Erick Fernandes - Academia.edu (original) (raw)

Papers by Erick Fernandes

Biodiversity and Conservation, 2013

Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forest... more Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forested landscapes in Sumatra, Indonesia and Mato Grosso, Brazil. Gradient-directed transects (gradsects) were sampled across a range of forested land use mosaics, using a uniform protocol to simultaneously record vegetation (vascular plant Electronic supplementary material The online version of this article (species, plant functional types (PFTs) and vegetation structure), vertebrates (birds, mammals) and invertebrates (termites), in addition to measuring site and soil properties, including carbon stocks. At both sites similar correlations were detected between major components of structure (mean canopy height, woody basal area and litter depth) and the diversities of plant species and PFTs. A plant species to PFT ratio [spp.:PFTs] was the best overall predictor of animal diversity, especially termite species richness in Sumatra. To a notable extent vegetation structure also correlated with animal diversity. These surrogates demonstrate generic links between habitat structural elements, carbon stocks and biodiversity. They may also offer practical low-cost indicators for rapid assessment in tropical forest landscapes.

Cattle production on Brachiaria pastures is a primary use of cleared forestland in the western Br... more Cattle production on Brachiaria pastures is a primary use of cleared forestland in the western Brazilian Amazon. About 6.8 million hectares in the States of Acre and Rondônia have been deforested, where 75% of land is now grazed (IBGE, 1998). The principal pasture species are B. brizantha and B. decumbens with the latter in decline from spittlebug susceptibility (Deois incompleta; Gonçalves et al., 1996). The general pattern of pasture establishment in the Amazon basin includes felling and burning forest biomass, planting annual crops for one to three years (especially on small farms), and then seeding to grasses. The conversion of tropical forest to pasture, the effects of that process on soil properties, and pasture degradation outcomes have been studied in the eastern Amazon region ( Serrao et al., 1978; Reiners et al., 1994; Sanchez and Salinas, 1981; Buschbacher et al., 1987; Moraes et al., 1996) but not in the remote western region. Most findings showed an initial increase in ...

The impacts of climate change on agriculture are projected to be significant in coming decades, s... more The impacts of climate change on agriculture are projected to be significant in coming decades, so response strategies and their likely costs should be evaluated now. Robust crop models are needed to estimate those impacts on agricultural productivity regionally, nationally, and even sub- nationally. But existing crop–climate change modeling platforms are not easily accessible to most stakeholders in developing countries. So there is less testing of those models than there might be, and there are fewer opportunities for further improvements based on local tests and emerging data. That is why this study produced an open-access crop-climate-economic impact modeling platform for Latin America and the Caribbean that can be extended to other regions—and modified and improved by users as new crop, climate, and economic datasets become available. The new platform projects the likely impacts of agroclimatic factors on crop productivity on the basis of climate projections from two general ci...

The Agro-ecological Zones Simulator (AZS) is a platform for data and models sharing for scientist... more The Agro-ecological Zones Simulator (AZS) is a platform for data and models sharing for scientists and policy makers, facilitating the analysis of climate change impacts and the identification of possible response strategies through a comprehensive regional-level analysis comprised of: (i) Geo-referenced climate, soil and terrain data, combined into a land resources database;(ii) Crop suitability assessment and land productivity of cropping systems; (iii) Procedures for calculating the potential agronomically attainable yield; (iv) Procedures for computing actual yields as limited by water availability and management, biotic and abiotic factors; and (v) Selected agricultural production systems with defined input and management relationships, crop-specific environmental requirements and adaptability characteristics. The software core of the platform is given by an instance of the BioMA platform. The platform facilitates the evaluation of the impacts of projected changes in temperatur...

Competition for limited water resources and low rice yields in developing countries has renewed t... more Competition for limited water resources and low rice yields in developing countries has renewed the interest in finding better ways to grow more rice with less water. In recent years alternate wet-dry (AWDI) and non-flooded (NF) irrigation have shown promise for reducing water consumption without significant effect on rice grain yield. In 2001, a survey of 109 farmers was conducted

Our objectives were to evaluate strate- gies to improve productivity and economic returns from be... more Our objectives were to evaluate strate- gies to improve productivity and economic returns from beef and dual-purpose cattle systems based on data collected on one dual-purpose (Bostaurus ×Bosindicus) and two beef (Nellore) cattle farms in the western Ama- zon region of Brazil. Forage chemical composition and digestion rates of carbohydrate fractions of grazed Brachiaria decumbens and Brachiaria brizantha cv. Marandu grasses and Pueraria phaseoloides (tropical kudzu) legume were measured monthly during a 9-mo period from the end of one dry season to the end of the subsequent rainy season. Measurements of milk and growth responses to grazing these forages were used to predict animal productivity responses to dietary nu- trient availability throughout an annual cycle. The ME available for gain in our simulations was always more limiting than metabolizable protein. The predicted ME available for gain was 0.50 kg/d for steers grazing B.

