Volume 5 Special Issue 1 2011
Soil Organic Matter: Brazilian Perspectives

ISBN 978-4-903313-83-2

How to reference: Leite LFC, Sagrilo E, Maciel GA, Iwata BF (2011) Simulation model to estimate carbon sequestration under management systems in tropical soils of Brazil. In: Leite LF, Madari BE (Eds) Soil Organic Matter: Brazilian Perspectives. Dynamic Soil, Dynamic Plant 5 (Special Issue 1), 1-6

Guest Editors

Luiz F. Leite
Embrapa Mid-North, Brazil
www.cpamn.embrapa.br

Beata E. Madari
Embrapa Rice and Beans, Brazil
www.cnpaf.embrapa.br

CONTENTS AND ABSTRACTS

Luiz Fernando Carvalho Leite, Edvaldo Sagrilo, Giovana Alcântara Maciel, Bruna de Freitas Iwata (Brazil) Simulation Model to Estimate Carbon Sequestration under Management Systems in Tropical Soils of Brazil (pp 1-6)

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ABSTRACT

Invited Mini-Review: Soil organic carbon (SOC) represents a major pool of carbon within the biosphere and acts as source and a sink for carbon and nutrients. Several simulation models have been developed and evaluated to estimate SOC stocks in different agroecosystems such as, CENTURY or ROTHC which are considered mechanistic, complex and based on qualitative concepts rather than measurable entities. Because of this complexity, it is important that simpler but mechanistic SOC models, like CQESTR (a contraction of C sequestration), be developed and tested under several soil and climate conditions. CENTURY and CQESTR have been evaluated to estimate SOC stocks in different management systems. Particularly in tropical soils, both models have estimated an increase in the SOC stocks in the no-tillage compared to conventional tillage system. However, it is necessary to improve the model accuracy including important variables to tropical areas like soil structure or soil mineralogy.

Edvaldo Sagrilo, Luiz Fernando Carvalho Leite, Giovana Alcântara Maciel (Brazil) Soil Organic Matter as Affected by Green Manure at Brazilian Conditions (pp 7-11)

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ABSTRACT

Invited Mini-Review: The use of green manure has been associated with increasing soil organic matter (SOM), which is an essential component of high-quality agricultural soils, especially in tropical environments such as Brazil. The aim of this review was to present evidence of the effectiveness that green manures use has on the improvement of Brazilian SOM stocks. The contribution of soil aggregation to SOM stabilization, the importance of returning high amounts of plant residues to the soil, and the effectiveness of including N-fixing legumes in the cropping systems are all summarized. Soil aggregation is highly dependent on the continual addition of crop residues to the soil, and creates favorable conditions for SOM accumulation. SOM build-up is directly correlated to the amount of crop residues added to the soil and it is closely dependent on the duration, in the long-term, of this soil residue input. Moreover, the quality of these crop residues is of major importance, considering not only the high content of C directly added to the soil by the green manures, but also their N content, which is a determinant in the growth of subsequent crops, resulting in increased amounts of residue-derived C returned to the soil. The inclusion of green manures in cropping systems, especially legume species, in association with appropriate soil management practices, is a feasible and sustainable way to increase long-term SOM stocks in Brazilian tropical conditions.

Vanderlise Giongo, Sandra Regina da Silva Galvão, Alessandra Monteiro Salviano Mendes, Carlos Alberto Tuão Gava, Tony Jarbas Ferreira Cunha (Brazil) Soil Organic Carbon in the Brazilian Semi-arid Tropics (pp 12-20)

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ABSTRACT

Invited Mini-Review: The Brazilian semi-arid tropics occupies an area of 969,589 km² that represents 11% of the national territory and the Caatinga is its most representatives Biome with an area of 844.453 km². However, approximately 46% of this area is deforested. The conversion of Caatinga preserved vegetation in degraded areas has contributed to global climatic changes; therefore, a series of scientific research studies has as its objective to quantify the C reservoirs in different semi-arid regions of the world, as well as to identify the factors that control its dynamic. Recently, network research studies for measuring C stock and balance in natural vegetation and disturbed areas, firstly related to livestock and dry land farming that are dominant activities in the region, and secondly related to irrigated agricultural exploitation due to its high impact in the productive system, have been developed. The studies comprise C determination in soil, plant, micro-organism and atmosphere systems, involving C and energy balance and the effect of land use on C stock relations. C stocks in the Brazilian semi-arid tropics varies from 20 to 48.4 t ha^-1 at 0-20 cm soil layer, while for the aerial part of natural vegetation the values vary from 1 to 80 mg ha^-1. It can be observed, for the same soil and vegetation type, that changes in land use decrease soil C stock and that plant cover management can behave as C source.

