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Irrigated forage production
ELSEVIER
Field CropsResearch37 (1994) 145-148
Field Crops Research
Book reviews Irrigated Forage Production Irrigated Forage Production. Amos Dovrat (Editor). Elsevier, Amsterdam, 1993, 388 pp., Dfl. 295.00, ISBN 0444-88300-2. Irrigated Forage Production is divided into two sections or parts following a brief introduction (Chapter 1). Part One: The Biomass, provides background in Yield Formation (Chapter 2), Water Relations and Irrigation (Chapter 3), and Forage Quality (Chapter 4). The authors (Chapters 2 and 4, A. Dovrat; Chapter 3, Y. Cohen) do not attempt a critical, state-of-the-science review on any of these topics. Rather, in all three of these chapters, they cover some of the basic concepts that have figured prominently in the philosophy of those disciplines, but which also have a bearing on forage production practices. In the chapter on Yield Formation, topics include plant morphology and its influence on defoliation responses, photosynthetic productivity from the leaf to canopy level, and mineral nutrition. Concepts of crop water use and water use efficiency are presented in Chapter 3 by Cohen, including methods for estimating water use, management problems with low-quality water, and irrigation systems. Dovrat finishes this section with a brief chapter summarizing forage quality, focusing on chemical and structural aspects of quality and digestibility. Due to the abbreviated nature of these introductory chapters, some of the presentation suffers slightly from an unbalanced and less-than-comprehensive treatment. However, to address this problem, the authors often cite authoritative references on various topics they are able to cover only briefly. In Part Two: The Production, six chapters cover the details of six irrigated forages: alfalfa, irrigated pasture, forage corn, berseem clover, annual ryegrass and fodElsevierScienceB.V.
der beet. Most of the chapters follow a similar outline: an introduction, followed by sections on development and growth, establishment, crop water requirements and irrigation, mineral nutrition and fertilizer use, harvest management, forage quality and utilization, and a conclusion. The format for the chapter on irrigated pasture is different, focusing on plant components, soil and site factors, land preparation and sowing, management (including irrigation, fertilization, grazing and overseeding), and finally animal components. I found Part Two: The Production to be the most useful section of the book, as it presents a unique and well-documented compilation of information about the different forages in the context of irrigation practices. The chapter on alfalfa is particularly comprehensive (51 pages covering many aspects of alfalfa culture and use), with examples and concepts developed from numerous different environments around the world. The other five 'forage' chapters are each about half that length, but are similarly well-documented. Due to the breadth of topics Dovrat examines in each chapter, he continues to supply the reader with references of other works where more in-depth information may be obtained. On balance, his coverage is good. A final chapter by A. Goldman in Part Two: The Production explores the economic considerations of various forage production options through computer simulation analysis. This treatment seems relevant given the increased access to personal computers. Goldman stresses that the requirement of a large data matrix for simulation models, like the one presented, will necessitate collaboration among researchers, extension specialists and farmers for this approach to work. The topic of irrigated forage production is a complex one, with numerous management options. Dovrat and his colleagues have taken much of the scientific liter-
146
Book reviews/Field Crops Research 37 (1994) 145-148
ature and accumulated wisdom and synthesized it into a document that ought to appeal to a wide audience of readers, including students, producers and scientists. His book successfully straddles the domains of basic and applied research. As such, it is a useful storehouse of concepts, philosophies and applications. The reader is advised that this book does not contain simple recipes for successful forage management. Nor does it sufficiently cover all aspects of any one particular species to qualify as a critical state-of-the-science review. Rather, it provides a solid background, supplemented with references for further study, for understanding and