Soil Biology and Biochemistry, 2006

We compared differences in soil phosphorus fractions between large earthworm casts (Family Glosso... more We compared differences in soil phosphorus fractions between large earthworm casts (Family Glossoscolecidae) and surrounding soils, i.e., Oxisols in 10 year-old upland agroforestry system (AGR), pasture (PAS), and secondary forest (SEC) in the Central Brazilian Amazon. AGR and PAS both received low-input fertilization and SEC received no fertilization. We found that earthworm casts had higher levels of organic hydroxide P than surrounding soils, whereas fertilization increased inorganic hydroxide P. Inorganic P was increased by fertilization, and organic P was increased by earthworm gut passage and/or selection of ingested materials, which increased available P (sum of resin and bicarbonate fractions) and moderately available P (sum of hydroxide and dilute acid fractions), and P fertilizer application and land-use increased available P. The use of a modified sequential P fractionation produced fewer differences between earthworm casts and soils than were expected. We suggest the use of a condensed extraction procedure with three fractions (Available P, Moderately Available P, and Resistant P) that provide an ecologically based understanding of the P availability in soil. Earthworm casts were estimated to constitute 41.0, 38.2, and 26.0 kg ha K1 of total available P stocks (sum of resin and bicarbonate fractions) in the agroforestry system, pasture, and secondary forest, respectively. Published by Elsevier Ltd.

Soil and Tillage Research, 2007

Grain production shortfalls in northern Ethiopia are commonly associated with occurrence of intra... more Grain production shortfalls in northern Ethiopia are commonly associated with occurrence of intra-seasonal dry spells or droughts and rapid land degradation which adversely impact crop yields. Suitable practices that use available rainwater more efficiently to mitigate impact of dry spells on crops and that protect soil are needed to stabilize and improve grain yields in the predominately rainfed agriculture. During three cropping seasons on-farm experiments tested conservation tillage techniques implemented with oxen-drawn plows on clay loam soil. Tested tillage techniques are subsoiling, open and tied ridges, no till, and conventional tillage with the local maresha plow (the control). Effectiveness in improving root zone soil moisture, limiting soil erosion, and improving sorghum (Sorghum bicolor (L.) Moench.) and chickpea (Cicer arietinum L.) grain yield were determined. Results demonstrate that performance of the tillage techniques varied with seasonal rainfall distribution and intensity and land slope gradient. Tied and open ridge increased seasonal root zone soil moisture 15-24%. Subsoiling slightly (3%) increased and no till slightly decreased soil moisture but were not statistically different from conventional tillage. Tied ridge and no till significantly reduced seasonal soil loss by up to 11 Mg ha À1 during seasons with moderate intensity storms, but during a season with high intensity storms tied ridge on over 9% slope gradient increased soil loss (up to 35 Mg ha À1 ). The increased soil disturbance of subsoiling led to higher soil loss rates (up to 32 Mg ha À1 ) than conventional tillage during all seasons. Grain yield decreased and runoff and erosion rates increased rapidly with increasing land slope gradient. During a season with moderate intensity rainfall open and tied ridge increased sorghum yield by 67-73% over the control (730 kg ha À1 ) while no till decreased yield by 25%. During a season when high intensity rainfall events damaged the ridges, subsoiling had the best sorghum yield with 42% increase over the control (1430 kg ha À1 ). Poor early season rainfall and fungus attacks resulted in low chickpea yields (200-320 kg ha À1 ) and statistically insignificant differences between tillage methods. Overall results of the study suggest that on slopes below 8% gradient oxen-drawn ridge tillage and subsoiling, to a lesser degree, can effectively improve conditions that mitigate impact of short dry spells especially during seasons with less intense rainfall events. # 2007 Published by Elsevier B.V.