Beáta Emöke Madari, Tony Jarbas Ferreira Cunha, Ricardo Soares (Brazil) Organic Matter of the Anthropogenic Dark Earths of Amazônia (pp 21-28)

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ABSTRACT

Invited Review: The anthropogenic dark earths (ADE, Terra Preta de Índio or terra preta arqueológica, as are often referred to in Portuguese) feature unique properties that are interesting not only from a pedological point of view but have important agronomic and economic relevance. Among other properties, the organic matter (SOM) of these soils is considerably different from that of other mineral soils. Besides the quantity of SOM, its origin, composition and, consequently, function in the soil is different. Carbonized biomass (pyrogenic carbon) is a principal constituent of ADE that was, to our best knowledge, gradually incorporated into these soils, 4 to 10 thousand years ago, by native dwellers of the Amazon region. The carbon of pyrogenic origin was not only accumulated in ADE, but it also played important role in the transformation of organic matter and the humification process. As a result of this, the SOM of ADE is relatively stable, compared to the SOM of adjacent ferralsols, and at the same time it has chemical reactivity that is the major responsible for the higher cation exchange capacity and good buffer properties of these soils. These properties have very important environmental and agronomic relevance in the tropics due to organic carbon conservation in the soil and enhanced soil fertility. The ADE soils are excellent model for the development of modern soil fertility management practices.

Giovana Alcantara Maciel, Sandro Manuel Carmelino Hurtado, Luiz Fernando Carvalho Leite, Edvaldo Sagrilo, Adriana Monteiro da Costa (Brazil) Influence of Integrated Crop-Livestock-Forest Systems on Soil Organic Matter in Tropical Regions (pp 29-35)

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ABSTRACT

Invited Mini-Review: Soil organic matter (SOM) plays important functions in soil physical, chemical and biological processes. A reduction of SOM enhances the soil degradation process by reducing the biomass production and causing the loss of nutrients, water and soil. A mix of annual crops, tree species and pasture on the same area in an Integrated Crop-Livestock-Forest System (ICLFS) ensures abundant supplies of residues and an elevated amount of accumulated organic material in the soil thus constituting a promising alternative for tropical regions. Land areas aimed at fodder production, if well managed, produce large quantities of residues, which associated with a non-disturbed soil, favor the accumulation of SOM. In ICLFS, the cultivation of grain crops prior to the use of the land for pastures ensures more efficient use of residual nutrients by the plants, thus increasing the productivity of pastures. The adoption of technologies aiming at sustainability, as an improved soil management system, with better use of natural resources, increases the soil carbon levels. This condition results in the economic feasibility of cropping systems, through the improvement of soil, water and consequently, the environment quality. This chapter discusses the main advantages of integrated production systems and the influence of ICLFS on the supply and maintenance of SOM in tropical and subtropical regions.

Cristiane Pereira de Assis, Francisco Alisson da Silva Xavier, Stoécio Malta Ferreira Maia, Rafaella Silva Nogueira, Guilherme Viana de Alencar, Teógenes Senna de Oliveira (Brazil) Soil Organic Matter Changes in Agroforestry and Organic Farming in the Semi-Arid Region of Northeastern Brazil (pp 36-44)

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ABSTRACT

Invited Review: The development of management strategies aiming to increase soil quality in Brazilian semi-arid regions, including the improvement of soil organic matter (SOM) status, is still scarce. In general, most of the traditional farming practices adopted in agricultural fields in Northeast Brazil (semi-arid) contribute to a reduction of in SOM levels, thus alternative management practices must be implemented to improve soil quality in different agricultural production systems. Within this context, agroforestry and organic farming have been considered suitable management options to cope with the semi-arid climate despite of its environmental constraints. This study aimed at presenting results from well established experiments on agroforestry and organic farming performed in Sobral, Guaraciaba do Norte and Ubajara counties, all located in the State of Ceará, Brazil. In agroforestry, agrosilvopastoral and silvopastoral designs may be considered as important options to increase soil organic C stocks, with consequences in the different SOM pools, including labile C. Organic farming has been implemented in both small and large scale agriculture, and it too represents a good strategy to increase the status of SOM, even in sandy soils as observed at Ubajara county. Obviously, agronomic, economic and social aspects should be linked to the environmental benefits brought about through the adoption of agroforestry and/or organic cultivation. Notwithstanding, the discussion involving the improvement of food production in Brazilian semi-arid must regard both types of agroecosystems as suitable options to increase the status of SOM, which represents the starting point for recovering soil quality, and consequently, enhancing productivity.

