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Cimélio Bayer - One of the best experts on this subject based on the ideXlab platform.
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cropping systems including legume cover crops favour mineral organic associations enriched with microbial metabolites in no till soil
Soil Research, 2019Co-Authors: Murilo G Veloso, Deborah Pinheiro Dick, Janaina Berne Da Costa, Cimélio BayerAbstract:Long-term carbon (C) stabilisation in tropical and Subtropical Soils under no-tillage (NT) rests on the formation of mineral–organic associations (MOAs) that can be enriched with microbial metabolites. In this work, we assessed the role of long-term tillage and cropping systems and mineral N fertilisation in enriching MOAs with microbial metabolites in a Subtropical soil. For this purpose, we sampled a sandy clay loam Acrisol up to 1 m depth involved in an ongoing 30-year-old experiment under two different tillage systems (conventional tillage and NT) in the presence and absence of legume cover crops and mineral nitrogen (N) fertilisation. The soil samples were subjected to particle size fractionation and n-alkane analysis. The NT and the presence of legume cover crops in the surface soil layer (0−5 cm) increased the abundance of plant-derived lipids (i.e. compounds with n-alkane chains of 25−33 C atoms) in the whole soil. Microbial-derived lipids (i.e. compounds with shorter n-alkane chains (15−24 C atoms)) were more abundant in the clay fraction of the surface (0−5 cm) and sub-surface soil layers (20−30 and 75−100 cm) in NT soil receiving high-quality residues of legume cover crops. However, N fertilisation decreased the abundance of microbial-derived lipids in the clay fraction of the 0−5 and 20−30 cm soil layers. Our findings highlight the role of N-rich residues of legume cover crops, but not of mineral N fertilisation, in the long-term stabilisation of C in MOAs in NT Soils through the action of microbial residues.
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legume cover crops under no tillage favor organomineral association in microaggregates and soil c accumulation
Soil & Tillage Research, 2019Co-Authors: Murilo G Veloso, Diego Cecagno, Cimélio BayerAbstract:Abstract Both no-tillage and legume cover crops have been shown to increase soil organic carbon (SOC) in Subtropical Soils. However, the mechanisms underpinning management system effects on SOC accumulation are still not well understood. We used a combination of aggregate size and density fractionation to elucidate these mechanisms at a 30-year old experiment on an Acrisol in southern Brazil. The effects of two tillage systems [conventional system (CT) and no-tillage (NT)] combined with three cropping systems [oat/maize (O/M), vetch/maize (V/M) and oat + vetch/maize + cowpea (OV/MC)] were evaluated in the top 20 cm soil layer. Overall, macroaggregation (>0.25 mm) was significantly influenced by tillage with NT showing values 14% greater than CT in the 0–5 cm soil depth. On average, the occluded light fraction-C content in macroaggregates was more than twice as high under NT compared to CT (4.4 vs. 1.8 g kg−1). This effect was more pronounced when legume cover crops were grown. However, the most significant effect of cover crops was observed in the organomineral fraction of microaggregates, especially under NT (12.1 under O/M and 19.8 g kg−1 under OV/MC). Our results suggest that, although NT increased the occluded light fraction-C compared to CT, this effect was smaller than the gains that legume cover crops offered in organomineral association.
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soil nitrous oxide emissions as affected by long term tillage cropping systems and nitrogen fertilization in southern brazil
Soil & Tillage Research, 2015Co-Authors: Cimélio Bayer, Jeferson Dieckow, Josileia Accordi Zanatta, Frederico Costa Beber Vieira, Juliana A S Gomes, Marisa De Cassia Piccolo, Johan SixAbstract:Abstract Soil nitrous oxide (N2O) emissions are affected by management practices, but little information is available on the interactive effects of tillage, cropping systems and N sources in tropical and Subtropical Soils. In an 18-yr old experiment located in a Subtropical Acrisol of Southern Brazil we conducted a sequence of two trials. The 1-year trial (October 2003–2004) was set to evaluate the long-term effects of tillage [CT: conventional; and NT: no-tillage] and cropping systems [O/M: black oat (Avena strigosa Schreb.)/maize (Zea mays L.); and V/M: vetch (Vicia sativa L.)/maize] on soil N2O emissions, either in the post-management period (45 days after desiccation and knife-rolling of winter cover crops) or in the whole year. The second and short-term trial (October–November 2004) was carried out to compare the impact of N sources [urea (mineral) and legume-residue of vetch (biologically fixed), both at 180 kg N ha−1] on soil N2O emissions during 53 days after cover-crop management. Air sampling was carried out by static chambers and N2O analysis by gas chromatography. In the 45-day post-management period of the 1-year trial, soil N2O emissions were practically not affected by tillage systems, but increased 4 times due to vetch residues (average of 0.40 ± 0.08 kg N ha−1 in V/M versus 0.10 ± 0.05 kg N ha−1 in O/M) and related with soil contents of NO3−-N, NH4+-N, and dissolved organic C (DOC). Over the whole year, soil N2O emissions under CT were similar for grass- and legume-based cropping systems and averaged 0.43 ± 0.17 kg N ha−1, while NT exacerbated N2O emissions in the legume-based cropping system (0.80 ± 0.07 kg N ha−1 in V/M versus −0.07 ± 0.06 kg N ha−1 in O/M). Maize yield was not affected by tillage, but increased from 2.32 Mg ha−1 in O/M to 4.44 Mg ha−1 in V/M. Yield-scaled N2O emissions varied from −33 g N2O-N Mg−1 grain in NT O/M to 179 g N2O-N Mg−1 grain in NT V/M, and were intermediate in CT soil (106 and 156 g N2O-N Mg−1grain in V/M and O/M cropping systems, respectively). In the short-term trial, the N2O emitted in excess relative to the control treatment (O/M without N fertilizer) was at least 3 times greater with urea-N (0.44% of applied N) than with legume-residue-Nsource (0.13% of applied N). Yield-scaled N2O emission after vetch residues management (67 g N Mg−1 grain) was half of that after urea-N application (152 g N Mg−1 grain). Partially supplying the maize N requirements with winter legume cover-crops may be a feasible strategy to mitigate soil N2O emissions in the Subtropical conservation agriculture.
