Effect of tillage and crop rotations on the light fraction organic carbon and carbon mineralization in Chernozemic soils of Saskatchewan

2003 ◽  
Vol 83 (1) ◽  
pp. 65-72 ◽  
Author(s):  
B. C. Liang ◽  
B. G. McConkey ◽  
J. Schoenau ◽  
D. Curtin ◽  
C. A. Campbell ◽  
...  
Keyword(s):  
Soil Quality ◽  
Crop Production ◽  
Field Experiments ◽  
Light Fraction ◽  
Crop Rotations ◽  
Soil Organic C ◽  
Organic C ◽  
Chernozemic Soil ◽  
Soil Zone ◽  
The Impact

Light fraction of soil organic C (LFOC) represents a major portion of labile soil organic C (SOC) and is a key attribute of soil quality. Soil respiration (Cmin) is an important index depicting the potential activity of the labile SOC. Six field experiments, varying in duration (8 to 25 yr), in location (Brown, Dark Brown and Black Chernozemic soil zones of Saskatchewan) and soil texture, were conducted to evaluate the impact of tillage and crop rotations on crop production and soil quality. We sampled the 0-7.5-cm depth of soil in these experiments to determine the treatment effects on LFOC, the proportion of LFOC in the SOC (LFOC/SOC) and Cmin. Increasing the frequency of summer fallow in cropping systems decreased the LFOC in all soil zones; it also decreased the proportion of LFOC in SOC and Cmin. Tillage had little impact on LFOC in the Brown and Dark Brown Chernozemic soil zones, although it significantly decreased LFOC in the Black Chernozemic soil zone. Thus, crop rotation had a greater impact on LFOC than tillage. Tillage did not influence Cmin in any soil zone. Because adoption of no-till management increased SOC in all soil zones, we concluded that LFOC was not a sensitive indicator of the impact of tillage on this soil quality attribute for these Chernozemic soils in Saskatchewan. We also found that LFOC/SOC is directly proportional to sand content. This relationship may assist us in partitioning SOC pools with differing turnover times when modeling SOC dynamics. Key words: Soil organic C, light fraction organic C, tillage, crop rotations, texture, mineralizable C

scholarly journals Nitrogen fertilization impact on soil carbon pools and their stratification and lability in subtropical wheat-mungbean-rice agroecosystems

PLoS ONE ◽  
2021 ◽  
Vol 16 (10) ◽  
pp. e0256397
Author(s):  
Rafeza Begum ◽  
Mohammad Mofizur Rahman Jahangir ◽  
M. Jahiruddin ◽  
Md. Rafiqul Islam ◽  
Md. Taiabur Rahman ◽  
...  
Keyword(s):  
Soil Quality ◽  
Crop Production ◽  
Biological Activities ◽  
Block Design ◽  
N Fertilization ◽  
Basal Respiration ◽  
Organic C ◽  
C Pools ◽  
Labile C ◽  
The Impact

Nitrogen (N) is the prime nutrient for crop production and carbon-based functions associated with soil quality. The objective of our study (2012 to 2019) was to evaluate the impact of variable rates of N fertilization on soil organic carbon (C) pools and their stocks, stratification, and lability in subtropical wheat (Triticum aestivum)—mungbean (Vigna radiata)—rice (Oryza sativa L) agroecosystems. The field experiment was conducted in a randomized complete block design (RCB) with N fertilization at 60, 80, 100, 120, and 140% of the recommended rates of wheat (100 kg/ha), mungbean (20 kg/ha), and rice (80 kg/ha), respectively. Composite soils were collected at 0–15 and 15–30 cm depths from each replicated plot and analyzed for microbial biomass (MBC), basal respiration (BR), total organic C (TOC), particulate organic C (POC), permanganate oxidizable C (POXC), carbon lability indices, and stratification. N fertilization (120 and 140%) significantly increased the POC at both depths; however, the effect was more pronounced in the surface layer. Moreover, N fertilization (at 120% and 140%) significantly increased the TOC and labile C pools when compared to the control (100%) and the lower rates (60 and 80%). N fertilization significantly increased MBC, C pool (CPI), lability (CLI), and management indices (CMI), indicating improved and efficient soil biological activities in such systems. The MBC and POC stocks were significantly higher with higher rates of N fertilization (120% and 140%) than the control. Likewise, higher rates of N fertilization significantly increased the stocks of labile C pools. Equally, the stratification values for POC, MBC, and POXC show evidence of improved soil quality because of optimum N fertilization (120–140%) to maintain and/or improve soil quality under rice-based systems in subtropical climates.

