This book is a state-of-the-art compilation of the latest information on watershed rehabilitation of agroforestry. The last two decades have seen a surge in literature on sustainable agriculture practices, including those in agroforestry. The integration of trees on agricultural farms improves water, soil, and land productivity; economics, carbon sequestration, and ultimately, the environment. The field of agroforestry is being promoted for its erosion and runoff control, improved nutrients and water cycle, carbon sequestration, and streambank stability. Benefits arising from this nature-based management practice can have a tremendous impact beyond the borders of the region and can even reverse pre-existing environmental damage.    

Although these claims have been widely accepted, and agroforestry adoption and research have expanded all over the world, a systematic compilation of information on watershed rehabilitation is missing in the literature. This book is an attempt to fill that void by synthesizing all the current literature on watershed rehabilitation. The book consists of 15 chapters that cover various topics including watershed processes, types of water, measurement procedures, special topics on watershed improvements, and directions for planning watershed rehabilitation. In addition to presenting the multiple dimensions of watershed rehabilitation by major agroforestry practices, the book also details case studies from both tropical and temperate regions of the world.

Section one of this book consists of the introductory chapter (1) on current global issues on water, reasons for watershed rehabilitation, and a short introduction on each chapter. Two chapters (2 & 3) in section two explain basic principles of watershed processes on precipitation, evaporation, vegetation, and soil functions. Three chapters (4, 5, & 6) in section three describe main functions related to surface runoff, soil water dynamics, and groundwater. Section four contains three chapters (7, 8, & 9) that describe measurement procedures related to surface runoff, soil water, and ground water. The fifth section (chapters 10-13) contains special topics that can influence sustainability of watersheds. The chapter titles in section five are hydraulic redistribution, soil health, carbon sequestration, and streambank stability. These chapters describe agroforestry approaches that can be used to minimize soil degradation, improve water relations, stabilize streambanks, and avoid sand deposition on crop lands. The two chapters of the last section of the book are on rehabilitation planning, implementation, monitoring, evaluation, and designing rehabilitation.

Information from this book can be used to design land management practices for climate change mitigation, ecosystem benefits, agricultural productivity and sustainability, and for the survival and profitability of family farms. While synthesizing information on watershed processes, the book also outlines numerous agroforestry services to enhance adoption of agroforestry so that society at large can enjoy their important benefits. The book can be used for senior undergraduate and graduate students as a textbook as well for personal use by farm owners.

Ranjith Udawatta is a emeritus professor at the University of Missouri in Columbia, Missouri, USA. Ranjith received his BS in Agriculture from University of Peradeniya, Sri Lanka. His MS and PhD both in Soil Science were completed at University of Florida and University of Missouri, respectively. His current research studies explore the use of conservation practices including agroforestry, cover crops, riparian buffers,  upland buffers and prairies to address issues related to water, soil, land productivity, carbon sequestration, and competition for resources among plants at micrometer to watershed scales.