2
Understanding Food Supply Chains

2.1    Current Methods of Assessing Food Supply Chain Efficiencies That Enable Food Security Projections

This book aims to develop a framework for developing food security worldwide using data and knowledge held by whole supply chains. The twenty-first century has seen the emergence of big data scenarios in that we can obtain volumes of data regarding supply, consumption, and purchase of foods like never before. The food system itself is now at a point where we need to assess the importance of these data and how we can use them to provide sustainable and secure outcomes for food supply globally. The impetus to do this has been made clear by many writers, who are not the focus of this particular study; this book aims to make the reader aware of these writers and commentators and place them into an integrated context so that the reader can make rational decisions that will develop leadership in food security. This cannot be achieved without considering the role of the policymaker, who is anyone who can plan a vision where security and sustainability of food is defined by projecting the outcomes of supply chain activities so that we can plan for a sustainable future.

A dominant theme within policy development is changing goals, and within the food system, it has become a cacophony of changing messages, different values, and continuing demand for a supply chain that can deliver over consumption as the notion of a sustainable meal. From this arena of what sometimes can only be described as noise, a policymaker who aims to change actions for the better must pick out attributes that can help determine a route for what can be regarded as secure and sustainable consumption food policy. The melting pot that is the food system contains both privately controlled and publically controlled elements that can confound any attempts by enlightened and innovative solutions to develop sustainable practices. This is why the food industry has always struggled with profit, assurance, traceability, and contamination. The supply chain has demand attributes that are often focused on analysis of how population growth and higher incomes affect consumption of foods. These relationships are well defined in economics, but they often only consider the outcome of sating demand in populations and rarely consider why demand increases in the first place. In the context of food security, we must largely consider the role of agriculture, but mining of minerals as nutrients will have a crucial role in the development of populations and demand.

2.2    How Population Growth and Limiting Factors Define Demand and Food Security

No discussion of population growth and demand can go ahead without a consideration of Malthusian dynamics that still dominate much of the thinking in the food system. Thomas Malthus realised in the eighteenth century that exponential population growth was possible when resources were available to allow it. This will ultimately create an overshoot in growth that in turn results in a decline in population growth if technological or social innovations do not respond to cater for larger populations.1 The second half of the twentieth century saw a resurgence in credibility for the Malthusian world view, and many commentators interpreted increasing population growth to mean an unsustainable future scenario. Professor Paul Ehrlich's essay and later book, The Population Time Bomb, expounded a Malthusian view of the future and brought Malthusian thinking into the food security debate.2 Other notable projections came from the Meadow's projections on the limits to growth at this time. They are notable because they were presented to the Club of Rome, which is associated with development of the current European Commission (EC).3 The EC itself has become an important source of policy for agriculture, and the impacts of agriculture on society and the Meadows' projections demonstrated that the overshoot of populations with respect to resources may happen, with catastrophic impacts on societies.

The greatest weaknesses of the Malthusian world views are they have never happened globally with the impacts that the advocates of Thomas Malthus projected. Naturally, they would say that this is because they have influenced policy to consider impact as well as growth. There is no doubt that Malthusian principles have contributed to the sustainability debate, but we must question why humankind has always managed to provide some form of regulation between the supply of resources and demand of populations.4 If we are to consider the limits of growth and place them into the context of population projections, it is not simply a case of stating Malthus got it wrong; many commentators have shown this is too simplistic and simply not the case.5 It is certainly the case that all Malthusian projections tend to overlook the power of adaptive modelling and the introduction of new technologies that will overcome limits by identifying new materials and technologies that will result in more efficient use of current materials. This has evidently been the case for the global food system, where humanity can now control genetic performance and production of biomass.1 Professor Tony Trewavas has developed a viewpoint based on current capacities of agricultural technologies that seriously question the limits that Ehrlich and others identify.6 His understanding of new technologies is well grounded in a career that has used biotechnology to decipher how calcium is used by plants to sense environmental stress, but it is the foiling of Malthusian principles that concerns us here. Trewavas points to the delay and misunderstanding of biotechnology as providing limits to current agricultural technologies. His approach is proving correct, as many governments are beginning to reevaluate the role of biotechnology in agriculture. However, he also acknowledges the need to understand the qualitative nature of the biotechnology solutions and their interaction with consumers, warning that the ‘cult of the amateur’ will result in an unjust representation of the biotechnology industry, which has become completely transparent to the consumer.7