scholarly journals The interaction of seasonal rainfall and nitrogen fertiliser rate on soil N2O emission, total N loss and crop yield of dryland sorghum and sunflower grown on sub-tropical Vertosols

Soil Research ◽  
2016 ◽  
Vol 54 (5) ◽  
pp. 604 ◽  
Author(s):  
G. D. Schwenke ◽  
B. M. Haigh
Keyword(s):  
Crop Yield ◽  
Crop Production ◽  
Field Experiments ◽  
N2o Emission ◽  
N2o Emissions ◽  
N Loss ◽  
N Losses ◽  
Total N ◽  
Tropical Regions ◽  
The Impact

Summer crop production on slow-draining Vertosols in a sub-tropical climate has the potential for large emissions of soil nitrous oxide (N2O) from denitrification of applied nitrogen (N) fertiliser. While it is well established that applying N fertiliser will increase N2O emissions above background levels, previous research in temperate climates has shown that increasing N fertiliser rates can increase N2O emissions linearly, exponentially or not at all. Little such data exists for summer cropping in sub-tropical regions. In four field experiments at two locations across two summers, we assessed the impact of increasing N fertiliser rate on both soil N2O emissions and crop yield of grain sorghum (Sorghum bicolor L.) or sunflower (Helianthus annuus L.) in Vertosols of sub-tropical Australia. Rates of N fertiliser, applied as urea at sowing, included a nil application, an optimum N rate and a double-optimum rate. Daily N2O fluxes ranged from –3.8 to 2734g N2O-Nha–1day–1 and cumulative N2O emissions ranged from 96 to 6659g N2O-Nha–1 during crop growth. Emissions of N2O increased with increased N fertiliser rates at all experimental sites, but the rate of N loss was five times greater in wetter-than-average seasons than in drier conditions. For two of the four experiments, periods of intense rainfall resulted in N2O emission factors (EF, percent of applied N emitted) in the range of 1.2–3.2%. In contrast, the EFs for the two drier experiments were 0.41–0.56% with no effect of N fertiliser rate. Additional 15N mini-plots aimed to determine whether N fertiliser rate affected total N lost from the soil–plant system between sowing and harvest. Total 15N unaccounted was in the range of 28–45% of applied N and was presumed to be emitted as N2O+N2. At the drier site, the ratio of N2 (estimated by difference)to N2O (measured) lost was a constant 43%, whereas the ratio declined from 29% to 12% with increased N fertiliser rate for the wetter experiment. Choosing an N fertiliser rate aimed at optimum crop production mitigates potentially high environmental (N2O) and agronomic (N2+N2O) gaseous N losses from over-application, particularly in seasons with high intensity rainfall occurring soon after fertiliser application.