Francisco Alisson da Silva Xavier, Eduardo de Sá Mendonça (Brazil) Agroforestry for Recovering Soil Organic Matter: A Brazilian Perspective (pp 45-52)

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ABSTRACT

Invited Review: The recovery of soil organic matter (SOM) can be considered as one of the most important goals in recovering soil quality. The evaluation of changes in SOM levels as a result of soil management practices is essential to identify strategies to increase agricultural production, avoid soil degradation, and decrease the emission of greenhouse gases. Agroforestry systems are considered to be a suitable land use alternative to maintain SOM levels through the supply of litter and root residues. In Brazil, no-tillage is widely accepted as a soil management alternative to enhance soil organic carbon (C) sequestration in different ecosystems. Nevertheless, only few studies have been conducted to evaluate the effect of agroforestry on SOM recovering. Interest in agroforestry has increased in the last decade, especially its adoption by smallholding agriculture. The most consistent Brazilian agroforestry experiences have been developed basically in three main macro-regions of the country: the North, Northeast and Southeast Regions. In the North, multistrata agroforestry designs are preferentially adopted in the Amazonian Region, whereas silvopastoral, agrosilvopastoral and alley cropping are mainly adopted in the Northeast Region. Coffee-agroforestry systems are examples of well established agroforestry experiences in the Southeast. The potential of soil C sequestration by agroforestry systems in Brazil varies substantially among the different regions. The potential of organic C storage depends on the design of the systems, tree species, climate and soil characteristics. The biomass production (through litterfall) in some Brazilian agroforestry systems may vary from 1.39 to 25.92 Mg ha^-1 year^-1 and the respective potential for organic C storage from 0.62 to 11.66 Mg ha^-1 year^-1.

Claudia Maria B. F. Maia, Beata E. Madari, Etelvino H. Novotny (Brazil) Advances in Biochar Research in Brazil (pp 53-58)

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ABSTRACT

Invited Mini-Review: To mitigate global warming, major changes in the global carbon balance are expected as the world’s larger economies migrate to energy matrices that emit less greenhouse gases (GHG). Alternatives of carbon-neutral technologies have led to significant alterations in the global balance of carbon. One example is biochar, which is any source of biomass previously heated under low or no oxygen supply with the purpose of application on soil. This review aims to give an overview about the research carried out in Brazil on biochar-to-soil technology, from its structural characterization to field trials all over the country.

Lilian B. P. Zaidan, Maria Angela M. Carvalho (Brazil) Nitrogen Effects on Growth and Fructan Production in Vernonia herbacea (Vell.) Rusby, an Asteraceae from the Brazilian Cerrado (pp 59-64)

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ABSTRACT

Invited Mini-Review: The Cerrado, second largest biome in Brazil, hosts a high biodiversity and is listed as one of the most endangered ecosystems (hotspots) of the world. The cerrado soils are old, deep, with low water retention, poor in nutrients and with high levels of aluminum. Although plants native to the cerrado are well adapted to oligotrophic soils, growth and productivity can be increased by addition of mineral nutrients. Vernonia herbacea is a perennial herb accumulating about 80% of inulin-type fructans in the underground organs, thus being considered an alternative source for inulin production. The present review is focused on the role of nitrogen in growth, biomass allocation and inulin production in plants of V. herbacea grown in the field and under glasshouse conditions. The studies here reported summarize the efforts towards the understanding of the physiology and biochemistry of this promising species of the Cerrado and could contribute to the sustainable use of this biome.

Gooty Jaffer Mohiddin, Mandala Srinivasulu, Mekapogu Madakka, Kondeti Subramanyam, Vengatampalli Rangaswamy (India) Influence of Selected Insecticides on Enzyme Activities in Groundnut (Arachis hypogaea L.) Soils (pp 65-69)

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ABSTRACT

Original Research Paper: The influence of acephate and imidacloprid on important soil enzyme activities, such as dehydrogenase and urease in two groundnut (Arachis hypogaea L.) soils, collected from Anantapur District of Andhra Pradesh, India, was studied under laboratory conditions. The activity of dehydrogenase, in terms of formazan formed from triphenyl tetrazolium chloride, was more pronounced in both soils treated with 2.5 kg ha^-1 of the acephate and imidacloprid. But higher concentrations (5.0, 7.5 and 10 kg ha^-1) were toxic to dehydrogenase activity. The activity of urease in terms of ammonia formed from hydrolysis of urea was higher in both soils, treated with acephate and imidacloprid at 5.0 kg ha^-1, but higher levels (7.5 and 10 kg ha^-1) were toxic or innocuous to urease activity.

