To feed a world population that will exceed 9 billion by 2050 requires an estimated 60% increase over current primary agricultural productivity. Closing the common and often large gap between actual and attainable crop yield is critical to achieve this goal. To close yield gaps in both small and large scale cropping systems worldwide we need (1) definitions and techniques to measure and model yield at different levels (actual, attainable, potential) and different scales in space (field, farm, region, global) and time (short and long term); (2) identification of the causes of gaps between yield levels; (3) management options to reduce the gaps where feasible and (4) policies to favour adoption of sustainable gap-closing solutions. The aim of this publication is to critically review the methods for yield gap analysis, hence addressing primarily the first of these four requirements, reporting a wide-ranging and well-referenced analysis of literature on current methods to assess productivity of crops and cropping systems.

Continued population growth, rapidly changing consumption patterns and the impacts of climate change and environmental degradation are driving limited resources of food, energy, water and materials towards critical thresholds worldwide. These pressures are likely to be substantial across Africa, where countries will have to find innovative ways to boost crop and livestock production to avoid becoming more reliant on imports and food aid. Sustainable agricultural intensification - producing more output from the same area of land while reducing the negative environmental impacts - represents a solution for millions of African farmers. This volume presents the lessons learned from 40 sustainable agricultural intensification programmes in 20 countries across Africa, commissioned as part of the UK Government's Foresight project. Through detailed case studies, the authors of each chapter examine how to develop productive and sustainable agricultural systems and how to scale up these systems to reach many more millions of people in the future. Themes covered include crop improvements, agroforestry and soil conservation, conservation agriculture, integrated pest management, horticulture, livestock and fodder crops, aquaculture, and novel policies and partnerships.

In this major 1993 work, Lloyd Evans provides an integrated view of the domestication, adaptation and improvement of crop plants, bringing together genetic diversity, plant breeding, physiology and aspects of agronomy. Considerations of yield and maximum yield provide continuity throughout the book. Food, feed, fibre, fuel and pharmaceutical crops are all discussed. Cereals, grain legumes and root crops, both temperate and tropical, provide many of the examples, but pasture plants, oilseeds, leafy crops, fruit trees and others are also considered. After the introductory chapter, the increasing significance of crop yields to the world's food supply is highlighted. The next three chapters consider changes to crop plants over the last ten thousand years, including domestication, adaptation and improvement. Aimed at research workers and advanced students in crop physiology and ecology, agronomy and plant breeding, this book also reaches conclusions of relevance to those concerned with developmental policy, agricultural research and management, environmental quality, resource depletion and human history.

A thirsty world; Alternative futures for water; Consequences of key policy changes; Implications for the future.

As the global population grows and incomes in poor countries rise, so too, will the demand for food, placing additional pressure on sustainable food production. Climate change adds a further challenge, as changes in temperature and precipitation threaten agricultural productivity and the capacity to feed the world's population. This study assesses how serious the danger to food security might be and suggests some steps policymakers can take to remedy the situation.Using various modeling techniques, the authors project 15 different future scenarios for food security through 2050. Each scenario involves an alternative combination of potential population and income growth and climate change. The authors also examine the specific test case of a hypothetical extended drought in South Asia, to demonstrate the possible effects of increased climate variability on a particular world region. They conclude that the negative effects of climate change on food security can be counteracted by broad-based economic growthparticularly improved agricultural productivityand robust international trade in agricultural products to offset regional shortages. In pursuit of these goals, policymakers should increase public investment in land, water, and nutrient use and maintain relatively free international trade. This inquiry into the future of food security should be of use to policymakers and others concerned with the impact of climate change on international development.

Long-awaited second edition of classic textbook, brought completely up to date, for courses on tropical soils, and reference for scientists and professionals.