scholarly journals Biological and biochemical quality of pastoral soils: spatial and temporal variability

1996 ◽  
pp. 211-218 ◽  
Author(s):  
A. Ghani ◽  
U. Sarathchandra ◽  
K.W. Perrott ◽  
D.A. Wardle ◽  
P. Singleton ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Ph ◽  
Dairy Farms ◽  
Seasonal Effect ◽  
Climatic Data ◽  
Soil C ◽  
Olsen P ◽  
Significant Difference ◽  
C And N ◽  
Microbial C

This paper reports results of the first year of soil biochemical and microbiological monitoring programme carried out to establish "normal" ranges of values for these soil attributes. Study was conducted on 24 farm sites on yellow-brown loam soils around the Waikato area. Twelve dairy farms and a similar number of sheep-beef farms were selected on the basis of high productivity. Soil samples (0-75 mm depth) were collected at 3- monthly intervals and the following measurements were carried out: soil microbial- C, N, S and P, CO2 evolution, substrate-induced respiration, anaerobic mineralisable N, dehydrogenase activity, fluorescein diacetate (FDA) hydrolysis, amounts of soluble-C and N, extractable NO3 and NH4, soil pH, Olsen P, KH2PO4 extractable SO4-S and organic S, and hydraulic conductivity. Climatic data, records of fertiliser and other additives and productivity were also collected to interpret the variations in these properties. Variables measured from the Horotiu and Tirau silt loam soils showed considerable similarity, however, Otorohanga soils had significantly higher amounts of total and extractable soil C and N. As expected, being a higher input system, soil nutrient status (P, SO4, NO3 and NH4) on dairy farms was generally higher than the sheep-beef farms. The most significant difference was for the Olsen P values, which were about 60-70% higher under dairying. Soil pH on dairy farms was significantly higher than sheep- beef farms. However, total C and N values were significantly higher under sheep-beef than dairy farms. Similarly, the amounts of mineralisable N in all seasons were much higher for the sheep-beef than dairy farms. Apart from total microbial S, none of the other microbial biomass measurements showed any significant effect of season or difference among the soil types. This lack of seasonal effect on microbial biomass can be attributed to the unusual mild seasonal variation during the study. For the various microbial biomass measurements, sheep-beef farms generally had significantly higher values than dairy farms. Microbial C, N, SO4 and total S values were significantly higher for sheep-beef than dairying. The ratios between soil C, N to microbial C, N and microbial C:N showed no consistent pattern between the farm types. Keywords: C and N, enzyme activity, microbial biomass, seasonal variations, soil fertility

Changes in extractable and microbial C, N, and P in a Western Australian wheatbelt soil following simulated summer rainfall

Soil Research ◽  
1998 ◽  
Vol 36 (5) ◽  
pp. 841 ◽  
Author(s):  
A. M. McNeill ◽  
G. P. Sparling ◽  
D. V. Murphy ◽  
P. Braunberger ◽  
I. R. P. Fillery
Keyword(s):  
Organic N ◽  
Land Uses ◽  
Simulated Rainfall ◽  
Soil Extracts ◽  
Rainfall Events ◽  
Olsen P ◽  
Significant Difference ◽  
C And N ◽  
Microbial C ◽  
Western Australian

The effects of simulated rainfall events during the summer fallow period on extractable and microbial carbon (C), nitrogen (N), and phosphorus (P) in soils under either continuous wheat or the second-year pasture phase of a 2-pasture-1-wheat rotation in the Western Australian wheatbelt were investigated. A ‘single wetting’ treatment (45 mm rainfall on Day 0) was compared with a 55 mm ‘multiple wetting’ treatment (45 mm at Day 0, 5 mm at Day 3, and 5 mm at Day 8). Soil samples from 0{10 cm depth were taken prior to, and at regular intervals up to 14 days following, the inital wetting event. Soil extracts were assayed for total soluble N (TSN), total oxidisable C (TOC), Olsen-P, and ninhydrin-positive compounds (NPC). Prior to the simulated rainfall events, extractable TSN and TOC in the air-dry fallow soils were significantly higher (P < 0·01), and Olsen-P significantly lower, for the pasture land use compared with the continuous wheat. However, subsequent to wetting there were no significant differences between the 2 land uses, or single and multiple wetting treatments, for extractable TSN, TOC, Olsen P, or NPC. Extractable soluble organic N (SON), calculated by subtracting measured inorganic N from TSN, decreased within 48 h of each wetting event to a minimal value but, after the first 2 wetting events, subsequently increased to at least the prewet value. Microbial C, N, and P were estimated from the difference in TOC, TSN, and Olsen-P of extracts from fumigated and unfumigated soils (microbial ‘flush’) and microbial C and N were also estimated from the NPC ‘flush’. There was generally good agreement between the 2 estimates of microbial N (NPC and TSN, R2 = 0·50), but less so for the 2 estimates of microbial C (NPC and TOC, R2 = 0 ·31). There was no significant difference in microbial C, N, or P between the 2 land uses, but there was a highly significant response of the microbial biomass to wetting events and also significant differences in temporal patterns between the single and multiple wetting treatments. Microbial C and N increased in the period following initial wetting, more rapidly in the wheat than the pasture, reaching a peak at Day 2 for wheat and Day 3 for pasture. Subsequently, for the single wet treatment, there was a steady linear decline in microbial C and N until Day 10, whereas over the same period (Days 4-10) in the multiple wet treatment there were 2 highly significant quadratic responses to time, manifest as a linear increase in microbial C and N following each re-wetting event, to a peak value 24 h after the event, and a subsequent decline to the pre-wet value after a further 24 h.