Pedobiologia, 2003

In the Brazilian Amazon region, millions of hectares of forest land have been converted into catt... more In the Brazilian Amazon region, millions of hectares of forest land have been converted into cattle pastures and then been abandoned. Agroforestry is a potential option for the transformation of in parts degraded lands into productive agricultural systems. The re-establishment of a diversified soil macrofauna can help in the process of recuperation of the often compacted soil structure of the pastures. The soil macrofauna community was studied during the rainy season in four different agroforestry systems near Manaus in Central Amazonia: 1. a high-input silvopastoral system (ASPh), 2. a low-input silvopastoral system (ASPl), 3. a palm based system with four tree crop species (AS1) and 4. a high-diversity tree crop system with ten tree crop species (AS2), plus a spontaneous fallow for comparison. The sampling method recommended by the Tropical Soil Biology and Fertility Programme was used. The highest diversity of fauna groups was observed in the ASPh and ASPl where trees were associated with the leguminous cover crop, Desmodium ovalifolium. The cover crop exerted a favorable effect on the soil fauna presumably by maintaining the soil moist and shaded and providing litter as a substrate. Of the 15 soil fauna groups that were found in all systems, four were absent from AS1. Within the AS2 system a significantly greater density of the soil fauna was observed under peach palm (Bactris gasipaes) and cupuaçu (Theobroma grandiflorum) (3107 and 524 ind.m -2 , respectively) than under the other three tree species. The soil under peach palm and cupuaçu also tended to have a higher number of soil fauna groups. In AS1, the soil under peach palm had a higher fauna density than the soil under cupuaçu, probably caused by the abundant residues of the heart of palm harvest on the soil. The earthworm biomass was particularly high in AS1. Under cupuaçu approximately 7 times more earthworms were found in AS1 (17.9) than in AS2 (2.4). The study of the macrofauna community, including both the litter layer and the superficial soil layers, allows to identify the plant species/management combinations which favour the increase of the diversity of the invertebrates.

Nutrient Cycling in Agroecosystems, 2006

In Malawi, agroforestry is very promising for N replenishment; however, there are still large var... more In Malawi, agroforestry is very promising for N replenishment; however, there are still large variations in the performance of these agroforestry technologies on farmers' fields. A study was conducted on-farm to determine the influence of three landscape positions on N dynamics in maize (Zea mays L.)-based agroforestry systems. The agroforestry systems were relay fallow using Sesbania sesban (L.) Merr or Tephrosia vogelii (Hook F.), simultaneous fallow using Gliricidia sepium(Jacq.) Walp., and maize without trees as a control. Sesbania was superior to other systems in the bottom slope, producing the highest tree biomass (1,861 kg ha -1 ), whereas, gliricidia gave the highest tree biomass production in the midslope

Global Change Biology, 2007

ABSTRACT

Geoderma, 1997

... 79 (1997) 49-67 GEODE~ Management control of soil organic matter dynamics in tropical land-us... more ... 79 (1997) 49-67 GEODE~ Management control of soil organic matter dynamics in tropical land-use systems Erick CM Fernandes a,*, Peter P. Motavalli ... transfer of C via the rhizosphere is just as important in the formation of SOM (Ladd and Martin, 1983; Martin and Merckx, 1993 ...

Earth Interactions, 2005

The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; h... more The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; however, the return of forest and canopy structure following abandonment is not well understood. This study examined the development of leaf area index (LAI), canopy cover, aboveground biomass, stem density, diameter at breast height (DBH), and basal area (BA) by growth form and diameter class for 10 SFs regenerating from abandoned pastures. Biomass accrual was tree dominated, constituting Ն94% of the total measured biomass in all forests abandoned Ն4 to 6 yr. Vine biomass increased with forest age, but its relative contribution to total biomass decreased with time. The forests were dominated by the tree Vismia spp. (>50%). Tree stem density peaked after 6 to 8 yr (10 320 stems per hectare) before declining by 42% in the 12-to 14-yr-old SFs. Small-diameter tree stems in the 1-5-cm size class composed >58% of the total stems for all forests. After 12 to 14 yr, there was no significant leaf area below 150-cm height. Leaf area return (LAI ‫ס‬ 3.2 after 12 to 14 yr) relative to biomass was slower than literature-reported recovery following slash-and-burn, where LAI can reach primary forest levels (LAI ‫ס‬ 4-6) in 5 yr. After 12 to 14 yr, the colonizing vegetation returned some components of forest structure to values reported for primary forest. Basal area and LAI were 50%-60%, canopy cover and stem density were nearly 100%, and the rapid tree-dominated biomass accrual was 25%-50% of values reported for primary forest. Biomass accumulation may reach an asymptote earlier than expected because of even-aged, monospecific, untiered stand structure. The very slow leaf area accumulation relative to biomass and to reported values for recovery following slash-and-burn indicates a different canopy development pathway that warrants further investigation of causes (e.g., nutrient limitations, competition) and effects on processes such as evapotranspiration and soil water uptake, which would influence long-term recovery rates and have regional implications.

