Characterization, classification and suitability evaluation of soils under sugarcane (Saccharum officinarum L.) cultivation at the Sugar Research Farm, University of Ilorin, Nigeria

A reconnaissance survey conducted at the University of Ilorin Sugar Research Farm (USRF) revealed four dominant soils at Site 1 (USRF1) and one at Site 2 (USRF2). The soils were characterized and classified according to both the Soil Taxonomy (ST) and the World Reference Base for Soil Resources (WRB). Also, the suitability of the soils for sugarcane cultivation was evaluated using the limitation approach. While the USRF1 soils were reddish, the USRF2 soil was greyish due to poor drainage. The USRF1 soils were loamy sand with the AB-horizons of pedons II and III being gravelly. Pedon V had sandy loam surface, sandy clay loam subsurface and clay loam subsoil. The USRF1 soils were moderately acid while the USRF2 soil was slightly acid to slightly alkaline. Exchangeable calcium (Ca2+) content of the USRF2 soil which averaged 4.00 cmolc kg–1 was 2-3 times higher than that of the USRF1 soils. The USRF2 soil also contained higher Mg2+, K+ and Na+, 2-3 folds higher effective cation exchange capacity and > 10 folds higher soil organic carbon (with mean of 11.60 g kg–1) and total nitrogen (mean of 0.94 g kg–1). Under ST, pedons I and IV classified as Typic Haplustepts, II and III as Lithic Haplustepts and V as a Kanhaplic Haplustalf. Under WRB, pedons I and IV classified as Eutric Regosols (arenic), II and III as Endo-pisoplinthic Cambisols (arenic) and V as a Gleyic Lixisol (loamic). Pedon V was highly suitable (85.25%), I and IV moderately suitable (64.53%), II marginally suitable (47.40%) and III unsuitable (35.62%) for sugarcane cultivation.

The Pedogenesis of Soil Derived from Carbonate Rocks along a Climosequence in a Subtropical Mountain, China

Revealing the pedogenesis of soil on carbonate rocks is a key step in determining the boundaries of soil types along a climosequence. However, related research is lacking for a subtropical mountain. In this study, eight pedons were sampled across an elevation gradient (789–2322 m) having large variation in mean annual precipitation (MAP) (1189–1764 mm) and mean annual temperature (MAT) (5.7–14.9 °C). General processes were performed, including physical, chemical, and morphological characterizations, X-ray diffraction (XRD), total elements’ content, and soil classification of the carbonate rock. In the climo-toposequence, the illite had been transformed into illite-smectite below 1300–1500 m of elevation, 1300–1370 mm of MAP, and above 10.5–11.5 °C of MAT, and into vermiculite above this climate. These findings indicated that the effects of temperature on soil mineral transformation had weakened with the gradual increases in elevation. The pedon at 861 m of elevation, 1206 mm of MAP, and 14.5 °C of MAT, which accounted for the argic horizons, was divided into Argosols after human activities. The finding revealed that changes from forest to cultivated land could potentially accelerate the formation of argic horizons, and it provided a theoretical basis for global carbonate rocks’ weathering conditions and ecological problems in subtropical mountains. When the soils reached approximately 1100–1200 m of elevation, 1250–1300 mm of MAP, and 11.5–13.5 °C of MAT, the argic horizons of the soil could be accounted for, as evolved from the Cambosols in Chinese Soil Taxonomy (CST) (Inceptisols in Soil Taxonomy (ST), Cambisols in the World Reference Base for Soil Resources (WRB)) to the Argosols in CST (Alfisols in ST, Luvisols or Alisols in WRB) under natural vegetation. Therefore, it was indicated that the soil types changed significantly in the CST, ST, and WRB with increases of MAP and decreases of MAT, which provides a reference for determining the boundaries of the soil types along a climosequence in subtropical mountains.

​Fuzzy Logic Expert System for Taxonomic Variation of Solonchaks

Background: The main objective of this research is to apply fuzzy logic to four Solonchaks, in order to determine their degree of remoteness or rapprochement with their central taxonomic concept. Therefore, we identify their possible seasonal taxonomic variation on the criteria established by World Reference Base (WRB). Methods: We have studied the seasonal evolution of salinity in a region of Algeria (Case of Rélizane), during two years 2012 and 2013 by applying fuzzy logic on the four soils. Result: The results reveal that the salinity increased during the dry period for all soils and it decreased during the wet period. On the taxonomic level, the application of fuzzy logic on the four soils revealed that the Solonchaks indices (Is) are always significantly higher than those of Calcisols indices (Ic). The four profiles have a similar behavior regarding the variation of Is. Indeed, when the salinity increases the soils come closer to the central taxonomic concept of the Solonchaks. Likewise, when the salinity decreases the soils move away from their central taxonomic concept. Consequently, they approach the central taxonomic concept of Calcisols. Thus, the variation of Isis closely related to the seasonal variation of salinity. Fuzzy logic, exhibited high precision concerning the membership value between soils over time. The application of fuzzy logic for other soil classifications in the world is possible.

GIS IN SOIL SURVEY AND SOIL MAPPING

The main goal of this paper is to present a methodology for land evaluation by supporting decision-makers with reliable information for the land-use planning process. One of the focuses of this paper is given to the survey process and interpretation between soil survey, soil survey interpretation, and physical land evaluation. Such processes are realized using mobile mapping tools with integrated Global Position Systems (GPS) and Geographic Information Systems (GIS). Both have increased the efficiency of data communication technologies by enabling real-time communication between people located in the field and office as well. For the soil classification as a key component of soil surveys is used World Reference Base (WRB) for Soil Resources. This is a common tool to summarize the wealth of information from soil profiles for the purpose of land evaluation. The final results showed a soil classification map. Such results are derived from many activities, since it includes a preliminary land evaluation, field soil survey with auger holes and profiles as well. This methodology is used for the first time in the selected study area.

