Elevated ambient carbon dioxide and Trichoderma inoculum could enhance cadmium uptake of Lolium perenne explained by changes of soil pH, cadmium availability and microbial biomass

2015 ◽  
Vol 85 ◽  
pp. 56-64 ◽  
Author(s):  
Ningning Song ◽  
Yibing Ma ◽  
Yujie Zhao ◽  
Shirong Tang
2011 ◽  
Vol 39 (1) ◽  
pp. 107
Author(s):  
Mignon S. SANDOR ◽  
Traian BRAD ◽  
Aurel MAXIM ◽  
Constantin TOADER

A mesocosm study was conducted in order to evaluate the effects of short-term rainfall and temperature variation on soil microbial biomass and bacteria to fungi ratio. In addition, the relation between the decomposition process of two organic fertilizers, cattle manure and barley straw, and the activity of soil microbial biomass was also studied. In order to assess the effect of biological activity on soil fertility the dynamics of soil pH, N-NO3-, N-NH4+, Corg and Nt during plant growing season was measured. The results suggest that short-term variation of climate had a significant effect on microbial biomass with dry periods distinguished by a reduced microbial biomass compared to wet periods. The ratio bacteria to fungi seems also to be sensitive to variations in rainfall and temperature regime, however further studies are required to draw a definitive conclusion. Regarding the type of fertilizer used, the straw treatments showed higher microbial biomass than the manure treatments, but higher decomposition rate was observed in manure fertilized soil. The effect of soil biological activity on soil pH was limited for both manure and straw treatments while the changes of the soil nitrate amounts are related to the microbial biomass. The study indicates that nitrate immobilization and mineralization processes are influenced by meteorological conditions and microbial biomass dynamics. In contrast, soil organic carbon and total nitrogen did not seem to be affected by variations in temperature, rainfall and microbial activity.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Josabeth Navarro ◽  
Jahdiel Salazar ◽  
James Jihoon Kang ◽  
Jason Parsons ◽  
Chu-Lin Cheng ◽  
...  

South Texas is located in a subtropical semiarid climate, and due to high temperature and irregular precipitation, farmers opt to leave their fields fallow during the summer months jeopardizing overall soil health. We evaluated whether sweet potato (Ipomoea batatas) cultivation coupled with drip irrigation could restore soil biological activities compared with bare fallow. Additionally, because sweet potatoes have high demand of soil nutrients, especially potassium (K), we evaluated the nutrient supply of locally sourced soil amendments. Sweet potato was cultivated during summer 2018 in McAllen, Texas, under control (no fertilizer), NPK (synthetic fertilizer), RC (yard-waste compost), and AC (compost produced under an enhanced composting process), and biochar (gasified walnut shell at 900°C), each with three replicates. Soil amendments were applied at different amounts to result in a rate of 80 kg K ha−1. Soil biological indicators were microbial biomass phosphorous, phosphatase activity, and the rate of fluorescein diacetate hydrolysis (FDA). Available nitrogen, phosphorus, potassium, and sodium were also quantified. Aboveground biomass and storage root yield estimated sweet potato’s agronomic performance. Cultivation and irrigation stimulated soil enzyme activities and microbial biomass-phosphorous. Sweet potato yields were the highest in NPK treatment but still 2.8 times lower than variety’s potential yield. Storage root yield was inversely related to aboveground biomass, suggesting that growing conditions benefited the production of shoot versus roots. Both biochar and AC treatments stimulated FDA rates and K availability. Soil pH and sodium concentration increased in all treatments over the growing season, possibly due to river-sourced irrigation water. Together, these findings show that crop cultivation promoted soil biological activities and the maintenance of nutrient cycling, compared to bare-fallow conditions. For a better agronomic performance of sweet potato, it would be necessary to identify management practices that minimize increase in soil pH and salinity.


2020 ◽  
Author(s):  
Marta Cattin ◽  
Marc Stutter ◽  
Alfonso Lag-Brotons ◽  
Phil Wadley ◽  
Kirk T. Semple ◽  
...  