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mineralogy and phosphorus adsorption in Soils of south and central west brazil under conventional and no tillage systems
Acta Scientiarum-agronomy, 2014Co-Authors: Jesse Rodrigo Fink, Cimélio Bayer, Alberto Vasconcellos Inda, Jose Torrent, Vidal BarronAbstract:The low phosphorus availability in tropical and Subtropical Soils, normally related to adsorption of phosphate to the minerals surfaces, can be attenuated when organic matter (OM) accumulates in the Soils. Herein, we report the results of long-term experiments (18-32 years) aimed at quantifying the maximum phosphorus adsorption capacity (MPAC) and its determinant mineralogical variables in Brazilian Soils and at assessing the effect of no-tillage (NT) in mitigating the phosphorus adsorption of Soils. The MPAC of Soils ranged from 297 to 4,561 mg kg -1 in the 0.00-0.10 m layer and from 285 to 4,961 mg kg -1 in the 0.10-0.20 m layer. The MPAC was correlated with the concentrations of iron oxides, goethite and ferrihydrite, gibbsite/(gibbsite+kaolinite) ratio and the specific surface area. The OM increased in the 0.00-0.10 m layer of NT Soils, which was not reflected on the decrease of MPAC for the no-tillage Soils.
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Carbon accumulation at depth in Ferralsols under zero-till Subtropical agriculture
Global Change Biology, 2010Co-Authors: Robert M. Boddey, Joao Mielniczuk, Cimélio Bayer, Jeferson Dieckow, Paulo Cesar Conceicao, Claudia Pozzi Jantalia, Josiléia Acordi Zanatta, Henrique Pereira Dos Santos, José Eloir Denardin, Celso AitaAbstract:Conservation agriculture can provide a low-cost competitive option to mitigate global warming with reduction or elimination of soil tillage and increase soil organic carbon (SOC). Most studies have evaluated the impact of zero till (ZT) only on surface soil layers (down to 30 cm), and few studies have been performed on the potential for C accumulation in deeper layers (0–100 cm) of tropical and Subtropical Soils. In order to determine whether the change from conventional tillage (CT) to ZT has induced a net gain in SOC, three long-term experiments (15–26 years) on free-draining Ferralsols in the Subtropical region of South Brazil were sampled and the SOC stocks to 30 and 100 cm calculated on an equivalent soil mass basis. In rotations containing intercropped or cover-crop legumes, there were significant accumulations of SOC in ZT Soils varying from 5 to 8 Mg ha−1 in comparison with CT management, equivalent to annual soil C accumulation rates of between 0.04 and 0.88 Mg ha−1. However, the potential for soil C accumulation was considerably increased (varying from 0.48 to 1.53 Mg ha−1 yr−1) when considering the soil profile down to 100 cm depth. On average the estimate of soil C accumulation to 100 cm depth was 59% greater than that for soil C accumulated to 30 cm. These findings suggest that increasing sampling depth from 30 cm (as presently recommended by the IPCC) to 100 cm, may increase substantially the estimates of potential CO2 mitigation induced by the change from CT to ZT on the free-draining Ferralsols of the tropics and subtropics. It was evident that that legumes which contributed a net input of biologically fixed N played an important role in promoting soil C accumulation in these Soils under ZT, perhaps due to a slow-release of N from decaying surface residues/roots which favored maize root growth.
Zucong Cai - One of the best experts on this subject based on the ideXlab platform.
