The use of nutrients in crop plants

The Use of nutrients in crop plants is the latest text in a series by this prolific plant specialist, and follows some 40 years of research experience on the mineral nutrition of crop plants. The text provides the reader with a comprehensive coverage of each of the 14 essential mineral nutrients required by plants. Its focus is different from other books on plant nutrition, in that there is a strong practical bent towards understanding and managing the efficiency of applied nutrient use. Here the focus is on the use of added inorganic fertilizer, and the aim is to increase crop yield without damaging the environment. The author makes the point that this will be the important task for agricultural managers if we are to produce sufficient food to feed 9 billion human inhabitants by the middle of the 21st Century. The author provides a very useful coverage of each of the mineral nutrients, after an introductory chapter on the basic issues relating to the yield of different crop plants, and the association between nutrient uptake and crop yield. Each essential nutrient is then covered in a separate chapter, starting with the macronutrient nitrogen and ending with nickel. The coverage is fairly consistent for each nutrient. After a general introduction, the topics covered include the availability of the nutrient in the soil, its functioning in plants and its deficiency symptoms, its concentration in and uptake by plant shoots, interactions with other nutrients, and then the focus is on issues relating to use efficiency with the aim of maximizing and breeding for use efficiency. There is minimal coverage of the role of each nutrient in plant metabolism and the research findings that explain such roles: indeed, the reader is often provided with a just a list of the different roles that each nutrient plays in plant function. This deficiency, though, is balanced by the more practical coverage of how the nutrient can be used efficiently in cropping systems. The book contains many figures and tables of experimental data involving a wide range of soil and plant measurements. The content is fully referenced, with a list of references at the end of each chapter, and this will be very useful for those involved in research, teaching and extension work alike. The majority of the research data are the results of the author's own work. This unfortunately creates a real bias towards the summer-growing crops, such as rice, corn, dry beans and soybeans that are are grown in Brazilian oxisols and inceptisols. Nevertheless there is a wealth of information on many aspects of plant nutrition, albeit in these South American farming systems. Practically all important topics are well covered and so the reader is able to gain a clear understanding of the issue as well as an indication of the latest references in the scientific literature. The text therefore provides an understanding of many of the key concepts and principles that underpin the discipline of plant nutrition. The text is easy to read and is broken up by many black and white photographs, together with tables and figures containing experimental data. Unfortunately the quality of the figures is only average; many are cluttered with regression equations containing coefficients to the 4th decimal point with lines and symbols varying in thickness and size, respectively. Sometimes the reader has to read into the text to understand what the context is for the data in the tables. The lack of colour photographs also reduces the impact of some of the deficiency symptoms. Obviously the lower quality of the illustrations will lower the cost of the book and keep it in reach of most readers. No text on the use of fertilizer nutrients for crop plants can be complete without an adequate coverage of the impact of fertilizer nutrients on the environment. The major culprits here are nitrogen and phosphorus, with nitrate enrichment of groundwater, nitrous oxide emission from soils to the atmosphere, and phosphate enrichment of water bodies being the problem areas. These topics are generally covered well, particularly in the section on phosphorus versus the environment. However, the section on managing nitrous oxide emissions is limited. The impact of these emissions is creating considerable interest. It would be hard to keep any text up to date, as governments around the word grapple with the problem of greenhouse gas emissions and climate change. There will be a significant market for this book as it will be a useful reference text for researchers, students and extension workers in many countries. We must be grateful to Dr Nand Fageria for sharing his knowledge and understanding of the role of mineral nutrients in the food production systems with which he has worked. Perhaps the most important contribution that the text will make will be the increased awareness of how we must improve the efficiency with which we use plant nutrients, if we are to provide the food for our expanding human and animal populations.