Impact of irrigation strategies on maize (Zea mays L.) production in the savannah region of northern Togo (West Africa)

In northern Togo where rainfed maize is one of the major crops grown, agriculture is subject to frequent yield losses due to erratic rainfall. To ensure food availability and improve agricultural productivity, it is necessary to produce maize during the dry season under irrigation. A sound application of full and deficit irrigation requires a thorough understanding of the crop parameters and yield response to water. Thus, this study investigated the effect of full and deficit irrigation on maize plant above-ground biomass, leaf area index, canopy cover, plant height, and grain yield. A field experiment was carried out from December 2017 to April 2018 in northern Togo at the agronomic research institute. Full irrigation (FI), 80% FI, and 60% FI treatments were applied. The results showed that in the late-season stage, the differences in biomass between FI and 60% FI were significant (p < 0.05). On average, FI had the greatest grain yield (2 200.4 kg/ha), while the lowest grain yield was recorded under 60% FI (1 068.3 kg/ha). The grain yield differences between FI and 60% FI were significant. Nevertheless, the grain yield differences between FI and 80% FI were not significant (p > 0.05). 80% FI had water use efficiency (WUE) (0.22 kg/m3) similar to that of FI (0.21 kg/m3), on average. The results of this study illustrate that deficit irrigation must be carefully managed since slight differences in the application volumes affect the biomass and yield of maize significantly. Under a moderate level of deficit irrigation (vegetative and reproductive growth stages) the biomass and the grain yield of maize are reduced. However, a moderate level of deficit irrigation during the vegetative growth stage could result in similar values of WUE to that of FI.Keywords: evapotranspiration, deficit irrigation, water use efficiency, crop yield, maiz

ELEMENTOS LIMITANTES DA OFERTA DE HABITAÇÃO DE INTERESSE SOCIAL NA CIDADE DO SALVADORBA

Nas metrópoles como Salvador, de elevada densidade populacional,produzir habitações de interesse social é crucial para melhorar as condiçõesde vida da população e para atender as demandas sociais. Estetrabalho visa identificar algumas dificuldades que levam à baixa ofertadesses imóveis, realizando entrevistas junto aos representantes dos órgãosgovernamentais, entidades de classe e empresários ligados à produçãoimobiliária. A crise de renda e emprego da população, a escasseze alto custo de terrenos edificáveis, falta de gestão empresarial, de coerênciae de redirecionamento das políticas públicas, de regulamentaçãofundiária e legalização, apresentaram-se como elementos desestruturantespara implantação desses empreendimentos

Unconventional Water Resources: Global Opportunities and Challenges

Water is of central importance for reaching the Sustainable Development Goals (SDGs) of the United Nations. With predictions of dire global water scarcity, attention is turning to resources that are considered to be unconventional, and hence called Unconventional Water Resources (UWRs). These are considered as supplementary water resources that need specialized processes to be used as water supply. The literature encompasses a vast number of studies on various UWRs and their usefulness in certain environmental and/or socio-economic contexts. However, a recent, all-encompassing article that brings the collective knowledge on UWRs together is missing. Considering the increasing importance of UWRs in the global push for water security, the current study intends to offer a nuanced understanding of the existing research on UWRs by summarizing the key concepts in the literature. The number of articles published on UWRs have increased significantly over time, particularly in the past ten years. And while most publications were authored from researchers based in the USA or China, other countries such as India, Iran, Australia, and Spain have also featured prominently. Here, twelve general types of UWRs were used to assess their global distribution, showing that climatic conditions are the main driver for the application of certain UWRs. For example, the use of iceberg water obviously necessitates access to icebergs, which are taken largely from arctic regions. Overall, the literature review demonstrated that, even though UWRs provide promising possibilities for overcoming water scarcity, current knowledge is patchy and points towards UWRs being, for the most part, limited in scope and applicability due to geographic, climatic, economic, and political constraints. Future studies focusing on improved documentation and demonstration of the quantitative and socio-economic potential of various UWRs could help in strengthening the case for some, if not all, UWRs as avenues for the sustainable provision of water

Evaluación de la carga física de trabajo del albañil durante la ejecución de mampostería con bloques

