scholarly journals Organic matter and soil aggregation in agricultural systems with different adoption times

2019 ◽  
Vol 40 (6Supl3) ◽  
pp. 3443 ◽  
Author(s):  
Jean Sérgio Rosset ◽  
Maria do Carmo Lana ◽  
Marcos Gervasio Pereira ◽  
Jolimar Antonio Schiavo ◽  
Leandro Rampim ◽  
...  
Keyword(s):  
Organic Matter ◽  
Structural Stability ◽  
Soil Aggregation ◽  
Total Carbon ◽  
Management Systems ◽  
Physical Fractionation ◽  
Positive Effects ◽  
Brachiaria Ruziziensis ◽  
No Till ◽  
Soil Structural Stability

In conservation management systems, such as no-till (NT), it is important to analyze the pattern of changes in soil quality as a function of the time since adoption of the system. This study evaluated the physical fractions of organic matter and soil aggregation in management systems in areas cultivated with different times since implementation of NT: 6, 14, and 22 successive years of soybean and maize/wheat crops (NT6, NT14, and NT22, respectively); 12 years of no-till with successive years of soybean and maize/wheat crops, and the last 4 years with integration of maize and ruzi grass (Brachiaria ruziziensis) - (NT+B); pasture; and forest. Physical fractionation of organic matter determined the total carbon (TC), particulate organic matter (POM), and mineral organic matter (MOM) by calculating the carbon management index (CMI) and variables related to soil structural stability. Forest and pasture areas showed the highest contents of TC, POM, and MOM, as well as higher stocks of POM and MOM. Among the cultivated areas, higher TC and particulate fractions of organic matter and the best CMI values were observed in the area of NT22. There were changes in aggregation indices, depending on the time since implementation of NT. Areas of NT22, pasture, and forest showed the greatest evolution in C-CO2, indicating increased biological activity, with positive effects on soil structural stability.

Stratification ratio of organic matter pools influenced by management systems in a weathered Oxisol from a tropical agro-ecoregion in Brazil

Soil Research ◽  
2013 ◽  
Vol 51 (2) ◽  
pp. 133 ◽  
Author(s):  
C. C. Figueiredo ◽  
D. V. S. Resck ◽  
M. A. C. Carneiro ◽  
M. L. G. Ramos ◽  
J. C. M. Sá
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Soil Carbon ◽  
Microbial Biomass Carbon ◽  
Conventional Tillage ◽  
Carbon Stocks ◽  
Total Carbon ◽  
Management Systems ◽  
No Till ◽  
The Impact

Enhancement of organic matter plays an essential role in improving soil quality for supporting sustainable food production. Changes in carbon stocks with impacts on emissions of greenhouse gases may result from the stratification of organic matter as a result of soil use. The objective of this study was to evaluate the impact of soil management systems on soil carbon stocks and stratification ratios (SR) of soil organic matter pools. Total organic carbon (TOC), particulate organic carbon (POC), mineral-associated organic carbon, microbial biomass carbon (MBC) and nitrogen, basal respiration, and particulate organic matter nitrogen (PON) were determined. The field experiment comprised several tillage treatments: conventional tillage, no-till with biannual rotation, no-till with biannual rotation combined with a second crop, no-till with annual rotation, and pasture. The labile fractions indicated a high level of variation among management systems. Pasture proved to be an excellent option for the improvement of soil carbon. While the conventional tillage system reduced total carbon stocks of the soil (0–40 cm), no-tillage presented TOC stocks similar to that of native vegetation. Sensitivity of the TOC SR varied from 0.93 to 1.28, a range of 0.35; the range for POC was 1.76 and for MBC 1.64. The results support the hypothesis that the labile fractions (POC, MBC, and PON) are highly sensitive to the dynamics of organic matter in highly weathered soils of tropical regions influenced by different management systems. Reductions to SRs of labile organic matter pools are related to the impacts of agricultural use of Cerrado soils.

scholarly journals Assessment of Soil Structural Properties in Relation to Land Use Change in South-East Asia