Soil organic carbon sequestration potential for Canadian Agricultural Ecoregions calculated using the Introductory Carbon Balance Model

2008 ◽  
Vol 88 (4) ◽  
pp. 451-460 ◽  
Author(s):  
M A Bolinder ◽  
O. Andrén ◽  
T. Kätterer ◽  
L -E Parent
Keyword(s):  
Biological Activity ◽  
Carbon Balance ◽  
Crop Production ◽  
Field Experiments ◽  
Balance Model ◽  
Agricultural Crop ◽  
Organic C ◽  
Soil Biological Activity ◽  
Sequestration Potential

The potential for storage of atmospheric CO2-C as soil organic C (SOC) in agroecosystems depends largely on soil biological activity and the quantity and quality of annual C inputs to soil. In this study we used the Introductory Carbon Balance Model (ICBM) approach driven by daily standard weather station data, specific soil properties and crop characteristics at the scale of Canadian agricultural ecoregions. The objectives were to calculate a climate-dependent soil biological activity parameter representative for annual agricultural crop production systems (re_crop) and to estimate the effect of fallow (re_fallow). These parameters are based on the daily product of soil temperature and stored water that influence biological activity in the arable layer, and are used to adjust the decomposition rates of the ICBM SOC pools. We also tested re_crop and re_fallow on SOC stock change data for different site and treatment combinations from long-term field experiments located in some of the ecoregions. An re_crop value of 0.95 for western ecoregions was on average 0.23 units lower than that of the eastern ecoregions, indicating a lower decomposition rate of SOC. Although the estimated annual C inputs to soil for small-grain cereals were on average ≈7.5% higher in the eastern ecoregions (305 vs. 285 g C m-2 yr-1), the overall results suggest that the western ecoregions would have a greater potential to maintain high SOC levels in the long term. However, these parameters varied between ecoregions and, consequently, the SOC sequestration potential was not always higher for the western ecoregions. The effect of fallow was on average ≈0.04, i.e., SOC decomposed slightly faster under fallow. Predictions for 24 out of 33 site and treatment combinations across Canada were significantly improved (P = 0.003), compared with a previous application with the ICBM that did not differentiate between crops and fallow. The methodology used here enabled us to examine regional differences in the potential for SOC sequestration as a balance between annual C inputs to soil and soil biological activity. Key words: Annual C inputs, climate, fallow, soil biological activity, agroecosystems

Soil acidification and the carbon cycle in a cropping soil of north-eastern Victoria

Soil Research ◽  
1998 ◽  
Vol 36 (2) ◽  
pp. 273 ◽  
Author(s):  
W. J. Slattery ◽  
D. G. Edwards ◽  
L. C. Bell ◽  
D. R. Coventry ◽  
K. R. Helyar
Keyword(s):  
Soil Depth ◽  
Organic C ◽  
Soil Layers ◽  
Soil C ◽  
Soil Zone ◽  
North Eastern ◽  
Soil Buffering ◽  
The Impact ◽  
Total Organic C

Changes in soil organic matter were determined for a long-term (1975–95) experiment at the Rutherglen Research Institute in north-eastern Victoria. The crop rotations in this experiment were continuous lupins (LL) and continuous wheat (WW). The soil at this site was a solodic or Yellow Dermosol with a soil pH of 6·08 (pH in 0·01 М CaCl2 1 : 5) in 1975 in the surface 10 cm, which had declined by 0·8 and 1·5 pH units for WW and LL, respectively, in the 0–20 cm soil zone by 1992. Acidification rates decreased with increasing soil depth. The acidification rate in the 0–60 cm soil zone was 12·5 kmol(H+)/ha·year for the LL rotation and 4·6 kmol(H+)/ha·year for the WW rotation. The amount of CaCO3 required to neutralise the acidification of wheat-lupin rotations as calculated in this paper was up to 3·8 t/ha ·10 years for a WLWL rotation or 3 ·3 t/ha ·10 years for a WWL rotation; these amounts are significantly higher than previously reported rates. In this paper, we calculate the impact of changes in soil carbon (C) status over time, and therefore soil buffering, on the rates of acidification in incremental soil layers to a depth of 60 cm. Total organic C for these rotations in 1992 was 1·12% for WW and 1·17% for LL in the 0–10 cm soil zone. An investigation of the humic and fulvic acid fractions of these 2 rotations to a depth of 60 cm showed that the LL rotation had significantly higher (P < 0·05) C at depth than the WW rotation. Acidification due to the net decrease in soil C over the 15-year study period plus acidification due to the alkali removed in the seed was calculated to be –4·88 kmol(H+)/ha·year for the LL rotation and –6·52 kmol(H+)/ha·year for the WW rotation.