scholarly journals Alteration of soil carbon and nitrogen pools and enzyme activities as affected by increased soil coarseness

2017 ◽  
Vol 14 (8) ◽  
pp. 2155-2166 ◽  
Author(s):  
Ruzhen Wang ◽  
Linyou Lü ◽  
Courtney A. Creamer ◽  
Feike A. Dijkstra ◽  
Heyong Liu ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Enzyme Activities ◽  
Organic C ◽  
Soil C ◽  
N Limitation ◽  
Soil C And N ◽  
C And N ◽  
Microbial C ◽  
Sandy Grasslands ◽  
Acid Phosphomonoesterase

Abstract. Soil coarseness decreases ecosystem productivity, ecosystem carbon (C) and nitrogen (N) stocks, and soil nutrient contents in sandy grasslands subjected to desertification. To gain insight into changes in soil C and N pools, microbial biomass, and enzyme activities in response to soil coarseness, a field experiment was conducted by mixing native soil with river sand in different mass proportions: 0, 10, 30, 50, and 70 % sand addition. Four years after establishing plots and 2 years after transplanting, soil organic C and total N concentrations decreased with increased soil coarseness down to 32.2 and 53.7 % of concentrations in control plots, respectively. Soil microbial biomass C (MBC) and N (MBN) declined with soil coarseness down to 44.1 and 51.9 %, respectively, while microbial biomass phosphorus (MBP) increased by as much as 73.9 %. Soil coarseness significantly decreased the enzyme activities of β-glucosidase, N-acetyl-glucosaminidase, and acid phosphomonoesterase by 20.2–57.5 %, 24.5–53.0 %, and 22.2–88.7 %, used for C, N and P cycling, respectively. However, observed values of soil organic C, dissolved organic C, total dissolved N, available P, MBC, MBN, and MBP were often significantly higher than would be predicted from dilution effects caused by the sand addition. Soil coarseness enhanced microbial C and N limitation relative to P, as indicated by the ratios of β-glucosidase and N-acetyl-glucosaminidase to acid phosphomonoesterase (and MBC : MBP and MBN : MBP ratios). Enhanced microbial recycling of P might alleviate plant P limitation in nutrient-poor grassland ecosystems that are affected by soil coarseness. Soil coarseness is a critical parameter affecting soil C and N storage and increases in soil coarseness can enhance microbial C and N limitation relative to P, potentially posing a threat to plant productivity in sandy grasslands suffering from desertification.

scholarly journals Perennial herbaceous legumes as live soil mulches and their effects on C, N and P of the microbial biomass

2003 ◽  
Vol 60 (1) ◽  
pp. 139-147 ◽  
Author(s):  
Gustavo Pereira Duda ◽  
José Guilherme Marinho Guerra ◽  
Marcela Teixeira Monteiro ◽  
Helvécio De-Polli ◽  
Marcelo Grandi Teixeira
Keyword(s):  
Microbial Biomass ◽  
Soil Depth ◽  
Vegetation Management ◽  
Pueraria Phaseoloides ◽  
Organic C ◽  
Arachis Pintoi ◽  
Factorial Combination ◽  
C And N ◽  
Microbial C ◽  
Macroptilium Atropurpureum