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mechanisms behind the stimulation of nitrification by n input in Subtropical acid forest soil
Journal of Soils and Sediments, 2017Co-Authors: Wei Zhao, Jinbo Zhang, Christoph Müller, Zucong CaiAbstract:Purpose Input of N as NH4+ is known to stimulate nitrification and to enhance the risk of N losses through NO3− leaching in humid Subtropical Soils. However, the mechanisms responsible for this stimulation effect have not been fully addressed.
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effect of land use on the denitrification abundance of denitrifiers and total nitrogen gas production in the Subtropical region of china
Biology and Fertility of Soils, 2014Co-Authors: Jinbo Zhang, Tongbin Zhu, Wenwen Chen, Wenhui Zhong, Zucong CaiAbstract:The potential denitrification (PD) rate, NO, N2O, and N2 emission were determined after treatment with 50 mg NO3 −−N kg−1 soil using the acetylene inhibition method, and meanwhile abundance of four denitrifying genes (i.e., narG, nirK, norB, nosZ) was also investigated in Subtropical Soils of China. Soil samples were collected from conifer forest (C), shrub forest, and farmland. These Soils were derived from Quaternary red earth and granite. The PD rate and N gas emissions significantly (p 0.05). The norB gene copies in farmland Soils were significantly higher than in conifer and shrub forest Soils (p < 0.01). Both norB and nosZ gene copies were linearly correlated with soil pH, and the PD rate and N2 emission rate were significantly correlated with the abundance of norB (p < 0.05). Probably, soil pH affected denitrifiers targeted by the norB gene, thus decreasing the reduction of NO and N2O.
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heterotrophic nitrification is the predominant no3 production pathway in acid coniferous forest soil in Subtropical china
Biology and Fertility of Soils, 2013Co-Authors: Yanchen Zhang, Jinbo Zhang, Tongbin Zhu, Tianzhu Meng, Christoph Müller, Zucong CaiAbstract:To date, occurrence and stimulation of different nitrification pathways in acidic Soils remains unclear. Laboratory incubation experiments, using the acetylene inhibition and 15N tracing methods, were conducted to study the relative importance of heterotrophic and autotrophic nitrification in two acid Soils (arable (AR) and coniferous forest) in Subtropical China, and to verify the reliability of the 15N tracing model. The gross rate of autotrophic nitrification was 2.28 mg kg−1 day−1, while that of the heterotrophic nitrification (0.01 mg kg−1 day−1) was negligible in the AR soil. On the contrary, the gross rate of autotrophic nitrification was very low (0.05 mg kg−1 day−1) and the heterotrophic nitrification (0.98 mg kg−1 day−1) was the predominant NO3− production pathway accounting for more than 95 % of the total nitrification in the coniferous forest soil. Our results showed that the 15N tracing model was reliable when used to study soil N transformation in acid Subtropical Soils.
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Agricultural land use affects nitrate production and conservation in humid Subtropical Soils in China
Soil Biology and Biochemistry, 2013Co-Authors: Jinbo Zhang, Tongbin Zhu, Tianzhu Meng, Yanchen Zhang, Jiajia Yang, Wenyan Yang, Christoph Müller, Zucong CaiAbstract:Abstract To date, very few studies have been conducted to investigate the characteristics of gross nitrogen (N) transformations in Subtropical agricultural Soils. In this study, 12 natural woodland and 10 agricultural Soils were collected to investigate the effects of land use on soil gross N transformations in the humid Subtropical zones in China. The results showed that gross autotrophic nitrification rates (average 0.19 mg N kg −1 d −1 ) in the woodland Soils were significantly lower than those determined in the agricultural Soils (average 1.81 mg N kg −1 d −1 ) ( p 3 − immobilization rates (average 0.10 mg N kg −1 d −1 ) in the agricultural Soils were significantly lower than in the woodland Soils (average 0.47 mg N kg −1 d −1 ) ( p 3 − produced could be immobilized into organic-N in the woodland Soils, while, it accounted for only 10% in the agricultural Soils. These differences in gross N transformations resulted in the inorganic N being dominated by NH 4 + in the woodland Soils; however, NO 3 − dominated the inorganic N in the agricultural Soils. The risk of N leaching and runoff from soil sharply increases after woodland Soils are converted to agricultural Soils. Application of organic fertilizers with high C/N ratios to agricultural Soils in Subtropical regions to increase soil organic C content and the C/N ratio is expected to improve NO 3 − immobilization capacity and reduce the risk of N leaching and runoff from soil.