Biodiversity and Conservation, 2013

Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forest... more Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forested landscapes in Sumatra, Indonesia and Mato Grosso, Brazil. Gradient-directed transects (gradsects) were sampled across a range of forested land use mosaics, using a uniform protocol to simultaneously record vegetation (vascular plant Electronic supplementary material The online version of this article (species, plant functional types (PFTs) and vegetation structure), vertebrates (birds, mammals) and invertebrates (termites), in addition to measuring site and soil properties, including carbon stocks. At both sites similar correlations were detected between major components of structure (mean canopy height, woody basal area and litter depth) and the diversities of plant species and PFTs. A plant species to PFT ratio [spp.:PFTs] was the best overall predictor of animal diversity, especially termite species richness in Sumatra. To a notable extent vegetation structure also correlated with animal diversity. These surrogates demonstrate generic links between habitat structural elements, carbon stocks and biodiversity. They may also offer practical low-cost indicators for rapid assessment in tropical forest landscapes.

Applied Soil Ecology, 2007

sions on study methodology, and J.M. Anderson and Armand van Wambeke on review of the manuscript.... more sions on study methodology, and J.M. Anderson and Armand van Wambeke on review of the manuscript. We thank Reginaldo Constantino (University of Brasilia) for his identification of the termite species. We thank Emanoel dos Santos Alencar, Edilza da Silva Rocha, Estevã o Oliveira dos Santos, and Maria de Rosá rio of Embrapa Amazonia Ocidental for their assistance in soil analyses, and Eleusa Barros, Orlando Ferreira Cruz Junior, and the personnel of the Laborató rio de Sementes for laboratory support at INPA. We thank IBAMA for the permission to collect termites.

It has been proposed that the C/N ratio, or quality, of litter or mulch mixtures affects N releas... more It has been proposed that the C/N ratio, or quality, of litter or mulch mixtures affects N release. Although total N release from these mixtures and the effects on soil N are relatively well understood, a mechanistic understanding of the interactions between litter species with respect to their N release is still lacking. This study examines decomposition and N dynamics in mixtures of high-quality leguminous mulch, gliricidia [Gliricidia sepium (Jacq.) Kunth. ex Walp.] with a C/N ratio of 13, and low-quality cupuaçu [Theobroma grandiflorum (Wild. ex Spring) Schumann] litter with a C/N ratio of 42, which occur in combination in agroforestry systems. Ratios of 100:0, 80:20, 50:50, 20:80, 0:100 of fresh 15 N-enriched gliricidia leaves and senescent cupuaçu leaves, totaling the same dry weight of 6.64 t ha K1 , were applied to an Oxisol and sampled at 6, 14, 38, and 96 days after application. After more than 40% of the N in the gliricidia leaves had been released and the microbial biomass N reached its peak, a significant increase in available soil N occurred at day 14, which was more pronounced with greater amounts of gliricidia in the leaf mixture. However, relative to the N applied in the leaf mixture, there was no significant difference in available soil N with greater proportions of gliricidia. Total N release from the mixtures corresponded to the total N applied by gliricidia. Until day 38, cupuaçu C mineralization was significantly faster in the presence of the highest proportion of gliricidia compared to lower proportions. This faster C mineralization of more than 0.5% per day, however, did not increase total C loss or N release from cupuaçu leaves after 96 days. The use of 15 N tracers identified an N transfer from gliricidia leaves and the soil to cupuaçu leaves and consequently, a lower N release from gliricidia to the soil in the presence of cupuaçu leaves. Though we expected that available N in the soil would also decrease with greater amounts of cupuaçu litter in the mixture, our results indicated an additive effect of the two species on N release and soil mineral N, with gross interactions between them canceling net interactive effects. Therefore, N release of leaf mixtures behaved as predicted from a calculated sum of individual release patterns, in spite of a transfer of N from the high-to the low-quality leaves. q

Agroforestry Systems, 2005

Page 1. -1 Carbon and nutrient stocks in the litter layer of agroforestry systems in central Amaz... more Page 1. -1 Carbon and nutrient stocks in the litter layer of agroforestry systems in central Amazonia, Brazil Sandra C. Tapia-Coral1, Fla´vio J. Luiza˜o1,*, Elisa Wandelli2 and Erick CM Fernandes3 1National Institute of Amazonian ...