2.3    Global Population Estimates and Projections

The total global population estimate has consistently increased since industrialisation. These figures represent a global average and there are drastic differences between nations and regions of the world with regard to the amount of population growth. Analysis of population growth generally shows increased rates of growth in developing regions of the world and stable growth in developed regions. The average global trend also hides a significant move from rural population growth to urban population growth, with the later increasing significantly over rural population growth. This is an important trend because population becomes more concentrated in urban areas, requiring intensification of food production and supply mechanisms. The impact of population growth and distribution is a key consideration in environmental quality impacts. When populations become more concentrated and their requirement for efficient food supply more apparent, the need for assessing the impact of agricultural operations will become more important. There are a number of methods for doing this, including the development of indicator frameworks.

Supplying and increasing world population with due consideration of the capacity of the food system is an important international concern, and the provision of a productive agricultural systems to do this is essential. This must be achieved within the bounds of political, economic, and technical abilities that are always changing. For example, a technical attribute, such as crop nutrition, is an important indicator of agri-system efficiency and the supply of food to the global population. Crop nutrition is a component of producing food that can be represented in terms of crop yield, calorie sufficiency, and quantity of foodstuffs. It is also an important component of food quality, with trace element nutrition being vital to the production of food with high nutritive quality as well as calorific content.

The complexity of the food sustainability goal is embodied in the impact of continued global population growth and cultural transitions. The United Nations population projections and the UN Food and Agricultural Organisation food production and consumption trends provide a means to develop an assessment regarding the question of how much food needs to be produced in the next 40 years. Research presented by Keating and Carberry (2010) provide scenarios based on low and medium world population projections of 8.0–9.0 billion in 2050. They have assumed human fertility trends and consumption remain constant based on previous population data. The scenarios show the world will need to produce over 380 to over 400 exa calories (1 exa calorie = 1018 calories) over the period of 2000 to 2050 if an average consumption of 2255 kcal/person/day is maintained. This is equivalent to the food the world has produced over the 200 years pre-2000 in order to feed its population.

A further scenario presented by Keating and Carberry (2010)8 assumed that a mean global consumption of 3590 kcal/person/day by 2050 is reached. This might be considered more realistic if current consumption trends continue and the resulting demand will be for over 450 exa-calories, which is the equivalent to the food produced in 330 years pre-2000. The scenarios presented provide an assessment of the challenge that faces food supply over the next 30 years; in reality, we will have to produce food at an efficiency which is up to 10-fold greater than we are currently doing. This means that the agricultural segment of the food supply chain is critical to producing these calories required by the growing demands of populations. Population growth is tracked and projected using models that have become increasingly robust, but consumption of food is also dependent on the cultural values, changes in individual taste preference, and trends in food category popularity. When these cultural variables are interfaced with supply–demand functions, the food system is clearly extremely complex and not just about supplying calories and protein.

2.4    Consumption and Population Growth: Demonstrating the Impact of Dietary Changes and Transitions

The food security implications of population projections become even more profound when we relate them to the consumption of protein. This is because 65% of global protein consumption is from just seven major food ingredients, as reported by the FAO statistical database, FAOSTAT. These are wheat (20%), rice (12%), maize (5%), dairy (10%), beef (6%), poultry (6%), and pork (6%). Furthermore, livestock product consumption provides specific stressors on the global food system, because feed protein is consumed by livestock to produce meat as a protein source at conversion efficiencies that range from 5% for beef products to 40% for dairy products.9 The nutrient transition of the world food system to more meat-containing diets has resulted in an increased demand for meat, creating a dilemma for sustainability of resource use because of the demand for feed protein that directly diverts protein from food supply chains.10,11