The use of living mulch with legumes is increasing but the impact of this management technique on the soil microbial pool is not well known. In this work, the effect of different live mulches was evaluated in relation to the C, N and P pools of the microbial biomass, in a Typic Alfisol of Seropédica, RJ, Brazil. The field experiment was divided in two parts: the first, consisted of treatments set in a 2 x 2 x 4 factorial combination of the following factors: live mulch species (Arachis pintoi and Macroptilium atropurpureum), vegetation management after cutting (leaving residue as a mulch or residue remotion from the plots) and four soil depths. The second part had treatments set in a 4 x 2 x 2 factorial combination of the following factors: absence of live mulch, A. pintoi, Pueraria phaseoloides, and M. atropurpureum, P levels (0 and 88 kg ha-1) and vegetation management after cutting. Variation of microbial C was not observed in relation to soil depth. However, the amount of microbial P and N, water soluble C, available C, and mineralizable C decreased with soil depth. Among the tested legumes, Arachis pintoi promoted an increase of microbial C and available C content of the soil, when compared to the other legume species (Pueraria phaseoloides and Macroptilium atropurpureum). Keeping the shoot as a mulch promoted an increase on soil content of microbial C and N, total organic C and N, and organic C fractions, indicating the importance of this practice to improve soil fertility.

Anaerobic Digestate Fraction and Nutrient Stoichiometry Significantly Influence the Carbon Cycle in Grassland Soils

2020 ◽  
Author(s):  
Marta Cattin ◽  
Marc Stutter ◽  
Alfonso Lag-Brotons ◽  
Phil Wadley ◽  
Kirk T. Semple ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Ph ◽  
Soil Nutrient ◽  
Nutrient Status ◽  
Microbial Biomass C ◽  
Grassland Soils ◽  
Soil Nutrient Status ◽  
Soil C ◽  
C Cycle ◽  
Soil C Cycle

&lt;p&gt;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. &amp;#160;&lt;/p&gt;&lt;p&gt;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&lt;sub&gt;2&lt;/sub&gt;-C efflux, microbial biomass C (C&lt;sub&gt;micro&lt;/sub&gt;) and pH were determined. &amp;#160;&lt;/p&gt;&lt;p&gt;In each of the two incubations, the application of digestate significantly increased cumulative CO&lt;sub&gt;2&lt;/sub&gt;-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.&amp;#160;&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

scholarly journals Introducing Grasslands into Crop Rotations, a Way to Restore Microbiodiversity and Soil Functions

Agriculture ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 909
Author(s):  
Wassila Riah-Anglet ◽  
Elodie Cusset ◽  
Rémi Chaussod ◽  
Stéven Criquet ◽  
Marie-Paule Norini ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Soil Ph ◽  
Enzyme Activities ◽  
Crop Rotations ◽  
Microbial Abundance ◽  
Soil Functions ◽  
Soil C ◽  
Permanent Grassland ◽  
Soil C And N ◽  
C And N

The aims of this study were to investigate (i) the influence of aging grassland in the recovery of soil state by the comparison of permanent grassland, two restored grasslands, two temporary grasslands, and a continuous crop in the same pedoclimatic conditions, (ii) the extent and the persistence of the potential changes following a grassland/or cropland phase. We hypothesized that the level of microbial communities and enzyme activities could achieve a profile close to that of permanent grassland after the introduction of grassland for a few years in crop rotations. Soil biophysicochemical properties were studied. Our results indicated that the abundance of microbial communities and enzyme activities were positively correlated to soil C and N contents and negatively correlated to soil pH. The changes in microbial abundance level were strongly linked to the changes in functional level when grasslands are introduced into crop rotations. We also showed that a continuous crop regime had a stronger legacy on the soil biota and functions. By contrast, the legacy of a grassland regime changed quickly when the grassland regime is interrupted by recent culture events. A grassland regime enabled the restoration of functions after more than five cumulative years in the grassland regime.

scholarly journals Effects of species-dominated patches on soil organic carbon and total nitrogen storage in a degraded grassland in China

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6897 ◽  
Author(s):  
Yujuan Zhang ◽  
Shiming Tang ◽  
Shu Xie ◽  
Kesi Liu ◽  
Jinsheng Li ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Total Nitrogen ◽  
Microbial Biomass Nitrogen ◽  
Soil C ◽  
Artemisia Frigida ◽  
C Stocks ◽  
Soil C And N ◽  
C And N

Background Patchy vegetation is a very common phenomenon due to long-term overgrazing in degraded steppe grasslands, which results in substantial uncertainty associated with soil carbon (C) and nitrogen (N) dynamics because of changes in the amount of litter accumulation and nutrition input into soil. Methods We investigated soil C and N stocks beneath three types of monodominant species patches according to community dominance. Stipa krylovii patches, Artemisia frigida patches, and Potentilla acaulis patches represent better to worse vegetation conditions in a grassland in northern China. Results The results revealed that the soil C stock (0–40 cm) changed significantly, from 84.7 to 95.7 Mg ha−1, and that the soil organic carbon content (0–10 cm) and microbial biomass carbon (0–10 and 10–20 cm) varied remarkably among the different monodominant species communities (P < 0.05). However, soil total nitrogen and microbial biomass nitrogen showed no significant differences among different plant patches in the top 0–20 cm of topsoil. The soil C stocks under the P. acaulis and S. krylovii patches were greater than that under the A. frigida patch. Our study implies that accurate estimates of soil C and N storage in degenerated grassland require integrated analyses of the concurrent effects of differences in plant community composition.