Mekapogu Madakka, Gooty Jaffer Mohiddin, Mandala Srinivasulu, Vengatampalli Rangaswamy (India) Influence of Pesticides, Alone and in Combination, on Phosphatase Activity in Soils of Groundnut (Arachis hypogaea L.) Fields (pp 70-74)

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ABSTRACT

Original Research Paper: Pesticides such as thiram and difenoconazole (fungicides), and deltamethrin and profenofos (insecticides), alone and in combination with insecticides viz., profenofos (organophosphate) + cypermethrin (synthetic pyrethroid) and deltamethrin (synthetic pyrethroid) + endosulfan (organochlorine) were applied at five concentrations (0.0, 1.0, 2.5, 5.0, 7.5 and 10.0 kg ha^-1) to test their non-target effects towards the activity of phosphatase in black clay and red sandy clay soils of groundnut (Arachis hypogaea L.) fields under laboratory conditions. Phosphatase activity was more pronounced in soil samples treated with 2.5 kg ha^-1 of the insecticide combinations and individual pesticides. The activity of phosphatase was increased with increasing concentration of insecticide combinations up to 2.5 kg ha^-1. Higher levels of these pesticides and insecticide combinations eliminated phosphatase activity. Soil samples receiving 2.5 kg ha^-1 of insecticide combinations profenofos + cypermethrin and deltamethrin + endosulfan accumulated para-nitrophenol most after 20 days of incubation; enzyme activity decreased as the period of incubation increased. Results of this study suggest that enzyme activity is influenced by the concentration of profenofos + cypermethrin and deltamethrin + endosulfan combinations.

Mekapogu Madakka, Mandala Srinivasulu, Gooty Jaffer Mohiddin, Vengatampalli Rangaswamy (India) Effect of Pesticides on Microbial Diversity and Urease in Groundnut (Arachis hypogaea L.) Soil (pp 75-82)

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ABSTRACT

Original Research Paper: The influence of four pesticides viz., profenofos, deltamethrin, thiram and difenoconazole and two insecticide combinations viz., profenofos + cypermethrin and deltamethrin + endosulfan at 0.0, 1.0, 2.5, 5.0, 7.5 and 10.0 kg ha^-1 were assessed for their effects on the activity of urease (measured in terms of hydrolysis of urea by sodium hypochlorite method) and microbial populations like bacteria, fungi and actinomycetes in two agricultural soils, collected from a fallow groundnut (Arachis hypogaea Linn.) fields of Anantapur district. The effects of selected pesticides profenofos, deltamethrin, thiram and difenoconazole and profenofos + cypermethrin and deltamethrin + endosulfan on microbial population and urease activity were dose dependent. Urease activity and microbial populations increased with increasing concentrations of the pesticides up to 5.0 kg ha^-1. Higher rates (7.5, 10.0 kg ha^-1) of these pesticides were either toxic or innocuous to the urease activity and microbial population. The significant stimulation in the activity of urease was associated with 2.5 kg ha^-1 of pesticides in black soil, where as in red soil it was 5.0 kg ha^-1 of profenofos, 2.5 kg ha^-1 of deltamethrin, thiram, difeneconozole. In the insecticide combinations urease activity was 5.0 kg ha^-1 profenofos + cypermethrin, 5.0 kg ha^-1 of deltamethrin + endosulfan in black clay soils whereas in red sandy clay soils, population of microorganisms increased with 2.5 to 5.0 kg ha^-1 of pesticides. With further incubation the activity of urease was significantly more at day 20 and enzyme activity decreased progressively with increasing incubation period.

