Dinitrogen fixation - Biology, Agronomy and Ecology

Agro-Ecosystems, 5 ( 1 9 7 9 ) 1 8 1 - - 1 8 6

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© Elsevier Scientific P u b l i s h i n g C o m p a n y , A m s t e r d a m - - P r i n t e d in T h e N e t h e r l a n d s

Book Reviews C H E M I C A L S IN A G R I C U L T U R E

Jealott's Hill. Fifty Years o f Agricultural Research, 1928--1978. F.C. Peacock (Editor). Imperial Chemical Industries Ltd., Bracknell, 1978, viii + 160 pp., £ 4.50, ISBN 0--901747--01--7. As biological production in general, agriculture depends upon transformations of many inorganic and organic compounds drawn from nature. Obviously not all of these compounds are provided by nature in the right amount and at the best moment. Many correctives are welcome. Thus chemicals, enabling a spectacular 'intensification' of many branches of animal and plant production to take place, characterize present,lay agricultural techniques. But they also attract criticism from many corners. In fact, they may have led to the existence of this journal. An exposure of the agricultural activities of I.C.I., one of the leading firms in this respect, has been given in this book. It has been compiled on the occasion of the 50th anniversary of its Agricultural Research Station at Jealott's Hill. It contains accounts of innovations in the fields of fertilizers, soil improvers, feed additives, pesticides (also for public health campaigns) and microbial protein as an alternative feeding stuff. The material has not been presented purely as a success story, but a number of research and development lines have been treated that were abandoned. A chapter on environmental studies emphasizes the concern about the more remote but nevertheless far reaching effects that are imaginable if chemicals are used only on the basis of their immediate economical usefulness. Although the text is on a scientific level, it does not supply the many technical data needed to absorb the intricate details of the trains of thought followed in the book. Some literature cited at the end of each chapter and some excellent illustrations provide a certain amount of help. G.J. V E R V E L D E

(Wageningen, The Netherlands) DINITROGEN FIXATION -- BIOLOGY, AGRONOMY AND ECOLOGY

A Treatise on Dinitrogen Fixation. Section III: Biology. R.W.F. Hardy and W.S. Silver (Editors). John Wiley and Sons, New York, N.Y., London, Sydney, N.S.W., Toronto, Ont., 1977, xii + 675 pp., 67 figures and plates, 44 tables, US$ 43.00, £ 25.00, ISBN 0--471--35138--5 (Section 3). A Treatise on Dinitrogen Fixation. Section IV: Agronomy and Ecology. R.W.F. Hardy and A.H. Gibson (Editors). John Wiley and Sons, New

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York, N.Y., London, Sydney, N.S.W., Toronto, Ont., 1977, xii + 527 pp., 20 figures, 27 tables, US$ 39.40, £ 23.00, ISBN 0--471--02343--4 (Section 4). SECTION III This book is the third section of a four-section treatise on N2 fixation. Section I deals with inorganic and physical chemistry, Section II with biochemistry and Section IV with agronomy and ecology (see below). Section III consists of 13 chapters. The first, by C.A. Parker, has the stated aim of placing biological N2 fixation in perspective as a natural phenomenon and as an essential part of the ecosystem. In addition to a brief summary of the N economy of the biosphere and of N2 fixation, it includes some of the author's own imaginative questions about the biology of N2 fixers. The general overview of Chapter 1 is followed by five chapters on particular N2-fixing organisms and associations: the bacteria are dealt with by T.A. La Rue, blue--green algae by W.D.P. Stewart, lower plant associations by J.W. Millbank, foliar associations by W.S. Silver, and root and stem associations in higher plants other than legumes by J.H. Becking. Each is a scholarly and detailed summary of published information. An obvious effort has been made to include the latest references. For instance, Chapter 2 includes nine references added in proof, one of them being to J.M. Day and J. Dobereiner's recent work with Spirillurn from grass roots. Six chapters are devoted to the important Rhizobium--legume symbiosis. The sub-division into general microbiology of Rhizobiurn (J.M. Vincent), infection and development of nodules (P. Dart), biology of N2 fixation -perhaps more accurately described as the whole-plant physiology of N2 fixation (J.S. Pate), physiological chemistry of N2 fixation (F.J. Bergersen), and the genetics of nodulation and N2 fixation (two chapters, one on the host plant by B.E. CaldweU and H.G. Vest, the other on Rhizobium by E.A. Schwinghamer) is very successful, with little omission or redundancy. Section III concludes with a chapter by S. Streicher and R.C. Valentine on the genetic basis of N~ fixation in Klebsiella pneumoniae, an area of basic research in which exciting advances have occurred recently. The text is relatively free of misprints, though gremlins seem to have interfered with the captions to plates 8.2 and 8.3. It is a pity also that the dark lettering is so difficult to read against the background of the excellent black and white photographs in P. Dart's chapter. The index appears adequate from a few spot checks, and the reader is assisted by an effective list of headings on each chapter. Co-ordination between chapters is generally satisfactory though it is confusing to find different terms used to classify nodulation and N2 fixation in the pair of chapters dealing with the genetics of those processes. A general assessment of Section III is given below.