Biodiversity and Conservation, 2013

Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forest... more Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forested landscapes in Sumatra, Indonesia and Mato Grosso, Brazil. Gradient-directed transects (gradsects) were sampled across a range of forested land use mosaics, using a uniform protocol to simultaneously record vegetation (vascular plant Electronic supplementary material The online version of this article (species, plant functional types (PFTs) and vegetation structure), vertebrates (birds, mammals) and invertebrates (termites), in addition to measuring site and soil properties, including carbon stocks. At both sites similar correlations were detected between major components of structure (mean canopy height, woody basal area and litter depth) and the diversities of plant species and PFTs. A plant species to PFT ratio [spp.:PFTs] was the best overall predictor of animal diversity, especially termite species richness in Sumatra. To a notable extent vegetation structure also correlated with animal diversity. These surrogates demonstrate generic links between habitat structural elements, carbon stocks and biodiversity. They may also offer practical low-cost indicators for rapid assessment in tropical forest landscapes.

Cattle production on Brachiaria pastures is a primary use of cleared forestland in the western Br... more Cattle production on Brachiaria pastures is a primary use of cleared forestland in the western Brazilian Amazon. About 6.8 million hectares in the States of Acre and Rondônia have been deforested, where 75% of land is now grazed (IBGE, 1998). The principal pasture species are B. brizantha and B. decumbens with the latter in decline from spittlebug susceptibility (Deois incompleta; Gonçalves et al., 1996). The general pattern of pasture establishment in the Amazon basin includes felling and burning forest biomass, planting annual crops for one to three years (especially on small farms), and then seeding to grasses. The conversion of tropical forest to pasture, the effects of that process on soil properties, and pasture degradation outcomes have been studied in the eastern Amazon region ( Serrao et al., 1978; Reiners et al., 1994; Sanchez and Salinas, 1981; Buschbacher et al., 1987; Moraes et al., 1996) but not in the remote western region. Most findings showed an initial increase in ...

The impacts of climate change on agriculture are projected to be significant in coming decades, s... more The impacts of climate change on agriculture are projected to be significant in coming decades, so response strategies and their likely costs should be evaluated now. Robust crop models are needed to estimate those impacts on agricultural productivity regionally, nationally, and even sub- nationally. But existing crop–climate change modeling platforms are not easily accessible to most stakeholders in developing countries. So there is less testing of those models than there might be, and there are fewer opportunities for further improvements based on local tests and emerging data. That is why this study produced an open-access crop-climate-economic impact modeling platform for Latin America and the Caribbean that can be extended to other regions—and modified and improved by users as new crop, climate, and economic datasets become available. The new platform projects the likely impacts of agroclimatic factors on crop productivity on the basis of climate projections from two general ci...

The Agro-ecological Zones Simulator (AZS) is a platform for data and models sharing for scientist... more The Agro-ecological Zones Simulator (AZS) is a platform for data and models sharing for scientists and policy makers, facilitating the analysis of climate change impacts and the identification of possible response strategies through a comprehensive regional-level analysis comprised of: (i) Geo-referenced climate, soil and terrain data, combined into a land resources database;(ii) Crop suitability assessment and land productivity of cropping systems; (iii) Procedures for calculating the potential agronomically attainable yield; (iv) Procedures for computing actual yields as limited by water availability and management, biotic and abiotic factors; and (v) Selected agricultural production systems with defined input and management relationships, crop-specific environmental requirements and adaptability characteristics. The software core of the platform is given by an instance of the BioMA platform. The platform facilitates the evaluation of the impacts of projected changes in temperatur...

Competition for limited water resources and low rice yields in developing countries has renewed t... more Competition for limited water resources and low rice yields in developing countries has renewed the interest in finding better ways to grow more rice with less water. In recent years alternate wet-dry (AWDI) and non-flooded (NF) irrigation have shown promise for reducing water consumption without significant effect on rice grain yield. In 2001, a survey of 109 farmers was conducted

Our objectives were to evaluate strate- gies to improve productivity and economic returns from be... more Our objectives were to evaluate strate- gies to improve productivity and economic returns from beef and dual-purpose cattle systems based on data collected on one dual-purpose (Bostaurus ×Bosindicus) and two beef (Nellore) cattle farms in the western Ama- zon region of Brazil. Forage chemical composition and digestion rates of carbohydrate fractions of grazed Brachiaria decumbens and Brachiaria brizantha cv. Marandu grasses and Pueraria phaseoloides (tropical kudzu) legume were measured monthly during a 9-mo period from the end of one dry season to the end of the subsequent rainy season. Measurements of milk and growth responses to grazing these forages were used to predict animal productivity responses to dietary nu- trient availability throughout an annual cycle. The ME available for gain in our simulations was always more limiting than metabolizable protein. The predicted ME available for gain was 0.50 kg/d for steers grazing B.

