scholarly journals A comparative account of the microbial biomass-N and N-mineralization of soils under natural forest, grassland and crop field from dry tropical region, India

2009 ◽  
Vol 55 (No. 6) ◽  
pp. 223-230 ◽  
Author(s):  
S. Singh Jay ◽  
D.P. Singh ◽  
A.K. Kashyap
Keyword(s):  
Soil Moisture ◽  
Microbial Biomass ◽  
N Mineralization ◽  
Mixed Forest ◽  
Microbial Biomass N ◽  
Tropical Region ◽  
Net N Mineralization ◽  
Inorganic N ◽  
Total N ◽  
Biomass N

This study investigated microbial biomass-N (MB-N) and N-mineralization in soils of four different vegetation systems including forest (sal), mixed forest, savanna and cropland ecosystems in the Vindhyan region, India. A change was noted in the above region due to physiographic differences and anthropogenic disturbances. Annually the soil moisture (SM) content across the different study sites ranged from 7.5 to 24.3% being maximum in forest sites compared to savanna and cropland sites. The NH<sub>4</sub><sup>+</sup>-N, NO <sup>-</sup><sub>3</sub> -N and MB-N concentrations varied from 4.3 to 10.2 &mu;g/g, 1.1 to 5.8 &mu;g/g and 21.3 to 90.2 &mu;g/g dry soil, respectively, with minimum values in the wet and maximum values in the dry season. The trend of seasonal variation in net N-mineralization was similar to that of moisture content but counter to the concentrations of inorganic-N and MB-N. The net N-mineralization rates at different investigated sites ranged from 4.5 to 37.6 &mu;g/g month. Cultivation reduced the N-mineralization and MB-N by 58.5% and 63.5%, respectively. Experiments showed that the percentage contribution of MB-N to total-N was 8.01 to 19.15%. MB-N was positively correlated with the inorganic-N (<i>n</i> = 180,<i>r</i>.80,<i>P</I> < 0.001) but negatively with soil moisture (<i>n</i> = 180, <i>r</i> = 0.79, <i>P</I> < 0.001) and net N-mineralization rates (<i>n</i> = 180, <i>r</i> = 0.92, <i>P</I> < 0.0001). The higher N-mineralization and MB-N in the soil of forest ecosystem was reported compared to savanna and cropland and the order of soil MB-N levels and net N-mineralization followed the sequence: forest (sal) > mixed forest > savanna > cropland.

scholarly journals Maturity indices of composting plant materials with Trichoderma asperellum as activator

2020 ◽  
Vol 53 (1) ◽  
pp. 19-27
Author(s):  
Adenike Fisayo Komolafe ◽  
Christopher Olu Adejuyigbe ◽  
Adeniyi Adebowale Soretire ◽  
Isaac OreOluwa Olatokunbo Aiyelaagbe
Keyword(s):  
Microbial Biomass ◽  
Microbial Biomass N ◽  
Cow Dung ◽  
Trichoderma Asperellum ◽  
Plant Materials ◽  
Total N ◽  
Compost Maturity ◽  
Randomized Design ◽  
Maturity Indices ◽  
Biomass N

AbstractCompost maturity is a major factor in its use for nutrient supply without adverse effect on crop germination. Composting may be accelerated with inclusion of some microorganisms as activators. This study was conducted to determine the effect of Trichoderma asperellum and length of composting of different plant materials and cattle manure on compost maturity in Ibadan, Nigeria. Composting of two plant materials with cow dung at ratio 3:1 was done in triplicate with or without Trichoderma activation to obtain twelve heaps of four different types of composts; Panicum-based compost with Trichoderma, Tridax-based compost with Trichoderma, Panicum-based compost without Trichoderma and Tridax-based compost without Trichoderma. The process was a 2×2 factorial experiment, laid out a completely randomized design. The Trichoderma activated compost (TAC) at four weeks of composting (4WC) had 56% total N, 21% organic matter, 38% total K, 51% total P and 66.6% microbial biomass N increase over non-activated compost (NAC). Carbon to nitrogen ratio was within the ideal range (10–20) in TAC while it was greater than it in NAC. Microbial biomass and lignin contents had a 56% and 41% increase, respectively, in NAC over TAC. Trichorderma-activated compost has a potential to hasten maturation and makes the compost ready for field on or before four weeks without posing a threat to crop germination.

