To illuminate the spatio-temporal variation characteristics and geochemical driving mechanism of soil pH in the Nenjiang River Basin,the National Multi-objective Regional Geochemical Survey data of topsoil,the Second ...To illuminate the spatio-temporal variation characteristics and geochemical driving mechanism of soil pH in the Nenjiang River Basin,the National Multi-objective Regional Geochemical Survey data of topsoil,the Second National Soil Survey data and Normalized Difference Vegetation Index(NDVI)were analyzed.The areas of neutral and alkaline soil decreased by 21100 km^(2)and 30500 km^(2),respectively,while that of strongly alkaline,extremely alkaline,and strongly acidic soil increased by 19600 km^(2),18200 km^(2),and 15500 km^(2),respectively,during the past 30 years.NDVI decreased with the increase of soil pH when soil pH>8.0,and it was reversed when soil pH<5.0.There were significant differences in soil pH with various surface cover types,which showed an ascending order:Arbor<reed<maize<rice<high and medium-covered meadow<low-covered meadow<Puccinellia.The weathering products of minerals rich in K_(2)O,Na_(2)O,CaO,and MgO entered into the low plain and were enriched in different parts by water transportation and lake deposition,while Fe and Al remained in the low hilly areas,which was the geochemical driving mechanism.The results of this study will provide scientific basis for making scientific and rational decisions on soil acidification and salinization.展开更多
[Objectives]In order to explore the feasibility of using straw and biochar returned to the soil to improve soil physical properties and pH value in cold rice regions of China.[Methods]the effects of straw directly ret...[Objectives]In order to explore the feasibility of using straw and biochar returned to the soil to improve soil physical properties and pH value in cold rice regions of China.[Methods]the effects of straw directly returned to the soil and charred straw(biochar)returned to the soil on soil bulk density,porosity,temperature and pH value of cold paddy soil were studied in this paper.[Results]The results showed that compared with conventional production,straw(6 t/ha),a small amount of biochar(2 t/ha)and a large amount of biochar(40 t/ha)returned to the soil reduced paddy soil bulk density at different growth stages by 6.02%-11.86%,2.69%-6.67%and 8.58%-11.32%,respectively,increased total porosity by 7.41%-14.93%,3.19%-8.38%and 9.81%-14.27%,respectively,and increased aeration porosity by 22.28%-192.11%,17.80%-92.11%and 52.44%-157.11%,respectively.Straw and a small amount of biochar returned to the soil had no significant effect on soil temperature and pH value of paddy field,but a large amount of biochar returned to the soil could significantly increase soil temperature by 5.13%-8.79%and pH value by 3.15%-5.96%in the later stage of rice growth.[Conclusions]The straw and biochar returned to the soil could reduce soil bulk density,increase total porosity and aeration porosity,and only a large amount of biochar returned to the soil could significantly increase soil temperature and pH value.展开更多
pH is one of the significant properties of soil,and is closely related to the decomposition of soil organic matter,anion-cation balance,growth of plants and many other soil processes.In the present work,laser-induced ...pH is one of the significant properties of soil,and is closely related to the decomposition of soil organic matter,anion-cation balance,growth of plants and many other soil processes.In the present work,laser-induced breakdown spectroscopy(LIBS) technique coupled with random forest(RF) was proposed to quantify the pH of soil.First,LIBS spectra of soil was collected,and some common elements in soil were identified based on the National Institute of Science and Technology database.Then,in order to obtain a better predictive result,the influence of different input variables(full spectrum,different spectral ranges,the intensity of characteristic bands and characteristic lines) on the predictive performance of RF calibration model was explored with the evaluation indicators of root mean square error(RMSE) and coefficient of determination(R2),the characteristic bands of four elements(AI,Ca,Mg and Si) were determined as the optimal input variables.Finally,the predictive performance of RF calibration model was compared with partial least squares calibration model with the optimal input variables and model parameters,and RF calibration model showed a better predictive performance,and the four evaluation indicators of R_p^2,RMSEP,mean absolute error and mean relative error were 0.9687,0.1285,0.1114 and 0.0136,respectively.It indicates that LIBS technique coupled with RF algorithm is an effective method for pH determination of soil.展开更多