Soil Biology and Biochemistry, 2006

We compared differences in soil phosphorus fractions between large earthworm casts (Family Glosso... more We compared differences in soil phosphorus fractions between large earthworm casts (Family Glossoscolecidae) and surrounding soils, i.e., Oxisols in 10 year-old upland agroforestry system (AGR), pasture (PAS), and secondary forest (SEC) in the Central Brazilian Amazon. AGR and PAS both received low-input fertilization and SEC received no fertilization. We found that earthworm casts had higher levels of organic hydroxide P than surrounding soils, whereas fertilization increased inorganic hydroxide P. Inorganic P was increased by fertilization, and organic P was increased by earthworm gut passage and/or selection of ingested materials, which increased available P (sum of resin and bicarbonate fractions) and moderately available P (sum of hydroxide and dilute acid fractions), and P fertilizer application and land-use increased available P. The use of a modified sequential P fractionation produced fewer differences between earthworm casts and soils than were expected. We suggest the use of a condensed extraction procedure with three fractions (Available P, Moderately Available P, and Resistant P) that provide an ecologically based understanding of the P availability in soil. Earthworm casts were estimated to constitute 41.0, 38.2, and 26.0 kg ha K1 of total available P stocks (sum of resin and bicarbonate fractions) in the agroforestry system, pasture, and secondary forest, respectively. Published by Elsevier Ltd.

Soil and Tillage Research, 2007

Grain production shortfalls in northern Ethiopia are commonly associated with occurrence of intra... more Grain production shortfalls in northern Ethiopia are commonly associated with occurrence of intra-seasonal dry spells or droughts and rapid land degradation which adversely impact crop yields. Suitable practices that use available rainwater more efficiently to mitigate impact of dry spells on crops and that protect soil are needed to stabilize and improve grain yields in the predominately rainfed agriculture. During three cropping seasons on-farm experiments tested conservation tillage techniques implemented with oxen-drawn plows on clay loam soil. Tested tillage techniques are subsoiling, open and tied ridges, no till, and conventional tillage with the local maresha plow (the control). Effectiveness in improving root zone soil moisture, limiting soil erosion, and improving sorghum (Sorghum bicolor (L.) Moench.) and chickpea (Cicer arietinum L.) grain yield were determined. Results demonstrate that performance of the tillage techniques varied with seasonal rainfall distribution and intensity and land slope gradient. Tied and open ridge increased seasonal root zone soil moisture 15-24%. Subsoiling slightly (3%) increased and no till slightly decreased soil moisture but were not statistically different from conventional tillage. Tied ridge and no till significantly reduced seasonal soil loss by up to 11 Mg ha À1 during seasons with moderate intensity storms, but during a season with high intensity storms tied ridge on over 9% slope gradient increased soil loss (up to 35 Mg ha À1 ). The increased soil disturbance of subsoiling led to higher soil loss rates (up to 32 Mg ha À1 ) than conventional tillage during all seasons. Grain yield decreased and runoff and erosion rates increased rapidly with increasing land slope gradient. During a season with moderate intensity rainfall open and tied ridge increased sorghum yield by 67-73% over the control (730 kg ha À1 ) while no till decreased yield by 25%. During a season when high intensity rainfall events damaged the ridges, subsoiling had the best sorghum yield with 42% increase over the control (1430 kg ha À1 ). Poor early season rainfall and fungus attacks resulted in low chickpea yields (200-320 kg ha À1 ) and statistically insignificant differences between tillage methods. Overall results of the study suggest that on slopes below 8% gradient oxen-drawn ridge tillage and subsoiling, to a lesser degree, can effectively improve conditions that mitigate impact of short dry spells especially during seasons with less intense rainfall events. # 2007 Published by Elsevier B.V.

