خيارات البحث
النتائج 1 - 10 من 2,838
Reclamation status of a degraded pasture based on soil health indicators النص الكامل
2015
Santos, Cristiane Alcantara dos | Krawulski, Cristina Célia | Bini, Daniel | Goulart Filho, Tadeu | Knob, Adriana | Medina, Cristiane Conti | Andrade Filho, Galdino | Nogueira, Marco Antonio
Reclamation status of a degraded pasture based on soil health indicators النص الكامل
2015
Santos, Cristiane Alcantara dos | Krawulski, Cristina Célia | Bini, Daniel | Goulart Filho, Tadeu | Knob, Adriana | Medina, Cristiane Conti | Andrade Filho, Galdino | Nogueira, Marco Antonio
Pasture degradation is a concern, especially in susceptible sandy soils for which strategies to recover them must be developed. Microbiological and biochemical soil health indicators are useful in the guindace of soil management practices and sustainable soil use. We assessed the success of threePanicum maximum Jacq. cultivars in the reclamation of a pasture in a sandy Typic Acrudox in the northwest of the state of Paraná, Brazil, based on soil health indicators. On a formerly degraded pasture withUrochloa brizantha (Hochst. ex A. Rich.) R.D. Webster, a trial with threeP. maximum (cv. Massai, Tanzânia, or Mombaça) was conducted. Lime and phosphate were applied at set-up, and mineral N and K as topdressing. A remnant of degraded pasture adjacent to the trial was used as control. Twenty-three chemical, physical, microbiological and biochemical attributes were assessed for the 0-10 cm topsoil. The procedures for reclamation improved most of the indicators of soil health in relation to the degraded pasture, such as soil P, mineral N, microbial biomass C, ammonification rate, dehydrogenase activity and acid phosphatase. CO2 evolution decreased, whereas microbial biomass C increased in the pasture under reclamation, resulting in a lower metabolic quotient (qCO2) that points to a decrease in metabolic stress of the microbial community. The reclamation of the pasture withP. maximum, especially cv. Mombaça, were evidenced by improvements in the microbiological and biochemical soil health indicators, showing a recovery of processes related to C, N and P cycling in the soil.
اظهر المزيد [+] اقل [-]Reclamation status of a degraded pasture based on soil health indicators النص الكامل
2015
Cristiane Alcantara dos Santos | Cristina Célia Krawulski | Daniel Bini | Tadeu Goulart Filho | Adriana Knob | Cristiane Conti Medina | Galdino Andrade Filho | Marco Antonio Nogueira
Pasture degradation is a concern, especially in susceptible sandy soils for which strategies to recover them must be developed. Microbiological and biochemical soil health indicators are useful in the guindace of soil management practices and sustainable soil use. We assessed the success of threePanicum maximum Jacq. cultivars in the reclamation of a pasture in a sandy Typic Acrudox in the northwest of the state of Paraná, Brazil, based on soil health indicators. On a formerly degraded pasture withUrochloa brizantha (Hochst. ex A. Rich.) R.D. Webster, a trial with threeP. maximum (cv. Massai, Tanzânia, or Mombaça) was conducted. Lime and phosphate were applied at set-up, and mineral N and K as topdressing. A remnant of degraded pasture adjacent to the trial was used as control. Twenty-three chemical, physical, microbiological and biochemical attributes were assessed for the 0-10 cm topsoil. The procedures for reclamation improved most of the indicators of soil health in relation to the degraded pasture, such as soil P, mineral N, microbial biomass C, ammonification rate, dehydrogenase activity and acid phosphatase. CO2 evolution decreased, whereas microbial biomass C increased in the pasture under reclamation, resulting in a lower metabolic quotient (qCO2) that points to a decrease in metabolic stress of the microbial community. The reclamation of the pasture withP. maximum, especially cv. Mombaça, were evidenced by improvements in the microbiological and biochemical soil health indicators, showing a recovery of processes related to C, N and P cycling in the soil.