Through field experiment,we explore the impact of long-term drip fertigation on growth and distribution of lychee root and changes of soil pH in different layers of soil in lychee garden.The results show that drip fer...Through field experiment,we explore the impact of long-term drip fertigation on growth and distribution of lychee root and changes of soil pH in different layers of soil in lychee garden.The results show that drip fertigation can significantly promote the growth of lychee roots,and increase the contact area of root and soil;if it experiences six years of drip fertigation successively,the dry weight of root,root length and surface area of root in soil in drip fertigation area,will be 2.29 times,2.17 times and 2.25 times that in non-drip fertigation area,respectively.The lychee root is mainly distributed in 0-40 cm layer of soil,but there is conspicuous difference between drip fertigation area and non-drip fertigation area in terms of root distribution in 0-20 cm and 20-40 cm layer of soil.Drip fertigation is more favorable for the root to go deep inside the soil.Under long-term drip fertigation,the soil acidification in lychee garden is prominent,and in comparison with non-drip fertigation area,there is the greatest decline in soil pH in 10-20 cm layer of soil in drip fertigation area,reaching 1.47 units.展开更多
[Objective]The paper was to study the relationship between spatial distribution characteristics of soil p H and bacterial wilt in tobacco-growing area in Henan Province.[Method]The 21 tobacco-growing fields infected b...[Objective]The paper was to study the relationship between spatial distribution characteristics of soil p H and bacterial wilt in tobacco-growing area in Henan Province.[Method]The 21 tobacco-growing fields infected by bacterial wilt and 91 tobacco-growing fields with no cases were selected from Henan Province,and the pH of fields was determined.[Result]Bacterial wilt mainly occurred in the tobacco-growing fields in Luoshan,Pingqiao,Queshan,Biyang,Suiping,and Xiping,and the soil pH mainly ranged from 5.5 to 6.5(accounted for 84.75%of total surveyed tobacco fields);bacterial wilt had not been found in tobacco-growing fields in Tanghe,Zhengyang,Shangcai,Sheqi,Wuyang and Chenqu,and the soil pH mainly ranged from 6.5 to 7.0(accounted for 81.25%of total surveyed tobacco fields).There were significant differences in soil pH between the fields with and without bacterial wilt,and soil pH 6.5 could be regarded as the threshold for the occurrence of tobacco bacterial wilt in Henan Province.There was extremely significantly positive linear correlation between soil p H and latitude(y=0.7375 x-17.799,R2=0.386,P<0.01).The geographical boundary of soil pH 6.5 was roughly 33°N,and bacterial wilt was less likely to occur in the north tobacco-growing areas of the boundary.[Conclusion]The study will provide a scientific basis for the prevention and control of tobacco bacterial wilt in Henan.展开更多
Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems.We analyzed the historical(1990-2005) observations on four agricultu...Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems.We analyzed the historical(1990-2005) observations on four agricultural long-term experiments in China(Changping,Chongqing,Gongzhuling and Qiyang) under four different fertilizations,i.e.,no-fertilizer(control),sole chemical nitrogen fertilizer(F N),sole chemical phosphorous and potassium fertilizers(F PK) and chemical nitrogen,phosphorous and potassium fertilizers(F NPK).The significant decline in topsoil pH was caused not only by chemical N fertilization(0.29 and 0.89 pH at Gongzhuling and Qiyang,respectively) but also by chemical PK fertilization(0.59 pH at Gongzhuling).The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P(168-599%)>available K(16-189%)>available N(9-33%).The relative rate of soil pH decline was lower under long-term judicious chemical fertilization(-0.036-0.034 pH yr-1) than that under long-term sole N or PK fertilization(0.016-0.086 pH yr-1).Long-term judicious chemical fertilization with N,P and K elements decreases the nutritional limitation to normal crop growth,under which more N output was distributed in biomass removal rather than the loss via nitrate leaching.We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.展开更多
Archaeal and bacterial ammonia-oxidizers drive the first step of nitrification,ammonia oxidation.Despite their importance,the relative contribution of soil factors influencing the abundance,diversity and community com...Archaeal and bacterial ammonia-oxidizers drive the first step of nitrification,ammonia oxidation.Despite their importance,the relative contribution of soil factors influencing the abundance,diversity and community composition of ammonia oxidizing archaea(AOA)and bacteria(AOB)are seldom compared.In this study,the AOA and AOB communities in soils from a long-term fertilization experiment(which formed gradients of pH and nutrients)were measured using 454 pyrosequencing of the amoA gene.Results showed that both AOA and AOB communities were influenced by fertilization practice.Changes of AOA abundance,diversity and community structure were closely correlated with a single factor,soil pH,and the abundance and diversity of AOA were lower under the acidified treatments.By contrast,AOB abundance was higher in the acidified soil than in the control soil while AOB diversity was little impacted by soil acidification,and both the abundance and diversity of AOB were most highly correlated with soil carbon and available phosphorus.These results indicated that AOB diversity seemed more resistant to soil acidification than that of AOA,and also suggested that AOB have greater ecophysiological diversity and broader range of habitats than AOA in this lime concretion black soil,and the potential contribution of AOB to ammonia oxidation in acid environments should not be overlooked.展开更多