Proceedings ◽  
2020 ◽  
Vol 36 (1) ◽  
pp. 182
Author(s):  
Rachel de Lastic ◽  
Thảo Hoàng ◽  
Phuong Nguyen ◽  
Sovanda Son ◽  
Vuthy Suos ◽  
...  
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Hydraulic Conductivity ◽  
Land Use Change ◽  
Structural Stability ◽  
Fruit Tree ◽  
Total Carbon ◽  
Tree Plantations ◽  
Soil Structural Stability

For many emerging economies, rapid land use change from forest to farmland is resulting in high levels of land degradation. Farming systems such as maize cultivation under conventional tillage after slash and burn degrade the soil resource through declining soil structural stability. Cultivation enhances mineralisation and hence loss of soil organic matter, which in turn reduces soil structures stability and promotes further carbon losses through soil erosion. Alternative land uses such as fruit tree plantations, or practise change to reduced tillage or conservation agriculture have the potential to counter this spiral of accelerated soil degradation through improving soil structural stability and build-up of soil organic matter. This project assessed how land use influences soil structural stability in Cambodia near Battambang and the North-Western Mountain regions of Vietnam where maize based system are most common. Soil properties measured were: (1) total carbon and nitrogen content analysis, (2) particle and aggregate size distribution using laser refraction, (3) hydraulic conductivity, (4) bulk density and (5) microbial CO2 respiration. Information on land use history was also collected through farmer surveys. Land use significantly influenced aggregate stability and hydraulic conductivity. This was largely associated with differences in soil organic carbon content. Forest system had the highest, and conventional maize systems had the lowest amount of large aggregates. Fruit tree plantations are relatively new to these regions but they already showed improved soil aggregate sizes though the level of improvement varied and depended on remnant soil.

Particulate organic matter in soil under different management systems in the Brazilian Cerrado

Soil Research ◽  
2012 ◽  
Vol 50 (8) ◽  
pp. 685 ◽  
Author(s):  
Arcângelo Loss ◽  
Marcos Gervasio Pereira ◽  
Adriano Perin ◽  
Fernando Silva Coutinho ◽  
Lúcia Helena Cunha dos Anjos
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Organic Carbon ◽  
The Other ◽  
Management Systems ◽  
Soil Conditions ◽  
Brazilian Cerrado ◽  
Cerrado Vegetation ◽  
No Till ◽  
Planting System

The combination of the no-till planting system (NTS) and pasture (e.g. brachiaria grass, Urochloa sp.) for livestock production constitutes a crop–livestock integration (CLI) system. CLI systems significantly increase the total organic carbon (TOC) content of soil and the particulate organic carbon (POC) of soil organic matter (SOM). The present study evaluated TOC and the granulometric fractions of SOM under different management systems in a Cerrado area in the state of Goiás. Two areas applying crop rotation were evaluated, one using CLI (corn/brachiaria grass/bean/cotton/soybean planted sequentially) and the other NTS (sunflower/pearl millet/soybean/corn planted sequentially). A third area covered with natural Cerrado vegetation (Cerradão) served as a reference to determine original soil conditions. Soil was randomly sampled at 0–5, 5–10, 10–20, and 20–40 cm. The TOC, POC, and mineral-associated organic carbon (MOC) were assessed, and POC and MOC stocks calculated. The CLI system resulted in greater TOC levels than NTS (0–5, 5–10, and 10–20 cm). Compared with the Cerradão, CLI areas exhibited higher stocks of TOC (at 5–10 and 10–20 cm) and POC (at 0–40 cm). Results obtained for TOC and POC fractions show that land management with CLI was more efficient in increasing SOM than NTS. Moreover, when compared with NTS, the CLI system provided better POC stratification.

scholarly journals Soil chemical management drives structural degradation of Oxisols under a no-till cropping system

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 819 ◽  
Author(s):  
Márcio R. Nunes ◽  
Alvaro P. da Silva ◽  
José E. Denardin ◽  
Neyde F. B. Giarola ◽  
Carlos M. P. Vaz ◽  
...  
Keyword(s):  
Surface Layer ◽  
Structural Stability ◽  
Subsurface Layer ◽  
Structural Degradation ◽  
Chemical Management ◽  
No Till ◽  
Cultivated Soil ◽  
Water Percolation ◽  
Soil Structural Stability ◽  
Dispersible Clay

