Study On Runoff Agriculture Of Rainfed Areas In The Loess Plateau Of China

Dryland agriculture takes a much important place in the agricultural production in China and all over the world. As the population increase and the social and economic development, demands of limited water resources become more and more, which is detrimental to the sustainable development, and high attention has been paid to the development of rainfed agriculture.The Loess Plateau, situated at the second stairs of geomorphic features in China, has a long history of agriculture development and is the cradle of Chinese agriculture. The features of hill and gully and highland, together with over land-use and wars and disaster, make water and soil lost, vegetation damaged, land fragmented, environment deteriorated, and crop productivity lowed, which bringing the areas into barren and poverty-stricken region being financially supported by the state with emphasis. In view of the trends that water circulation becomes seriously hindered as well as the drought and water shortage, more and more importance has been attached to development of rainwater resources, and runoff water management technologies has been taken as a leading measure to resolve these problems.Considering the current situation of water and soil in the Loess Plateau and the limitations of Water-Soil Conserving Agriculture to improve water use efficiency and resolve the moisture deficits in crop production, based on the implementation of the State Dryland Agriculture Project, this research has been conducted to find a new approach of agriculture and rural economy development in rainfed areas, by rainwater-harvesting and its high efficient use in agricultural production.The paper is divided into 8 chapters. Chapter one is introduction, which presents the thoughts of the research and defines the concepts of Runoff Agriculture based on the discussions of trend of increasingly severe water resources shortage and drought damages, and the summaries of advances of runoff water collecting and its use in China and abroad. Chapter two, founded on physical features and land slope and rainfall use, analyses the foundation of collecting and storing and usingrunoff water, and proposes the suitable development regions of runoff water harvesting. Chapter three defines and gives the potential concepts and formulas of rainfall resources availability, and computers and evaluates potentials of available runoff water to be harvested in the Middle and East part of Gansu. Chapter four outlines engineering construction of rainwater harvesting systems. Chapter five brings forward the preference plan of effective and efficient use of runoff water stored in cellars through detail studying effects of limited irrigation on WUE in different crops. Chapter six puts forward the concepts of in-field water resources richening and concentrating in place, and studies systematically the mechanism of improving water production potential of farmland and the technologic effects of in-field water harvesting and conservation on WUE and crops yield. Chapter seven discusses the importance of runoff water management technologies to increase water use efficiency and fanners' income, to better ecological environment, and to force sustainable development of the Loess Plateau. Chapter eight summarizes main conclusions of the research, and makes discussions on related questions.The main conclusions made in the research are as follows:(1) Based on the analysis and summary of runoff harvesting and its use in China and abroad, definitions of Runoff Agriculture are given in the paper. Runoff Agriculture ofRainfed Areas (KARA), centering on rainfall resource availability, is an integrated water management technological systems, which consists of surface runoff water and soil infiltration control, to address the water satisfaction of water supply relative to crop water requirement and to increase the land productivity, by transferring runoff water occurring in catchment surfaces, such as roads and concrete yard grounds and slope land etc, to farmland and in-field water richening and concentrati...