In an agricultural field,the water content and salt content are defined as soil moisture and soil salinity and have to be estimated precisely.The changing of these two factors can be assessed using remote sensing tech...In an agricultural field,the water content and salt content are defined as soil moisture and soil salinity and have to be estimated precisely.The changing of these two factors can be assessed using remote sensing technology.This study was conducted by analysing the Landsat 8 satellite images,soil data of field surveys,laboratory analyses and statistical computations.Soil properties such as soil moisture and soil salinity were estimated using soil moisture index(SMI)and soil salinity index(SSI),respectively.The research combined and integrated the soil data from survey and laboratory with Landsat 8 satellite images to build two multiple regression equations model named the soil pH Index(SpHI).They are based on bare soil and paddy leaf models as the explanatory factors of soil moisture and soil salinity changes.All the computation processes were replicated three times using three different dates of Landsat 8 satellite images to produce the multi-temporal analysis.Soil moisture increased after 30 days,while the salt content was only trace amounts.Both proposed models detected 4.49–7.59 of soil pH,4.66 in bare soil model and 6.62 in paddy leaf model.During the planting period,the soil pH in bare soil model decreased to 2.12–6.47 while the paddy leaf model increased to 4.49–7.59 with RMSE 1.40 and PRMSE 24%of accuracy.The spatial relationship between soil pH,soil salinity and soil moisture are linear but varied in correlation level from weak,moderate to strong.Based on the bare soil model,the relationship between soil pH and soil moisture shows a weak negative relationship with R28.37%and a strong positive relationship with R281.94%in paddy area and bare soil area respectively,as like as in paddy area based on the paddy leaf model with R2100%.The relationship between soil temperature and soil pH shows a weak negative relationship for all models and a moderate negative relationship of soil salinity and soil pH in bare soil area based on the bare soil model with R234.89%.展开更多
Fungi play important roles in ecosystem processes, and the elevational pattern of fungal diversity is still unclear. Here, we examined the diversity of fungi along a 1,000 m elevation gradient on Mount Nadu, Southwest...Fungi play important roles in ecosystem processes, and the elevational pattern of fungal diversity is still unclear. Here, we examined the diversity of fungi along a 1,000 m elevation gradient on Mount Nadu, Southwestern China. We used MiSeq sequencing to obtain fungal sequences that were clustered into operational taxonomic units(OTUs) and to measure the fungal composition and diversity. Though the species richness and phylogenetic diversity of the fungal community did not exhibit significant trends with increasing altitude, they were significantly lower at mid-altitudinal sites than at the base. The Bray-Curtis distance clustering also showed that the fungal communities varied significantly with altitude. A distance-based linear model multivariate analysis(DistLM) identified that soil pH dominated the explanatory power of the species richness(23.72%),phylogenetic diversity(24.25%) and beta diversity(28.10%) of the fungal community. Moreover, the species richness and phylogenetic diversity of the fungal community increased linearly with increasing soil pH(P<0.05). Our study provides evidence that pH is an important predictor of soil fungal diversity along elevation gradients in Southwestern China.展开更多
The distributions of microbial tetraether lipids i.e. glycerol dialkyl glycerol tetraethers (GDGTs) were investigated in a variety of Chinese soils featured by a wide range of pH values in different climate zones. The...The distributions of microbial tetraether lipids i.e. glycerol dialkyl glycerol tetraethers (GDGTs) were investigated in a variety of Chinese soils featured by a wide range of pH values in different climate zones. The bacterial branched GDGTs and archaeal isoprenoid GDGTs were found to be widely distributed in Chinese soils and their relative abundance was controlled primarily by soil pH. The bacterial bGDGTs usually dominate over archaeal iGDGTs in abundance when the soil pH is below 8.0. However archaeal iGDGTs become dominant and the abundance of halophilic archaea characterized by GDGT V without cyclopentyl ring increases dramatically in the alkaline soil with pH greater than 8.0. The relative abundance of archaeal iGDGTs to bacterial bGDGTs was defined here as RAI index. The RAI index decreases with elevated soil pH and a linear correlation is found between them indicating that the relative abundance of archaeal iGDGTs to bacterial bGDGTs increases with increased pH. The RAI index thus could be a novel proxy of the pH values of paleosol. The terrestrial input index BIT (Branched and Isoprenoid Tetraethers Index) decreases with increased soil pH suggesting that soil pH should be taken into consideration when the terrestrial contribution to marine sediments is estimated by BIT index. Moreover the TEX86 index cannot be used to reconstruct sea surface temperature in the sediments featured by a large terrestrial input.展开更多
