摘Kigezi highlands currently experiences changes in precipitation and temperature which modify the evaporation and soil moisture storage leading to alterations in runoff and other components of hydrological systems. Extreme events, like floods and droughts, are more intense and frequent. Furthermore heavy unpredictable rainfall has become frequent in the area, causing soil erosion and floods that destroy crops. Soil erosion is particularly a pressing challenge due to steep-sided hills leading to deterioration of soil nutrients including soil fertility. The unpredictable rains and droughts are attributed to climate change and variability. Consequently, climate change and variability have caused a significant impact on soil nutrients which have affected the agricultural productivity in the area. This paper presents findings of empirical study which explored the climate variability and soil nutrient status along altitudinal gradient. The paper particularly addresses key questions of: land management practices in the study area, nutrient availability and their effects on productivity of selected crops along altitudinal gradient in changing climate and variability. Independent variables such as topographic sequence along altitudinal gradient were evaluated against dependent variables such as yield harvests of selected grown crops and soil nutrients. Samples for crop yields were collected along transect of 0.5 kilometer using a quadrant of 4 × 4 m<sup>2</sup> along attitudinal gradient. Soil samples were taken from selected plots at 0-20cm soil depth for nutrient analysis. Analysis of physical and chemical soil parameters was carried out on soil samples and these include: soil pH, soil organic content, total nitrogen, available soil phosphorous and exchangeable bases (Ca, Mg, K and Na). The study showed that middle parts of the transects had the highest concentration of most soil nutrients, probably because the middle parts could have been a deposition centre for some organic matter from the upper parts of the hills, and lower lying areas were being affected by floods that affects the decomposition of organic matter which is the main source of nutrients. Similarly, the middle parts of the study were the most fertile due to the high concentration of soil nutrient compositions. This indicates that crop yields were significantly affected by availability of soil nutrients along same gradient, attributable to the severity in soil erosion, nutrients leaching and farming practices.
文摘Fire has been used to prepare land during tree plantation establishment for many years but uncertainty about how ecosystems respond to prescribed burning makes it difficult to predict the effects of fire on soil nutrients.The aim of this study was to determine the effect of burning accumulated forest residues(slash)on soil chemical properties and how trees respond.We analyzed 40 burned and unburned sites and compared growth of Eucalyptus grandis W.Hill ex Maiden between sites.Soil pH increased by 39%after fire,suggesting reduced soil acidity and increased liming.Total nitrogen increased by 100%;other nutrients(Ca^2+,Mg^2+and K^+)also increased.Increase in nutrients had a significant effect on the growth of E.grandis;larger and taller trees were associated more with burned than unburned sites.This study provides evidence that burning accumulated slash during land preparation prior to plantation establishment alters soil nutrient status and enhances the growth of E.grandis.
基金Supported by Science and Technology Research and Technology Development Plan of Xixiangtang District,Nanning City(2019021702)Special Project of the Science and Technology Vanguard Special Action of Guangxi Academy of Agricultural Sciences(GNKM 202114)+2 种基金Guangxi Selenium-rich Featured Crops Experimental Station(GTS2016011)Team Project of Guangxi Academy of Agricultural Sciences(GNK 2020YT039)Nanning Science and Technology Research and Technology Development Key R&D Program Project(20202087,20212020).
文摘[Objectives]This study was conducted to investigate the effects of raising chickens under Moringa oleifera forests on soil nutrient changes and selenium absorption by M.oleifera.[Methods]The nutrient contents of the soil and the selenium contents of different parts of M.oleifera were determined and analyzed.[Results]Raising chickens under the investigated M.oleifera forest improved the soil.Compared with the control,the soil organic matter,hydrolyzable nitrogen,available phosphorus,and available potassium of the plots for underforest chicken raising were significantly improved;the changes were the most significant within the range of 2 m from the chicken houses,respectively,and the values were 1.39,1.38,1.52 and 1.31 times of the control,respectively;soil bulk density decreased,total porosity increased,soil structure and permeability improved,and soil pH values at 2 and 5 m away from the chicken houses were significantly higher than the control by 0.34 and 0.28 unit,respectively;and raising chickens under the forest promoted the absorption and utilization of selenium in M.oleifera,and the selenium contents in stems and leaves of M.oleifera were 1.64 times and 1.51 times of the control,respectively.[Conclusions]This study provides a theoretical basis for the high-value selenium-enriching compound economic model of raising chickens under M.oleifera forests.