اظهر المزيد [+] اقل [-]A microbial biomass and respiration of soil, peat and decomposing plant litter in a raised mire النص الكامل
2015
S. Hall | D.W. Hopkins
We have compared microbial biomass and respiration rates in soils and decomposition of peat materials from the different components of a raised mire system. The microbial biomass in the lagg fen was not greater than that of the mineral soil or the mire expanse, but the respiration rate of the decomposer organisms in the lagg fen exceeded that of either the mire expanse or surrounding mineral soils. The respiration rate of microorganisms in litter recovered from litter bags in the lagg fen was greater than that in the mire expanse, and the microbial biomass of the litter was greater for the lagg fen than for either the mineral soil or the mire expanse. Further, the litter from minerotrophic plants decomposed faster than the ombrotrophic species.
اظهر المزيد [+] اقل [-]Assessment of biomass transfer from green manure to soil macrofauna in agroecosystem-soil macrofauna biomass النص الكامل
2015
ml opondo-mbai | mj swift | f.o. ayuke | mr rao
F.O. Ayuke, MR Rao, MJ Swift, ML Opondo-Mbai, 'Assessment of biomass transfer from green manure to soil macrofauna in agroecosystem-soil macrofauna biomass', Academy Science Publishers (ASP); Centro Internacional de Agricultura Tropical (CIAT), 2015
اظهر المزيد [+] اقل [-]Cover Crops for Managing Weeds, Soil Chemical Fertility and Nutritional Status of Organically Grown Orange Orchard in Sicily النص الكامل
2015
Mauro, Rosario Paolo | Anastasi, Umberto | Lombardo, Sara | Pandino, Gaetano | Pesce, Roberto | Restuccia, Alessia | Mauromicale, Giovanni
Cover Crops for Managing Weeds, Soil Chemical Fertility and Nutritional Status of Organically Grown Orange Orchard in Sicily النص الكامل
2015
Mauro, Rosario Paolo | Anastasi, Umberto | Lombardo, Sara | Pandino, Gaetano | Pesce, Roberto | Restuccia, Alessia | Mauromicale, Giovanni
Cover crops can offer significant advantages in the agronomic management of citrus orchards in Mediterranean environments. Therefore, a three-year research was conducted in eastern Sicily aimed at studying the effects of four cover crop sequences (Sinapis arvensis-Trigonella foenum-graecum-T. foenum-graecum; Medicago scutellata-Avena sativa-Lolium perenne; Vicia faba minor-A. sativa-A. sativa; A. sativa-V. faba. minor-L. perenne) on weeds, major soil chemical properties and nutritional status of an organically grown orange orchard. The results highlighted that, among the studied cover crop sequences, Vicia faba-Avena-Avena was the most beneficial for weeds control within the orchard (92%, of cover crop cover, and 586 and 89 g DW m–² of cover crop aboveground biomass and weeds aboveground biomass, respectively). Overall, the chemical fertility of the soil was positively influenced. In particular, it was observed an increase of the content of total nitrogen and available phosphorus in the soil by both Sinapis-Trigonella-Trigonella (0.75 g kg–¹ and 59.0 mg kg–¹, respectively) and Vicia faba-Avena-Avena (0.70 g kg–¹ and 56.0 mg kg–¹, respectively) cover crop sequences. Medicago-Avena-Lolium sequence seemed to be the most useful to ensure a better nutritional status of the orange orchard.
اظهر المزيد [+] اقل [-]Cover crops for managing weeds, soil chemical fertility and nutritional status of organically grown orange orchard in Sicily النص الكامل
2015
Rosario Paolo Mauro | Umberto Anastasi | Sara Lombardo | Gaetano Pandino | Roberto Pesce | Restuccia Alessia | Giovanni Mauromicale
Cover crops can offer significant advantages in the agronomic management of citrus orchards in Mediterranean environments. Therefore, a three-year research was conducted in eastern Sicily aimed at studying the effects of four cover crop sequences (Sinapis arvensis-Trigonella foenum-graecum-T. foenum-graecum; Medicago scutellata-Avena sativa-Lolium perenne; Vicia faba minor-A. sativa-A. sativa; A. sativa-V. faba. minor-L. perenne) on weeds, major soil chemical properties and nutritional status of an organically grown orange orchard. The results highlighted that, among the studied cover crop sequences, Vicia faba-Avena-Avena was the most beneficial for weeds control within the orchard (92%, of cover crop cover, and 586 and 89 g DW m–2 of cover crop aboveground biomass and weeds aboveground biomass, respectively). Overall, the chemical fertility of the soil was positively influenced. In particular, it was observed an increase of the content of total nitrogen and available phosphorus in the soil by both Sinapis-Trigonella-Trigonella (0.75 g kg–1 and 59.0 mg kg–1, respectively) and Vicia faba-Avena-Avena (0.70 g kg–1 and 56.0 mg kg–1, respectively) cover crop sequences. Medicago-Avena-Lolium sequence seemed to be the most useful to ensure a better nutritional status of the orange orchard.