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influence of land use type on moisture effect of nitrification in Subtropical red Soils
Environmental Sciences, 2010Co-Authors: Chen Qian, Zucong CaiAbstract:Air-drying is always accompanied by soil moisture loss. The different influences of air-drying on soil nitrification might due to the different nitrification responses to moisture changing of acid Subtropical Soils. So, after applying 0 and 150 mg x kg(-1) of ammonium bicarbonate, a 35-day incubation study was conducted to determine the nitrification potential of four acid Subtropical Soils under 5 soil moisture levels, namely 30% water-holding capacity (WHC), 45% WHC, 60% WHC, 75% WHC and 90% WHC. Four Soils, designated QR, QU, SR and SU, derived from Quaternary red earth and Tertiary red sandstone, were collected from rice and upland field. The results indicated that the soil nitrification was significantly influenced by the moisture content (p < 0.01), and the nitrification sensitivities to soil moisture content varied with land-use types. For the treatments without ammonium input, the ranges of nitrification ratio were 11% and 8% in upland Soils, QU and SU respectively, which were obviously lower than those in paddy Soils (35% for QR, and 20% for SR). The ammonium input would increase the ranges of nitrification ratio which were 56%, 26%, 31%, and 26% for soil QR, QU, SR, and SU, respectively. And the ammonium input would accelerate soil acidification under high moisture levels. In a word, the land-use type presents a significant influence on the nitrification response to moisture content, which might lead to the difference of air-drying effect.
Joao Mielniczuk - One of the best experts on this subject based on the ideXlab platform.
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Carbon accumulation at depth in Ferralsols under zero-till Subtropical agriculture
Global Change Biology, 2010Co-Authors: Robert M. Boddey, Joao Mielniczuk, Cimélio Bayer, Jeferson Dieckow, Paulo Cesar Conceicao, Claudia Pozzi Jantalia, Josiléia Acordi Zanatta, Henrique Pereira Dos Santos, José Eloir Denardin, Celso AitaAbstract:Conservation agriculture can provide a low-cost competitive option to mitigate global warming with reduction or elimination of soil tillage and increase soil organic carbon (SOC). Most studies have evaluated the impact of zero till (ZT) only on surface soil layers (down to 30 cm), and few studies have been performed on the potential for C accumulation in deeper layers (0–100 cm) of tropical and Subtropical Soils. In order to determine whether the change from conventional tillage (CT) to ZT has induced a net gain in SOC, three long-term experiments (15–26 years) on free-draining Ferralsols in the Subtropical region of South Brazil were sampled and the SOC stocks to 30 and 100 cm calculated on an equivalent soil mass basis. In rotations containing intercropped or cover-crop legumes, there were significant accumulations of SOC in ZT Soils varying from 5 to 8 Mg ha−1 in comparison with CT management, equivalent to annual soil C accumulation rates of between 0.04 and 0.88 Mg ha−1. However, the potential for soil C accumulation was considerably increased (varying from 0.48 to 1.53 Mg ha−1 yr−1) when considering the soil profile down to 100 cm depth. On average the estimate of soil C accumulation to 100 cm depth was 59% greater than that for soil C accumulated to 30 cm. These findings suggest that increasing sampling depth from 30 cm (as presently recommended by the IPCC) to 100 cm, may increase substantially the estimates of potential CO2 mitigation induced by the change from CT to ZT on the free-draining Ferralsols of the tropics and subtropics. It was evident that that legumes which contributed a net input of biologically fixed N played an important role in promoting soil C accumulation in these Soils under ZT, perhaps due to a slow-release of N from decaying surface residues/roots which favored maize root growth.
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land use tillage texture and organic matter stock and composition in tropical and Subtropical brazilian Soils
European Journal of Soil Science, 2009Co-Authors: Jeferson Dieckow, Ladislau Martinneto, Joao Mielniczuk, Cimélio Bayer, Paulo Cesar Conceicao, Josileia Accordi Zanatta, D B M Milori, J C Salton, M M Macedo, L C HernaniAbstract:Summary We examined the influence of land use change, tillage system and soil texture on organic carbon (C) stocks and on organic matter composition of tropical and Subtropical Soils from Brazil at four long-term experiments (11–25 years) based on fine- and coarse-textured Soils. Soil samples were collected from the 0–5, 5–10 and 10–20 cm layers of conventional tillage (CT) and no-till (NT) plots, and of the adjoining soil under native vegetation (NV) of Cerrado (tropical) or grassland (Subtropical). Conversion of NV to CT resulted in losses of 7–29% of the original C stock of 0–20 cm; conversion to NT increased this C stock by 0–12% compared with CT. Organic matter composition of the 0–5 cm layer, assessed by solid state CPMAS- 13 C-NMR, ESR and laser induced fluorescence spectroscopies, was affected by land use and tillage systems. Conversion of NV to CT decreased O-alkyl and increased aromatic, carbonyl, aromatic/O-alkyl ratio, free radicals concentration and fluorescence signal. The opposite trend was observed when NT replaced CT. The relative losses and gains of C and qualitative changes resulting from land use and tillage were less evident in fine- than in coarse-textured Soils, suggesting a greater resistance and a smaller resilience of fine- compared with coarse-textured Soils. The direct relation between increase in C stock and increase in potentially labile moieties (e.g. O-alkyl) and the decrease in more recalcitrant moieties (e.g. aromatics) in NT Soils suggests that spatial inaccessibility by aggregates is playing a major role, compared with selective preservation, in promoting C accumulation in NT Soils.