El creciente interés por la búsqueda de la calidad y productividad en la construcción civil está estimulando a conducir estudios que conlleven a mejorías en los puestos de trabajos, más seguridad y disminución de las enfermedades, aumentando de esta forma la satisfacción de los empleados. Así, la aplicación de conocimientos del área de ergonomía a este sector cada vez más adquiere una mayor importancia, debido a que muchos obreros ejecutan actividades con alto grado de peligrosidad y dificultad. Este artículo presenta un método para evaluar la carga física de trabajo del albañil en la ejecución de paredes de mampostería de bloques cerámicos, basado en los registros continuos de la frecuencia cardíaca de los obreros en su puesto de trabajo, utilizándose el monitor Polar Sport Tester y un software específico para el cálculo del costo fisiológico. Se pretende demostrar la aplicabilidad de este método en el análisis de esta tarea. El objetivo principal de este estudio es determinar el costo fisiológico de la tarea e investigar si éste varía de acuerdo con el tipo de bloque empleado, así como también identificar las posturas y planos de trabajo más desfavorables. Los resultados indican que el mayor gasto energético ocurre en la ejecución de las filas al nivel del piso, en la cual es necesaria la posición más desfavorable. El costo energético presentó diferencia significativa de acuerdo con el tipo de bloque.The increasing demand for improving quality and productivity in the construction industry has encouraged the development of research studies related to the improvement of working conditions, site safety and hygiene, and satisfaction of the work force. For that reason, the application of ergonomics in this sector should become more important due to the heavy and hazardous physical demand of workers that typically exists in construction sites This paper presents a method to measure the workload of bricklayers during the construction of brickwalls, based on their heart rate, monitored by an electronic equipment named Polar Sport Tester, and an estimate for the work physiological cost. The applicability of this method for the bricklaying task was evaluated in a case study. The main objective of the case study was to determine the physiological cost of the task and to examine how it was affected by the weight of ceramic blocks. Posture alignments and unfavorable positions during the tasks were also analyzed. The results indicated that the physiological cost was higher for the bricklayers while working in the first layer. The type of block used also had a significant effect on the energy cost

Capacity challenges in water quality monitoring: understanding the role of human development

Monitoring the qualitative status of freshwaters is an important goal of the international community, as stated in the Sustainable Development Goal (SDGs) indicator 6.3.2 on good ambient water quality. Monitoring data are, however, lacking in many countries, allegedly because of capacity challenges of less-developed countries. So far, however, the relationship between human development and capacity challenges for water quality monitoring have not been analysed systematically. This hinders the implementation of fine-tuned capacity development programmes for water quality monitoring. Against this background, this study takes a global perspective in analysing the link between human development and the capacity challenges countries face in their national water quality monitoring programmes. The analysis is based on the latest data on the human development index and an international online survey amongst experts from science and practice. Results provide evidence of a negative relationship between human development and the capacity challenges to meet SDG 6.3.2 monitoring requirements. This negative relationship increases along the course of the monitoring process, from defining the enabling environment, choosing parameters for the collection of field data, to the analytics and analysis of five commonly used parameters (DO, EC, pH, TP and TN). Our assessment can be used to help practitioners improve technical capacity development activities and to identify and target investment in capacity development for monitoring

Making the Water–Soil–Waste Nexus Work: Framing the Boundaries of Resource Flows

The Sustainable Development Goals have placed integrated resources management, such as integrated water resource management, at the heart of their targets. The upcoming “International Decade for Action—Water for Sustainable Development”, 2018–2028 has highlighted the importance of promoting efficient water usage at all levels, taking into account the water, food, energy, and environmental nexus. While integrated resource management approaches have been defined and applied for decades, nexus approaches are more recent. For these latter approaches to be implemented on the ground, their system boundaries need to be clarified. While the Water–Energy–Food Nexus focuses on sectors, the Water–Soil–Waste Nexus addresses linkages between environmental resources—namely water, soil and waste—to tackle sustainable management. In this paper, we analyzed integrated management systems and how their system boundaries are defined. From this we determined that in order for system boundaries to be applicable, they should be clear, wide and flexible. Based on this, we propose the boundary of the Water–Soil–Waste Nexus system. We use two case studies to exemplify the usefulness of these system boundaries

Impact of irrigation strategies on maize (Zea mays L.) production in the savannah region of Northern Togo (West Africa)

In northern Togo where rainfed maize is one of the major crops grown, agriculture is subject to frequent yield losses due to erratic rainfall. To ensure food availability and improve agricultural productivity, it is necessary to produce maize during the dry season under irrigation. A sound application of full and deficit irrigation requires a thorough understanding of the crop parameters and yield response to water. Thus, this study investigated the effect of full and deficit irrigation on maize plant above-ground biomass, leaf area index, canopy cover, plant height, and grain yield. A field experiment was carried out from December 2017 to April 2018 in northern Togo at the agronomic research institute.  Full irrigation (FI), 80% FI, and 60% FI treatments were applied. The results showed that in the late-season stage, the differences in biomass between FI and 60% FI were significant (p < 0.05). On average, FI had the greatest grain yield (2 200.4 kg/ha), while the lowest grain yield was recorded under 60% FI (1,068.3 kg/ha). The grain yield differences between FI and 60% FI were significant. Nevertheless, the grain yield differences between FI and 80% FI were not significant (p > 0.05). 80% FI had water use efficiency (WUE) (0.22 kg/m3) similar to that of FI (0.21 kg/m3), on average. The results of this study illustrate that deficit irrigation must be carefully managed since slight differences in the application volumes affect the biomass and yield of maize significantly. Under a moderate level of deficit irrigation (vegetative and reproductive growth stages) the biomass and the grain yield of maize are reduced. However, a moderate level of deficit irrigation during the vegetative growth stage could result in similar values of WUE to that of FI

Potential of Deficit and Supplemental Irrigation under Climate Variability in Northern Togo, West Africa