اظهر المزيد [+] اقل [-]Characteristics of rhizosphere and bulk soil microbial communities in rubber plantations in Hainan Island, China النص الكامل
2015
Wang, W. B. | Guo, H. C. | Luo, X. H. | Wu, X. P.
Phospholipid fatty acid analysis was used to investigate spatial variations in microbial communities of rhizosphere and bulk soil in rubber plantations in Hainan Island. Rhizosphere and bulk soil were collected from immature and mature rubber trees in areas with four different soil parent material types. For each site, total microbial biomass and biomass of bacteria, fungi, actinomycetes and ratio of fungi to bacteria in rhizosphere were significantly higher than those in bulk soil. The rhizosphere/bulk soil ratio for fungi in soil derived from basalt ranged from 10.44 to 12.33, which were significantly higher than those in soil derived from granitic gneiss, shallow marine deposits and granite (2.22–6.00). Total microbial biomass and bacterial biomass were positively correlated with soil organic carbon and total N in both rhizosphere and bulk soil. Total microbial biomass and biomass of bacteria, fungi and actinomycetes were correlated with soil total P in the rhizosphere. Rhizosphere total microbial biomass decreased in soil derived from basalt and increased in soil derived from shallow marine deposits with increasing age of rubber trees. The main factor affecting the composition of microbial communities in bulk and rhizosphere soil was soil parent material.
اظهر المزيد [+] اقل [-]The relationship between soil microbial activity and microbial biomass, soil structure and grassland management النص الكامل
2015
Cui, Junfang | Holden, Nicholas M.
The question of how soil structure interacts with microbial biomass is poorly understood. Most research on soil structure and soil microbial activity has been based on laboratory measurements of soil properties that are indirectly indicative of soil structure, and very few have used direct field data. This study assessed soil structural quality in situ by visual evaluation of soil structure method (VESS) and measured microbial activity related to soil carbon (C) and nitrogen (N) cycles under various grassland management to assess whether soil structure is correlated with microbial activity, both of which are regulated by agricultural management. Soil structure (indicated by Sq score) was strongly negatively correlated with both soil respiration and enzyme activity, indicating a decline in microbial activity with poorer soil structural quality. Both frequent reseeding and N fertilizer application were positively correlated with enzyme activity indicating that these management activities, planned to improve yield can have positive impacts on C input to the soil as well. The increase in enzyme activity under higher stocking rate was perhaps driven by soil C re-location to depth by animal trampling. The strong correlation between soil structure and C and microbial activity and C indicated a two-way ‘bridge’ function of soil C regulated by management. Good structure is supportive of soil organic matter decomposition by supplying optimal physical conditions, which supply food source for soil microbes and the soil processes of soil C dominated by microbial activity are beneficial for soil structure formation. However, further research is required to better understand this two-way C ‘bridge’ function.
اظهر المزيد [+] اقل [-]Effect of long term cropping hybrid sorrel (Rumex patientia x Rumex tianshanicus) on soil biota النص الكامل
2015
Heděnec, Petr | Novotný, David | Ust'ak, Sergej | Honzík, Roman | Váňa, Vojtěch | Petříková, Vlasta | Frouz, Jan
Our study is focused on the effects of long-term cultivation of hybrid sorrel on basal soil respiration, specific microbial respiration, microbial biomass carbon, the composition of the cultivable soil fungal community, and the composition of soil meso- and macrofauna communities. In a split-plot field experiment in Chotýšany near Vlašim (Central Bohemia, Czech Republic), fields with hybrid sorrel (2 and 10 years old), oilseed rape/wheat rotation (>10 years old), and cultural meadow (>10 years old) were compared. The density and composition of soil meso- and macrofauna communities differed among fields. Soil meso- and macrofauna density were lowest in soils covered by oilseed rape/wheat rotation, while highest density was found in soil overgrown by cultural meadow species. Hybrid sorrel fields contained more pathogenic fungi than oilseed rape/wheat fields or cultural meadows but the difference was only marginally significant. Basal soil respiration and specific microbial respiration (qCO2) were highest in oilseed rape/wheat fields, and microbial biomass was highest in cultural meadows. In conclusion results show that long term effect of hybrid sorrel cultivation alters soil community structure, however the range is in the variation between existing annual and perennial landscape cover. Only exception is higher occurrence of pathogenic fungi but its ecological relevance require future attention.
