Effects of temperature and application rate of a nitrification inhibitor, dicyandiamide (DCD), on nitrification rate and microbial biomass in a grazed pasture soil

Soil Research ◽  
2004 ◽  
Vol 42 (8) ◽  
pp. 927 ◽  
Author(s):  
H. J. Di ◽  
K. C. Cameron
Keyword(s):  
Microbial Biomass ◽  
Soil Temperature ◽  
Nitrate Leaching ◽  
Half Life ◽  
Soil Microbial Biomass ◽  
Nitrification Inhibitor ◽  
Application Rate ◽  
Nitrification Rate ◽  
Soil Microbial ◽  
Grazed Pasture

Abstract. The nitrification inhibitor dicyandiamide (DCD) has recently been shown to be effective in reducing nitrate leaching from grazed pasture soils. The objective of this study was to determine the influence of temperature and application rate on the effectiveness of DCD in nitrification inhibition. Possible effects on soil microbial biomass were also determined. The soil, Lismore silt loam (Pallic orthic brown soil; Udic Haplustept loamy skeletal), was incubated at a moisture content near field capacity under 2 temperatures (8 or 20°C). Urea was applied at 25 kg N/ha and dairy cow urine at 1000 kg N/ha. DCD was applied at 2 rates equivalent to 7.5 or 15 kg/ha. The results show that at a soil temperature of 8°C, the half-life of DCD was 111–116 days. The half-life of NH4+ changed from 44 days without DCD to 243–491 days when DCD was applied. In contrast, at a soil temperature of 20°C the half-life of DCD was 18–25 days. The half-life of NH4+ changed from 22 days without DCD to 64–55 days with DCD. The 2 different rates of DCD had a small effect on the NH4+ concentration in the soil. The application of DCD did not have a significant effect on soil microbial biomass. DCD would therefore be most effective in inhibiting nitrification and thus reducing nitrate leaching in late autumn–winter–early spring in most parts of New Zealand when daily average soil temperatures are generally below 10°C and when drainage is high.

Dynamics of soil microbial biomass C, soluble organic C and CO2 evolution after three years of manure application

1998 ◽  
Vol 78 (2) ◽  
pp. 283-290 ◽  
Author(s):  
P. Rochette ◽  
E. G. Gregorich
Keyword(s):  
Microbial Biomass ◽  
Soil Respiration ◽  
Soil Temperature ◽  
Soil Microbial Biomass ◽  
N Fertilizer ◽  
Microbial Biomass C ◽  
Organic C ◽  
Soil Microbial ◽  
Manure Amendments ◽  
Soluble C

Application of manure and fertilizer affects the rate and extent of mineralization and sequestration of C in soil. The objective of this study was to determine the effects of 3 yr of application of N fertilizer and different manure amendments on CO2 evolution and the dynamics of soil microbial biomass and soluble C in the field. Soil respiration, soluble organic C and microbial biomass C were measured at intervals over the growing season in maize soils amended with stockpiled or rotted manure, N fertilizer (200 kg N ha−1) and with no amendments (control). Manure amendments increased soil respiration and levels of soluble organic C and microbial biomass C by a factor of 2 to 3 compared with the control, whereas the N fertilizer had little effect on any parameter. Soil temperature explained most of the variations in CO2 flux (78 to 95%) in each treatment, but data from all treatments could not be fitted to a unique relationship. Increases in CO2 emission and soluble C resulting from manure amendments were strongly correlated (r2 = 0.75) with soil temperature. This observation confirms that soluble C is an active C pool affected by biological activity. The positive correlation between soluble organic C and soil temperature also suggests that production of soluble C increases more than mineralization of soluble C as temperature increases. The total manure-derived CO2-C was equivalent to 52% of the applied stockpiled-manure C and 67% of the applied rotted-manure C. Estimates of average turnover rates of microbial biomass ranged between 0.72 and 1.22 yr−1 and were lowest in manured soils. Manured soils also had large quantities of soluble C with a slower turnover rate than that in either fertilized or unamended soils. Key words: Soil respiration, greenhouse gas, soil carbon

scholarly journals Short term changes of microbial processes in Icelandic soils to increasing temperatures

2010 ◽  
Vol 7 (2) ◽  
pp. 671-682 ◽  
Author(s):  
R. Guicharnaud ◽  
O. Arnalds ◽  
G. I. Paton
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Temperature ◽  
Temperature Regime ◽  
Soil Microbial Biomass ◽  
Microbial Biomass Carbon ◽  
Biomass Carbon ◽  
Labile Carbon ◽  
Short Term ◽  
Soil Microbial