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carbon sequestration in two brazilian cerrado Soils under no till
Soil & Tillage Research, 2006Co-Authors: Cimélio Bayer, Ladislau Martinneto, Joao Mielniczuk, Aurelio Pavinato, Jeferson DieckowAbstract:Abstract A considerable proportion of the 200 million hectares of the Brazilian Cerrado is suitable for annual crops but little is known about the effects of tillage on the C dynamics of Cerrado Soils. We evaluated the role of two representative Cerrado Oxisols (350 and 650 g clay kg−1) as sources or sinks of atmospheric C when managed under three tillage systems (conventional tillage (CT), reduced tillage (RT), and no-till (NT)) in 8- and 5-year long-term experiments. A literature review was also carried out and the mean C sequestration rates in no-till Soils of tropical and Subtropical regions of Brazil were calculated and compared with values for Soils from temperate regions of the world. The original C stocks in 0–20 cm layer of Soils under native Cerrado were higher in the clayey (54.0 Mg ha−1) than in the sandy clay loam soil (35.4 Mg ha−1), suggesting a higher physical stability of organic matter associated with variable clay minerals in the clayey Oxisol. The original C stocks of the native Cerrado Soils appear not to have decreased after 23 years of conventional tillage in the sandy clay loam Oxisol, except when the soil had been subjected to erosion (15% loss of C), or after 25 years in the clayey Oxisol. Compared to conventionally tilled soil, the C stocks in no-till sandy clay loam Oxisol increased by 2.4 Mg ha−1 (C sequestration rate = 0.30 Mg ha−1 year−1) and in the clayey Oxisol by 3.0 Mg ha−1 (C sequestration rate = 0.60 Mg ha−1 year−1). The mean rate of C sequestration in the no-till Brazilian tropical Soils was estimated to be 0.35 Mg ha−1 year−1, similar to the 0.34 Mg ha−1 year−1 reported for Soils from temperate regions but lower than the 0.48 Mg ha−1 year−1 estimated for southern Brazilian Subtropical Soils. Considering the large area (about 70 million hectares) of the Cerrado which is currently used and potentially available for cropland, the adoption of no-till systems could turn the Cerrado Soils into a significant sink for atmospheric C and contribute to the mitigation of global climate change.
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stocks and humification degree of organic matter fractions as affected by no tillage on a Subtropical soil
Plant and Soil, 2002Co-Authors: Cimélio Bayer, Ladislau Martinneto, Joao Mielniczuk, Paulo Roberto ErnaniAbstract:Assessment of particulate (>53-μm) and mineral-associated (<53-μm) soil organic matter (SOM) fractions is a useful approach to understand the dynamic of organic matter in Soils. This study aimed to compare the long-term (9-yr) effects of no-tillage (NT) and conventional tillage (CT) on C and N stocks in the two above mentioned organic fractions in a Brazilian Acrisol. The degree of SOM humification, which has been associated with the concentration of semiquinone-type free radicals (`spin') determined by electron spin resonance (ESR), was also evaluated. Soil under no-tillage had 7.55 Mg ha−1 (25%) more C and 741 kg ha−1 (29%) more N than conventionally tilled soil in the 0–175-mm depth. Both particulate and mineral-associated SOM increased in the no-tilled soil. The increase of C and N stocks in the mineral-associated SOM accounted for 75% and 91% of the difference in total soil C and N stocks between NT and CT, respectively. Averaged across tillage systems, C and N stocks were respectively 4.6 and 16.8 times higher in the mineral-associated SOM than in particulate SOM. The higher C and N stocks were associated with greater recalcitrance of mineral-associated SOM to biological decomposition, resulting, probably, from its interaction with variable charge minerals. This is corroborated by a positive relationship between concentrations of C and iron oxides and kaolinite in the 53–20, 20–2 and <2-μm particle size classes, of the 0–25-mm soil layer. The degree of SOM humification, assessed by ESR, decreased in both the 53–20 and 20–2-μm fractions under NT. However, it was unaffected by tillage in the <2-μm fraction, which normally presented the lowest `spin' concentration. Since quality as well as quantity of SOM improved in the no-tillage soil, adoption of this system is highly recommended for amelioration of degraded tropical and Subtropical Soils.
