Biotechnology Commission (AEBC) Research Agendas Workstream

Meeting 26 November 2004

Paper RA5.1: A Brief Commentary on Soil Science Developments – A Paper to Stimulate Discussion by Jeff Maxwell

Introduction and Summary

1. The soil is a highly complex and dynamic system. Understanding its physical and chemical properties is hard enough, but it also harbours a remarkable biodiversity. The relationships between these abiotic and biotic components and the soil’s many functions are still poorly understood. Nevertheless, since its beginnings in the 19th century, soil science has helped to produce the vastly improved yields of modern agriculture.



2. The soil’s role in a host of other processes, such as carbon cycling and climate change, pollution and ecosystem function mean that factors other than a desire to improve agricultural productivity can influence research agendas. In the last twenty five years, the key drivers behind soil science have changed considerably as technical advances have begun to allow fundamental soil processes to be understood. Soil science is an interesting case study of how a particular area of science is adapting to changing priorities and as technical developments allow new approaches to be taken.


The Nineteenth Century


3. The early stages of soil science from the beginning to the late 19th century developed along two separate lines – the agricultural soil chemistry path and the weathered rock, soil physics and agrogeology path (1). There was little significant interaction between them until the beginning of the 20th century. However, there were a number of important developments over this period: Liebig’s mineral theory of plant nutrients of the 1840’s; the recognition of the importance of the soil profile (later pedon) by Darwin and Dokuchaev; the identification of soil forming processes (e.g. the role of earthworms in soil mixing, Darwin 1881); the variable nature of humus (soil organic matter) and its role in soil forming processes (e.g. Mueller, 1840-1926);



4. Consequent upon and following the establishment of the long-term field experiments by Lawes and Gilbert in the 1840’s the research at Rothamsted focussed on the relationship between soil conditions and fertility and its effect on crop yield. Out of these experiments and many others the first edition of Soil Conditions and Plant Growth by Sir E John Russell was published in 1912. His son, Walter Russell, published the eighth edition in 1973, and the 11th multi-authored edition was published in 1988. The several editions of this book have played no small part in shaping the evolution of soil science in Britain and in many other countries of the world (2) recognising that soil science and soil management is a multi-disciplined activity embracing pedology, soil chemistry, soil physics, soil biology, plant nutrition and other branches of the life sciences.



5. The principle drivers of research during the 19th century were curiosity and a need to understand how to use soils and fertilise them to maintain and increase crop yields. The design of the long-term Rothamsted experiments reflects this; a comparison of the yield of crops grown on soils receiving farm yard manure plus inorganic nitrogen and soils receiving inorganic nitrogen, phosphorus and potassium compound fertilisers. The funding came from trusts and farmers committed to improving their husbandry techniques and the output from their farms. Farmers were involved in the research.


The Twentieth Century


6. At the beginning of the 20th century an understanding of the role of microbes in the decomposition of plant residues in returning nutrients to the soil (e.g. Waksman, 1888-1973) was developed, and towards the middle of the century following Jenny’s model (1941) of soil nutrient dynamics, different types of model were developed to understand the medium and long term dynamics of soil organic matter. The early part of the 20th century saw also the beginnings of soil survey in Britain which led ultimately to the production of the 1:250,000 scale soil survey of England and Wales in 1983 and of Scotland in 1989 (3).



7. During the first half of the 20th century a greater understanding of soil chemistry and plant nutrition provided the impetus both to establish the extent of variation in agricultural soils through soil survey and to gain greater understanding of how to mange their nutrient status to support a variety of crops. This was a period during which the Agricultural Research Council was established (1934) and the Departments of Agriculture began to take initiatives during and after World War II to improve output from British agriculture. Thus the funding for soil science during this period was predominantly from the public purse. The rapid development of soil science and the need to increase crop yields were primary drivers during this period.


From 1975


8. These drivers continued to influence developments into the third quarter of the 20th century. In parallel with the other sciences supporting agriculture there was a rapid growth in funding for soil science and in technological development to produce the bulk of our ‘food from our own resources’. This was the case not only in the UK but also in the USA. Commenting on this period, Warkentin (1992), states ‘Crop production was the engine driving this effort, and its emphasis was on inputs rather than on managing systems. …..During this period there was little emphasis on reasoning from processes, it was considered better to measure effect even if it were over short time periods.’



9. Excellent empirical solutions to problems came out of this effort. For example, answers to how much N fertiliser should be added for maximum crop production were sought and given. There was, therefore, little information developed on the underlying processes or on phenomena that had time scales of more than one or two years. This seems to have delayed an interest in and understanding of the biological processes in soils (4). Much of the research of this period was classified as being applied and descriptive. Nevertheless, through the application of more sophisticated soil analysis techniques and the use of soil survey data to produce land capability and suitability maps, soil technology and the results of ‘fertiliser dose-response’ experiments provided the basis for increasing crop yields significantly during this period.



10. Then, following first the Rothschild Report in 1971, which embodied the customer-contractor principle but which was critical of the Agricultural Research Council and second, the report of the Advisory Committee for Applied Research and Development in 1975, which emphasised the relevance of public research to manufacturing and industry, funding for agricultural research was reduced. Consequently Agricultural Departments and the ARC began a process of prioritisation and a reduction in the numbers of scientists involved in agricultural research.



11. By the early to mid 1980’s this process had gathered pace: furthermore the increased output from agriculture and the oversupply of agricultural commodities within Europe brought into question the continued public investment in agricultural research. This was considered also in relation to the need for public research investment to support other industries and the need to improve their competitiveness. The lack of private and commercial investment in agricultural research also began to influence funding policy. Moreover, in 1984 ARC became AFRC, the Agricultural and Food Research Council, with responsibility to include research to address concerns about food safety. Funding for agricultural research continued to be redeployed.