S. Viveka, B. Leena Grace (India) Utilization of Weeds as Substrates for Vermifertilizer (pp 83-86)

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ABSTRACT

Original Research Paper: Aquatic weeds interfere with the normal functioning of water bodies. Among the aquatic weeds, water hyacinth is considered to be the most obnoxious weed ranked eighth in the world. Ipomoea carnea is a cosmopolitan species of weed in disturbed habitats. Compost is known to improve crop production by improving soil fertility and soil physical properties. Earthworms make important contributions in the decomposition of organic material. In the present study, Lampito mauritii, an indigenous earthworm, was utilized for the decomposition of commonly available aquatic weeds viz., Eichhornia crassipes and I. carnea for the production of good quality vermicompost. After the completion of vermicomposting the cocoons, juveniles, non-clitellated and adult earthworms were separated and counted. Physico-chemical parameters of the compost were analyzed in the initial and final stages of vermicomposting. Bacterial and fungal density and their generic and species level identification analysis were also carried out. The pH value increased in the final stage and was 7.2. The EC improved from initial (0.82,0.85) to final stages (1.43,0.99) in both Eichhornia- and Ipomoea-based composts. The temperature in the final stage of Eichhornia- and Ipomoea-based vermicompost was 28.9 and 28.7°C, respectively. Bulk density decreased significantly with increasing water holding capacity and porosity. N, P, K and organic carbon values were higher in both Eichhornia- and Ipomoea-based vermicompost than the initial state. Bacterial density of Eichhornia and Ipomoea composts was 2.16 ´ 10⁷ and 2.83 ´ 10⁷ CFU/g, respectively. The fungal density of Eichhornia and Ipomoea composts were 2.76 ´ 10⁴ and 2.30 ´ 10⁴CFU/g, respectively. E. crassipes and I. carnea, bothweeds, could be effectively utilized as substrates for vermicomposting.

Mojtaba Zeraat Pishe, Farhad Khormali, Ali Shahriari (Iran) The Relationship between Specific Surface Area and Soil Organic Carbon in Loess-Derived Soils of Northern Iran (pp 87-89)

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ABSTRACT

Short Communication: Soil organic carbon (SOC) can act as a sink or source of atmospheric carbon dioxide, therefore, it is important to understand the amount and composition of SOC in terrestrial ecosystems, the spatial variation in SOC, and the underlying mechanisms that stabilize SOC. Relationships between minerals specific surface area and organic carbon (OC) concentration were examined for sediments and soil A-horizons from throughout the world. The organic compositions can be absorbed by minerals surface, and also exist a positive relation between specific surface area (SSA) and OC. Much of our current understanding is based on laboratory experiments, the results of which often do not support observations made in the field. The present study attempted to demonstrate the relationship between specific surface area, SOC rate and clay content in the pasture soils, in Golestan province. 7 soil profiles formed under different moisture regimes (udic, xeric and aridic regimes) were sampled from their surface horizons (0-30 cm depth). Correlation and linear regressions were performed between SOC, SSA and particle clay size. Results indicate that the content of clay showed significant liner correlations with SSA (R² = 0.63, P < 0.05) but SOC did not show significant liner correlations with SSA (R² = 0.50, P < 0.07). The results demonstrated that mean residence time of organic carbon in soil increase with higher specific surface area. Soils with high clay levels show greater SOC than soils with high sand contents.

Mojtaba Zeraat Pishe, Farhad Khormali (Iran) Estimation of Organic Carbon Loss Potential in a Climosequence in Golestan Province, Northern Iran (pp 90-93)

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ABSTRACT

Short Communication: Soil carbon oxidized by neutral KMnO₄ has been used as index of labile C by several workers. Study area a climosequence (udic-xeric-aridic regimes) with loess parent material in Golestan province, Iran. Samples from 7 different soil orders with pasture land use (Mollisols, Inceptisols, Aridisols and Entisols) were collected at (0-20 cm) depth. Permanganate-oxidizable carbon (POC), an index of soil labile carbon, was used to show soil potential loss of organic carbon (OC). This index shows the maximum loss of OC in a given soil. Maximum loss of OC for each soil was estimated through POC and bulk density. The potential losses of OC were estimated between 1930.6 and 69180.9 Kg ha^-1 C. The lowest organic C loss was related to Entisols because of containing the lowest OC, and maximum potential loss of OC has been detected in Mollisols mainly due to having a lot of fresh organic tissue in mollic epipedon. In addition, the total amount of OC which were oxidised by KMnO₄ ranged from 15.6 to 60.73% of the total C. The effect of soil texture on POC was examined, clay + silt/OC, silt/OC and clay/OC accounts for 63, 68 and 51%, respectively, of the variability in soil POC (P < 0.05). And also soil POC of 7 soil sample were regressed with their total C contents and were found to be highly correlated (R² = 0.94, P < 0.01). Stable organic constituents in the soil include humic substances and other organic macromolecules that are intrinsically resistant against microbial attack, or that are physically protected by adsorption on mineral surfaces or entrapment within clay and mineral aggregates.