اظهر المزيد [+] اقل [-]Can Biochar From Contaminated Biomass Be Applied Into Soil for Remediation Purposes? النص الكامل
2015
Břendová, Kateřina | Tlustoš, Pavel | Száková, Jiřina
The carbon rich material obtained from pyrolysis process, i.e. biochar, has been widely discussed during the last decade due to its utilisation as a soil amendment. Furthermore, there is an unsolved question of biomass disposal from phytoremediation technologies. The idea of contaminated biomass pyrolysis has appeared, but there is lack of information about possible biochar utilisation obtained by this process. The aim of our study was to observe sorption properties of biochar prepared from contaminated biomass and release of contaminants from biochar back into the environment. The biomass of fast growing trees and maize was harvested on a site significantly damaged by risk element contamination (Cd, Pb and Zn). Plant biomass was pyrolysed and then the batch (de)sorption experiments were settled. The results confirmed no significant differences in metal sorption ability between biochars prepared from contaminated and uncontaminated biomass under the same conditions. The trend of maximum sorption capacity of observed matrices followed the order: wood biochar + soil (WB + soil) > wood uncontaminated biochar + soil (WUB + soil) > maize biochar + soil (MB + soil) > soil for cadmium, WB + soil > WUB + soil > soil for lead and MB + soil > WUB + soil > WB + soil > soil for zinc. Despite of increase of Zn desorption from wood biochars, maximum sorption capacity of the final WB + soil system was comparable to the WUB+soil sample. Our laboratory experiments showed high potential of biochar from contaminated plants as a soil amendment with sorption abilities and minimal risk of metal release.
اظهر المزيد [+] اقل [-]Plant diversity drives soil microbial biomass carbon in grasslands irrespective of global environmental change factors النص الكامل
2015
Thakur, Madhav Prakash | Milcu, Alexandru | Manning, Pete | Niklaus, Pascal A. | Roscher, Christiane | Power, Sally | Reich, Peter B. | Scheu, Stefan | Tilman, David | Ai, Fuxun | Guo, Hongyan | Ji, Rong | Pierce, Sarah | Ramirez, Nathaly Guerrero | Richter, Annabell Nicola | Steinauer, Katja | Strecker, Tanja | Vogel, Anja | Eisenhauer, Nico
Soil microbial biomass is a key determinant of carbon dynamics in the soil. Several studies have shown that soil microbial biomass significantly increases with plant species diversity, but it remains unclear whether plant species diversity can also stabilize soil microbial biomass in a changing environment. This question is particularly relevant as many global environmental change (GEC) factors, such as drought and nutrient enrichment, have been shown to reduce soil microbial biomass. Experiments with orthogonal manipulations of plant diversity and GEC factors can provide insights whether plant diversity can attenuate such detrimental effects on soil microbial biomass. Here, we present the analysis of 12 different studies with 14 unique orthogonal plant diversity × GEC manipulations in grasslands, where plant diversity and at least one GEC factor (elevated CO₂, nutrient enrichment, drought, earthworm presence, or warming) were manipulated. Our results show that higher plant diversity significantly enhances soil microbial biomass with the strongest effects in long‐term field experiments. In contrast, GEC factors had inconsistent effects with only drought having a significant negative effect. Importantly, we report consistent non‐significant effects for all 14 interactions between plant diversity and GEC factors, which indicates a limited potential of plant diversity to attenuate the effects of GEC factors on soil microbial biomass. We highlight that plant diversity is a major determinant of soil microbial biomass in experimental grasslands that can influence soil carbon dynamics irrespective of GEC.
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