Manuel practique: Cartographie numérique des sols

Ce document aborde les étapes du processus et les outils utilisés dans le cours d'initiation à l'utilisation de la cartographie numérique des sols réalisé par le Centre International d'Agriculture Tropical (CIAT) dans le cadre du projet «Cultures innovantes et technologies agricoles terrestres à Haiti» et financé par le Fond International de Développement Agricole (FIDA – sigle anglais IFAD

Evaluación del potencial de mitigación de las estrategias de adaptación implementadas en los Territorios Sostenibles Adaptados al Clima (TeSAC)

El propósito de este estudio fue identificar el patrón espacial de la erosión hídrica del suelo actual y potencial y determinar el efecto de la condiciones de clima (precipitación), cobertura, prácticas de conservación e implementación de estrategias de adaptación al cambio climático para la zona de estudio delimitada en el municipio de Popayán – Colombia y en el departamento de Matagalpa – Nicaragua, por medio de la ecuación de pérdida de suelo (USLE), la cual se rige por cinco factores: Factores de erosión del suelo (K), índice de erosión de lluvia y escurrimiento (R), cultivo/vegetación y factor de manejo (C), factor de prácticas de conservación (P) y factor topográfico (LS). Donde se logró identificar que el efecto de la cobertura de suelo y las estrategias de adaptación a largo plazo son un factor importante como medida de conservación del recurso suelo

Manual: practica en mapeo digital de propiedades de suelos

Este documento es un paso a paso de los procesos y herramientas que se utilizaran en el curso de Introducción al Mapeo Digital de Suelos realizado por el Centro Internacional para Agricultura Tropical (CIAT) en el marco del proyecto Innovative Crop and Soil-based Technologies in Haiti y financiado por el Fondo Internacional de Desarrollo Agrícola (IFAD)

Soil carbon under current and improved land management in Kenya, Ethiopia and India: Dynamics and sequestration potentials

Agriculture is a major contributor to climate change, emitting the three major greenhouse gases (GHGs) – carbon dioxide (CO2), methane and nitrous oxide – into the atmosphere. According to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the Agriculture, Forestry and Other Land Use sector “is responsible for just under a quarter (~10–12 Gt CO2eq/yr) of [all] anthropogenic GHG emissions mainly from deforestation and agricultural emissions from livestock, soil and nutrient management”. Land use change – often associated with deforestation – contributes about 11.2% to this share, while agricultural production is responsible for 11.8% (IPCC, 2014). To reduce emissions from agriculture, while providing and maintaining global food security, there is a growing interest to develop and promote low-emission greengrowth pathways for future agricultural production systems. Sub-Saharan Africa (SSA) faces two concerns in that respect: a) agriculture is the major emitter of GHGs on this sub-continent, and b) agriculture is largely underperforming. To feed a growing population, productivity and total production need to increase significantly. To achieve this while reducing emissions from agriculture at the same time is a major challenge. Climate-smart agriculture (CSA) sets out to address this challenge by transforming agricultural systems affected by the vagaries of climate change. CSA aims at improving food security and system’s resilience while addressing climate change mitigation

Variability of soil surface characteristics in a mountainous watershed in Valle del Cauca, Colombia: Implications for runoff, erosion, and conservation

Understanding catchment sediment or solute transport frequently relies on understanding of soil nutrient conditions and physical properties. This study investigates hydropedological patterns in a tropical catchment by understanding soil nutrient and soil surface changes. Soil nutrient concentrations and hydraulic properties were measured from the La Vega micro watershed in the southwestern Colombian Andes at 16 distributed locations in four elevation ranges (between 1450 and 1700 m a.s.l.). The site is a part of a conservation partnerships which implements programs and monitor impacts. Soil samples were analyzed for total nitrogen (TN), Bray II-available phosphorus, exchangeable cations, pH, organic matter, and texture. Soil hydraulic conductivities at two depths (0–5 cm and 5–10 cm) were determined in conservation implementation areas (enclosures and natural regrowth). In the upper elevation range, regrowth of natural vegetation was found on deep soils (∼3 m) with moderate infiltration (26 cm hr−1), the lowest bulk density (0.92 g cm−3), and the highest TN (0.4%). The lowest elevation (mixed land use of grazing and riparian forests with deep profiles) had the lowest infiltration (4 cm hr−1), highest bulk density (1.02 g cm−3), and the lowest TN (0.26%). In the middle elevation ranges, conserved tropical forest vegetation were located on shallow soil depths with high organic matter (∼6%) and high infiltration (86 cm hr−1). The lowest infiltration rate average (2.3 cm hr−1) exceeded the estimated erosive regional precipitation intensity (∼2.5 cm hr−1) about 60% of the time, while the median infiltration rate (10 cm hr−1) exceeded rainfall intensities 94% of the time, indicating that infiltration excess and saturation excess runoff mechanisms are both present. Coupling data with sediment concentration and solute concentration patterns can help discern correlations between scales and will help to monitor effectiveness of conservation programs aimed at sustaining ecosystem services

Physical topsoil properties in Murugusi, Western Kenya

General: Lab determined topsoil bulk density, contents of sand, clay and organic carbon in Murugusi, W. Kenya, together with spatial coordinates of where the soil samples were taken (rounded to the closest center point of a 250 m × 250 m raster). All lab analyses were carried out at the ILRI/CIAT lab in Nairob, Kenya. Soil sampling: At each sample location, one composite topsoil sample was taken; three cores of 7 cm in diameter taken within an area of one square meter. The soil was taken from 0-0.2 m depth below any organic (O) horizon. Determination of soil properties: The bulk density of the soil was determined by taking two undisturbed soil samples (0-10 cm and 10-20 cm depth) of known volume (100 cm2) and weighting them after air drying. Soil fractions of clay (<0.002 mm) and sand (0.05-2 mm) were determined by the hydrometer method (Estefan et al., 2014), using 10% sodium hexametaphosphate as the dispersing agent. Soil pH was determined potentiometrically on a soil suspension of 1:2 (soil: water). Total carbon was measured after dry combustion using an elemental analyser (Elementar Vario max cube; ISO 10694, first edition 1995-03-01) Reference: Estefan G., Sommer R., Ryan J. (2014) Analytical Methods for Soil-Plant and Water in Dry Areas. A Manual of Relevance to the West Asia and North Africa Region. 3rd Edition, International Center for Agricultural Research in the Dry Areas, Aleppo, 255 pp. Available online at: http://repo.mel.cgiar.org:8080/handle/20.500.11766/7512?show=full. Verified: October 9, 2018. Acknowledgements: We are deeply thankful for the good services provided by John Mukulama (soil sampling), John Yumbya Mutua (soil sampling) and Francis Mungthu Njenga (lab analyses) The project was carried out within the CGIAR Research Program on Water, Land and Ecosystems (WLE)