The impact of pH changes on microbial biomass carbon (Cmic) and microbial biomass phosphorus (Pmic)were examined for 3 red soils under citrus production with different lengths of cultivation. Soil pH significantly aff...The impact of pH changes on microbial biomass carbon (Cmic) and microbial biomass phosphorus (Pmic)were examined for 3 red soils under citrus production with different lengths of cultivation. Soil pH significantly affected Cmic and Pmic. The Cmic and Pmic changes, as a function of soil pH, appeared to follow a normal distribution with the original soil pH value at the apex and as pH increased or decreased compared to the original soil pH, Cmic and Pmic declined. Moreover, there were critical pH values at both extremes (3.0 on the acidic side and 8.0 to 8.5 on the alkaline side), beyond which most of microorganisms could never survive.The effect of pH on Cmic and Pmic was also related to the original soil pH. The higher the original soil pH was, the less Cmic or Pmic were affected by pH change. It is suggested that soil microorganisms that grow in a soil environment with a more neutral soil pH range (I.e. pH 5.5-7.5) may have a greater tolerance to pH changes than those growing in more acidic or more alkaline soil pH conditions.展开更多
Declining soil fertility is a major constraint to potato farming, the second most important food crop in Kenya. The objective of the study was to determine the effect of different rates of biochar and inorganic fertil...Declining soil fertility is a major constraint to potato farming, the second most important food crop in Kenya. The objective of the study was to determine the effect of different rates of biochar and inorganic fertilizer on some soil properties;soil pH, soil phosphomonoesterases, inorganic nitrogen and extractable phosphorus. The study was conducted for two seasons (short and long rains) at two locations (Egerton University agricultural field and farmer’s field in Mau Narok) using a split-plot design in a randomized complete block (RCBD) arrangement with variety as the main plot and soil amendments as the subplot. Biochar and Diammonium Phosphate (DAP) at 0, 5, and 10 t⋅ha<sup>−1</sup> and 0, 250, and 500 kg⋅ha<sup>−1</sup> respectively, were applied, resulting in nine treatment combinations. Two potato varieties (Shangi and Destiny) were used in the study. A combination of 5 t⋅ha<sup>−1</sup> biochar and 500 kg⋅ha<sup>−1</sup> DAP and sole application of biochar at 5 t⋅ha<sup>−1</sup> resulted in an increase of 1.25, 2.54 units in soil pH in two seasons, respectively. Similarly, a combination of 5 t⋅ha<sup>−1</sup> biochar and 250 kg⋅ha<sup>−1</sup> DAP increased soil available phosphorus by 105 units from 30.7 mg⋅kg<sup>−1</sup> to 136 mg⋅kg<sup>−1</sup>. The application rate of 5 t⋅ha<sup>−1</sup> biochar with 250 or 500 kg⋅ha<sup>−1</sup> DAP significantly increased soil nitrate by 102.11 and 116.14 units, respectively. Soils amended with biochar at 5 t⋅ha<sup>−1</sup> combined with 500 kg⋅ha<sup>−1</sup> DAP, 10 t⋅ha<sup>−1</sup> of biochar combined with either 250 kg or 500 kg of DAP gave the highest alkaline enzymes (mM pNP × kg<sup>−1</sup> × h<sup>−1</sup>). However, the highest acid soil phosphomonoesterases were obtained under the sole application of DAP at 500 ha<sup>−1</sup>. Thus, using biochar with chemical fertilizer seems a plausible option to ameliorate the declining nutrient base of farmland in Kenya, which could sustainably support potato growth.展开更多
为量化生物炭施用对土壤pH的影响,为生物炭在改良土壤、培肥地力中提供理论依据,采用数据整合分析(Meta-analysis)的方法,基于中国知网、万方数据和Web of Science数据库,用关键词“生物炭”“Biochar”“土壤pH”和“土壤酸碱度”进行...为量化生物炭施用对土壤pH的影响,为生物炭在改良土壤、培肥地力中提供理论依据,采用数据整合分析(Meta-analysis)的方法,基于中国知网、万方数据和Web of Science数据库,用关键词“生物炭”“Biochar”“土壤pH”和“土壤酸碱度”进行检索,收集到国内外关于生物炭对土壤酸碱度影响研究已公开发表的59篇文献中413组试验数据,分析土壤条件、生物炭特性、生物炭施用量等对土壤pH的定量影响。结果表明,与不施生物炭相比,生物炭施用能显著提高土壤pH,平均增幅为8.70%。其中,以强酸性(4.5<pH≤5.5)和极强酸性土壤(pH≤4.5)增幅最大,分别为15.17%和9.68%;不同原料生物炭对土壤pH的提升效果表现为秸秆类生物炭(10.04%)>壳渣类生物炭(7.02%)>木材类生物炭(6.61%)。不同热解温度下,以≤400℃制得的生物炭提升效果最佳,为15.26%;而在热解温度400~700℃时,随着热解温度升高,提升效果降低。施用生物炭3个月内土壤pH的增幅最大,之后增幅逐渐减缓。以上结果表明在强酸性(4.5<pH≤5.5)土壤中,优先选用秸秆低温(≤400℃)热解生物炭施用能更好地改善土壤pH,结果为生物炭的推广应用提供科学依据。展开更多
基金supported by China Geological Survey(DD20230554,DD20230089)the Strategic Priority Research Program of the Chinese Academy of Science(XDA28020302)the funding project of Northeast Geological S&T Innovation Center of China Geological Survey(QCJJ2022-40).