scholarly journals Grass-Legume Mixtures for Improved Soil Health in Cultivated Agroecosystem

2018 ◽  
Vol 10 (8) ◽  
pp. 2718 ◽  
Author(s):  
Dhruba Dhakal ◽  
M. Islam
Keyword(s):  
Microbial Biomass ◽  
Production System ◽  
Soil Microbial Biomass ◽  
Soil Health ◽  
Soil Samples ◽  
N Fertilizer ◽  
Entire Study ◽  
Soil C ◽  
Soil Microbial ◽  
C And N

Planting grass-legume mixtures may be a good option to improve soil health in addition to increased forage productivity, improved forage nutritive value, and net farm profit in a hay production system. A field experiment was conducted from 2011 to 2014 at Lingle, Wyoming to evaluate soil microbial biomass under different seeding proportions of two forage grasses (meadow bromegrass, Bromus biebersteinii Roem. & Schult.; and orchardgrass, Dactylis glomerata L.) and one legume (alfalfa, Medicago sativa L.). Nine treatments included monoculture grass, monoculture legume, one grass and one legume mixture, two grasses and one legume mixture, and a control (not seeded with grass or legume). Monoculture grass received either no nitrogen (N) or N fertilizer (150 kg N ha−1 year−1 as urea) whereas monoculture legume, grass-legume mixtures, and control plots received no N fertilizer. The study was laid out as a randomized complete block design with three replications. The plots were harvested 3–4 times each year after the establishment year. Soil samples were collected and analyzed for microbial biomass using phospholipid fatty acid (PLFA) analysis at the end of May in 2013 and 2014. Soil samples were also analyzed for mineralizable carbon (C) and N in 2013 and 2014. The total above-ground plant biomass was higher in 50–50% mixture of grass and alfalfa than monoculture alfalfa and monoculture grass (with and without N fertilizer) during the entire study period. The application of N fertilizer to the grass hay production system had little effect on improving mineralizable soil C, N, and soil microbial biomass. However, grass-legume mixture without N fertilizer had great effect on improvement of mineralizable soil C and N, and total, bacterial, and actinomycetes microbial biomass in soil. The 50–50% mixture of grass and alfalfa performed consistently well and can be considered to use in Wyoming conditions for improving soil health and forage productivity.

scholarly journals Introduction of Dalbergia odorifera enhances nitrogen absorption on Eucalyptus through stimulating microbially mediated soil nitrogen-cycling

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xianyu Yao ◽  
Qianchun Zhang ◽  
Haiju Zhou ◽  
Zhi Nong ◽  
Shaoming Ye ◽  
...  
Keyword(s):  
Microbial Biomass ◽  
Soil Ph ◽  
N Cycling ◽  
N Availability ◽  
Soil N ◽  
Total N ◽  
Available N ◽  
Soil C ◽  
Hot Season ◽  
Dalbergia Odorifera

Abstract Background There is substantial evidence that Eucalyptus for nitrogen (N) absorption and increasing the growth benefit from the introduction of N-fixing species, but the underlying mechanisms for microbially mediated soil N cycling remains unclear. Methods We investigated the changes of soil pH, soil water content (SWC), soil organic carbon (SOC), total N (TN), inorganic N (NH4+-N and NO3−-N), microbial biomass and three N-degrading enzyme activities as well as the biomass and N productivity of Eucalyptus between a pure Eucalyptus urophylla × grandis plantation (PP) and a mixed Dalbergia odorifera and Eucalyptus plantation (MP) in Guangxi Zhuang Autonomous Region, China. Results Compared with the PP site, soil pH, SWC, SOC and TN in both seasons were significantly higher at the MP site, which in turn enhanced microbial biomass and the activities of soil N-degrading enzymes. The stimulated microbial activity at the MP site likely accelerate soil N mineralization, providing more available N (NH4+-N in both seasons and NO3−-N in the wet-hot season) for Eucalyptus absorption. Overall, the N productivity of Eucalyptus at the MP site was increased by 19.7% and 21.9%, promoting the biomass increases of 15.1% and 19.2% in the dry-cold season and wet-hot season, respectively. Conclusion Our results reveal the importance of microbially mediated soil N cycling in the N absorption on Eucalyptus. Introduction of D. odorifera enhances Eucalyptus biomass and N productivity, improve soil N availability and increased soil C and N concentration, which hence can be considered to be an effective sustainable management option of Eucalyptus plantations.