基金Supported by National Natural Science Foundation of China(41471234)Chongqing Basic and Cutting-edge Research Project(cstc2015jcyjB X0141)+2 种基金Natural Science Foundation of Chongqing(CSTC,2010BB0326)Social Sciences Project of Chongqing Municipal Education Commission(08JWSK043)Ph.D.Fund Project of Chongqing Normal University(05XLB)
文摘In this study,taking the typical terracing land in Wushan County of Chongqing Municipality for example,we study the distribution of soil nutrients in the terracing land under different land use patterns in Three Gorges Reservoir Area. We conduct field survey and sampling on three different land use patterns( cash crop land,food crop land and abandoned land),and do the indoor experimental analysis of soil nutrient indicators. The results indicate that there is significant or very significant impact on soil nutrients under different land use patterns. The content of soil organic matter declines in sequence from abandoned land,food crop land to cash crop land; the content of soil N declines in sequence from cash crop land,abandoned land to food crop land; the content of soil P declines in sequence from cash crop land,food crop land to abandoned land; the content of soil K declines in sequence from abandoned land,cash crop land to food crop land. The result is in close relation to land use patterns,human cultivation activity,land disturbance and application of fertilizer.
文摘Based on previous studies,the research methods and influencing factors of spatial variation of soil nutrients are summarized.It is concluded that the spatial variation of soil nutrients is studied generally by geostatistics methods,and the spatial distribution of nutrients is visually observed by using Kriging interpolation method.The influencing factors mainly include topography,sampling method,sampling spacing,sampling density and sampling scale.The influence of random sampling and grid sampling on interpolation is analyzed based on the specific conditions of the actual study area.The influence of sampling density and topography on the spatial variation of soil nutrients cannot be ignored,especially on available nutrients.When samples are collected in a large area(under a small and medium scale),the spatial variation of soil nutrients is large,and they have strong spatial autocorrelation;in a small area(namely under a large scale),the spatial variability of soil nutrients is small,and they have obvious spatial autocorrelation.This study can provide intuitive and convenient reference materials for the following researchers.
基金Supported by Program of Jinlin Province Science and Technology Department(20160308010YY)
文摘Through analyzing the soil organic matters(N,P,K) of farmland cultivated with different years of Panax ginseng,this paper studied the changes in soil nutrients of farmland with different vertical depths and cultivation years of P.ginseng.Results indicated that the vertical structure was obvious in soil nutrients of farmland with different cultivation years of P.ginseng;in most cases,the soil nutrient content gradually declined with the fibrous roots of P.ginseng spreading downward;the soil electrical conductivity(EC),total nitrogen(TN),total phosphorus(TP),total potassium(TK),available nitrogen,available phosphorus were manifested as surface layer > root layer > bottom layer,while the available potassium was manifested as surface soil and bottom layer > root layer;the soil pH changed in the range of 5.69-6.22,suitable for growth of P.ginseng.It is expected to provide theoretical basis for improvement of soil nutrients of farmland with cultivation of P.ginseng.