COMPARATIVE ASSESSMENT OF TROPICAL RAINFOREST SOILS FORMED FROM DIFFERENT GEOLOGIC FORMATIONS IN SOUTHEASTERN NIGERIA

Data on the nature, properties and potentials of soils is grossly inadequate in the rainforest belt of southeastern Nigeria. As such, policymakers and other land users have tended to subscribe to unduly generalized ideas about the soils of the region. This has led to improper land use planning and aggravated land degradation. This necessitated the need for the comparative evaluation of the nature and potentials of the soils of the region to determine their degree of variability. Profile pits were dug in four towns underlain by different geologic formations: Umungwa (Benin Formation), Umuawa Ogii (Nsukka Formation), Ikpem (Igbaku Sandstones) and Amuro (Imo Clay Shales). The soils were characterized and classified using the World Reference Base for Soil Resources (WRB), United States Department of Agriculture (USDA) Soil Taxonomy and land capability classification. The variability of soils across the different sites was subsequently analysed using the coefficient of variation (CV). The results show that the variability of sand across the study sites was moderate (20 – 21 %), silt was high (63 %), clay ranged from moderate (34 %) to high (52 %), while hydraulic conductivity was very high (128 – 144 %). Similarly, with regards to the chemical properties, soil pH and base saturation ranged from moderate (20 – 49 %) to high (52 %), while effective cation exchange capacity (ECEC) and aluminium saturation were high (70 – 77 %). It was concluded that the soils of southeastern Nigeria are very heterogeneous. Undue generalization should consequently be discouraged.

Estudio Etnoedafológico de tipos de uso de la tierra asociados con cadenas productivas en el ejido Santa Cruz, Durango

La Etnoedafología tiene como objeto de estudio que los productores conozcan la naturaleza y capacidad productiva de sus tierras con el enfoque de potenciar su productividad sustentable de cosechas con relación al mercado. El objetivo de la presente investigación es determinar los tipos de uso de la tierra relacionados con las cadenas productivas agropecuarias. La presente investigación se llevó a cabo en el ejido Santa Cruz de Guadalupe, Nombre de Dios, Durango. Los productores fueron entrevistados sobre sus tierras, manejo, rendimientos y conocimiento de cadenas productivas. En cada clase de tierra se excavó un perf il modal representativo y se determinaron en campo y laboratorio sus propiedades edáf icas para su caracterización y clasif icación científ ica con la WRB (World Reference Base versión actualizada, 2015). Los productores reconocen 14 clases de tierras, las cuales se integran en cinco grupos de referencia (Kastañozems, Phaeozems, Calcisols, Solonetz y Regosols). El ejido tiene 48 tipos de uso de la tierra que se describen por las variables de: uso mayor (ganadería, agricultura de riego y de temporal); tipo de productor (propietario o arrendatario); tipos de labranza (convencional, vertical con subsoleo o la combinación de ambas); sistema de cultivos (mono y policultivos y rotaciones), y el producto obtenido. En el ejido se manejan 11 cultivos, de los cuales sólo el maíz-silo y cebada corresponden 100% a las cadenas productivas, dejando a un lado otros productos como frijol, alfalfa. El estudio etnoedafológico permite la integración de conocimientos desde el inicio de la producción a través en los diferentes tipos de uso de la tierra hasta el mercado f inal, y logra identif icar con detalle las articulaciones de las cadenas productivas de la zona de estudio.

Geospatial assessment of wetland soils for rice production in Ajibode using geospatial techniques

Wetlands played an important role in human development and nature nutrient store for rice cultivation. Spatial techniques have gained importance in monitoring wetland changes. The study aimed to assess wetland soils for rice production using spatial techniques. The area was sample using stratified grid sampling. Nutrient availability and rice suitability were assessed in ArcGIS 10.6 environment. The soil was characterized into Eutric fluvaquent (Soil Survey Staff, 2010) and correlated as fluvisols in the World Reference Base system. The results of the land cover changes showed that built-up, waterbody, and farmland have increased by 39, 18, and 29%, respectively, and 13% decrease was observed in vegetation. The study concluded that soils of the studied area varied from marginally (75%), not suitable (20%), and permanently not suitable (5%) for rice production. Therefore, without proper assessment and management of these studied soils, rice production will continue to be futile.

Classification and geovisualization process of soil data using a web-based spatial information system

Because of the increased demand for information, the scientific community have published their results on the Internet over the last 20 years, adapting to society requirements. Due to the development of web-based spatial information soil systems, access to data on various themes and of varying quality has become substantially easier. The focus of our paper is to demonstrate a freely accessible and usable web-based soil database and soil information system (Soil Information and Soil Classifier System), which is suitable for geovisualization uploaded soil data and for determining reference soil groups (RSGs) in accordance with the World Reference Base of Soil Resources (WRB; RSG). In order to achieve this, we algorithmized the diagnostic soil classification process of the WRB, then we created decision trees to correspond input soil data to the WRB system. In order to facilitate geovisualization of the spatial data, the Keyhole Markup Language file format supported by Google API was applied.