Cotton-based rotation systems on a sodic Vertosol under irrigation: effects on soil quality and profitability

2002 ◽  
Vol 42 (3) ◽  
pp. 341 ◽  
Author(s):  
N. R. Hulugalle ◽  
P. C. Entwistle ◽  
T. B. Weaver ◽  
F. Scott ◽  
L. A. Finlay
Keyword(s):  
Electrical Conductivity ◽  
Soil Properties ◽  
Soil Quality ◽  
Faba Bean ◽  
Irrigation Water ◽  
Soil Organic C ◽  
Gross Margin ◽  
Organic C ◽  
Exchangeable Ca ◽  
Gross Margins

An experiment was established in 1993 on a sodic Vertosol (Vertisol, Typic Haplustert) at Merah North, north–western New South Wales, to evaluate the sustainability of selected irrigated cotton (Gossypium hirsutum L.)–rotation crop sequences. Crop sequences were selected following discussions with local cotton growers. The indices used to evaluate sustainability included soil quality, microbiology, yield and profitability. This paper presents data on soil properties [soil organic C, structure as air–filled porosity of oven–dried soil, exchangeable Ca, Mg, K and Na, pH, electrical conductivity (EC1:5) and EC1:5/exchangeable Na in the 0–0.6 m depth], lint yield and profitability (as gross margins/ha and gross margins/ML of irrigation water). The 6 cropping systems sown after minimum tillage were: continuous cotton (R1), long–fallow cotton (R2), cotton–green manured faba bean (Vicia faba L.) (R3), cotton–dolichos (Lablab purpureus L.)–green manured faba bean in the first year followed by cotton–wheat (Triticum aestivum L.) (R4), cotton–dolichos (R5), cotton–fertilised dolichos (with P and K removed by cotton replaced as fertiliser) (R6). In 1996, air–filled porosity of oven–dried soil was highest with R4 at the surface but lowest with R1 in the 0.15–0.30 m depth. In subsequent years, air–filled porosity of oven–dried soil was higher with R2 and R4 in the deeper depths, although differences between cropping sequences were small. Air–filled porosity of oven–dried soil increased between 1996 and 1998 in all treatments, and was probably caused by the change from intensive to minimum tillage in 1993, irrigation with moderately saline water and application of gypsum resulting in an increase in EC1:5/exchangeable Na. In general, differences in soil properties such as soil organic C, exchangeable Ca, Mg, K and Na, pH, electrical conductivity (EC1:5) and EC1:5/exchangeable Na between cropping sequences were far less than those which occurred with time. The key changes were decreases in pH, exchangeable sodium percentage, exchangeable cations and organic C between 1994 and 1996, and increases in air–filled porosity of oven–dried soil, EC1:5 and EC1:5/exchangeable Na between 1996 and 1998. A decrease in air–filled porosity of oven–dried soil occurred between 1998 and 1999 as a consequence of preparing land and sowing cotton under very wet conditions. R1 had the highest cumulative gross margin/ha and R3 had the lowest. R2 had the highest cumulative gross margin/ML of irrigation water and R3 again the lowest. Among crop sequences, R2 and R4 gave the best returns with respect to both land and water resources.

scholarly journals Soil management effects on organic carbon in isolated fractions of a Gray Luvisol

2006 ◽  
Vol 86 (1) ◽  
pp. 141-151 ◽  
Author(s):  
A. F. Plante ◽  
C. E. Stewart ◽  
R. T. Conant ◽  
K. Paustian ◽  
J. Six
Keyword(s):  
Organic Matter ◽  
Crop Production ◽  
N Fertilization ◽  
Residue Management ◽  
Soil Organic C ◽  
Organic C ◽  
Straw Management ◽  
Soil C ◽  
C Pools