Physical degradation of the subsurface layer of soils reduces the effectiveness of no-till (NT) as a sustainable soil management approach in crop production. Chemical factors may reduce the structural stability of Oxisols and thereby exacerbate compaction from machinery traffic. We studied the relationship between chemical management and structural degradation in Oxisols cultivated under NT at three sites in southern Brazil. The surface and subsurface layers of the soils were characterised chemically and mineralogically and three physical attributes related to soil structural stability (readily dispersible clay in water, mechanically dispersible clay in water, and water percolation) were quantified for each layer. The same characterisations were performed on Oxisols collected from adjacent non-cultivated areas, to provide reference data for non-degraded soil. The levels of dispersed clay in the cultivated soil from the surface layer matched those of the non-cultivated soil, but for the subsurface layer higher dispersed clay levels in the cultivated soil showed that it was physically degraded relative to the non-cultivated soil. Water percolation was found to be slower through the Oxisols cultivated under NT, irrespective of the soil layer. The relationships between the three indicators of soil structural stability and the measured chemical and mineralogical variables of the soils were explored through an analysis of canonical correlation. The principal variables associated with the lower stability of the cultivated vs non-cultivated Oxisols were the lower concentrations of organic carbon and exchangeable aluminium and, for the surface layer, the higher pH. It is argued that structural degradation of Oxisols cultivated under NT, observed predominantly in the subsurface layer, has been aggravated by the accumulation of amendments and fertilisers in the surface soil and reduced levels of organic matter, especially in the subsurface layer.

scholarly journals Effect of management systems and cover crops on organic matter dynamics of soil under vegetables

2014 ◽  
Vol 38 (3) ◽  
pp. 923-933 ◽  
Author(s):  
Rodrigo Fernandes de Souza ◽  
Cícero Célio de Figueiredo ◽  
Nuno Rodrigo Madeira ◽  
Flávia Aparecida de Alcântara
Keyword(s):  
Organic Matter ◽  
Cover Crops ◽  
Microbial Biomass Carbon ◽  
Block Design ◽  
Soil Tillage ◽  
Management Systems ◽  
Vegetable Production ◽  
Tillage Systems ◽  
Positive Effects ◽  
Organic Matter Dynamics

Vegetable production in conservation tillage has increased in Brazil, with positive effects on the soil quality. Since management systems alter the quantity and quality of organic matter, this study evaluated the influence of different management systems and cover crops on the organic matter dynamics of a dystrophic Red Latosol under vegetables. The treatments consisted of the combination of three soil tillage systems: no-tillage (NT), reduced tillage (RT) and conventional tillage (CT) and of two cover crops: maize monoculture and maize-mucuna intercrop. Vegetables were grown in the winter and the cover crops in the summer for straw production. The experiment was arranged in a randomized block design with four replications. Soil samples were collected between the crop rows in three layers (0.0-0.05, 0.05-0.10, and 0.10-0.30 m) twice: in October, before planting cover crops for straw, and in July, during vegetable cultivation. The total organic carbon (TOC), microbial biomass carbon (MBC), oxidizable fractions, and the carbon fractions fulvic acid (C FA), humic acid (C HA) and humin (C HUM) were determined. The main changes in these properties occurred in the upper layers (0.0-0.05 and 0.05-0.10 m) where, in general, TOC levels were highest in NT with maize straw. The MBC levels were lowest in CT systems, indicating sensitivity to soil disturbance. Under mucuna, the levels of C HA were lower in RT than NT systems, while the C FA levels were lower in RT than CT. For vegetable production, the C HUM values were lowest in the 0.05-0.10 m layer under CT. With regard to the oxidizable fractions, the tillage systems differed only in the most labile C fractions, with higher levels in NT than CT in the 0.0-0.05 m layer in both summer and winter, with no differences between these systems in the other layers. The cabbage yield was not influenced by the soil management system, but benefited from the mulch production of the preceding maize-mucuna intercrop as cover plant.