Soil-plant nitrogen dynamics following incorporation of a mature rye cover crop in a lettuce production system

1995 ◽  
Vol 124 (1) ◽  
pp. 17-25 ◽  
Author(s):  
L. J. Wyland ◽  
L. E. Jackson ◽  
K. F. Schulbach
Keyword(s):  
Microbial Biomass ◽  
Cover Crop ◽  
Microbial Biomass N ◽  
N Availability ◽  
N Content ◽  
N Transformations ◽  
Total N ◽  
Mineralizable N ◽  
Biomass N ◽  
Bare Soils

SUMMARYWinter non-leguminous cover crops are included in crop rotations to decrease nitrate (NO3-N) leaching and increase soil organic matter. This study examined the effect of incorporating a mature cover crop on subsequent N transformations. A field trial containing a winter cover crop of Merced rye and a fallow control was established in December 1991 in Salinas, California. The rye was grown for 16 weeks, so that plants had headed and were senescing, resulting in residue which was difficult to incorporate and slow to decompose. Frequent sampling of the surface soil (0–15 cm) showed that net mineralizable N (anaerobic incubation) rapidly increased, then decreased shortly after tillage in both treatments, but that sustained increases in net mineralizable N and microbial biomass N in the cover-cropped soils did not occur until after irrigation, 20 days after incorporation. Soil NO3-N was significantly reduced compared to winter-fallow soil at that time. A 15N experiment examined the fate of N fertilizer, applied in cylinders at a rate of 12 kg 15N/ha at lettuce planting, and measured in the soil, microbial biomass and lettuce plants after 32 days. In the cover-cropped soil, 59% of the 15N was recovered in the microbial biomass, compared to 21% in the winter-bare soil. The dry weight, total N and 15N content of the lettuce in the cover-cropped cylinders were significantly lower; 28 v. 39% of applied 15N was recovered in the lettuce in the cover-cropped and winter-bare soils, respectively. At harvest, the N content of the lettuce in the cover-cropped soil remained lower, and microbial biomass N was higher than in winter-bare soils. These data indicate that delayed cover crop incorporation resulted in net microbial immobilization which extended into the period of high crop demand and reduced N availability to the crop.

scholarly journals Comparison of inorganic nitrogen uptake dynamics following snowmelt and at peak biomass in subalpine grasslands

2013 ◽  
Vol 10 (11) ◽  
pp. 7631-7645 ◽  
Author(s):  
N. Legay ◽  
F. Grassein ◽  
T. M. Robson ◽  
E. Personeni ◽  
M.-P. Bataillé ◽  
...  
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Plant Communities ◽  
Inorganic Nitrogen ◽  
N Uptake ◽  
Microbial Biomass N ◽  
Inorganic N ◽  
Peak Biomass ◽  
Biomass N ◽  
Subalpine Grasslands

Abstract. Subalpine grasslands are highly seasonal environments and likely subject to strong variability in nitrogen (N) dynamics. Plants and microbes typically compete for N acquisition during the growing season and particularly at plant peak biomass. During snowmelt, plants could potentially benefit from a decrease in competition by microbes, leading to greater plant N uptake associated with active growth and freeze-thaw cycles restricting microbial growth. In managed subalpine grasslands, we expect these interactions to be influenced by recent changes in agricultural land use, and associated modifications in plant and microbial communities. At several subalpine grasslands in the French Alps, we added pulses of 15N to the soil at the end of snowmelt, allowing us to compare the dynamics of inorganic N uptake in plants and microbes during this period with that previously reported at the peak biomass in July. In all grasslands, while specific shoot N translocation (per g of biomass) of dissolved inorganic nitrogen (DIN) was two to five times greater at snowmelt than at peak biomass, specific microbial DIN uptakes were similar between the two sampling dates. On an area basis, plant communities took more DIN than microbial communities at the end of snowmelt when aboveground plant biomasses were at least two times lower than at peak biomass. Consequently, inorganic N partitioning after snowmelt switches in favor of plant communities, allowing them to support their growing capacities at this period of the year. Seasonal differences in microbial and plant inorganic N-related dynamics were also affected by past (terraced vs. unterraced) rather than current (mown vs. unmown) land use. In terraced grasslands, microbial biomass N remained similar across seasons, whereas in unterraced grasslands, microbial biomass N was higher and microbial C : N lower at the end of snowmelt as compared to peak biomass. Further investigations on microbial community composition and their organic N uptake dynamics are required to better understand the decrease in microbial DIN uptake.

scholarly journals Comparison of inorganic nitrogen uptake dynamics following snowmelt and at peak biomass in subalpine grasslands

2013 ◽  
Vol 10 (5) ◽  
pp. 8887-8917 ◽  
Author(s):  
N. Legay ◽  
F. Grassein ◽  
T. M. Robson ◽  
E. Personeni ◽  
M.-P. Bataillé ◽  
...  
Keyword(s):  
Land Use ◽  
Microbial Biomass ◽  
Microbial Communities ◽  
Plant Communities ◽  
N Uptake ◽  
Microbial Biomass N ◽  
Inorganic N ◽  
Peak Biomass ◽  
Biomass N ◽  
Subalpine Grasslands