文摘To illuminate the spatio-temporal variation characteristics and geochemical driving mechanism of soil pH in the Nenjiang River Basin,the National Multi-objective Regional Geochemical Survey data of topsoil,the Second National Soil Survey data and Normalized Difference Vegetation Index(NDVI)were analyzed.The areas of neutral and alkaline soil decreased by 21100 km^(2)and 30500 km^(2),respectively,while that of strongly alkaline,extremely alkaline,and strongly acidic soil increased by 19600 km^(2),18200 km^(2),and 15500 km^(2),respectively,during the past 30 years.NDVI decreased with the increase of soil pH when soil pH>8.0,and it was reversed when soil pH<5.0.There were significant differences in soil pH with various surface cover types,which showed an ascending order:Arbor<reed<maize<rice<high and medium-covered meadow<low-covered meadow<Puccinellia.The weathering products of minerals rich in K_(2)O,Na_(2)O,CaO,and MgO entered into the low plain and were enriched in different parts by water transportation and lake deposition,while Fe and Al remained in the low hilly areas,which was the geochemical driving mechanism.The results of this study will provide scientific basis for making scientific and rational decisions on soil acidification and salinization.
基金Doctoral Research Start-up Fund Project of Liaoning Province(2019-B-237)National Special Project for the Construction of Modern Agricultural Industrial Technology System(CARS-01-51).
文摘[Objectives]In order to explore the feasibility of using straw and biochar returned to the soil to improve soil physical properties and pH value in cold rice regions of China.[Methods]the effects of straw directly returned to the soil and charred straw(biochar)returned to the soil on soil bulk density,porosity,temperature and pH value of cold paddy soil were studied in this paper.[Results]The results showed that compared with conventional production,straw(6 t/ha),a small amount of biochar(2 t/ha)and a large amount of biochar(40 t/ha)returned to the soil reduced paddy soil bulk density at different growth stages by 6.02%-11.86%,2.69%-6.67%and 8.58%-11.32%,respectively,increased total porosity by 7.41%-14.93%,3.19%-8.38%and 9.81%-14.27%,respectively,and increased aeration porosity by 22.28%-192.11%,17.80%-92.11%and 52.44%-157.11%,respectively.Straw and a small amount of biochar returned to the soil had no significant effect on soil temperature and pH value of paddy field,but a large amount of biochar returned to the soil could significantly increase soil temperature by 5.13%-8.79%and pH value by 3.15%-5.96%in the later stage of rice growth.[Conclusions]The straw and biochar returned to the soil could reduce soil bulk density,increase total porosity and aeration porosity,and only a large amount of biochar returned to the soil could significantly increase soil temperature and pH value.
基金support of National Natural Science Foundation of China(Nos.21873076,21675123,21605123,21375105)Natural Science Basic Research Plan in Shaanxi Province of China(No.2018JQ2013)Scientific Research Plan Projects of Shaanxi Education Department(No.17JK0780)。
文摘pH is one of the significant properties of soil,and is closely related to the decomposition of soil organic matter,anion-cation balance,growth of plants and many other soil processes.In the present work,laser-induced breakdown spectroscopy(LIBS) technique coupled with random forest(RF) was proposed to quantify the pH of soil.First,LIBS spectra of soil was collected,and some common elements in soil were identified based on the National Institute of Science and Technology database.Then,in order to obtain a better predictive result,the influence of different input variables(full spectrum,different spectral ranges,the intensity of characteristic bands and characteristic lines) on the predictive performance of RF calibration model was explored with the evaluation indicators of root mean square error(RMSE) and coefficient of determination(R2),the characteristic bands of four elements(AI,Ca,Mg and Si) were determined as the optimal input variables.Finally,the predictive performance of RF calibration model was compared with partial least squares calibration model with the optimal input variables and model parameters,and RF calibration model showed a better predictive performance,and the four evaluation indicators of R_p^2,RMSEP,mean absolute error and mean relative error were 0.9687,0.1285,0.1114 and 0.0136,respectively.It indicates that LIBS technique coupled with RF algorithm is an effective method for pH determination of soil.