基金Supported by National Natural Science Foundation of China(41001168)National Science and Technology Support Program(2011BAD31B03)+2 种基金Chongqing Natural Science Foundation(CSTC2010BB0326)Social Sciences Project of Chongqing Municipal Education Commission(08JWSK043)Doctoral Fund Project of Chongqing Normal University(05XLB)
文摘In order to accurately grasp the soil fertility in Three Gorges Reservoir Region after changing mountain slope into terrace field,we take Wushan County for example,and use the spatio-temporal substitution method to analyze the soil nutrient status and trend about the terrace field changed from mountain slope under different length of implementation.The results show that the soil fertility is generally low in the study area,and according to the soil nutrient grading standards in the second national land survey,the average content of total nitrogen,available potassium,organic matter and available phosphorus reaches Standard III,Standard III,Standard IV and Standard V,respectively,and the spatial heterogeneity of soil nutrients is small.Compared to the sloping land,the terrace field changed from mountain slope has increasing soil nutrients on the whole with the length of farming.The mean of various indicators about soil nutrients in the terrace field changed from mountain slope for 2 years is lower than in the sloping land,and there is the biggest difference in soil fertility,while the mean of various indicators about soil nutrients in the terrace field changed from mountain slope for 14 years shows a linear upward trend,and the difference in soil fertility decreases.
基金Supported by Science and Technology Project of Hunan Tobacco Monopoly Bureau(18-21Aa04).
文摘[Objectives]This study was conducted to clarify the improvement effects of different soil amelioration materials such as lime,green manure and bio-organic fertilizer on acidic tobacco-planting soil.[Methods]The dynamic changes of soil pH,soil nutrients and enzyme activity were studied by applying lime,lime+green fertilizer,and lime+green fertilizer+biological organic fertilizer.[Results]①After the application of amelioration materials,the soil pH and available phosphorus content of tobacco-growing soil showed a stepwise change of first increasing and then decreasing,and became stable at 60 d after tobacco transplanting;the soil organic matter,alkali-hydrolyzable nitrogen and available potassium content showed a gradual change trend of"high-low-high";and the soil invertase and urease activity showed a gradual change trend of"low-high-low".②To 90 d after tobacco transplanting,the application of amelioration materials increased soil pH by 1.29-1.62 units,and increased organic matter content by 15.21%-20.86%,alkali-hydrolyzable nitrogen content by 6.83%-18.17%,available phosphorus content by 54.15%-217.85%,rapidly available potassium content by 11.42%-30.86%,soil invertase activity by 70.09%-18.93%,and soil urease activity by 64.07%-130.47%.③The combination of lime+green manure+alkaline microbial organic fertilizer had the best effect on the improvement of acidic tobacco-growing soil,and the effect of lime+green manure+acid microbial organic fertilizer on acidic soil was the second.[Conclusions]When applying lime,green fertilizer and alkaline bio-organic fertilizer should be applied to achieve sustainable improvement of strongly acidic soil.
基金Supported by National Key R&D Project(2018YFD0800503)National Natural Science Foundation of China(31860595)。
文摘[Objectives]This study was conducted to investigate the effects of milk vetch(Astragalus sinicus)on soil nutrients and microorganisms in paddy fields after returning to the field.[Methods]Three treatments,no fertilization,single application of chemical fertilizers and milk vetch return combined with chemical fertilizers,were set up to determine soil nutrient contents and the quantity of microorganisms,respectively.[Results]The return of milk vetch combined with chemical fertilizers could significantly increase the contents of organic matter and total nitrogen in the paddy soil,while the contents of available potassium and available phosphorus decreased.Milk vetch return combined with chemical fertilizers could significantly increase the quantity of soil microorganisms in the paddy field.[Conclusions]The return of milk vetch can be used as a feasible measure to improve soil fertility.
