Grassland soil carbon and nitrogen stocks under temperate livestock grazing

Soil Research ◽  
2015 ◽  
Vol 53 (5) ◽  
pp. 485 ◽  
Author(s):  
Junfang Cui ◽  
Mohammad Sadegh Askari ◽  
Nicholas M. Holden

Sustainable grassland management is critical to many agricultural economies because of the significant proportion of agricultural commodities derived from grass-fed livestock (milk and meat). Mismanagement will result in a cycle of soil quality deterioration and reduced productivity. This study estimated carbon (C) and nitrogen (N) stocks in relation to grazing management in Ireland, with a focus on understanding the role of management intensity derived from the interaction of stocking rate, N fertiliser rate and reseeding frequency. Soil samples were taken from depths 0–10, 10–20 and 20–30 cm. Soil physical properties, C and N concentrations, and microbial biomass C were measured. Significant increases in C and N concentrations were observed along the texture gradient: sandy loam < loam < sandy clay loam < clay loam < silty clay loam. However, there was little difference in C and N stock according to soil texture class. Soil with 10–20-year-old grass sward contained the lowest soil C and N content, indicating that proper reseeding is necessary to maintain soil C and N storage capacity. Increased chemical N fertiliser rate did not cause changes of soil C and N content, whereas intensified stocking rate caused great changes in soil C and N content by re-locating soil C and N at depth. Moderately intensive management was associated with significantly lower C and N stocks, and highly intensive management was associated with greater capacity of soil C and N, but no interaction between texture and management intensity was found.

1992 ◽  
Vol 72 (3) ◽  
pp. 201-216 ◽  
Author(s):  
P. M. Rutherford ◽  
N. G. Juma

Modelling in soil ecological research is a means of linking the dynamics of microbial and faunal populations to soil processes. The objectives of this study were (i) to simulate bacterial-protozoan interactions and flows of C and N in clay loam Orthic Black Chernozemic soil under laboratory condtions; and (ii) to quantify the flux of C and N (inputs and outputs) through various pools using the simulation model. The unique features of this model are: (i) it combines the food chain with specific soil C and N pools, and (ii) it simultaneously traces the flows of C, 14C, N and 15N. It was possible to produce a model that fitted the data observed for the soil. The simulated CO2-C evolved during the first 12 d was due mainly to glucose addition (171 μg C g−1 soil) and cycling of C in the soil (160 μg C g−1 soil). During this interval, bacterial C uptake was 5.5-fold greater than the initial bacterial C pool size. In the first 12 d protozoa directly increased total CO2-C evolution by 11% and increased NH4-N mineralization 3-fold, compared to soil containing only bacteria. Mineralization of C and N was rapid when bacterial numbers were increased as a result of glucose addition. Key words: Acanthamoeba sp., modelling, N mineralization-immobilization, organic matter, Pseudomonas sp., Typic Cryoboroll


2004 ◽  
Vol 19 (6) ◽  
pp. 621-629 ◽  
Author(s):  
Wang Genxu ◽  
Yao Jinzhong ◽  
Luo Lin ◽  
Qian Ju

Soil Research ◽  
1996 ◽  
Vol 34 (6) ◽  
pp. 891 ◽  
Author(s):  
AJ Gijsman

An area of native savanna on an Oxisol in the Eastern Plains of Colombia was opened and sown to various rotations of grass or grass-legume pasture with rice. After 4.5 years, the soil was sampled for studying the effect of land conversion on soil aggregation and on the distribution of total and particulate soil organic matter across the aggregate size classes. The size distribution of undisturbed aggregates did not vary among treatments. Five different methods were used to measure wet aggregate stability (WAS). The choice of method affected the WAS average across treatments as well as the differences among treatments. The only consistent observation was the lower WAS under monocropped rice compared with the other treatments. Inclusion of a legume in a pasture hardly affected aggregate stability. In contrast to the WAS measurements, which were carried out with soil aggregates of 1-2 mm, wet sieving of whole-soil samples revealed additional differences among treatments: large macroaggregates (>2 mm) proved less stable under those treatments that involved soil disturbance through ploughing and harvesting. Total soil C and N content did not vary among treatments, despite considerable differences in plant production levels. The C concentration, but not the N concentration, declined with decreasing aggregate size. The distribution of whole-soil C and N content across aggregate size classes depended more on the amount of soil in a certain size class than on the size class's C or N concentration. Those treatments that involved frequent soil disturbance had a smaller fraction of large macroaggregates (>2 mm) and, as a consequence, less C and N in the large macroaggregate fraction. The particulate organic matter (POM) fraction accounted for only 6.2-8.5% of total soil carbon. The small size of this pool makes it unlikely that POM can serve in these Oxisols for estimating the amount of soil organic matter with medium turnover rate, as suggested by others.