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SECTION IV

As with Section III, Section IV consists of 13 chapters and commences with a general introductory review. N.S. Subba Rao discusses briefly the global N cycle and the incidence of N deficiency before dealing at more length with protein in human nutrition. It seems that Subba Rao inclines to the humane view that peoples' protein requirement is what they would prefer to eat rather than the bare minimum needed to keep them alive. Then follow five chapters dealing respectively with N2 fixation by asymbiotic bacteria (R. Knowles), by blue--green algae (T.H. Mague), by higher plant associations other than legumes (W.B. Silvester) and with the contributions of tropical legumes (J. Dobereiner and A.B. Campelo) and of temperate legumes (E.G. Mulder, T.A. Lie and A. Houwers). Seven relatively diverse chapters make up the remainder of the book. The chapters by R.A. Date and R.J. Roughley on preparation of legume inoculants, by J. Brockwell on application of inoculants, by R.W.F. Hardy and R.D. Holsten on the measurement of N2 fixation, and by W.F. Dudman on the application of serological techniques to N2 -fixing organisms are focussed primarily on methods, though they include an impressive amount of background information that explains the reasons for many of the recommended practices. A chapter by C.A. Parker, M.J. Trinick and D.L. Chatel reviews the microbiology and ecology of Rhizobium in the soil and rhizosphere, while D.N. Munns discusses the mineral nutrition of nodulated legumes used in agriculture and the diagnosis and correction of their nutritional disorders in the field. Copious agricultural experience is summarized succinctly here and in the complementary chapter by A.H. Gibson, which covers two main topics -- the effect of environmental factors on nodulated legumes and the management of crop and pasture legumes in agriculture. The standard of editing, indexing and production is as high in Section IV as in Section III. There are occasional blemishes. For instance, Fig. 9.1 is poorly explained in the caption and most of the chapter has to be read to understand its significance. The co-ordination between chapters is again effective. G E N E R A L COMMENTS ON SECTIONS III AND IV

The publication of these two books clearly is an outstanding achievement and amply justifies the claim on the jacket that they provide a key to an important and vastly scattered literature. The standard of organization and editing is high. The division between biology (Section III) and agronomy and ecology (Section IV) could have caused difficulties, but appears to have done so in only one case. Material on the distribution of non-legume, N2 -fixing higher plant associations in Chapter 6 of Section III is largely repeated in, and more properly belongs

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to, Chapter 4 of Section IV. There is little in either section that could be omitted as irrelevant except perhaps the discussion of the fate of fertilizer nitrogen added to grassland (Chapter 6, Section IV). It is pedantic to point out that many chapters are more accurately described as being on the biology, or the agronomy and ecology, of N2 -fixing organisms and associations rather than on N2 fixation per se. The reviewer suspects that Sections I and II are directed more specifically to N2 fixation. On the other hand, the diversity of Sections III and IV is likely to be thought an advantage by many readers, especially agricultural scientists. It also ought to be recorded that the treatment in some chapters, e.g. that by T.A. Mague in Section IV, is oriented very skilfully to the theme of N2 fixation. The value of overview chapters at the beginning of books such as these has to be questioned. Unless forewarned, their authors are in danger of being upstaged by more authoritative material appearing later in the same book. There is also the problem of making any meaningful brief statements about major pathways of the N cycle. For instance, a range of values for denitrification losses given without extensive qualification is virtually meaningless. Attempts at quantifying the N economy of ecosystems have appeared in two publications since these books went to press: Nitrogen, phosphorus and sulphur -- global cycles. SCOPE Report No. 7, 1976. Cycling of mineral nutrients in agricultural ecosystems. Agro-Ecosystems, Vol. 4, No. 1/2, 1977. Readers of 'Agro-Ecosystems' may be disappointed at the somewhat sketchy treatment of field measurements of N2 fixation in Section IV. This comment applies more particularly to fixation by legumes of agricultural importance, for W.B. Silvester in Chapter 4 makes effective use of ecological information about N in non-legume plant associations. R.W.F. Hardy and R.D. Holsten recommend the C2 H2 --C2 H4 assay but at the end of their chapter virtually discredit its use for in situ measurements in natural habitats. These are minor comments and do not detract from the overall high standard of scholarship in these two outstanding books. They are essential references for everyone working on N; fixation in agricultural or natural ecosystems. E.F. HENZELL

(Brisbane, Qld., Australia) REFERENCE

Day, J.M. and Dobereiner, J., 1976. Physiological aspects of N2-f'Lxation by a Spirillum from Digitaria roots. Soil Biol. Biochem., 8: 45--50.