文摘The implementation of appropriate tillage practices is of great significance for agricultural production. However, the effects of different tillage depths on soil nutrients content and microbial communities in tobacco-planting soils are still lacking systematic research. In this study, three different tillage depths of 15 cm (T1), 20 cm (T2), and 30 cm (T3) were set up for field experiments in Liupanshui, Guizhou Province, to explore the effects of tillage depth on tobacco-planting soil nutrients and bacterial and fungal communities based on 16S rRNA and ITS sequencing and figure out the key factors affecting soil microbial communities. The results showed that T2 and T3 increased the contents of organic matter, total nitrogen, total phosphorus, available phosphorus, and available potassium in tobacco-planting soil, and increased the diversity of bacterial communities compared with T1. There was no significant difference in the structure of bacterial and fungal communities in different tillage depth treatments, but some dominant genera were significantly enriched in T2 and T3. Desulfobacter, Setophoma, Humicola, and Acremonium were significantly enriched in T2. Chthonomonas and Fusarium were significantly enriched in T3. These genera favor the decomposition of organic matter and the cycling of nutrients, and control soil pests and diseases. Redundancy analysis indicated that TP and AK were the key factors influencing the dominant genera of bacteria and fungi. This study provides a scientific basis for the selection of soil tillage depth for tobacco production in this region.
基金financially supported by the Joint Funds of the National Natural Science Foundation of China(U22A20609)the National Key Research and Development Program of China(2021YFD1901102-4)+2 种基金the State Key Laboratory of Integrative Sustainable Dryland Agriculture(in preparation)the Shanxi Agricultural University,China(202003-3)the Open Fund from the State Key Laboratory of Soil Environment and Nutrient Resources of Shanxi Province,China(2020002)。
文摘Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.
基金the National Natural Science Foundation of China(51179054)the National Science Technology Support Project(2012BAB03B03)the Ministry of Water Resources Public Welfare Projects(201301017).
文摘Wastewater treated by compound microbial inoculant(CMI)in agricultural irrigation can enrich soil fertility and decompose the possible pollutants.In this study,a greenhouse experiment using tomato as the model crop was performed to investigate the effects of treated wastewater irrigation on soil nutrients and enzymes.For this purpose,certain parameters were measured,including soil total nitrogen(N),nitrate N,total phosphorus(P),available potassium(K)and the activities of the enzymes urease,acid phosphatase and catalase in soils irrigated with fresh water,wastewater and CMI-treated wastewater under three amount of irrigation water.The results showed that irrigation with both treated and untreated wastewater significantly increased soil total N,total P,and available K,however the treated wastewater showed higher effects on soil enrichment,especially on available K.The activity of soil urease and acid phosphatase reached highest with treated wastewater irrigation,whereas wastewater irrigation increased the activity of catalase obviously.Soil enzyme and nutrient with fresh water irrigation decreased with increasing water amount;the content of soil urease,nitrate-nitrogen,total N and total P in treated wastewater and wastewater irrigation rose with increasing water amount,but the highest activity of acid phosphatase and the lowest activity of catalase were found in medium irrigation water amount.Under the condition of tomato cultivation,total N,nitrate N and total P were closely correlated with soil urease and catalase;there were significant positive correlation among soil urease,catalase,total N,nitrate N and total P;there existed significantly positive correlation between acid phosphatase and all measured soil nutrient indexes.The results suggested that irrigation with CMI-treated wastewater is a security and effective strategy to agricultural land management.
基金Financial support was provided by the Talent Training Program of the West of the Chinese Academy of Sciences(2008DF02)National Chinese Medicine Resources Survey Project[Finance and Social Work(2017)66].
文摘Artemisia sacrorum communities with different growth years were selected to analyse soil nutrient characteristics,the variation in soil microbial properties,and their relationships in the loess hilly region.The results showed that with an increase in the number of growth years,soil microbial biomass carbon and nitrogen contents as well as soil phosphatase and urease activities initially decreased and then increased in the A.sacrorum communities.The soil organic carbon,organic nitrogen,and total nitrogen contents as well as soil respiration rate showed an increasing trend and reached a maximum at age(a)37.The soil available phosphorus content first decreased and then increased,with the lowest level observed at 18 a.By contrast,soil available potassium initially increased and then decreased.Soil microbial biomass carbon had a significant positive correlation with soil organic carbon,total nitrogen and organic nitrogen,while soil respiration had a significant positive correlation with organic nitrogen,soil phosphatase and organic carbon.Soil respiration had a highly significant positive correlation with organic carbon and total nitrogen,while soil phosphatase had a highly significant positive correlation with total nitrogen and organic nitrogen.In the A.sacrorum communities,the soil organic carbon and total nitrogen contents were mainly affected by soil respiration,soil available potassium content was mainly affected by soil urease activity,and soil organic nitrogen content was mainly affected by soil phosphatase activity.These findings indicate that soil basal respiration,urease activity and phosphatase activity were the major microbial factors affecting the characteristics of the soil nutrients in the A.sacrorum communities.In conclusion,the natural restoration process of A.sacrorum communities can enhance soil microbial activity and improve soil quality.