基金Supported by Ministry of Education Project of Integrating Production, Teaching and Research in Guangdong Province(2009B09030332)Science and Technology Plan Project in Guangdong Province (2010A020506022)Special Public Welfare Industry(Agriculture) Scientific Research Foundation of Ministry of Agriculture(201103003)
文摘Through field experiment,we explore the impact of long-term drip fertigation on growth and distribution of lychee root and changes of soil pH in different layers of soil in lychee garden.The results show that drip fertigation can significantly promote the growth of lychee roots,and increase the contact area of root and soil;if it experiences six years of drip fertigation successively,the dry weight of root,root length and surface area of root in soil in drip fertigation area,will be 2.29 times,2.17 times and 2.25 times that in non-drip fertigation area,respectively.The lychee root is mainly distributed in 0-40 cm layer of soil,but there is conspicuous difference between drip fertigation area and non-drip fertigation area in terms of root distribution in 0-20 cm and 20-40 cm layer of soil.Drip fertigation is more favorable for the root to go deep inside the soil.Under long-term drip fertigation,the soil acidification in lychee garden is prominent,and in comparison with non-drip fertigation area,there is the greatest decline in soil pH in 10-20 cm layer of soil in drip fertigation area,reaching 1.47 units.
基金Supported by Research Project of Zhumadian Branch of Henan Provincial Tobacco Company(201641170024101)。
文摘[Objective]The paper was to study the relationship between spatial distribution characteristics of soil p H and bacterial wilt in tobacco-growing area in Henan Province.[Method]The 21 tobacco-growing fields infected by bacterial wilt and 91 tobacco-growing fields with no cases were selected from Henan Province,and the pH of fields was determined.[Result]Bacterial wilt mainly occurred in the tobacco-growing fields in Luoshan,Pingqiao,Queshan,Biyang,Suiping,and Xiping,and the soil pH mainly ranged from 5.5 to 6.5(accounted for 84.75%of total surveyed tobacco fields);bacterial wilt had not been found in tobacco-growing fields in Tanghe,Zhengyang,Shangcai,Sheqi,Wuyang and Chenqu,and the soil pH mainly ranged from 6.5 to 7.0(accounted for 81.25%of total surveyed tobacco fields).There were significant differences in soil pH between the fields with and without bacterial wilt,and soil pH 6.5 could be regarded as the threshold for the occurrence of tobacco bacterial wilt in Henan Province.There was extremely significantly positive linear correlation between soil p H and latitude(y=0.7375 x-17.799,R2=0.386,P<0.01).The geographical boundary of soil pH 6.5 was roughly 33°N,and bacterial wilt was less likely to occur in the north tobacco-growing areas of the boundary.[Conclusion]The study will provide a scientific basis for the prevention and control of tobacco bacterial wilt in Henan.
基金provided by the National 973 Program of China(2011CB100501 and 2014CB441001)the National Natural Science Foundation of China(41071200)
文摘Long-term fertilization experiment provides the platform for understanding the proton budgets in nitrogen transformations of agricultural ecosystems.We analyzed the historical(1990-2005) observations on four agricultural long-term experiments in China(Changping,Chongqing,Gongzhuling and Qiyang) under four different fertilizations,i.e.,no-fertilizer(control),sole chemical nitrogen fertilizer(F N),sole chemical phosphorous and potassium fertilizers(F PK) and chemical nitrogen,phosphorous and potassium fertilizers(F NPK).The significant decline in topsoil pH was caused not only by chemical N fertilization(0.29 and 0.89 pH at Gongzhuling and Qiyang,respectively) but also by chemical PK fertilization(0.59 pH at Gongzhuling).The enhancement of available nutrients in the topsoil due to long-term direct nutrients supply with chemical fertilizers was in the descending order of available P(168-599%)>available K(16-189%)>available N(9-33%).The relative rate of soil pH decline was lower under long-term judicious chemical fertilization(-0.036-0.034 pH yr-1) than that under long-term sole N or PK fertilization(0.016-0.086 pH yr-1).Long-term judicious chemical fertilization with N,P and K elements decreases the nutritional limitation to normal crop growth,under which more N output was distributed in biomass removal rather than the loss via nitrate leaching.We concluded that the N distribution percentage of nitrate leaching to biomass removal might be a suitable indicator to the sensitivity of agricultural ecosystems to acid inputs.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB15010101)the National Natural Science Foundation of China(31870480)the National Key Research and Development Program of China(2017YFD0800604).
文摘Archaeal and bacterial ammonia-oxidizers drive the first step of nitrification,ammonia oxidation.Despite their importance,the relative contribution of soil factors influencing the abundance,diversity and community composition of ammonia oxidizing archaea(AOA)and bacteria(AOB)are seldom compared.In this study,the AOA and AOB communities in soils from a long-term fertilization experiment(which formed gradients of pH and nutrients)were measured using 454 pyrosequencing of the amoA gene.Results showed that both AOA and AOB communities were influenced by fertilization practice.Changes of AOA abundance,diversity and community structure were closely correlated with a single factor,soil pH,and the abundance and diversity of AOA were lower under the acidified treatments.By contrast,AOB abundance was higher in the acidified soil than in the control soil while AOB diversity was little impacted by soil acidification,and both the abundance and diversity of AOB were most highly correlated with soil carbon and available phosphorus.These results indicated that AOB diversity seemed more resistant to soil acidification than that of AOA,and also suggested that AOB have greater ecophysiological diversity and broader range of habitats than AOA in this lime concretion black soil,and the potential contribution of AOB to ammonia oxidation in acid environments should not be overlooked.
