5. Green manure in rice farming.

Publ. of the International Rice Research Institute, Los Banos, Philippines, 1988, 378 pp., USD 12.30

This book embodies the proceedings of a symposium on sustainable agriculture held in 1987, at the International Rice Research Institute (IRRI), Los Banos, Philippines.

Some 92 scientists from over the world participated in the conference.

Topics include the use of green manures in China, southern Asia, parts of Africa, USA and other areas, as well as topics on woody species, N transformation, soil redox dynamics, and others dealing with general principles.

This book contains a wealth of valuable information on perennial and annual legumes as a N source and for soil improvement in upland and lowland rice production. Basic concepts and practical applications are covered well.

Discussion of N transformation, crop uptake, losses and residual is handled in an thorough manner.

Several of the writers pointed out, the value of green manuring is greater than N supply per se, e.g., several physical and chemical properties are also modified beneficially.

Contributions of N by food-crop grain and food-crop legumes were presented as an important consideration, since the economics of appropriating land and time for N production is often not cost effective due to the cost constraints of labour, land opportunity and seeds. These constraints forced a steep decline in the use of green manures in rice production everywhere as N fertilizer became available and affordable.

The first chapter of the book, nine pages, consists of the recommendations that emerged from the symposium discussions, including research needs and proposed research areas.

Advantages und disadvantages of green manure use are listed.

The papers and discussions during the symposium reconfirmed that - broadly defined - green manure does increase rice yields. Moreover, empirical evidence and theoretical considerations strongly suggest that green manure can contribute to the sustainability of tropical agricultural systems in which rice is a major crop.

The information is presented in 25, generally well-written, edited and documented chapters.

The book is a valuable resource and the information is presented interestingly.

It is an excellent reference to those involved in rice production and possibly a textbook in courses in soil management and sustainable agriculture, especially looking to the future.

1242 92 - 12/68

Soil fertility

Africa, Nigeria, humid tropics, field trials, maize, cassava, low-input agriculture, green manure, IRRI

VAN DER HEIDE, J.