Statistical Analysis of Regional Yield Trials Statistical Analysis of Regional Yield Trials: AMMI Analysis of Factorial Designs. H.G. Gauch, 1992. Elsevier Science Publishers, 278 pp., US$175.00/ Dfl. 280.00, ISBN 0-444-89240-0. The AMMI in the title stands for Additive Main effects and Multiplicative Interaction effects and the book puts forward this method as a useful tool in the analysis of 'regional-yield' or variety trials. A typical regional-yield or variety trial is defined in the book as a genotype-by-environment two-way factorial usually with replication. The AMMI model is a combination of two simpler models. First, the genotype and environment additive or main effects are calculated using analysis of variance (ANOVA) and the residuals from this model (i.e. the interaction) are analysed using principal components analysis (PCA). Both methods were discovered many years ago, and in fact, Fisher and Mackenzie first applied both ANOVA and PCA separately, in 1923, to a single data set of 12 potato varieties grown with six fertilizers (environments) and three replications. However, it was not until the mid-1980s that the method gained popularity, with a paper by Kempton which shows AMMI's biplot graph as a statistical tool helpful for understanding complex genotype-environment interactions. Gauch produced several papers on the subject and has now produced this book. Chapter 1 provides an introduction to the subject, giving a background to the sort of trials where this analysis would be useful and giving a brief history of the analysis of field trials. Chapter 2 introduces and
comparing several irrigated forage systems. Irrigated Forage Production should be a valuable addition to the libraries of both producers and researchers interested in studying and managing irrigated forages. Jack A. Morgan
USDA-ARS Crops Research Lab 1701 Centre Ave. Fort Collins CO 80526, USA SSD10378-4290 ( 94 ) 0 0 0 2 9 - C
defines several basic statistical concepts used later in the book. Chapter 3 then introduces the AMMI model and several related models, including ANOVA and PCA and compares the relative merits of the various methods. Having dealt with the basic concepts, Chapter 4 is concerned with estimation and documents the accuracy of AMMI estimates. It is stated that "Typically AMMI models are as accurate as treatment means based on two to four times as many replications". Chapter 5 then considers the resultant potential improvement in selection of varieties, through the better accuracy of the AMMI model. Chapter 6 illustrates AMMI's usefulness for understanding or modelling large and complex regional-yield trials. The importance of the biplot, as an effective method for comprehending a large amount of information, is emphasised. Biplots are useful for diagnosing the best statistical method for a given data set and can help to identify major factors influencing yield. Chapter 7 examines the design of efficient experiments. For AMMI to be most efficient the experiment needs to be designed with AMMI's use in mind. The problems of balancing the relative number of genotypes, environments and replications which is always a difficult problem, is discussed. Finally, Chapter 8 draws some conclusions. The author concedes that at present only a tiny fraction of the world's yield trials are analysed by AMMI, but he believes from his experience that in the majority of these trials AMMI is the best model. He gives four main reasons for his conclusions: ( 1) Better Accuracy - AMMI can give more accurate yield estimates than basic treatment means.
Field CropsResearch37 (1994) 145-148
Field Crops Research
Book reviews Irrigated Forage Production Irrigated Forage Production. Amos Dovrat (Editor). Elsevier, Amsterdam, 1993, 388 pp., Dfl. 295.00, ISBN 0444-88300-2. Irrigated Forage Production is divided into two sections or parts following a brief introduction (Chapter 1). Part One: The Biomass, provides background in Yield Formation (Chapter 2), Water Relations and Irrigation (Chapter 3), and Forage Quality (Chapter 4). The authors (Chapters 2 and 4, A. Dovrat; Chapter 3, Y. Cohen) do not attempt a critical, state-of-the-science review on any of these topics. Rather, in all three of these chapters, they cover some of the basic concepts that have figured prominently in the philosophy of those disciplines, but which also have a bearing on forage production practices. In the chapter on Yield Formation, topics include plant morphology and its influence on defoliation responses, photosynthetic productivity from the leaf to canopy level, and mineral nutrition. Concepts of crop water use and water use efficiency are presented in Chapter 3 by Cohen, including methods for estimating water use, management problems with low-quality water, and irrigation systems. Dovrat finishes this section with a brief chapter summarizing forage quality, focusing on chemical and structural aspects of quality and digestibility. Due to the abbreviated nature of these introductory chapters, some of the presentation suffers slightly from an unbalanced and less-than-comprehensive treatment. However, to address this problem, the authors often cite authoritative references on various topics they are able to cover only briefly. In Part Two: The Production, six chapters cover the details of six irrigated forages: alfalfa, irrigated pasture, forage corn, berseem clover, annual ryegrass and fodElsevierScienceB.V.