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effect of no till cropping systems on soil organic matter in a sandy clay loam acrisol from southern brazil monitored by electron spin resonance and nuclear magnetic resonance
Soil & Tillage Research, 2000Co-Authors: Cimélio Bayer, Ladislau Martinneto, Joao Mielniczuk, Carlos Alberto CerettaAbstract:In weathered tropical and Subtropical Soils organic matter is crucial for soil productivity and its quantity depends heavily on soil management systems. This study evaluated the effect of no-till cropping systems on organic matter content and quality in a sandy clay loam Acrisol soil (Paleudult in US taxonomy) from Southern Brazil. Ten cropping systems with varying additions of C and N were conducted for 12 years (from 1983 to 1994). The addition of crop residues increased total organic carbon (TOC) and total nitrogen (TN) in the soil at 0‐17.5 cm depth, and this increase was directly related with C and N added or recycled by the systems. The crop residues added to the soil were associated with reduced semiquinone free radical concentration, detected by electron spin resonance (ESR), in the organo-mineral aggregates <53 mm and humic acid (HA) samples, in the soil at 0‐2.5 cm depth. This showed that stable organic matter originating from crop residues was less humidified than the original soil organic matter. Results obtained from organo-mineral aggregates showed a higher amplitude (highest and lowest values were 5.47 and 2.09 10 17 spins g ˇ1 of TOC, respectively) of semiquinone free radical concentration than HA samples (highest and lowest values were 2.68 and 1.77 10 17 spins g ˇ1 of HA, respectively). These data showed that alterations due to tillage in soil organic matter characteristics, e.g., humification degree can be better identified through a combination of soil physical fractionation and spectroscopic analysis. Semiquinone content in the HA samples, detected by ESR, related significantly to aromaticity, as measured by nuclear magnetic resonance (NMR) of 13 C. Management systems including no-till and cropping systems with high C and N additions to the soil improved its quality in Southern Brazil. # 2000 Elsevier Science B.V. All rights reserved.
Jeferson Dieckow - One of the best experts on this subject based on the ideXlab platform.
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soil nitrous oxide emissions as affected by long term tillage cropping systems and nitrogen fertilization in southern brazil
Soil & Tillage Research, 2015Co-Authors: Cimélio Bayer, Jeferson Dieckow, Josileia Accordi Zanatta, Frederico Costa Beber Vieira, Juliana A S Gomes, Marisa De Cassia Piccolo, Johan SixAbstract:Abstract Soil nitrous oxide (N2O) emissions are affected by management practices, but little information is available on the interactive effects of tillage, cropping systems and N sources in tropical and Subtropical Soils. In an 18-yr old experiment located in a Subtropical Acrisol of Southern Brazil we conducted a sequence of two trials. The 1-year trial (October 2003–2004) was set to evaluate the long-term effects of tillage [CT: conventional; and NT: no-tillage] and cropping systems [O/M: black oat (Avena strigosa Schreb.)/maize (Zea mays L.); and V/M: vetch (Vicia sativa L.)/maize] on soil N2O emissions, either in the post-management period (45 days after desiccation and knife-rolling of winter cover crops) or in the whole year. The second and short-term trial (October–November 2004) was carried out to compare the impact of N sources [urea (mineral) and legume-residue of vetch (biologically fixed), both at 180 kg N ha−1] on soil N2O emissions during 53 days after cover-crop management. Air sampling was carried out by static chambers and N2O analysis by gas chromatography. In the 45-day post-management period of the 1-year trial, soil N2O emissions were practically not affected by tillage systems, but increased 4 times due to vetch residues (average of 0.40 ± 0.08 kg N ha−1 in V/M versus 0.10 ± 0.05 kg N ha−1 in O/M) and related with soil contents of NO3−-N, NH4+-N, and dissolved organic C (DOC). Over the whole year, soil N2O emissions under CT were similar for grass- and legume-based cropping systems and averaged 0.43 ± 0.17 kg N ha−1, while NT exacerbated N2O emissions in the legume-based cropping system (0.80 ± 0.07 kg N ha−1 in V/M versus −0.07 ± 0.06 kg N ha−1 in O/M). Maize yield was not affected by tillage, but increased from 2.32 Mg ha−1 in O/M to 4.44 Mg ha−1 in V/M. Yield-scaled N2O emissions varied from −33 g N2O-N Mg−1 grain in NT O/M to 179 g N2O-N Mg−1 grain in NT V/M, and were intermediate in CT soil (106 and 156 g N2O-N Mg−1grain in V/M and O/M cropping systems, respectively). In the short-term trial, the N2O emitted in excess relative to the control treatment (O/M without N fertilizer) was at least 3 times greater with urea-N (0.44% of applied N) than with legume-residue-Nsource (0.13% of applied N). Yield-scaled N2O emission after vetch residues management (67 g N Mg−1 grain) was half of that after urea-N application (152 g N Mg−1 grain). Partially supplying the maize N requirements with winter legume cover-crops may be a feasible strategy to mitigate soil N2O emissions in the Subtropical conservation agriculture.