12. .The negative impact on agricultural soil science research funding in the UK over this period was considerable. During the process of prioritisation several factors appear to have influenced the reduction in resources allocated to soil science. The large increases in crop yields that had been achieved were the result of many improvements in technology – crop breeding, methods of disease and weed control, and not least the information that related crop yield to fertiliser inputs for different soil types and cultivation regimes. With regard to the latter soil science was deemed to have delivered. In addition, government policy development indicated that it wished to remove funding from ‘near market research’ such as this, which it did eventually in 1990.



13. Priorities were also determined by judgments about the potential for innovation within different areas of science supporting agriculture and the growth of agribusinesses. Developments in cell and molecular biology, and plant genomics were judged to show real promise: with its responsibility to fund science that had the potential to underpin future commercial developments the AFRC moved greater resources into this area of biotechnology. By the mid 80’s agricultural soil science seems to have reached a plateau in terms of development and lost some of its innovative zeal. Its period of empirical research appears to have been judged at this time to have been too applied and too ‘near market: therefore, in the ‘cut and thrust’ of prioritisation soil science ‘lost out’.


1990 onwards


14. A combination of several changes in research policy direction and an unfavourable view of the current innovative status of soil science at the time led to a greatly reduced capacity for agricultural soil science in the UK by the beginning of the 1990’s. While the principle driver for soil science up to the mid 80’s had been to improve crop yields, this was no longer a priority in terms of government research funding for the rest of the century. In terms of attracting funding agricultural soil science had lost its appeal.



15. However, a core capability was sustained and soil biologists were already contributing to approaches that moved the emphasis towards process based research and mathematical modelling. Modelling provided the impetus to gain a much clearer and quantitative understanding of nutrient cycling, particularly nitrogen and carbon. It also led to an interest in processes at the scale of the rhizosphere. Developments in microbiology have led to a greater ability to identify the role of populations of microbes in nutrient cycling and how specific organisms can be used to identify the resilience of soils to pollutant damage as well as being used as toxic indicators in water.



16. The early 90’s was a period of refocus for soil science in the UK. It became apparent that the issues of public concern were the impact of acid rain and fertilisers on water quality and the ecology of rivers, and the resilience of soils to the impact of waste, and heavy metals as pollutants. There was a decisive shift towards a broader interest in the role of soils in the environment and ecosystem function. As a corollary soil research for agriculture became concerned with the more efficient use of fertilisers and effective use of farmyard manures, and a small amount of research to support the development of organic farming. These were the issues that became the primary drivers during much of the 90’s for the limited amount of soil research that was funded.
    
    
17. At an international level an important impetus developed in the late 90’s prior to and following the Kyoto Protocol to the UN Framework Convention on Climate Change which was signed in December 1997. The Protocol contains legally binding commitments to limit or reduce greenhouse gas emissions within the period 2008-2012 by at least 5% below 1990 levels. Europe’s commitment is to achieve an 8% reduction and the UK has committed itself to a 12% cut with a voluntary target of 20% below that of 1990. However, associated changes in the net fluxes of two other greenhouse gases identified in the Protocol – nitrous oxide and methane – will have to be taken into account. The problem of how to quantify the soil sources and sinks, to maximise carbon sequestration, and to minimise soil emissions of methane and nitrous oxide presents a major scientific challenge to the soil science community over the next few years, (Smith, 1999) (5).
    
    
18. The European Commission has concluded that the management of our soil resource is central to environmental ecosystem sustainability; it requires to be managed, to be conserved and protected. This has led to the proposal to have a soil monitoring directive and the establishment of criteria of soil quality. Research in some countries of Europe including the UK has been stimulated in anticipation of having to implement these proposals.



19. A recent UK Soil Research Audit, commissioned by Defra as part of its Soil Action Plan for England 2004-06, concluded that now was a time of great opportunity and challenge for soil research because an increased knowledge base allowed some of the major environmental issues to be tackled, including climate change, pollution and sustainable land management.


Directions for the 21st Century?


20. Many now argue that biology lies at the heart of the scientific enterprise of the 21st century but also see soil science as an integral part of that enterprise. Important practical issues require soil biology knowledge. These include understanding the role of soil processes in global warming and strategies to ameliorate it; enhanced and safe recycling of waste from manures, urban and industrial activity; pollutant destruction at waste disposal sites as well as landscapes contaminated from natural processes; biological control of rhizosphere pests; enhanced groundwater quality; discovery of new biotechnological products, including pharmaceuticals, pesticides and enzymes from the undiscovered microbial diversity of soil; and optimising recycling of soil nutrients for sustainable agriculture and forestry, Tiedje, (2001) (6). The basic premise behind an attempt to understand the complex soil community is that further knowledge will pay off in improved agriculture, environmental decision-making and management, and many of the practical issues listed above.


Where do we go from here?


21. Questions:

• So where are we now? What are the current drivers for soil science in the UK? Are they explicit?



• Does our programme of soil science research reflect the issues that are of concern to the stakeholders and the public in so far as these can be defined? Are farmers’ concerns being addressed?



• Was the redirection of resources away from agricultural soil science in the 1980a appropriate in the limited funding environment of the time, given the plateau in its development and the promise of other areas? Has this had any negative consequences? Is there still a benefit to be gained from traditional agricultural soil science and is more needed?