der beet. Most of the chapters follow a similar outline: an introduction, followed by sections on development and growth, establishment, crop water requirements and irrigation, mineral nutrition and fertilizer use, harvest management, forage quality and utilization, and a conclusion. The format for the chapter on irrigated pasture is different, focusing on plant components, soil and site factors, land preparation and sowing, management (including irrigation, fertilization, grazing and overseeding), and finally animal components. I found Part Two: The Production to be the most useful section of the book, as it presents a unique and well-documented compilation of information about the different forages in the context of irrigation practices. The chapter on alfalfa is particularly comprehensive (51 pages covering many aspects of alfalfa culture and use), with examples and concepts developed from numerous different environments around the world. The other five 'forage' chapters are each about half that length, but are similarly well-documented. Due to the breadth of topics Dovrat examines in each chapter, he continues to supply the reader with references of other works where more in-depth information may be obtained. On balance, his coverage is good. A final chapter by A. Goldman in Part Two: The Production explores the economic considerations of various forage production options through computer simulation analysis. This treatment seems relevant given the increased access to personal computers. Goldman stresses that the requirement of a large data matrix for simulation models, like the one presented, will necessitate collaboration among researchers, extension specialists and farmers for this approach to work. The topic of irrigated forage production is a complex one, with numerous management options. Dovrat and his colleagues have taken much of the scientific liter-
146
Book reviews/Field Crops Research 37 (1994) 145-148
ature and accumulated wisdom and synthesized it into a document that ought to appeal to a wide audience of readers, including students, producers and scientists. His book successfully straddles the domains of basic and applied research. As such, it is a useful storehouse of concepts, philosophies and applications. The reader is advised that this book does not contain simple recipes for successful forage management. Nor does it sufficiently cover all aspects of any one particular species to qualify as a critical state-of-the-science review. Rather, it provides a solid background, supplemented with references for further study, for understanding and
Statistical Analysis of Regional Yield Trials Statistical Analysis of Regional Yield Trials: AMMI Analysis of Factorial Designs. H.G. Gauch, 1992. Elsevier Science Publishers, 278 pp., US$175.00/ Dfl. 280.00, ISBN 0-444-89240-0. The AMMI in the title stands for Additive Main effects and Multiplicative Interaction effects and the book puts forward this method as a useful tool in the analysis of 'regional-yield' or variety trials. A typical regional-yield or variety trial is defined in the book as a genotype-by-environment two-way factorial usually with replication. The AMMI model is a combination of two simpler models. First, the genotype and environment additive or main effects are calculated using analysis of variance (ANOVA) and the residuals from this model (i.e. the interaction) are analysed using principal components analysis (PCA). Both methods were discovered many years ago, and in fact, Fisher and Mackenzie first applied both ANOVA and PCA separately, in 1923, to a single data set of 12 potato varieties grown with six fertilizers (environments) and three replications. However, it was not until the mid-1980s that the method gained popularity, with a paper by Kempton which shows AMMI's biplot graph as a statistical tool helpful for understanding complex genotype-environment interactions. Gauch produced several papers on the subject and has now produced this book. Chapter 1 provides an introduction to the subject, giving a background to the sort of trials where this analysis would be useful and giving a brief history of the analysis of field trials. Chapter 2 introduces and
comparing several irrigated forage systems. Irrigated Forage Production should be a valuable addition to the libraries of both producers and researchers interested in studying and managing irrigated forages. Jack A. Morgan
USDA-ARS Crops Research Lab 1701 Centre Ave. Fort Collins CO 80526, USA SSD10378-4290 ( 94 ) 0 0 0 2 9 - C
defines several basic statistical concepts used later in the book. Chapter 3 then introduces the AMMI model and several related models, including ANOVA and PCA and compares the relative merits of the various methods. Having dealt with the basic concepts, Chapter 4 is concerned with estimation and documents the accuracy of AMMI estimates. It is stated that "Typically AMMI models are as accurate as treatment means based on two to four times as many replications". Chapter 5 then considers the resultant potential improvement in selection of varieties, through the better accuracy of the AMMI model. Chapter 6 illustrates AMMI's usefulness for understanding or modelling large and complex regional-yield trials. The importance of the biplot, as an effective method for comprehending a large amount of information, is emphasised. Biplots are useful for diagnosing the best statistical method for a given data set and can help to identify major factors influencing yield. Chapter 7 examines the design of efficient experiments. For AMMI to be most efficient the experiment needs to be designed with AMMI's use in mind. The problems of balancing the relative number of genotypes, environments and replications which is always a difficult problem, is discussed. Finally, Chapter 8 draws some conclusions. The author concedes that at present only a tiny fraction of the world's yield trials are analysed by AMMI, but he believes from his experience that in the majority of these trials AMMI is the best model. He gives four main reasons for his conclusions: ( 1) Better Accuracy - AMMI can give more accurate yield estimates than basic treatment means.