Pedobiologia, 2003

In the Brazilian Amazon region, millions of hectares of forest land have been converted into catt... more In the Brazilian Amazon region, millions of hectares of forest land have been converted into cattle pastures and then been abandoned. Agroforestry is a potential option for the transformation of in parts degraded lands into productive agricultural systems. The re-establishment of a diversified soil macrofauna can help in the process of recuperation of the often compacted soil structure of the pastures. The soil macrofauna community was studied during the rainy season in four different agroforestry systems near Manaus in Central Amazonia: 1. a high-input silvopastoral system (ASPh), 2. a low-input silvopastoral system (ASPl), 3. a palm based system with four tree crop species (AS1) and 4. a high-diversity tree crop system with ten tree crop species (AS2), plus a spontaneous fallow for comparison. The sampling method recommended by the Tropical Soil Biology and Fertility Programme was used. The highest diversity of fauna groups was observed in the ASPh and ASPl where trees were associated with the leguminous cover crop, Desmodium ovalifolium. The cover crop exerted a favorable effect on the soil fauna presumably by maintaining the soil moist and shaded and providing litter as a substrate. Of the 15 soil fauna groups that were found in all systems, four were absent from AS1. Within the AS2 system a significantly greater density of the soil fauna was observed under peach palm (Bactris gasipaes) and cupuaçu (Theobroma grandiflorum) (3107 and 524 ind.m -2 , respectively) than under the other three tree species. The soil under peach palm and cupuaçu also tended to have a higher number of soil fauna groups. In AS1, the soil under peach palm had a higher fauna density than the soil under cupuaçu, probably caused by the abundant residues of the heart of palm harvest on the soil. The earthworm biomass was particularly high in AS1. Under cupuaçu approximately 7 times more earthworms were found in AS1 (17.9) than in AS2 (2.4). The study of the macrofauna community, including both the litter layer and the superficial soil layers, allows to identify the plant species/management combinations which favour the increase of the diversity of the invertebrates.

Nutrient Cycling in Agroecosystems, 2006

In Malawi, agroforestry is very promising for N replenishment; however, there are still large var... more In Malawi, agroforestry is very promising for N replenishment; however, there are still large variations in the performance of these agroforestry technologies on farmers' fields. A study was conducted on-farm to determine the influence of three landscape positions on N dynamics in maize (Zea mays L.)-based agroforestry systems. The agroforestry systems were relay fallow using Sesbania sesban (L.) Merr or Tephrosia vogelii (Hook F.), simultaneous fallow using Gliricidia sepium(Jacq.) Walp., and maize without trees as a control. Sesbania was superior to other systems in the bottom slope, producing the highest tree biomass (1,861 kg ha -1 ), whereas, gliricidia gave the highest tree biomass production in the midslope

Global Change Biology, 2007

ABSTRACT

Geoderma, 1997

... 79 (1997) 49-67 GEODE~ Management control of soil organic matter dynamics in tropical land-us... more ... 79 (1997) 49-67 GEODE~ Management control of soil organic matter dynamics in tropical land-use systems Erick CM Fernandes a,*, Peter P. Motavalli ... transfer of C via the rhizosphere is just as important in the formation of SOM (Ladd and Martin, 1983; Martin and Merckx, 1993 ...

Earth Interactions, 2005

The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; h... more The area of secondary forest (SF) regenerating from pastures is increasing in the Amazon basin; however, the return of forest and canopy structure following abandonment is not well understood. This study examined the development of leaf area index (LAI), canopy cover, aboveground biomass, stem density, diameter at breast height (DBH), and basal area (BA) by growth form and diameter class for 10 SFs regenerating from abandoned pastures. Biomass accrual was tree dominated, constituting Ն94% of the total measured biomass in all forests abandoned Ն4 to 6 yr. Vine biomass increased with forest age, but its relative contribution to total biomass decreased with time. The forests were dominated by the tree Vismia spp. (>50%). Tree stem density peaked after 6 to 8 yr (10 320 stems per hectare) before declining by 42% in the 12-to 14-yr-old SFs. Small-diameter tree stems in the 1-5-cm size class composed >58% of the total stems for all forests. After 12 to 14 yr, there was no significant leaf area below 150-cm height. Leaf area return (LAI ‫ס‬ 3.2 after 12 to 14 yr) relative to biomass was slower than literature-reported recovery following slash-and-burn, where LAI can reach primary forest levels (LAI ‫ס‬ 4-6) in 5 yr. After 12 to 14 yr, the colonizing vegetation returned some components of forest structure to values reported for primary forest. Basal area and LAI were 50%-60%, canopy cover and stem density were nearly 100%, and the rapid tree-dominated biomass accrual was 25%-50% of values reported for primary forest. Biomass accumulation may reach an asymptote earlier than expected because of even-aged, monospecific, untiered stand structure. The very slow leaf area accumulation relative to biomass and to reported values for recovery following slash-and-burn indicates a different canopy development pathway that warrants further investigation of causes (e.g., nutrient limitations, competition) and effects on processes such as evapotranspiration and soil water uptake, which would influence long-term recovery rates and have regional implications.

