Larry W. Harrington

Cross-basin comparisons of water use, water scarcity and their impact on livelihoods: present and future.

We compare water availability, water use, water productivity and poverty across the diverse river basins studied by the CGIAR Challenge Program on Water and Food. Water productivity tends to be higher in drier areas and where livestock grazing is integrated with rainfed crop production. We find that links among water, food security and poverty are best understood within a historical perspective. We identify opportunities to reduce poverty through water-related interventions. The way in which water-related investments affect poverty is influenced by changes in demography, climate, and rural society. In most basins, these trends involve trade-offs that require good governance at local, regional and basin scales.

Water, food and development: the CGIAR Challenge Program on Water and Food

Providing the water needed to produce food for more than 9 billion people by 2050 seems simple: agriculture must produce more food with less water. However, three complex issues are involved: First, water, food production and rural development do not have a simple correlation. Second, there are interactions between processes at local, basin and global scales. Third, change involves people in complex networks of institutions. The Challenge Program on Water and Food brings together agriculturalists, hydrologists and development specialists in a global-to-local programme that focuses on change through institutions. We believe that this scale, complexity and involvement are necessary to deliver plausible change.

Achieving the Sustainable Development Goals: improving water services in cities affected by extreme weather events

Abstract This article discusses how key risks from extreme weather events might affect progress towards meeting Sustainable Development Goals 6 and 11 in cities in developing countries. It outlines the magnitude of the existing shortfall in safe water and sanitation services, and how climate change will exacerbate existing problems. It argues that the performance of many governments thus far has lacked urgency and purpose. Unless governments in particular become more committed, with redoubled effort, the goals are unlikely to be achieved.

Types of Rainfed Farming Systems Around the World

This world encompasses an enormous diversity of environments, and farming systems have evolved to fit into many of them. Rainfed farming systems are found in areas as diverse as the Sahelian zone of west and central Africa; eastern and southern Africa; west and central Asia; Afghanistan and Pakistan; central India; western China; semi-arid Australia; northern Mexico; and the prairies and central plains of USA and Canada. This chapter discusses ways of classifying rainfed farming systems for comparative, predictive and management purposes, and to assist in change from one type of system to another. Here, four categories of rainfed farming systems are distinguished: high-latitude rainfed systems with cold winters; mid-latitude rainfed systems with mild winters; subtropical and tropical rainfed highland farm systems; and semi-arid tropical and subtropical farming systems. Within these categories, systems are subdivided into two archetypes, based on low or high levels of productivity and farming intensity. Factors that influence the intensity and productivity of rainfed farming systems include the ratio of precipitation to potential evapotranspiration, water availability, drought risk, temperature regimes, soil quality, external input use, marketing margins, market access, tenure security, policy environment, and the purpose of crop–livestock integration. There are many interrelationships among these factors. For example, drought risk and water availability are affected by water harvesting practices, risk management practices, soil characteristics, and rainfall patterns and other climate variables. Soil characteristics are influenced by organic and inorganic fertiliser management and enterprise selection (including crop selection and crop–livestock integration). These are affected by input and product prices which in their turn are influenced by marketing margins and market access. Finally, all systems are affected by the quality of market infrastructure, and policies and institutional arrangements.

Principles of a systems approach to agriculture: some definitions and concepts

A systems approach is needed to understand and manage a ‘farm’. This chapter examines the definition and concepts of farm systems, their structure, operation and management, the relationships among internal and external factors, response to changing circumstances, and modifications to deal with change. Study of a system requires definition of goals and objectives, boundaries and the structure and function of its components. Feedback mechanisms and interactions are important features of farm system structure and operation. Farm systems can often be better understood through analysis and the study of their sub-systems; and circle or problem-cause diagrams can assist this. Farmers design their systems to make best use of the prevailing climate and soil but a wide range of technological, commercial, social, political and personal factors determine farmers’ goals and management. Important characteristics of systems include: productivity, profitability, efficiency, stability, sustainability, equity, flexibility, adaptability and resilience. Efficiency of resource use should be optimised, bearing in mind Liebscher’s Law of the Optimum. Efficient use of energy and water are necessary for profitable production.