基金supported by the National Key Research and Development Program of China(2019YFD1000103)National Natural Science Foundation of China(31872076)+1 种基金supported by the National Key Research and Development Program of China(2019YFD1000103)National Natural Science Foundation of China(31872076).
文摘The effect of soil nutrient content on fruit yield and fruit quality is very important.To explore the effect of soil nutrients on apple quality we investigated 200 fruit samples from 40 orchards in Feng County,Jiangsu Province.Soil mineral elements and fruit quality were measured.The effect of soil nutrient content on fruit quality was analyzed by artificial neural network(ANN)model.The results showed that the prediction accuracy was highest(R2=0.851,0.847,0.885,0.678 and 0.746)in mass per fruit(MPF),hardness(HB),soluble solids concentrations(SSC),titratable acid concentration(TA)and solid-acid ratio(SSC/TA),respectively.The sensitivity analysis of the prediction model showed that soil available P,K,Ca and Mg contents had the greatest impact on the quality of apple fruit.Response surface method(RSM)was performed to determine the optimum range of the available P,K,Ca,and Mg contents in orchards In Feng County,which were 10∼20 mg⋅kg^(−1),170∼200 mg⋅kg^(−1),1000∼1500 mg⋅kg^(−1),and 80∼200 mg⋅kg^(−1),respectively.The research also concluded that improving the content of available P and available Ca in orchard soil was crucial to improve apple fruit quality in Feng County,Jiangsu Province.
基金This research was financially supported by the National Natural Science Foundation of China(30600375)the National High Technology Research and Development Program of China(2006AA10A306,2006AA10Z271)。
文摘Spatial distribution of and interpolation methods for soil nutrients are the basis of soil nutrient management in precision agriculture.For study of application potential and characteristics of algebra hyper-curve neural network(AHCNN)in delineating spatial variability and interpolation of soil properties,956 soil samples were taken from a 50 hectare field with 20 m interval for alkaline hydrolytic nitrogen measurement.The test data set consisted of 100 random samples extracted from the 956 samples,and the training data set extracted from the remaining samples using 20,40,60,80,100 and 120 m grid intervals.Using the AHCNN model,three training plans were designed,including plan AHC1,using spatial coordinates as the only network input,plan AHC2,adding information of four neighboring points as network input,and plan AHC3,adding information of six neighboring points as network input.The interpolation precision of AHCNN method was compared with that of Kriging method.When the number of training samples was big,interpolation precisions of Kriging and AHCNN were similar.When the number of training samples was small,the precisions of both methods deteriorated.Since AHCNN method has no request on data distribution and it is non-linearization of neutron input variables,it is suitable for delineation of spatial distribution of nonlinear soil properties.In addition,AHCNN has an advantage of adaptive self-adjustment of model parameters,which makes it proper for soil nutrient spatial interpolation.After comparison of mean absolute error d,root mean squared error RMSE,and mean relative error%d,and the spatial distribution maps generated from different methods,it can be concluded that using spatial coordinates as the only network input cannot simulate the characteristics of soil nutrient spatial variability well,and the simulation results can be improved greatly after adding neighboring sample points’information and the distance effect as network input.When the number of samples was small,interpolation precision can be improved after properly increasing the number of neighboring sample points.It was also showed that evaluation of interpolation precision using conventional error statistic indexes was defective,and the spatial distribution map should be used as an important evaluation factor.