This can be demonstrated using current world production of meat reported by FAOSTAT in 2011, which is nearly 300 million tonnes. If we assume that a typical tonne of meat will need at least 10 tonnes of feed to produce it and this feed is wheat that achieves a world average yield of 3 tonnes for each hectare grown then we require 3 billion tonnes of wheat or 1 billion hectares to produce it. While I accept these are very much typical calculations, they do present important principles. If the reader needs to see detailed analysis regarding capacities of the food production system that exist and are utilised by policymakers, then investigating other projections that have been published will also show the principle and value of identifying baselines we can project scenarios from.12 We know that feed conversion into meat ranges from 2.3 kg (for fish), 4.2 (for chicken), 10.7 (for pork), and 31.7 (for beef) because Smil has reported these figures previously using USDA data.9 While these figures can be improved, they do represent an important reference point without carrying out detailed life cycle assessment (LCA) of crop to feed conversion in livestock systems. An energy balance approach is now discussed here as an important approach because it enables us to appreciate the scale of the meat supply issues. We would need 1 billion hectares of cereal production to feed the livestock currently produced globally if cereals were the main source of feed. The actual area of wheat harvested in 2012 was 217 million hectares, and of course the feed to animal production system is clearly not that straight-forward. Animal feeds include all cereals, where FAOSTAT reports 703 million hectares were harvested in 2012, and for oil crops, a further 281 million hectares were harvested.

Obtaining the near one billion hectares for livestock feed seems to have a complete solution here and the land resource limitation is overcome, but this is just for animal feed and does not include food, so we still have a problem. Of course this problem is solved by using grassland as grazing systems and forage production, that is, without the consideration of managing grazing and forages, the world livestock system would not work. They are essential to the world food system, and in 2011, FAOSTAT reports that there are nearly 3.4 billion hectares of grasslands globally, which are the engine for livestock production. These are the critical production considerations for the feed that supports a global system of producing grazing animals and livestock products. If we consider FAOSTAT data, there are 0.5 billion hectares of arable land globally; the demand for livestock feed will create increasing pressures on feed protein supply and the food system. Previous interventions to supplement feed protein have focused on improving grazing systems so that the 3 billion hectares of permanent pasture available globally can efficiently achieve optimal grazing and forage production to reduce demand for cereal and oilseed feeds. However, there is the increasing importance of processors and manufacturers in providing a means to ameliorate pressure on the meat consumption system by the utilisation of all co-product and waste streams for protein supply. Furthermore, the growing importance of using industrially produced protein that converts starch to protein at much higher efficiencies than livestock systems is emerging in response to these pressures.

The role of processors and manufacturers to convert biomass into different protein product ranges are critical to future conservation of livestock resources, and it can provide a basis for defining sustainable meal and diet planning for populations. The delivery of sufficient protein for human well-being is a human right, and the food processing and manufacturing industry offers many opportunities for providing routes to efficient feed protein and livestock protein production, and industrial starch to protein conversions. The processing industry is of huge importance in optimising protein consumption through the design of recipes, meals, and products so that consumer well-being is enhanced and environmental impacts are reduced. Relating product development to whole meals and diets is critical, and it requires a full appraisal of whole supply chain activities. As previously highlighted, processors and manufacturers operate in the middle of the supply chain and as such have an important place in determining traceability of food ingredients to assure safety or provide robust responses in crisis management. Naturally, one of the most important considerations for food supply chain management is population growth, which is further compounded by increasing urbanisation and nutrient transition trends. With this in our minds, we must start to determine what food supply functions result in security, and the nutrients used in agriculture are an important place to start because they ultimately determine the nutritive quality of the biomass produced by agricultural systems. This biomass can be enhanced by processing and manufacturing, but ultimately the quality of biomass produced will be an important determinant of eventual nutritive value of foods.

2.5    Optimising Nutrition across Supply Chains Is the Focus of the Second Green Revolution

As we have seen how the work of Borlaug, Evans, and Harlan have transformed how new crops are designed with respect to production demands, we must consider not only producing more food, but also more nutritious foods that are tailored for specific nutritional requirement. The world demand for specialised dietary products is likely to increase as global diets become calorie sufficient or, more worrying calorie over-sufficient. How this food quality goal in diet is distributed globally will be an important issue in the twenty-first century. The distribution of food in the global system has been characterised and we now have traceability standards associated with food categories that assure consumers.13 Whereas food distribution is characterised because of the requirements of food safety and traceability issues associated with supply chains, there is increasingly a need to qualify the sustainability of distribution with respect to environmental impacts and loss of nutritive value.14,15

Some commentators have said that this is the basis of a second ‘green’ revolution, where the first aimed for calorific- and supply-based goals, and the second will aim for these actions alongside qualitative goals associated with nutritional values of foods. These will be more closely linked to improving health of nations that have reached calorific sustainability. Nutrient availability and consumption have a huge effect on the ability to produce food of enough quantity and quality to support industrialised societies. The manner in which culture and societies develop in specific areas may not always be associated with the most favourable areas for food production, and the import of nutrient sources into these areas using efficient distribution networks becomes very important. The development of efficient supply chains has extreme social and economic impacts on national development programs and can create very specific environmental impacts.