文摘In an agricultural field,the water content and salt content are defined as soil moisture and soil salinity and have to be estimated precisely.The changing of these two factors can be assessed using remote sensing technology.This study was conducted by analysing the Landsat 8 satellite images,soil data of field surveys,laboratory analyses and statistical computations.Soil properties such as soil moisture and soil salinity were estimated using soil moisture index(SMI)and soil salinity index(SSI),respectively.The research combined and integrated the soil data from survey and laboratory with Landsat 8 satellite images to build two multiple regression equations model named the soil pH Index(SpHI).They are based on bare soil and paddy leaf models as the explanatory factors of soil moisture and soil salinity changes.All the computation processes were replicated three times using three different dates of Landsat 8 satellite images to produce the multi-temporal analysis.Soil moisture increased after 30 days,while the salt content was only trace amounts.Both proposed models detected 4.49–7.59 of soil pH,4.66 in bare soil model and 6.62 in paddy leaf model.During the planting period,the soil pH in bare soil model decreased to 2.12–6.47 while the paddy leaf model increased to 4.49–7.59 with RMSE 1.40 and PRMSE 24%of accuracy.The spatial relationship between soil pH,soil salinity and soil moisture are linear but varied in correlation level from weak,moderate to strong.Based on the bare soil model,the relationship between soil pH and soil moisture shows a weak negative relationship with R28.37%and a strong positive relationship with R281.94%in paddy area and bare soil area respectively,as like as in paddy area based on the paddy leaf model with R2100%.The relationship between soil temperature and soil pH shows a weak negative relationship for all models and a moderate negative relationship of soil salinity and soil pH in bare soil area based on the bare soil model with R234.89%.
基金supported by the National Natural Science Foundation of China(41071039)the Ministry of Science and Technology of China(2012CB417103)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA05060100)
文摘Fungi play important roles in ecosystem processes, and the elevational pattern of fungal diversity is still unclear. Here, we examined the diversity of fungi along a 1,000 m elevation gradient on Mount Nadu, Southwestern China. We used MiSeq sequencing to obtain fungal sequences that were clustered into operational taxonomic units(OTUs) and to measure the fungal composition and diversity. Though the species richness and phylogenetic diversity of the fungal community did not exhibit significant trends with increasing altitude, they were significantly lower at mid-altitudinal sites than at the base. The Bray-Curtis distance clustering also showed that the fungal communities varied significantly with altitude. A distance-based linear model multivariate analysis(DistLM) identified that soil pH dominated the explanatory power of the species richness(23.72%),phylogenetic diversity(24.25%) and beta diversity(28.10%) of the fungal community. Moreover, the species richness and phylogenetic diversity of the fungal community increased linearly with increasing soil pH(P<0.05). Our study provides evidence that pH is an important predictor of soil fungal diversity along elevation gradients in Southwestern China.
基金supported by National Basic Research Program of China (Grant No. 2011CB808800)National Natural Science Foundation of China (Grant Nos. 40930210 and 40921062)‘111’ Project (Grant No. B08030)
文摘The distributions of microbial tetraether lipids i.e. glycerol dialkyl glycerol tetraethers (GDGTs) were investigated in a variety of Chinese soils featured by a wide range of pH values in different climate zones. The bacterial branched GDGTs and archaeal isoprenoid GDGTs were found to be widely distributed in Chinese soils and their relative abundance was controlled primarily by soil pH. The bacterial bGDGTs usually dominate over archaeal iGDGTs in abundance when the soil pH is below 8.0. However archaeal iGDGTs become dominant and the abundance of halophilic archaea characterized by GDGT V without cyclopentyl ring increases dramatically in the alkaline soil with pH greater than 8.0. The relative abundance of archaeal iGDGTs to bacterial bGDGTs was defined here as RAI index. The RAI index decreases with elevated soil pH and a linear correlation is found between them indicating that the relative abundance of archaeal iGDGTs to bacterial bGDGTs increases with increased pH. The RAI index thus could be a novel proxy of the pH values of paleosol. The terrestrial input index BIT (Branched and Isoprenoid Tetraethers Index) decreases with increased soil pH suggesting that soil pH should be taken into consideration when the terrestrial contribution to marine sediments is estimated by BIT index. Moreover the TEX86 index cannot be used to reconstruct sea surface temperature in the sediments featured by a large terrestrial input.