2021 ◽  
Vol 9 ◽  
Author(s):  
Paulina B. Ramírez ◽  
Francisco J. Calderón ◽  
Michelle Haddix ◽  
Emanuele Lugato ◽  
M. Francesca Cotrufo

Large-scale quantification of soil organic carbon (C) and nitrogen (N) stocks and their distribution between particulate (POM) and mineral-associated (MAOM) organic matter is deemed necessary to develop land management strategies to mitigate climate change and sustain food production. To this end, diffuse reflectance mid-infrared spectroscopy (MIR) coupled with partial least square (PLS) analysis has been proposed as a promising method because of its low labor and cost, high throughput and the potential to estimate multiple soil attributes. In this paper, we applied MIR spectroscopy to predict C and N content in bulk soils, and in POM and MAOM, as well as soil properties influencing soil C storage. A heterogeneous dataset including 349 topsoil samples were collected under different soil types, land use and climate conditions across the European Union and the United Kingdom. The samples were analyzed for various soil properties to determine the feasibility of developing MIR-based predictive calibrations. We obtained accurate predictions for total soil C and N content, MAOM C and N content, pH, clay, and sand (R2&gt; 0.7; RPD&gt;1.8). In contrast, POM C and N content were predicted with lower accuracies due to non-linear dependencies, suggesting the need for additional calibration across similar soils. Furthermore, the information provided by MIR spectroscopy was able to differentiate spectral bands and patterns across different C pools. The strength of the correlation between C pools, minerals, and C functional groups was land use-dependent, suggesting that the use of this approach for long-term soil C monitoring programs should use land-use specific calibrations.


2014 ◽  
Vol 11 (8) ◽  
pp. 12159-12182 ◽  
Author(s):  
L. Ma ◽  
C. Guo ◽  
S. Yuan ◽  
R. Wang

Abstract. The unprecedented variations in global precipitation regime could profoundly impact terrestrial ecosystem structure and function, with consequent feedback to climatic change. However, little is known about complexity in precipitation effects on grassland ecosystem carbon (C) and nitrogen (N) processes at regional scales. We investigated the patterns of shoot and root biomass, litter mass, soil C and N content, microbial community composition and C and N mineralization at 18 sites along a 1000 km precipitation gradient in native Leymus chinensis grasslands of northeastern China. The results show that, with increasing mean annual precipitation (MAP), the biomass of total plant, shoot and litter gradually increased while root biomass remained nearly constant along the gradient. Surprisingly, both soil C and N mineralization rates showed quadratic relationships with MAP, likely due to the relative changes in temperature, soil arbuscular mycorrhizal fungi biomass and N availability. Although soil total C and N content presented sustained increases with water availability, heavy fractions of C and N content reached stable and saturated phases in mesic sites. Overall, ecosystem C and N sequestration enhanced with water availability in terms of C and N storage in shoot, root, litter, and soil along the precipitation gradient. It was concluded from the current study that regional precipitation regime and the indirect effects of precipitation on changes in soil properties and microbial communities would strongly influence on ecosystem C and N dynamics. The temperate grasslands of northeastern China could be utilized as significant ecosystem C and N sinks in the context of mitigating climate change.


2014 ◽  
Vol 312 ◽  
pp. 161-169 ◽  
Author(s):  
Yongfu Li ◽  
Jiaojiao Zhang ◽  
Scott X. Chang ◽  
Peikun Jiang ◽  
Guomo Zhou ◽  
...  

2018 ◽  
pp. 93-100 ◽  
Author(s):  
M. Nyborg ◽  
E.D. Solberg ◽  
S.S. Malhi ◽  
R.C. Izaurralde

Geoderma ◽  
2020 ◽  
Vol 359 ◽  
pp. 113990 ◽  
Author(s):  
Alexandra Rodríguez ◽  
Tommaso Chiti ◽  
Ana Rey ◽  
Jorge Durán

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