Decline in soil organic carbon and total nitrogen in relation to tillage, stubble management, and rotation

1995 ◽  
Vol 35 (7) ◽  
pp. 877 ◽  
Author(s):  
DP Heenan ◽  
WJ McGhie ◽  
FM Thomson ◽  
KY Chan

The influence of rotation, tillage, stubble management, and nitrogen (N) fertiliser on soil organic carbon (C) and total nitrogen (N) was studied between 1979 and 1993 in a field experiment at Wagga Wagga, New South Wales, on a red earth. The rotations included lupin-wheat (LW), subterranean clover-wheat (SW), and continuous wheat (WW) with and without N fertiliser (100 kg N/ha). At the start of the experiment the soil organic C and N in the surface 10 cm were high following many years of subterranean clover based pasture. The trends in soil organic C varied considerably between treatments from near equilibrium levels for SW direct-drilled and stubble-retained to annual losses of 400 kg/ha for WW conventionally cultivated and stubble burnt. Similarly, total soil N content over time varied from equilibrium levels to highly significant declines of 53 kg/ha. year for WW conventionally cultivated and stubble burnt. Both direct drilling and stubble retention reduced the losses of organic C and N compared with conventional cultivation and burning, with greatest loss occurring when cultivation and stubble burning were combined. SW and LW produced a similar contribution of fixed N to total N product removal, but greater benefits to following wheat crops were provided by SW rotations. Where losses of organic C and N were recorded there was no evidence of equilibrium levels being reached after 14 years.

2014 ◽  
Vol 94 (3) ◽  
pp. 303-315 ◽  
Author(s):  
Laura L. Van Eerd ◽  
Katelyn A. Congreves ◽  
Adam Hayes ◽  
Anne Verhallen ◽  
David C. Hooker

Van Eerd, L. L., Congreves, K. A., Hayes, A., Verhallen, A. and Hooker, D. C. 2014. Long-term tillage and crop rotation effects on soil quality, organic carbon, and total nitrogen. Can. J. Soil Sci. 94: 303–315. Long-term studies allow for quantification of the effects of crop production practices, such as tillage and crop rotation, on soil quality and soil C and N stores. In two experiments at Ridgetown, ON, we evaluated the long-term (11 and 15 yr) effect of tillage system and crop rotation on soil quality via the Cornell Soil Health Assessment (CSHA) at 0–15 cm and soil organic C (SOC) and total N at 5-, 10-, and 20-cm increments to 120 cm depth. The CSHA soil quality score and SOC and total N were higher with no-till (NT) than fall moldboard plough with spring cultivation (conventional tillage, CT) and rotations with winter wheat [soybean–winter wheat (S-W) and soybean–winter wheat–corn (S-W-C)] compared with rotations without winter wheat. In both long-term trials, NT had ca. 21 Mg ha−1more or 14% higher SOC than CT in the 0- to 100-cm soil profile, a trend which contrasts previous research in eastern Canada. Thus, the two long-term trial results at Ridgetown suggest that to improve soil quality and storage of C and N, growers on clay loam soil in southwestern Ontario should consider adopting NT production practices and including winter wheat in the rotation.


Soil Research ◽  
2018 ◽  
Vol 56 (3) ◽  
pp. 318 ◽  
Author(s):  
R. M. Lebenya ◽  
C. W. van Huyssteen ◽  
C. C. du Preez