Influence of organic matter, clay mineralogy, and pH on the effects of CROSS on soil structure is related to the zeta potential of the dispersed clay

Soil Research ◽  
2013 ◽  
Vol 51 (1) ◽  
pp. 34 ◽  
Author(s):  
Alla Marchuk ◽  
Pichu Rengasamy ◽  
Ann McNeill
Keyword(s):  
Organic Matter ◽  
Organic Carbon ◽  
Zeta Potential ◽  
Structural Stability ◽  
Soil Structure ◽  
Clay Mineralogy ◽  
Net Charge ◽  
Clay Dispersion ◽  
Soil Structural Stability ◽  
Negative Zeta Potential

The high proportion of adsorbed monovalent cations in soils in relation to divalent cations affects soil structural stability in salt-affected soils. Cationic effects on soil structure depend on the ionic strength of the soil solution. The relationships between CROSS (cation ratio of soil structural stability) and the threshold electrolyte concentration (TEC) required for the prevention of soil structural problems vary widely for individual soils even within a soil class, usually attributed to variations in clay mineralogy, organic matter, and pH. The objective of the present study was to test the hypothesis that clay dispersion influenced by CROSS values depends on the unique association of soil components, including clay and organic matter, in each soil affecting the net charge available for clay–water interactions. Experiments using four soils differing in clay mineralogy and organic carbon showed that clay dispersion at comparable CROSS values depended on the net charge (measured as negative zeta potential) of dispersed clays rather than the charge attributed to the clay mineralogy and/or organic matter. The effect of pH on clay dispersion was also dependent on its influence on the net charge. Treating the soils with NaOH dissolved the organic carbon and increased the pH, thereby increasing the negative zeta potential and, hence, clay dispersion. Treatment with calgon (sodium hexametaphosphate) did not dissolve organic carbon significantly or increase the pH. However, the attachment of hexametaphosphate with six charges on each molecule greatly increased the negative zeta potential and clay dispersion. A high correlation (R2 = 0.72) was obtained between the relative clay content and relative zeta potential of all soils with different treatments, confirming the hypothesis that clay dispersion due to adsorbed cations depends on the net charge available for clay–water interactions. The distinctive way in which clay minerals and organic matter are associated and the changes in soil chemistry affecting the net charge cause the CROSS–TEC relationship to be unique for each soil.

Soil Quality Indicators in Conventional and Conservation Tillage Systems in the Brazilian Cerrado

2021 ◽  
Author(s):  
Luiz Alberto da Silva Rodrigues Pinto ◽  
Sandra Santana de Lima ◽  
Cristiane Figueira da Silva ◽  
Rafael Gomes da Mota Gonçalves ◽  
Igor de Sousa Morais ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Quality ◽  
Conservation Tillage ◽  
Soil Aggregates ◽  
Conventional Tillage ◽  
Soil Aggregation ◽  
Reference Area ◽  
Quality Indices ◽  
Tillage Systems ◽  
No Till

Abstract Conventional and conservation tillage systems can alter soil aggregation and total and labile soil organic matter (SOM) contents. This study aimed to determine the degree of soil aggregation, quantify total carbon (TC), permanganate oxidizable carbon (POXC), light organic matter (LOM), and potentially mineralizable carbon (CO2-C) contents in soils aggregates, and assess soil quality indices at sites under conventional and conservation tillage in the Cerrado region of Minas Gerais State, Brazil. Four experimental areas were analyzed: a area under conventional tillage for 20 years, a area under no-till for 6 years, a area under no-till for 18 years, and a reference area of undisturbed Cerrado vegetation. Soil aggregates retained on 8.0 to 4.0 mm sieves were evaluated for size class distribution and mean weight diameter. TC, POXC, LOM, daily and total CO2-C emissions were also analyzed. These data were used to calculate the C/N ratio and sensitivity, carbon pool, and lability indices. The results of SOM compartments were in agreement with those obtained for the soil aggregation status. Environmental conditions at no-till areas promoted macroaggregate formation and preserved TC and LOM contents, resulting in a high degree of aggregate stability. Soil quality indices were sensitive to identify changes between the reference area and managed areas. Soil aggregates from no-till areas had higher CO2-C emissions and accumulations than those from the conventional tillage area.

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