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Carbon accumulation at depth in Ferralsols under zero-till Subtropical agriculture
Global Change Biology, 2010Co-Authors: Robert M. Boddey, Joao Mielniczuk, Cimélio Bayer, Jeferson Dieckow, Paulo Cesar Conceicao, Claudia Pozzi Jantalia, Josiléia Acordi Zanatta, Henrique Pereira Dos Santos, José Eloir Denardin, Celso AitaAbstract:Conservation agriculture can provide a low-cost competitive option to mitigate global warming with reduction or elimination of soil tillage and increase soil organic carbon (SOC). Most studies have evaluated the impact of zero till (ZT) only on surface soil layers (down to 30 cm), and few studies have been performed on the potential for C accumulation in deeper layers (0–100 cm) of tropical and Subtropical Soils. In order to determine whether the change from conventional tillage (CT) to ZT has induced a net gain in SOC, three long-term experiments (15–26 years) on free-draining Ferralsols in the Subtropical region of South Brazil were sampled and the SOC stocks to 30 and 100 cm calculated on an equivalent soil mass basis. In rotations containing intercropped or cover-crop legumes, there were significant accumulations of SOC in ZT Soils varying from 5 to 8 Mg ha−1 in comparison with CT management, equivalent to annual soil C accumulation rates of between 0.04 and 0.88 Mg ha−1. However, the potential for soil C accumulation was considerably increased (varying from 0.48 to 1.53 Mg ha−1 yr−1) when considering the soil profile down to 100 cm depth. On average the estimate of soil C accumulation to 100 cm depth was 59% greater than that for soil C accumulated to 30 cm. These findings suggest that increasing sampling depth from 30 cm (as presently recommended by the IPCC) to 100 cm, may increase substantially the estimates of potential CO2 mitigation induced by the change from CT to ZT on the free-draining Ferralsols of the tropics and subtropics. It was evident that that legumes which contributed a net input of biologically fixed N played an important role in promoting soil C accumulation in these Soils under ZT, perhaps due to a slow-release of N from decaying surface residues/roots which favored maize root growth.
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land use tillage texture and organic matter stock and composition in tropical and Subtropical brazilian Soils
European Journal of Soil Science, 2009Co-Authors: Jeferson Dieckow, Ladislau Martinneto, Joao Mielniczuk, Cimélio Bayer, Paulo Cesar Conceicao, Josileia Accordi Zanatta, D B M Milori, J C Salton, M M Macedo, L C HernaniAbstract:Summary We examined the influence of land use change, tillage system and soil texture on organic carbon (C) stocks and on organic matter composition of tropical and Subtropical Soils from Brazil at four long-term experiments (11–25 years) based on fine- and coarse-textured Soils. Soil samples were collected from the 0–5, 5–10 and 10–20 cm layers of conventional tillage (CT) and no-till (NT) plots, and of the adjoining soil under native vegetation (NV) of Cerrado (tropical) or grassland (Subtropical). Conversion of NV to CT resulted in losses of 7–29% of the original C stock of 0–20 cm; conversion to NT increased this C stock by 0–12% compared with CT. Organic matter composition of the 0–5 cm layer, assessed by solid state CPMAS- 13 C-NMR, ESR and laser induced fluorescence spectroscopies, was affected by land use and tillage systems. Conversion of NV to CT decreased O-alkyl and increased aromatic, carbonyl, aromatic/O-alkyl ratio, free radicals concentration and fluorescence signal. The opposite trend was observed when NT replaced CT. The relative losses and gains of C and qualitative changes resulting from land use and tillage were less evident in fine- than in coarse-textured Soils, suggesting a greater resistance and a smaller resilience of fine- compared with coarse-textured Soils. The direct relation between increase in C stock and increase in potentially labile moieties (e.g. O-alkyl) and the decrease in more recalcitrant moieties (e.g. aromatics) in NT Soils suggests that spatial inaccessibility by aggregates is playing a major role, compared with selective preservation, in promoting C accumulation in NT Soils.