Abstract. Temperature change is acknowledged to have a significant effect on soil biological processes and the corresponding sequestration of carbon and cycling of nutrients. Soils at high latitudes are likely to be particularly impacted by increases in temperature. Icelandic soils experience unusually frequent freeze and thaw cycles compare to other Arctic regions, which are increasing due to a warming climate. As a consequence these soils are frequently affected by short term temperature fluctuations. In this study, the short term response of a range of soil microbial parameters (respiration, nutrient availability, microbial biomass carbon, arylphosphatase and dehydrogenase activity) to temperature changes was measured in sub-arctic soils collected from across Iceland. Sample sites reflected two soil temperature regimes (cryic and frigid) and two land uses (pasture and arable). The soils were sampled from the field frozen, equilibrated at −20 °C and then incubated for two weeks at −10 °C, −2 °C, +2 °C and +10 °. Respiration and enzymatic activity were temperature dependent. The soil temperature regime affected the soil microbial biomass carbon sensitivity to temperatures. When soils where sampled from the cryic temperature regime a decreasing soil microbial biomass was detected when temperatures rose above the freezing point. Frigid soils, sampled from milder climatic conditions, where unaffected by difference in temperatures. Nitrogen mineralisation did not change with temperature. At −10 °C, dissolved organic carbon accounted for 88% of the fraction of labile carbon which was significantly greater than that recorded at +10 °C when dissolved organic carbon accounted for as low as 42% of the labile carbon fraction.

scholarly journals Effect of 7-year application of a nitrification inhibitor, dicyandiamide (DCD), on soil microbial biomass, protease and deaminase activities, and the abundance of bacteria and archaea in pasture soils

2013 ◽  
Vol 13 (4) ◽  
pp. 753-759 ◽  
Author(s):  
Yan J. Guo ◽  
Hong J. Di ◽  
Keith C. Cameron ◽  
Bowen Li ◽  
Andriy Podolyan ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Microbial Biomass ◽  
Nitrification Inhibitor ◽  
Soil Microbial

Weed Seed Persistence and Microbial Abundance in Long-Term Organic and Conventional Cropping Systems

Weed Science ◽  
2011 ◽  
Vol 59 (2) ◽  
pp. 202-209 ◽  
Author(s):  
Silke D. Ullrich ◽  
Jeffrey S. Buyer ◽  
Michel A. Cavigelli ◽  
Rita Seidel ◽  
John R. Teasdale
Keyword(s):  
Microbial Biomass ◽  
Half Life ◽  
Soil Microbial Biomass ◽  
Farming Systems ◽  
Conventional System ◽  
Weed Seed ◽  
Common Lambsquarters ◽  
Seed Persistence ◽  
Soil Microbial ◽  
Smooth Pigweed

Weed seed persistence in soil can be influenced by many factors, including crop management. This research was conducted to determine whether organic management systems with higher organic amendments and soil microbial biomass could reduce weed seed persistence compared with conventional management systems. Seeds of smooth pigweed and common lambsquarters were buried in mesh bags in organic and conventional systems of two long-term experiments, the Farming Systems Project at the Beltsville Agricultural Research Center, Maryland, and the Farming Systems Trial at the Rodale Institute, Pennsylvania. Seed viability was determined after retrieval at half-year intervals for 2 yr. Total soil microbial biomass, as measured by phospholipid fatty acid (PLFA) content, was higher in organic systems than in conventional systems at both locations. Over all systems, locations, and experiments, viable seed half-life was relatively consistent with a mean of 1.3 and 1.1 yr and a standard deviation of 0.5 and 0.3 for smooth pigweed and common lambsquarters, respectively. Differences between systems were small and relatively inconsistent. Half-life of smooth pigweed seeds was shorter in the organic than in the conventional system in two of four location-experiments. Half-life of common lambsquarters was shorter in the organic than in the conventional system in one of four location-experiments, but longer in the organic than in the conventional system in two of four location-experiments. There were few correlations between PLFA biomarkers and seed half-lives in three of four location-experiments; however, there were negative correlations up to −0.64 for common lambsquarters and −0.55 for smooth pigweed in the second Rodale experiment. The lack of consistent system effects on seed persistence and the lack of consistent associations between soil microbial biomass and weed seed persistence suggest that soil microorganisms do not have a dominating role in seed mortality. More precise research targeted to identifying specific microbial functions causing seed mortality will be needed to provide a clearer picture of the role of soil microbes in weed seed persistence.

Intercropping perennial aquatic plants with rice improved paddy field soil microbial biomass, biomass carbon and biomass nitrogen to facilitate soil sustainability

2021 ◽  
Vol 208 ◽  
pp. 104908
Author(s):  
Jiaxin Wang ◽  
Xuening Lu ◽  
Jiaen Zhang ◽  
Hui Wei ◽  
Meijuan Li ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Aquatic Plants ◽  
Paddy Field ◽  
Soil Microbial Biomass ◽  
Biomass Carbon ◽  
Field Soil ◽  
Soil Microbial ◽  
Soil Sustainability ◽  
Paddy Field Soil
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