scholarly journals Effects of litter and root manipulations on soil carbon and nitrogen in a Schrenk’s spruce (Picea schrenkiana) forest

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0247725
Author(s):  
Haiqiang Zhu ◽  
Lu Gong ◽  
Zhaolong Ding ◽  
Yuefeng Li
Keyword(s):  
Enzyme Activity ◽  
Microbial Biomass ◽  
Organic Carbon ◽  
Soil Carbon ◽  
Abiotic Factors ◽  
Soil C ◽  
Plant Detritus ◽  
Soil C And N ◽  
C And N ◽  
Root Exclusion

Plant detritus represents the major source of soil carbon (C) and nitrogen (N), and changes in its quantity can influence below-ground biogeochemical processes in forests. However, we lack a mechanistic understanding of how above- and belowground detrital inputs affect soil C and N in mountain forests in an arid land. Here, we explored the effects of litter and root manipulations (control (CK), doubled litter input (DL), removal of litter (NL), root exclusion (NR), and a combination of litter removal and root exclusion (NI)) on soil C and N concentrations, enzyme activity and microbial biomass during a 2-year field experiment. We found that DL had no significant effect on soil total organic carbon (SOC) and total nitrogen (TN) but significantly increased soil dissolved organic carbon (DOC), microbial biomass C, N and inorganic N as well as soil cellulase, phosphatase and peroxidase activities. Conversely, NL and NR reduced soil C and N concentrations and enzyme activities. We also found an increase in the biomass of soil bacteria, fungi and actinomycetes in the DL treatment, while NL reduced the biomass of gram-positive bacteria, gram-negative bacteria and fungi by 5.15%, 17.50% and 14.17%, respectively. The NR decreased the biomass of these three taxonomic groups by 8.97%, 22.11% and 21.36%, respectively. Correlation analysis showed that soil biotic factors (enzyme activity and microbial biomass) and abiotic factors (soil moisture content) significantly controlled the change in soil C and N concentrations (P < 0.01). In brief, we found that the short-term input of plant detritus could markedly affect the concentrations and biological characteristics of the C and N fractions in soil. The removal experiment indicated that the contribution of roots to soil nutrients is greater than that of the litter.

Abstract TMP54: Seasonal Patterns of Ischemic Stroke in the United States

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Stacy Y Chu ◽  
Margueritte Cox ◽  
Gregg C Fonarow ◽  
Eric Smith ◽  
Lee H Schwamm ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Hospital Mortality ◽  
The United States ◽  
Seasonal Effect ◽  
Climatic Data ◽  
Climate Variables ◽  
Odds Ratios ◽  
Climate Region ◽  
Significant Difference ◽  
Precipitation And Temperature

Background: Seasonal variation in stroke occurrence and outcomes has been reported in small populational studies but the significance of a seasonal effect is uncertain. The important patient and climate variables underlying this phenomenon have not yet been identified. Methods: Using Get With The Guidelines-Stroke data from 2011 to 2015, we studied 457,638 consecutive ischemic stroke patients at 896 sites. We calculated the relative prevalence of acute stroke admissions in each season. Baseline characteristics and discharge outcomes were compared across seasons and the effects of season, climate region (as defined by the National Climatic Data Center), and climate variables on outcomes were analyzed using logistic regression. In secondary analyses, odds ratios were calculated for various outcomes. Results: Among all cases of ischemic stroke, there was significant difference in the frequency distributions of cases across seasons (p<.0001), with the highest percentage of strokes occurring in winter (25.5%). Across seasons, winter patients had the highest percentage of atrial fibrillation (17.7%), longest median time to arrival (202 minutes), highest in-hospital mortality (4.4%), and most discharge mRS scores > 3 (43.7%). P<.0001 for all the above. Higher precipitation and temperature were associated with reduced mortality independent of climate region or season (OR .93, CI .89-.97, p=.0005 and OR .97, CI .97-.98, p<.0001, respectively). Odds ratios for in-hospital mortality are summarized in the accompanying table. Conclusions: More patients presented with acute ischemic stroke in winter relative to other seasons, accompanied by trends toward poorer outcomes. Although an association with mortality was seen for winter in our unadjusted analysis, confounding variables likely exist. Precipitation and temperature were independently associated with stroke mortality.

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