基金funded by the National Natural Science Foundation of China (31470496)the Fundamental Research Funds for the Central Universities, China (lzujbky-2021-sp42)the ‘111’ Programme 2.0, China (BP0719040)。
文摘Plastic film mulch in agricultural production becomes essential to maintaining crop yields in arid and semiarid areas.However,the presence of residual film in farmland soil has also drawn much attention.In this study,three experiments were conducted.The first two experimental designs included 0,450,1350,and 2700 kg ha^(-1) of residual film pieces of approximately 5 cm side length added to field soil(0-20 cm soil depth)for seven years and added to pots for four years.In the third experiment,1350 kg ha^(-1)of the residual film with different side lengths(2-5,5-10,10-15,and 15-20 cm)was added to field soil for six years to explore the effect of residual film fragment size on soil nutrients,soil microorganisms,crop growth and yields.The residual film had little effect on the soil moisture at a field depth of 0-2(or 0-1.8)m.There were no significant effects on organic carbon,total nitrogen,inorganic nitrogen,total phosphorus or available phosphorus in the 0-20 cm soil layer.The presence of residual film decreased the richness and diversity of the bacterial community of the surface soil of the residual film,but it had no significant effect on the microbial community of the non-surface soil.The emergence rates of wheat and lentils occasionally decreased significantly with different amounts of residue fragments added to the field.At 450-2700 kg ha^(-1),the residual film reduced the plant height and stem diameter of maize and significantly reduced the shoot biomass of harvested maize by 11-19%.The average yields of maize and potato over the seven years decreased,but there were almost no significant statistical differences among the treatments.These results provide important data for a comprehensive scientific understanding of the effects of residual film on soil and crops in dryland farming systems.
基金funded by the Key Program of the Chinese Academy of Sciences for International Cooperation(131551KYSB20190028)the Key Research and Development Projects Foundation of Sichuan,China(Grants No.2018JZ0075)。
文摘Soil chronosequences derived from landslides with certain time series are the great avenue to elevate our understanding on the processes of pedogenesis,nutrient dynamics,and ecosystem evolution.However,the construction of reliable soil chronosequence from historical landslides remains intricate.Here,we presented a 22,000-year soil chronosequence from multiple landslides on the upper reach of Minjiang River,western China.The variation in a variety of pedogenesis indices and soil nutrients verified the reliability of the chronosequence.The silica-alumina ratio and silica sesquioxide ratio decreased significantly with soil age.This reflected the enrichment of Al/Fe/Ti oxides but the depletion of Si oxides with the soil development.Meanwhile,the values of the Chemical Index of Weathering and the Chemical Index of Alteration increased significantly with soil age,especially from 5 to 89 years.These variations were attributed to the soil weathering,which led to the destruction of soil minerals with the rapid loss of most of cations(e.g.,K,Na,Ca,and Mg)during the soil development.The concentrations of carbon and nitrogen in topsoil increased with soil age,and the carbon accumulation rate slowed significantly from 5,500 to 22,000 years.The total phosphorus concentrations decreased with soil age,suggesting the gradual loss of soil phosphorus with soil development.The results indicate that the landslide chronosequence established on the upper reach of Minjiang River is reliable and delineates a long-term soil development process,which will provide a great platform for further improvement of biogeochemical theories and understanding sustainable vegetation restoration.