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carbon sequestration in two brazilian cerrado Soils under no till
Soil & Tillage Research, 2006Co-Authors: Cimélio Bayer, Ladislau Martinneto, Joao Mielniczuk, Aurelio Pavinato, Jeferson DieckowAbstract:Abstract A considerable proportion of the 200 million hectares of the Brazilian Cerrado is suitable for annual crops but little is known about the effects of tillage on the C dynamics of Cerrado Soils. We evaluated the role of two representative Cerrado Oxisols (350 and 650 g clay kg−1) as sources or sinks of atmospheric C when managed under three tillage systems (conventional tillage (CT), reduced tillage (RT), and no-till (NT)) in 8- and 5-year long-term experiments. A literature review was also carried out and the mean C sequestration rates in no-till Soils of tropical and Subtropical regions of Brazil were calculated and compared with values for Soils from temperate regions of the world. The original C stocks in 0–20 cm layer of Soils under native Cerrado were higher in the clayey (54.0 Mg ha−1) than in the sandy clay loam soil (35.4 Mg ha−1), suggesting a higher physical stability of organic matter associated with variable clay minerals in the clayey Oxisol. The original C stocks of the native Cerrado Soils appear not to have decreased after 23 years of conventional tillage in the sandy clay loam Oxisol, except when the soil had been subjected to erosion (15% loss of C), or after 25 years in the clayey Oxisol. Compared to conventionally tilled soil, the C stocks in no-till sandy clay loam Oxisol increased by 2.4 Mg ha−1 (C sequestration rate = 0.30 Mg ha−1 year−1) and in the clayey Oxisol by 3.0 Mg ha−1 (C sequestration rate = 0.60 Mg ha−1 year−1). The mean rate of C sequestration in the no-till Brazilian tropical Soils was estimated to be 0.35 Mg ha−1 year−1, similar to the 0.34 Mg ha−1 year−1 reported for Soils from temperate regions but lower than the 0.48 Mg ha−1 year−1 estimated for southern Brazilian Subtropical Soils. Considering the large area (about 70 million hectares) of the Cerrado which is currently used and potentially available for cropland, the adoption of no-till systems could turn the Cerrado Soils into a significant sink for atmospheric C and contribute to the mitigation of global climate change.
Chunjiang Liu - One of the best experts on this subject based on the ideXlab platform.
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correlated metabolic and elemental variations between the leaves and seeds of oak trees at contrasting geologically derived phosphorus sites
Science of The Total Environment, 2019Co-Authors: Jun Yuan, Ningxiao Sun, Umair Muhammad, Hongzhang Kang, Shan Yin, Chunjiang LiuAbstract:The leaves and seeds of plants frequently function as the source and sink organs for distinct metabolites, which can interactively vary in response to adverse site conditions. Subtropical Soils are typically characterized as having deficient phosphorus (P), calcium (Ca), and magnesium (Mg), with enriched aluminum (Al) and iron (Fe), while Al and manganese (Mn) are toxic at low pH. It remains largely unknown how leaf- and seed-sourced metabolites are synergistically linked to adapt to P-variable Soils for trees in Subtropical areas. Here we quantified the metabolic and elemental profiling in the mature leaves and immature seeds of Quercus variabilis at contrasting geologically-derived phosphorus sites in Subtropical China. The results revealed that carbon (C) and nitrogen (N) based metabolites (primarily sugars and organic acids), as well as enzyme- and protein/nucleic acid-related elements (N, P, Mg, and Mn) played important roles toward characterizing the profiling of metabolites and ionomes in leaves and seeds at two site types, respectively. These metabolites (sugars, amino acids, and fatty acids) and elements (N, P, Mg, and Mn) of seeds were closely related to the sugars, organic acids, and elements (N, P, Mg, and Mn) of leaves at the two site types. For the most part, the content of N and P in the soil affected the accumulation of materials (such as, starchs and proteins) in seeds, as well as N and P assimilation in leaves, by influencing C- and N-containing metabolites in leaves. These results suggested that correlated disparities of C- and N-containing metabolites, along with enzyme- and protein/nucleic acid-related elements in both leaves and seeds played important roles in plants to facilitate their adaptation to nutrient-variable sites in Subtropical zones.
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imbalanced plant stoichiometry at contrasting geologic derived phosphorus sites in subtropics the role of microelements and plant functional group
Plant and Soil, 2018Co-Authors: Jiahao Wen, Ningxiao Sun, Huimin Tao, Dafeng Hui, Chunjiang LiuAbstract:Subtropical Soils are generally characterized as deficient in phosphorus (P), calcium (Ca) and magnesium (Mg), but rich in iron (Fe) and aluminum (Al). However, Soils developed in phosphate rock are extremely P-rich in Subtropical forests, southwestern China. Factors controlling plant stoichiometric traits across variable P sites are still not clear. We investigated leaf macroelements (C, N, P, K, Ca and Mg), microelements (Mn, Fe, Zn, and Cu), and non-essential elements (Na and Al) and their element:P ratios for 21 woody plant species at both P-rich and P-deficient sites. Plants between the two P type sites were mainly discriminated by Mn, Al, N and their P ratios, and between functional groups by Cu, Fe, Zn and their P ratios. There were higher leaf N, P, K, Ca, Fe and Zn concentrations but lower Mn, Cu and Al at the P-rich sites. Evergreen conifers displayed strict homeostasis while evergreen and deciduous broadleaf were more plastic and had variable ratios across different nutrients. Microelements have strong influences on plant stoichiometry to differentiate geologic-derived P sites in subtropics, and three functional group plants have adopted different stoichiometric strategies under variable nutrient conditions.