Biodiversity and Conservation, 2013

Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forest... more Multi-taxon surveys were conducted in species-rich, lowland palaeotropical and neotropical forested landscapes in Sumatra, Indonesia and Mato Grosso, Brazil. Gradient-directed transects (gradsects) were sampled across a range of forested land use mosaics, using a uniform protocol to simultaneously record vegetation (vascular plant Electronic supplementary material The online version of this article (species, plant functional types (PFTs) and vegetation structure), vertebrates (birds, mammals) and invertebrates (termites), in addition to measuring site and soil properties, including carbon stocks. At both sites similar correlations were detected between major components of structure (mean canopy height, woody basal area and litter depth) and the diversities of plant species and PFTs. A plant species to PFT ratio [spp.:PFTs] was the best overall predictor of animal diversity, especially termite species richness in Sumatra. To a notable extent vegetation structure also correlated with animal diversity. These surrogates demonstrate generic links between habitat structural elements, carbon stocks and biodiversity. They may also offer practical low-cost indicators for rapid assessment in tropical forest landscapes.

Applied Soil Ecology, 2007

sions on study methodology, and J.M. Anderson and Armand van Wambeke on review of the manuscript.... more sions on study methodology, and J.M. Anderson and Armand van Wambeke on review of the manuscript. We thank Reginaldo Constantino (University of Brasilia) for his identification of the termite species. We thank Emanoel dos Santos Alencar, Edilza da Silva Rocha, Estevã o Oliveira dos Santos, and Maria de Rosá rio of Embrapa Amazonia Ocidental for their assistance in soil analyses, and Eleusa Barros, Orlando Ferreira Cruz Junior, and the personnel of the Laborató rio de Sementes for laboratory support at INPA. We thank IBAMA for the permission to collect termites.

It has been proposed that the C/N ratio, or quality, of litter or mulch mixtures affects N releas... more It has been proposed that the C/N ratio, or quality, of litter or mulch mixtures affects N release. Although total N release from these mixtures and the effects on soil N are relatively well understood, a mechanistic understanding of the interactions between litter species with respect to their N release is still lacking. This study examines decomposition and N dynamics in mixtures of high-quality leguminous mulch, gliricidia [Gliricidia sepium (Jacq.) Kunth. ex Walp.] with a C/N ratio of 13, and low-quality cupuaçu [Theobroma grandiflorum (Wild. ex Spring) Schumann] litter with a C/N ratio of 42, which occur in combination in agroforestry systems. Ratios of 100:0, 80:20, 50:50, 20:80, 0:100 of fresh 15 N-enriched gliricidia leaves and senescent cupuaçu leaves, totaling the same dry weight of 6.64 t ha K1 , were applied to an Oxisol and sampled at 6, 14, 38, and 96 days after application. After more than 40% of the N in the gliricidia leaves had been released and the microbial biomass N reached its peak, a significant increase in available soil N occurred at day 14, which was more pronounced with greater amounts of gliricidia in the leaf mixture. However, relative to the N applied in the leaf mixture, there was no significant difference in available soil N with greater proportions of gliricidia. Total N release from the mixtures corresponded to the total N applied by gliricidia. Until day 38, cupuaçu C mineralization was significantly faster in the presence of the highest proportion of gliricidia compared to lower proportions. This faster C mineralization of more than 0.5% per day, however, did not increase total C loss or N release from cupuaçu leaves after 96 days. The use of 15 N tracers identified an N transfer from gliricidia leaves and the soil to cupuaçu leaves and consequently, a lower N release from gliricidia to the soil in the presence of cupuaçu leaves. Though we expected that available N in the soil would also decrease with greater amounts of cupuaçu litter in the mixture, our results indicated an additive effect of the two species on N release and soil mineral N, with gross interactions between them canceling net interactive effects. Therefore, N release of leaf mixtures behaved as predicted from a calculated sum of individual release patterns, in spite of a transfer of N from the high-to the low-quality leaves. q

Agroforestry Systems, 2005

Page 1. -1 Carbon and nutrient stocks in the litter layer of agroforestry systems in central Amaz... more Page 1. -1 Carbon and nutrient stocks in the litter layer of agroforestry systems in central Amazonia, Brazil Sandra C. Tapia-Coral1, Fla´vio J. Luiza˜o1,*, Elisa Wandelli2 and Erick CM Fernandes3 1National Institute of Amazonian ...