Scientific studies report decreases, increases, or negligible changes in soil organic carbon (C) stocks upon afforestation; however, these studies neglect the potential role of total nitrogen (N), tree species, and soil drainage class on these changes. This paper therefore aimed to quantify the change in soil organic C and total N stocks in the Weatherley catchment, eight years after conversion of grassland to forestry. Twenty-seven soil profile sites in this catchment, situated in the north-eastern corner of the Eastern Cape Province of South Africa, were sampled to determine the soil organic C and total N concentrations for the estimation of stocks. These sites represented different vegetation (Pinus elliottii, P. patula, Eucalyptus nitens, and grass) and soil drainage class (poorly, moderately, and freely drained soils) areas. Eighteen of the 27 sites studied had decreases, and nine sites had increases in organic C stocks in the 0–300 mm soil layer after eight years of afforestation. Total N decreased in 18 sites and increased at nine sites. Eight years of afforestation with P. elliottii and E. nitens significantly decreased stocks of soil organic C (from 47.6 to 38.8 Mg/ha) and total N (from 3.22 to 2.87 Mg/ha), whereas P. patula only slightly increased the corresponding stocks from 43.8 to 48.6 Mg C/ha and from 2.80 to 3.68 Mg N/ha. Both soil organic C and total N stocks decreased in all three soil drainage classes upon afforestation. It is proposed that these findings be corroborated after another 8–10 years of afforestation.


Soil Research ◽  
2018 ◽  
Vol 56 (6) ◽  
pp. 632 ◽  
Author(s):  
Kathryn Conrad ◽  
Ram C. Dalal ◽  
Ryosuke Fujinuma ◽  
Neal W. Menzies

Stabilisation and protection of soil organic carbon (SOC) in macroaggregates and microaggregates represents an important mechanism for the sequestration of SOC. Legume-based grass pastures have the potential to contribute to aggregate formation and stabilisation, thereby leading to SOC sequestration. However, there is limited research on the C and N dynamics of soil organic matter (SOM) fractions in deep-rooted legume leucaena (Leucaena leucocephala)–grass pastures. We assessed the potential of leucaena to sequester carbon (C) and nitrogen (N) in soil aggregates by estimating the origin, quantity and distribution in the soil profile. We utilised a chronosequence (0–40 years) of seasonally grazed leucaena stands (3–6 m rows), which were sampled to a depth of 0.3 m at 0.1-m intervals. The soil was wet-sieved for different aggregate sizes (large macroaggregates, >2000 µm; small macroaggregates, 250–2000 µm; microaggregates, 53–250 µm; and <53 µm), including occluded particulate organic matter (oPOM) within macroaggregates (>250 µm), and then analysed for organic C, N and δ13C and δ15N. Leucaena promoted aggregation, which increased with the age of the leucaena stands, and in particular the formation of large macroaggregates compared with grass in the upper 0.2 m. Macroaggregates contained a greater SOC stock than microaggregates, principally as a function of the soil mass distribution. The oPOM-C and -N concentrations were highest in macroaggregates at all depths. The acid nonhydrolysable C and N distribution (recalcitrant SOM) provided no clear distinction in stabilisation of SOM between pastures. Leucaena- and possibly other legume-based grass pastures have potential to sequester SOC through stabilisation and protection of oPOM within macroaggregates in soil.


Soil Research ◽  
2007 ◽  
Vol 45 (1) ◽  
pp. 13 ◽  
Author(s):  
Fiona A. Robertson ◽  
Peter J. Thorburn

The Australian sugar industry is moving away from the practice of burning the crop before harvest to a system of green cane trash blanketing (GCTB). Since the residues that would have been lost in the fire are returned to the soil, nutrients and organic matter may be accumulating under trash blanketing. There is a need to know if this is the case, to better manage fertiliser inputs and maintain soil fertility. The objective of this work was to determine whether conversion from a burning to a GCTB trash management system is likely to affect soil fertility in terms of C and N. Indicators of short- and long-term soil C and N cycling were measured in 5 field experiments in contrasting climatic conditions. The effects of GCTB varied among experiments. Experiments that had been running for 1–2 years (Harwood) showed no significant trash management effects. In experiments that had been running for 3–6 years (Mackay and Tully), soil organic C and total N were up to 21% greater under trash blanketing than under burning, to 0.10 or 0.25 m depth (most of this effect being in the top 50 mm). Soil microbial activity (CO2 production) and soil microbial biomass also increased under GCTB, presumably as a consequence of the improved C availability. Most of the trash C was respired by the microbial biomass and lost from the system as CO2. The stimulation of microbial activity in these relatively short-term GCTB systems was not accompanied by increased net mineralisation of soil N, probably because of the greatly increased net immobilisation of N. It was calculated that, with standard fertiliser applications, the entire trash blanket could be decomposed without compromising the supply of N to the crop. Calculations of possible long-term effects of converting from a burnt to a GCTB production system suggested that, at the sites studied, soil organic C could increase by 8–15%, total soil N could increase by 9–24%, and inorganic soil N could increase by 37 kg/ha.year, and that it would take 20–30 years for the soils to approach this new equilibrium. The results suggest that fertiliser N application should not be reduced in the first 6 years after adoption of GCTB, but small reductions may be possible in the longer term (>15 years).