Abstract. Subalpine grasslands are highly seasonal environments and likely subject to strong variability in nitrogen (N) dynamics. Plants and microbes typically compete for N acquisition during the growing season and particularly at plant peak biomass. During snowmelt, plants could potentially benefit from a decrease in competition by microbes because of greater plant N uptake associated with active growth and freeze-thaw cycles restricting microbial growth. In managed subalpine grasslands, we expect these interactions to be influenced by recent changes in agricultural land-use, and associated modifications in plant and microbial communities. At a subalpine grassland site in the Central French Alps, a pulse of 15N was added to the soil at the end of snowmelt, allowing us to compare the dynamics of inorganic N uptake in plants and microbes during this period with that previously reported at the peak biomass in July. In all grasslands, specific plant (per g of biomass) dissolved inorganic N (DIN) uptake was two to five times greater at snow-melt than at peak biomass, whereas the specific microbial DIN uptakes were similar between the two sampling dates. On an area basis, plant communities took more DIN than microbial communities at the end of snowmelt, and the intensity of this DIN uptake by plants differed across land use types. Consequently, N partitioning after snowmelt switches in favor of plant communities allowing them to support their growing capacities at this period of the year. Seasonal differences in microbial and plant N-related dynamics were also affected by past (terraced vs. unterraced) rather than current (mown vs. unmown) land use. In terraced grasslands, microbial biomass N remained similar across seasons, whereas in unterraced grasslands, microbial biomass N was higher and microbial C : N lower at the end of snowmelt as compared to peak biomass. Further investigations on microbial community composition and their organic N uptake dynamics are required to better understand the decrease in microbial DIN uptake.

scholarly journals Climatic, Edaphic and Biotic Controls over Soil δ13C and δ15N in Temperate Grasslands

Forests ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 433
Author(s):  
Xing Zhao ◽  
Xingliang Xu ◽  
Fang Wang ◽  
Isabel Greenberg ◽  
Min Liu ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Large Scale ◽  
Microbial Biomass C ◽  
Microbial Biomass N ◽  
Temperate Grasslands ◽  
Total N ◽  
Δ13c And Δ15n ◽  
Biomass N ◽  
Soil Δ15n ◽  
Total P

Soils δ13C and δ15N are now regarded as useful indicators of nitrogen (N) status and dynamics of soil organic carbon (SOC). Numerous studies have explored the effects of various factors on soils δ13C and δ15N in terrestrial ecosystems on different scales, but it remains unclear how co-varying climatic, edaphic and biotic factors independently contribute to the variation in soil δ13C and δ15N in temperate grasslands on a large scale. To answer the above question, a large-scale soil collection was carried out along a vegetation transect across the temperate grasslands of Inner Mongolia. We found that mean annual precipitation (MAP) and mean annual temperature (MAT) do not correlate with soil δ15N along the transect, while soil δ13C linearly decreased with MAP and MAT. Soil δ15N logarithmically increased with concentrations of SOC, total N and total P. By comparison, soil δ13C linearly decreased with SOC, total N and total P. Soil δ15N logarithmically increased with microbial biomass C and microbial biomass N, while soil δ13C linearly decreased with microbial biomass C and microbial biomass N. Plant belowground biomass linearly increased with soil δ15N but decreased with soil δ13C. Soil δ15N decreased with soil δ13C along the transect. Multiple linear regressions showed that biotic and edaphic factors such as microbial biomass C and total N exert more effect on soil δ15N, whereas climatic and edaphic factors such as MAT and total P have more impact on soil δ13C. These findings show that soil C and N cycles in temperate grasslands are, to some extent, decoupled and dominantly controlled by different factors. Further investigations should focus on those ecological processes leading to decoupling of C and N cycles in temperate grassland soils.

SHORT COMMUNICATION: Soil microbial biomass C, N mineralization, and N uptake by corn in dairy cattle slurry- and urea-amended soils

1996 ◽  
Vol 76 (4) ◽  
pp. 469-472 ◽  
Author(s):  
J. W. Paul ◽  
E. G. Beauchamp
Keyword(s):  
Microbial Biomass ◽  
Dairy Cattle ◽  
N Mineralization ◽  
N Uptake ◽  
Organic N ◽  
Microbial Biomass C ◽  
Net N Mineralization ◽  
Cattle Slurry ◽  
Total N ◽  
Dairy Cattle Slurry