基金Project supported by the National Natural Science Foundation of China (No. 40025104).
文摘The impact of pH changes on microbial biomass carbon (Cmic) and microbial biomass phosphorus (Pmic)were examined for 3 red soils under citrus production with different lengths of cultivation. Soil pH significantly affected Cmic and Pmic. The Cmic and Pmic changes, as a function of soil pH, appeared to follow a normal distribution with the original soil pH value at the apex and as pH increased or decreased compared to the original soil pH, Cmic and Pmic declined. Moreover, there were critical pH values at both extremes (3.0 on the acidic side and 8.0 to 8.5 on the alkaline side), beyond which most of microorganisms could never survive.The effect of pH on Cmic and Pmic was also related to the original soil pH. The higher the original soil pH was, the less Cmic or Pmic were affected by pH change. It is suggested that soil microorganisms that grow in a soil environment with a more neutral soil pH range (I.e. pH 5.5-7.5) may have a greater tolerance to pH changes than those growing in more acidic or more alkaline soil pH conditions.
文摘Declining soil fertility is a major constraint to potato farming, the second most important food crop in Kenya. The objective of the study was to determine the effect of different rates of biochar and inorganic fertilizer on some soil properties;soil pH, soil phosphomonoesterases, inorganic nitrogen and extractable phosphorus. The study was conducted for two seasons (short and long rains) at two locations (Egerton University agricultural field and farmer’s field in Mau Narok) using a split-plot design in a randomized complete block (RCBD) arrangement with variety as the main plot and soil amendments as the subplot. Biochar and Diammonium Phosphate (DAP) at 0, 5, and 10 t⋅ha<sup>−1</sup> and 0, 250, and 500 kg⋅ha<sup>−1</sup> respectively, were applied, resulting in nine treatment combinations. Two potato varieties (Shangi and Destiny) were used in the study. A combination of 5 t⋅ha<sup>−1</sup> biochar and 500 kg⋅ha<sup>−1</sup> DAP and sole application of biochar at 5 t⋅ha<sup>−1</sup> resulted in an increase of 1.25, 2.54 units in soil pH in two seasons, respectively. Similarly, a combination of 5 t⋅ha<sup>−1</sup> biochar and 250 kg⋅ha<sup>−1</sup> DAP increased soil available phosphorus by 105 units from 30.7 mg⋅kg<sup>−1</sup> to 136 mg⋅kg<sup>−1</sup>. The application rate of 5 t⋅ha<sup>−1</sup> biochar with 250 or 500 kg⋅ha<sup>−1</sup> DAP significantly increased soil nitrate by 102.11 and 116.14 units, respectively. Soils amended with biochar at 5 t⋅ha<sup>−1</sup> combined with 500 kg⋅ha<sup>−1</sup> DAP, 10 t⋅ha<sup>−1</sup> of biochar combined with either 250 kg or 500 kg of DAP gave the highest alkaline enzymes (mM pNP × kg<sup>−1</sup> × h<sup>−1</sup>). However, the highest acid soil phosphomonoesterases were obtained under the sole application of DAP at 500 ha<sup>−1</sup>. Thus, using biochar with chemical fertilizer seems a plausible option to ameliorate the declining nutrient base of farmland in Kenya, which could sustainably support potato growth.
文摘为量化生物炭施用对土壤pH的影响,为生物炭在改良土壤、培肥地力中提供理论依据,采用数据整合分析(Meta-analysis)的方法,基于中国知网、万方数据和Web of Science数据库,用关键词“生物炭”“Biochar”“土壤pH”和“土壤酸碱度”进行检索,收集到国内外关于生物炭对土壤酸碱度影响研究已公开发表的59篇文献中413组试验数据,分析土壤条件、生物炭特性、生物炭施用量等对土壤pH的定量影响。结果表明,与不施生物炭相比,生物炭施用能显著提高土壤pH,平均增幅为8.70%。其中,以强酸性(4.5<pH≤5.5)和极强酸性土壤(pH≤4.5)增幅最大,分别为15.17%和9.68%;不同原料生物炭对土壤pH的提升效果表现为秸秆类生物炭(10.04%)>壳渣类生物炭(7.02%)>木材类生物炭(6.61%)。不同热解温度下,以≤400℃制得的生物炭提升效果最佳,为15.26%;而在热解温度400~700℃时,随着热解温度升高,提升效果降低。施用生物炭3个月内土壤pH的增幅最大,之后增幅逐渐减缓。以上结果表明在强酸性(4.5<pH≤5.5)土壤中,优先选用秸秆低温(≤400℃)热解生物炭施用能更好地改善土壤pH,结果为生物炭的推广应用提供科学依据。