In the context of a growing population in West Africa and frequent yield losses due to erratic rainfall, it is necessary to improve stability and productivity of agricultural production systems, e.g., by introducing and assessing the potential of alternative irrigation strategies which may be applicable in this region. For this purpose, five irrigation management strategies, ranging from no irrigation (NI) to controlled deficit irrigation (CDI) and full irrigation (FI), were evaluated concerning their impact on the inter-seasonal variability of the expected yields and improvements of the yield potential. The study was conducted on a maize crop (Zea mays L.) at a representative site in northern Togo with a hot semi-arid climate and pronounced dry and wet rainfall seasons. The OCCASION (Optimal Climate Change Adaption Strategies in Irrigation) framework was adapted and applied. It consists of: (i) a weather generator for simulating long climate time series; (ii) the AquaCrop model, which was used to simulate the irrigation system during the growing season and the yield response of maize to the considered irrigation management strategies; and (iii) a problem-specific algorithm for optimal irrigation scheduling with limited water supply. We found high variability in rainfall during the wet season which leads to considerable variability in the expected yield for rainfed conditions (NI). This variability was significantly reduced when supplemental irrigation management strategies (CDI or FI) requiring a reasonably low water demand of about 150 mm were introduced. For the dry season, it was shown that both irrigation management strategies (CDI and FI) would increase yield potential for the local variety TZEE-W up to 4.84 Mg/ha and decrease the variability of the expected yield at the same time. However, even with CDI management, more than 400 mm of water is required if irrigation would be introduced during the dry season in northern Togo. Substantial rainwater harvesting and irrigation infrastructures would be needed to achieve that

Translating the ‘water scarcity – water reuse’ situation into an information system for decision-making

One key challenge of water resources management is the identification and processing of the information necessary for decision-making. This article aims to provide avenues for translating a ‘water scarcity–water reuse’ (WS–WR) situation into an information system. It is dedicated to supporting an integrated assessment in decision-making with the final goal of optimising water scarcity risk reduction and water reuse sustainability. The approach combines the following two strands: (1) specific interpretation of systems thinking and (2) systemic characterisation and interlinkage of indicators. The result is an analytical concept that translates the WS–WR situation into an information system consisting of two structured components, a multi-layer (ML) and a lane-based (LB) approach. While the multi-layer approach supports the description of the elements of the biophysical and information systems such as endpoints and descriptors, respectively, the lane-based approach aids in understanding the importance of indicators within the entire system and their distribution across risk and sustainability realms. The findings from a generic exemplification of the analytical concept depict the feasibility of identifying system-based endpoints representing the WS–WR situation and their translation via descriptors to an interlinked indicator set to jointly assess water scarcity risk and sustainability of the water reuse measures. Therefore, this analytical concept supports addressing the water resources management information challenge via a structured representation of the system’s complexity and the quantification and visualisation of interlinkages between the social, economic, and environmental dimensions of water scarcity risk and water reuse sustainability

Evaluación de la carga física de trabajo del albañil durante la ejecución de mampostería con bloques

El creciente interés por la búsqueda de la calidad y productividad en la construcción civil está estimulando a conducir estudios que conlleven a mejorías en los puestos de trabajos, más seguridad y disminución de las enfermedades, aumentando de esta forma la satisfacción de los empleados. Así, la aplicación de conocimientos del área de ergonomía a este sector cada vez más adquiere una mayor importancia, debido a que muchos obreros ejecutan actividades con alto grado de peligrosidad y dificultad. Este artículo presenta un método para evaluar la carga física de trabajo del albañil en la ejecución de paredes de mampostería de bloques cerámicos, basado en los registros continuos de la frecuencia cardíaca de los obreros en su puesto de trabajo, utilizándose el monitor Polar Sport Tester y un software específico para el cálculo del costo fisiológico. Se pretende demostrar la aplicabilidad de este método en el análisis de esta tarea. El objetivo principal de este estudio es determinar el costo fisiológico de la tarea e investigar si éste varía de acuerdo con el tipo de bloque empleado, así como también identificar las posturas y planos de trabajo más desfavorables. Los resultados indican que el mayor gasto energético ocurre en la ejecución de las filas al nivel del piso, en la cual es necesaria la posición más desfavorable. El costo energético presentó diferencia significativa de acuerdo con el tipo de bloque.The increasing demand for improving quality and productivity in the construction industry has encouraged the development of research studies related to the improvement of working conditions, site safety and hygiene, and satisfaction of the work force. For that reason, the application of ergonomics in this sector should become more important due to the heavy and hazardous physical demand of workers that typically exists in construction sites This paper presents a method to measure the workload of bricklayers during the construction of brickwalls, based on their heart rate, monitored by an electronic equipment named Polar Sport Tester, and an estimate for the work physiological cost. The applicability of this method for the bricklaying task was evaluated in a case study. The main objective of the case study was to determine the physiological cost of the task and to examine how it was affected by the weight of ceramic blocks. Posture alignments and unfavorable positions during the tasks were also analyzed. The results indicated that the physiological cost was higher for the bricklayers while working in the first layer. The type of block used also had a significant effect on the energy cost