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6897 ◽  
Author(s):  
Yujuan Zhang ◽  
Shiming Tang ◽  
Shu Xie ◽  
Kesi Liu ◽  
Jinsheng Li ◽  
...  

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.


2021 ◽  
Author(s):  
Lucas Tabaud ◽  
Christian Walter ◽  
Clotilde Blancfene ◽  
Chantal Gascuel ◽  
Blandine Lemercier ◽  
...  

&lt;p&gt;Soils are crossroads of carbon and nitrogen geochemical cycles and were consequently identified as a potential sink for carbon (C) and a compartment storage for nitrogen (N). Monitoring the joint evolution over time of organic C and total N stocks in soils appears interesting because of the C/N ratio is an indicator of changes in the organic matter quality. Nevertheless, the temporal evolutions detected in most of the existing studies are in the order of a few gC.m&lt;sup&gt;-2&lt;/sup&gt;.yr&lt;sup&gt;-1&lt;/sup&gt; (C) and mgN.m&lt;sup&gt;-2&lt;/sup&gt;.yr&lt;sup&gt;-1 &lt;/sup&gt;(N). This study aims to assess uncertainties of soil organic carbon (SSOC) and soil total nitrogen (SSTN) stocks in the topsoil layer (0-25 cm) using three different methods (stochastic, deterministic and experimental), in order to identify the main sources of uncertainty and to evaluate the significance of SSOC and SSTN evolutions over the time. This study was based on a 1200 ha agricultural catchment area in Brittany (France) where systematic soil sampling was repeated at 108 sites in 2013 and 2018. Moreover, soil sampling was repeated three times in 2020 at the same sites by 3 different teams of experienced samplers. Comparing the three methods of uncertainty assessment, we found they provided equivalent results with a SSOC standard deviation of 0.85, 0.74 and 0.68 kgC.m&lt;sup&gt;-2&lt;/sup&gt; respectively for stochastic, deterministic and experimental approaches and 0.08, 0.07 and 0.06 kgN.m&lt;sup&gt;-2&lt;/sup&gt; for SSTN. Variance decomposition identified variations of fine earth mass as the main source of uncertainty (77 % of total variance) and attributed at least 16% of the uncertainties due to the operator procedure and were therefore reducible. Using the stochastic approach, the width of the 90 % confidence interval was estimated at each sampling site for C, N and C/N temporal changes. Changes were considered significant at respectively 59, 77 et 99 sites for SSOC, SSTN and C/N: a majority of sites lost organic carbon (-0.03 &amp;#177; 0.07 kgC.m&lt;sup&gt;-2&lt;/sup&gt;.yr&lt;sup&gt;-1&lt;/sup&gt;), gained total nitrogen (0.006 &amp;#177; 0.005 kgN.m&lt;sup&gt;-2&lt;/sup&gt;.yr&lt;sup&gt;-1&lt;/sup&gt;) and the C.N&lt;sup&gt;-1&lt;/sup&gt; (-0.17 &amp;#177; 0.09 yr&lt;sup&gt;-1&lt;/sup&gt;) ratio decreased. Finally, stock measurements uncertainty was mainly explained by soil natural variability but may still be reduced by a better control of the measurement procedure. In the agricultural context of the study area, the accuracy of the direct measurement appeared sufficient to detect SSOC and SSTN evolution over a time span of 5 years.&lt;/p&gt;