Agricultural management affects soil organic matter, which is important for sustainable crop production and as a greenhouse gas sink. Our objective was to determine how tillage, residue management and N fertilization affect organic C in unprotected, and physically, chemically and biochemically protected soil C pools. Samples from Breton, Alberta were fractionated and analysed for organic C content. As in previous reports, N fertilization had a positive effect, tillage had a minimal effect, and straw management had no effect on whole-soil organic C. Tillage and straw management did not alter organic C concentrations in the isolated C pools, while N fertilization increased C concentrations in all pools. Compared with a woodlot soil, the cultivated plots had lower total organic C, and the C was redistributed among isolated pools. The free light fraction and coarse particulate organic matter responded positively to C inputs, suggesting that much of the accumulated organic C occurred in an unprotected pool. The easily dispersed silt-sized fraction was the mineral-associated pool most responsive to changes in C inputs, whereas the microaggregate-derived silt-sized fraction best preserved C upon cultivation. These findings suggest that the silt-sized fraction is important for the long-term stabilization of organic matter through both physical occlusion in microaggregates and chemical protection by mineral association. Key words: Soil organic C, tillage, residue management, N fertilization, silt, clay

Soil quality as affected by amendments in bean-potato rotations

2011 ◽  
Vol 91 (4) ◽  
pp. 533-542 ◽  
Author(s):  
A. Moulin ◽  
K. Buckley ◽  
K. Volkmar
Keyword(s):  
Soil Quality ◽  
Aggregate Stability ◽  
Soil Surface ◽  
Water Soluble ◽  
Soil Organic C ◽  
Organic C ◽  
Water Soluble P ◽  
Pinto Bean ◽  
Soluble P ◽  
High Concentrations

Moulin, A. P., Buckley, K. E. and Volkmar, K. 2011. Soil quality as affected by amendments in pinto bean-potato rotations. Can. J. Soil Sci. 91: 533–542. The potential for adverse effects on soil quality and erosion in pinto bean–potato rotations is significant due to low levels of residue input to the soil following potatoes or beans, and the effect of tillage on soil structure, particularly in sandy-textured soils typical of the potato-growing area of Manitoba. Soil quality is reduced by low inputs of residue and carbon commensurate with an increase in the proportion of small and unstable aggregates susceptible to erosion. Furthermore N and P concentrations at the soil surface may be affected by various management options including fall cover crops, application of straw and the use of composted manure. In a study conducted at Carberry, MB, from 2000 to 2006, KCl-extractible NO3-N and Olsen P were determined in the fall prior to seeding in each year of the study. Water-soluble P, determined in the fall of 2005 for selected treatments, increased with application of compost. Soil organic C, total N and the proportion of erodible (<0.5-mm diameter) aggregates and stability of aggregates were measured in 2006 for treatments with fall-applied compost, cereal straw, and spring-applied anionic polyacrylamide (PAM). The proportion of erodible aggregates and aggregate stability were not consistently affected by treatment. Application of PAM did not affect stability of wet-sieved aggregates (1.3 to 2.0 mm), but decreased the proportion of small aggregates (<0.5 mm) in 2002. Soil C in the 0– to 5-cm depth increment increased with fall application of composted beef cattle manure. However, no effect was observed on the dry-sieved distribution of aggregates <0.5 mm in diameter. Soil quality, as indicated by an increase in soil organic C, can be improved by application of composted beef cattle manure, but levels of water-soluble P will increase, potentially increasing the risk of high concentrations of P in runoff. This research shows that the addition of compost and straw improves soil quality in terms of soil carbon and aggregate stability in bean–potato rotations. However, the proportion of erodible aggregates also increased, though not to levels that contribute significantly to soil erosion. Compost inputs must be monitored to reduce the potential for high concentrations and runoff of water-soluble P at the soil surface.

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