A spring application of dairy cattle slurry (300 kg total N ha−1) on high- and low-fertility sites resulted in higher microbial biomass C during the growing season than on a control soil or a soil receiving 100 kg N ha−1 as urea. Microbial biomass C was also significantly higher on the high-fertility site and was reflected in greater N mineralization and N uptake by corn. There was no greater net N mineralization in the manured soil than in the control or fertilized soil as would be expected as a result of higher microbial biomass C and significant organic N contribution from the manure. Key words: Animal manure, nitrogen mineralization, corn, grain yields, soil fertility

scholarly journals Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

2005 ◽  
Vol 2 (3) ◽  
pp. 499-535 ◽  
Author(s):  
B. Wick ◽  
E. Veldkamp ◽  
W. Z. de Mello ◽  
M. Keller ◽  
P. Crill
Keyword(s):  
Nitrous Oxide ◽  
Microbial Biomass ◽  
Dry Season ◽  
Microbial Biomass N ◽  
N Availability ◽  
Wet Season ◽  
Inorganic N ◽  
Forest Sites ◽  
Biomass N ◽  
Pasture Age

Abstract. We studied nitrous oxide (N2O) fluxes and soil nitrogen (N) cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N2O we measured 27 soil chemical, soil microbiological and soil physical variables. Soil N2O fluxes were higher in the wet season than in the dry season. Fluxes of N2O from forest soils always exceeded fluxes from pasture soils and showed no consistent trend with pasture age. At our forest sites, nitrate was the dominant form of inorganic N both during wet and dry season. At our pasture sites nitrate generally dominated the inorganic N pools during the wet season and ammonium dominated during the dry season. Net mineralization and nitrification rates displayed large variations. During the dry season net immobilization of N was observed in some pastures. Compared to forest sites, young pasture sites (≤2 years) had low microbial biomass N and protease activities. Protease activity and microbial biomass N peaked in pastures of intermediate age (4 to 8 years) followed by consistently lower values in older pasture (10 to 60 years). The C/N ratio of litter was low at the forest sites (~25) and rapidly increased with pasture age reaching values of 60–70 at pastures of 15 years and older. Nitrous oxide emissions at our sites were controlled by C and N availability and soil aeration. Fluxes of N2O were negatively correlated to leaf litter C/N ratio, NH4+-N and the ratio of NO3--N to the sum of NO3--N + NH4+-N (indicators of N availability), and methane fluxes and bulk density (indicators of soil aeration status) during the wet season. During the dry season fluxes of N2O were positively correlated to microbial biomass N, β-glucosidase activity, total inorganic N stocks and NH4+-N. In our study region, pastures of all age emitted less N2O than old-growth forests, because of a progressive decline in N availability with pasture age combined with strongly anaerobic conditions in some pastures during the wet season.

scholarly journals Nitrous oxide fluxes and nitrogen cycling along a pasture chronosequence in Central Amazonia, Brazil

2005 ◽  
Vol 2 (2) ◽  
pp. 175-187 ◽  
Author(s):  
B. Wick ◽  
E. Veldkamp ◽  
W. Z. de Mello ◽  
M. Keller ◽  
P. Crill
Keyword(s):  
Nitrous Oxide ◽  
Microbial Biomass ◽  
Dry Season ◽  
Microbial Biomass N ◽  
N Availability ◽  
Wet Season ◽  
Inorganic N ◽  
Forest Sites ◽  
Biomass N ◽  
Pasture Age

Abstract. We studied nitrous oxide (N2O) fluxes and soil nitrogen (N) cycling following forest conversion to pasture in the central Amazon near Santarém, Pará, Brazil. Two undisturbed forest sites and 27 pasture sites of 0.5 to 60 years were sampled once each during wet and dry seasons. In addition to soil-atmosphere fluxes of N2O we measured 27 soil chemical, soil microbiological and soil physical variables. Soil N2O fluxes were higher in the wet season than in the dry season. Fluxes of N2O from forest soils always exceeded fluxes from pasture soils and showed no consistent trend with pasture age. At our forest sites, nitrate was the dominant form of inorganic N both during wet and dry season. At our pasture sites nitrate generally dominated the inorganic N pools during the wet season and ammonium dominated during the dry season. Net mineralization and nitrification rates displayed large variations. During the dry season net immobilization of N was observed in some pastures. Compared to forest sites, young pasture sites (≤2 years) had low microbial biomass N and protease activities. Protease activity and microbial biomass N peaked in pastures of intermediate age (4 to 8 years) followed by consistently lower values in older pasture (10 to 60 years). The C/N ratio of litter was low at the forest sites (~25) and rapidly increased with pasture age reaching values of 60-70 at pastures of 15 years and older. Nitrous oxide emissions at our sites were controlled by C and N availability and soil aeration. Fluxes of N2O were negatively correlated to leaf litter C/N ratio, NH4+-N and the ratio of NO3--N to the sum of NO3--N + NH4+-N (indicators of N availability), and methane fluxes and bulk density (indicators of soil aeration status) during the wet season. During the dry season fluxes of N2O were positively correlated to microbial biomass N, β-glucosidase activity, total inorganic N stocks and NH4+-N. In our study region, pastures of all age emitted less N2O than old-growth forests, because of a progressive decline in N availability with pasture age combined with strongly anaerobic conditions in some pastures during the wet season.

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