1995 ◽  
Vol 35 (7) ◽  
pp. 923 ◽  
Author(s):  
NA Fettell ◽  
HS Gill

Differences in soil organic carbon (C), total nitrogen (N), and pH resulting from 14 and 15 years of different tillage, stubble, and fertiliser N management practices were measured for a red-brown earth at Condobolin in western New South Wales. The 5 main treatments comprised stubble burning or retention in factorial combination with cultivation and direct drilling, and stubble incorporation combined with cultivation. Two rates of N fertiliser (0 and 40 or 50 kg/ha) were applied annually, and wheat was grown each year. There were no significant differences between tillage and stubble treatments for soil organic C, total N, or pH. Fertiliser N application caused small but significant increases in organic C and total N but decreased the pH of the surface 2.5 cm of soil by 0.4-0.5 units compared with the nil fertiliser rate. The study indicates that direct drilling and stubble retention with continuous wheat have had little long-term effect on soil organic C and total N in this low rainfall environment.


Soil Research ◽  
1993 ◽  
Vol 31 (4) ◽  
pp. 481 ◽  
Author(s):  
MR Carter ◽  
WJ Parton ◽  
IC Rowland ◽  
JE Schultz ◽  
GR Steed

Maintenance and improvement of soil organic matter levels is an important concern in dryland farming systems of temperate regions. The Century soil organic matter model was used to simulate changes in soil organic C and total N under long-term wheat (Triticum aestivum L.) and pasture rotations at five sites in southern Australia. Average declines in soil organic C and total N of 14 and 10%, respectively, in continuous and wheat-fallow systems over a 10 to 20 year period were closely simulated by the model at each site. Additions of N fertilizer (80 kg N ha-1), which prevented soil organic matter decline in continuous wheat systems, was also well represented by the model. Trends in soil organic matter under long-term legume pasture were not adequately simulated by the model, probably due to the 'annual' nature of subterranean clover (Trifolium subterranean L.) in dry seasons and subsequent changes in the ratio of live to dead plant biomass and shoot to root ratios. Overall, the study emphasizes the importance of adequate total plant C production to prevent a decline in soil organic C.


2020 ◽  
Vol 8 (1) ◽  
pp. 1-8
Author(s):  
Refki Aulia Wiwaha ◽  
Syahrul Kurniawan

The Kali Kungkuk micro watershed which is located in the upper area of Brantas watershed, had experienced forest conversion to horticulture during the last fourth decades. Since the physiographic of Kali Kungkuk micro watershed is hilly, forest conversion to horticulture may result in soil nutrient stock changes. The research aimed to analyze soil nutrient stock from forest to horticulture land uses (i.e. apple orchard and vegetables) in the Kali Kungkuk micro watershed. The field research was conducted on three different land uses (i.e. vegetable land (PK), apple orchard (PA), and forest (PH)) and four land slope classes (i.e. slope 0-8% (K1), 8-15% (K2), 15-25% (K3), and > 25% (K4)), with three, replicates plots of each. Soil samples were collected at three different depths (0-10, 10-30, and 30- 50 cm) from each plot. The parameters measured included soil texture, bulk density, standing litter mass, canopy cover, basal area, soil organic carbon and total nitrogen. Data analysis was conducted with Linear Mixed Effect Models with a level of 5% and a further analysis of LSD test level of 5% as well as a correlation test between observational parameters. The results showed that differences in land use and slope affected to significant differences in the content of soil organic C and total N. In general, forests had higher soil C and N stocks as compared to other land uses (i.e. apple orchard and vegetables). Furthermore, soil organic C and total N was higher in the low slopes (i.e. 0-8%) and (8-15%) as compared to the high slopes (i.e. 15-25%) and (> 25%). The study found a positive correlation between soil nutrient stocks (i.e. C and N) and clay content. In contrast, soil C and N stock was negatively correlated with soil bulk density. Soil fertility degradation that occurs in the Kali Kungkuk micro watershed (i.e. apple orchard and vegetables) requires serious attention in soil management in order to ensure the sustainability of apple and vegetable production.


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