文摘It is important to understand the research trends and hotspots of global soil nutrient migration and control. Based on the core collection of WOS (Web of Science), citespace knowledge map analysis tool was used to analyze the number of publications, cooperation networks, disciplines, research hotspots and frontier trends on nutrient migration in soil. The results showed that: the number of publications on the study of soil nutrient migration showed a good growth from 1990 to 2021. 173 countries had cooperative relationships. The number of articles published in the United States and China was significantly higher than that in other countries, while Chinese Academy of Sciences was the institution with the largest number of publications. It was a comprehensive system that permeates with agriculture, environmental science, botany and other disciplines. The research of nutrient migration in soil mainly focused on the measures of microbial community in different land types to promote nutrient transformation, improve soil fertility and reduce nutrient loss. In the future, the research trends will be the management measures of soil nutrient loss, the relationship between the change of soil nutrient and plant community diversity, and the remediation of agricultural contaminated soil. Through the above analysis, there was an overall understanding of soil nutrient migration. The research on nutrient migration may continue to increase in the future. It is suggested that Chinese research institutions, teams and universities need to strengthen international cooperation, and speed up their integration with the international community.
基金funded by the Qinghai Provincial Natural Science Foundation Project(2020-ZJ-725)the Wetland Protection and Restoration Project of the Second Batch of Forestry Reform and Development Funds in Qinghai Province,China(QHTX-2020-043-02).
文摘Qilian Mountains in Northwest China is a significant ecological security barrier due to its distinctive geographic setting,which has significant biological resource and gene pool.In order to assess the soil quality and ecosystem health in this area,we identified the structural characteristics and functional groups of soil microbial communities.This study focused on Amidongsuo,a typical watershed of the Qilian Mountains,and researched the vertical distribution and dominant populations of soil microorganisms in different habitats,and the relationship between soil microorganisms and environmental factors.Soil microorganisms from three grassland plots,five shrubland plots,and five forest plots in Amidongsuo were studied using high-throughput sequencing.The Venn diagram showed that the types of bacteria were fewer than those of fungi in Amidongsuo.Soil bacteria Acidobacteriota,Proteobacteria,and Methylomirabilota as well as fungi Basidiomycota,Ascomycota,and Mortierellomycota played dominant roles in Amidongsuo,according to the LEfSe(linear discriminant analysis(LDA)effect size)and community structure analyses.According to the ANOSIM(analysis of similarities)result,for both bacteria and fungi,R values of grassland and shrubland were small(R^(2)=0.045 and R^(2)=0.256,respectively),indicating little difference between these two ecosystems.RDA(redundancy analysis)showed a closer relationship between soil nutrients and fungi,and a gradually decreasing correlation between soil nutrients and microorganisms with increasing soil depth.Bacteria were mainly affected by pH,nitrogen(N),and potassium(K),while fungi were mainly affected by K.Overall,fungi had more effect on soil quality than bacteria.Therefore,adjustment of soil K content might improve the soil environment of Amidongsuo in the Qilian Mountains.
基金Supported by Key R&D Program of Hainan Province in 2021(ZDYF2021XDNY152).
文摘[Objectives]To investigate the changes in soil organic matter,nitrogen and phosphorus content in the decomposition process of Korla fragrant pear branches by indoor mixed culture.[Methods]The branches of Korla fragrant pear in the orchard were collected and returned to the field for a period of 150 d for indoor mixed culture.[Results]Different ages of Korla fragrant pear branches have different effects on soil nutrient content during the simulated return to field decomposition process.Compared with the control in the same period,the treatment of returning to field reached a significant level(P<0.05).Compared with the control,the average values of organic matter,total nitrogen and available phosphorus content in treatment 1 and treatment 2 increased by 2.16 times and 1.93 times,61%and 59%,5.88 times and 6.88 times,respectively;compared with the control,the average increase performance of the alkaline hydrolysis nitrogen content of the two treatments was basically the same,and the treatment 2 was the best;compared with the control,the average total phosphorus content of treatment 1 and treatment 2 increased but not significantly.[Conclusions]The contents of soil organic matter,nitrogen and phosphorus were all increased during the decomposition of pear branches,and the overall improvement effect of 10-year-old trees was better than that of 5-year-old trees.Returning the pruned branches to the field can provide a reliable theoretical basis for solving the problem of organic fertilizer shortage in orchards,and also can ensure technical support for improving soil fertility and improving the rhizosphere micro-environment of pear trees.