<p>The application of digestate from anaerobic digestion to grassland soils is of growing interest as an agricultural practice. However, significant uncertainties surrounding the potential impacts of digestate application on processes associated with the soil microbial community remain, particularly for processes governing Carbon Use Efficiency (CUE) and the broader soil C cycle. In this research, we examined how the C:N stoichiometry of digestate and the nutrient status of soil influenced the impact of digestate application on the soil C cycle.  </p><p>Three fractions of digestate (whole [WD], solid [SD] and liquid [LD]), spanning a range of C:N, were each applied to two soils of contrasting starting nutrient status (high and low) and compared to unamended controls (Ctr). Two short-term incubations, each lasting seven days, were undertaken. In the first, applications of WD, SD and LD each achieved the same total N input to soils. In the second, digestate applications were adjusted to provide consistent total C input to soils. In each incubation, CO<sub>2</sub>-C efflux, microbial biomass C (C<sub>micro</sub>) and pH were determined.  </p><p>In each of the two incubations, the application of digestate significantly increased cumulative CO<sub>2</sub>-C efflux compared to control soils. However, the precise effect of digestate application varied between the two incubations and with both soil nutrient status and digestate fraction. Microbial biomass C was largely unchanged by the treatments in both incubations. During the first incubation, soil pH decreased substantially following each digestate treatment in both soil types. A similar pattern was observed within the second incubation in the high nutrient soil. However, in contrast, soil pH increased substantially following LD and WD application to the low nutrient soil in the second incubation. Varying CUE responses are likely to be observed following the application of digestate to agricultural soils, dependent on digestate fraction, C:N ratio of the digestate, and the initial soil nutrient status. Therefore, digestate application rates and soil management must be carefully planned in order to avoid adverse impacts of digestate application to land. </p><p> </p>


2014 ◽  
Vol 60 (3) ◽  
pp. 423-434 ◽  
Author(s):  
Hironori Arai ◽  
Abdul Hadi ◽  
Untung Darung ◽  
Suwido H. Limin ◽  
Hidenori Takahashi ◽  
...  

1986 ◽  
Vol 16 (5) ◽  
pp. 1076-1081 ◽  
Author(s):  
James A. Entry ◽  
Nellie M. Stark ◽  
Howard Loewenstein

Microbial biomass and relative bacterial and fungal percentages were measured in organic forest soil from a Rocky Mountain site subjected to four harvesting treatments: RL, clear-cut and residue left; RR, clear-cut and residue removed; RB, clear-cut and residue burned; C, uncut control. Microbial biomass peaked in spring and fall regardless of treatment. Biomass in soil from the RB treatment was significantly (p < 0.05) less than that in soil from the other treatments most of the year; biomass did not significantly differ in soil from the RR and C treatments. During summer and winter, microbial biomass in soil from the RL treatment was significantly greater than that in soil from any other treatment, probably because of the large amount of organic residue left after harvest; moreover, this residue insulated the soil, preventing it from drying or freezing. At soil temperatures above 5 °C, microbial biomass correlated positively with soil moisture regardless of treatment; at soil temperatures below 2.5 °C, microbial biomass correlated positively with increasing soil temperature. During periods with snow cover, bacterial and fungal percentages were roughly equal regardless of treatment; during the rest of the year, bacterial percentages were high in the RL and RB treatments and low in the RR and C treatments. During periods without snow cover, bacterial and fungal percentages correlated positively with increasing soil pH; however, at near-freezing temperatures the percentage of bacteria and fungi seemed unaffected by soil pH. These findings suggest that treatments that remove a large portion of available site nutrients while reducing soil microbial activity could limit stand development.


2020 ◽  
Author(s):  
Sam P. Jones ◽  
Aurore Kaisermann ◽  
Jerome Ogee ◽  
Steven Wohl ◽  
Alexander W. Cheesman ◽  
...  

Abstract. The oxygen isotope composition (δ18O) of atmospheric carbon dioxide (CO2) can be used to estimate gross primary production at the ecosystem-scale and above. Understanding how and why the rate of oxygen isotope exchange between soil water and CO2 (kiso) varies can help to reduce uncertainty in the retrieval of such estimates. The expression and activity of carbonic anhydrases in soils are important drivers of variations in kiso. Here we estimate kiso and measure associated soil properties in laboratory incubation experiments using 44 soils sampled from sites across western Eurasia and northeastern Australia. Observed kiso exceeded theoretical uncatalysed rates indicating the significant influence of carbonic anhydrases on the variability observed among the soils studied. We identify soil pH as the principal source of variation, with greater kiso under alkaline conditions suggesting that shifts in microbial community composition or intra-extra cellular dissolved inorganic carbon gradients induce the expression of more or higher activity forms of carbonic anhydrases. We also show for the first time in soils that the presence of nitrate under acidic conditions reduces kiso, potentially reflecting the direct or indirect inhibition of carbonic anhydrases. This effect was confirmed by a supplementary ammonium nitrate fertilisation experiment conducted on a subset of the soils. Future changes in atmospheric nitrogen deposition or land-use may thus influence carbonic anhydrase activity. Greater microbial biomass also increased kiso under a given set of chemical conditions likely highlighting the ubiquity of carbonic anhydrase expression by soil microbial communities. These data provide the most extensive analysis of spatial variations in soil kiso to date and indicate key controls required to predict variations in kiso at the scales needed to improve efforts to constrain gross primary productivity using the δ18O of atmospheric CO2.


2006 ◽  
Vol 52 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Hiroyuki Hattori ◽  
Kouki Kuniyasu ◽  
Kaori Chiba ◽  
Mitsuo Chino
Keyword(s):  
Soil Ph ◽  

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