The need for nutrients to be economically assessed by producers at the beginning of the food supply chain is of extreme importance; they must consider the yield potential of a particular landscape and soil with the benefits of using optimal amounts of nutrients for increased biomass yields. This must then be equated against the cost of nutrients and their distribution and application for achieving optimal yield. Integrated Plant Nutrition Systems (IPNS) emphasise the importance of economic assessments being made that align with agronomic yield potential, so that the economic and technological factors for production are taken into account together, not as separate factors. Environmental assessment of farm inputs such as plant nutrients is an important consideration, and it can be formalised as a farm nutrient management plan because the ecology for a particular landscape can be significantly changed by different farming practices. For example, reduction of wind- and water-enhanced soil erosion has clear economic benefits in conserving the nutrients in top soils. Soil conservation and landscape management are key components of IPNS, and by enacting soil conservation procedures, farmers can ensure environmental and regulatory compliance.

2.6    The Emergence of Sustainable Farming Reconnecting Supply Chains: A Case Study of the Establishment of the Landcare Movement in Australia

These types of approaches to landscape management described here were perhaps first placed into farming systems and the food supply chains associated with them by the founders of the Australian Landcare movement at the end of the 1980s in South West Victoria. Sue Marriott and Andrew Campbell, among others, started this by providing a forum for groups of farmers to discuss farm planning that improved business operations and developed sustainability criteria associated with farms, such as water and soil conservation.16 The Landcare movement started with a number of farms working together to share management information in a project supported by the Ian Potter Foundation; they became known as the ‘Potter Farms’. Management systems, such as the sward management system, Prograze™, developed from these actions, and John Marriott pushed forward a programme of farm benchmarking to improve business performance with respect to economic and sustainability criteria.17 The initial decade of the Landcare movement demonstrated that important tasks could be met by farmers worldwide in obtaining a sustainable and secure food system.18,19 At its heart was an understanding of natural resources and how the use of soil management, plant nutrients, crop and livestock protection, and water and energy balance could be used to develop a farming system to be proud of.20 The future challenges were to integrate this with the food supply chain and land use industries, which to some extent defines where the second green revolution goals are, that is, looking towards the consumer components of the supply chain.

2.7    The Long-Term Field Experiments at Rothamsted and Their Power of Demonstrating Good Nutrient Balance in Agriculture Has Been Crucial to the Development of Sustainable Food Supply

In order to grow and develop satisfactorily, all plants need a supply of carbon, hydrogen, and oxygen, which they get from soil, air, and water environments. There are also 13 essential mineral elements (nutrients) shown in Table 3.1. These elements are normally obtained by plants from the soil, and it is useful to reflect on where our current understanding of soil fertility derives from. The facts that provide these foundations for modern agronomy were initially researched by Justus von Liebig in the early to mid-nineteenth century and applied by Sir John Bennet Lawes of Rothamsted and Sir Joseph Henry Gilbert of Rothamsted in initiating the modern fertiliser industries. Liebig made measurements of how dry matter was gained in plant systems and hypothesised that much of the nutrient required for growth would come from the soil but he thought nitrogen was essentially obtained from the atmosphere. These ideas were later developed by John Lawes, the founder of the Rothamsted Long-Term Agricultural Experiments, and Henry Gilbert, the chemist who worked with Lawes to develop the field trial database that still exists today.21 Their experiments have also established our current understanding of the nitrogen cycle, which shows plants obtain nitrogen from soils and its bioavailability is critical to the production of all biomass.22

All natural resources are finite and optimising plant nutrient supplies for an ever-growing global population remains as important today as ever, and this provides a critical role for the data obtained from long-term experiments, such as those at Rothamsted.23 The maintenance of the amount of food produced and the nutritional value of food will be dependent of the minerals supplied to crops during production. This means that the importance of plant nutrition is one of the most important components of production. The consumption of nitrogen (N), phosphate (P), and potassium (K) globally reflects the importance of providing enough nutrients to support an efficient food production system.24,25 The historical evidence obtained from the Rothamsted trials can demonstrate the sustainability of crop production in the arable farming systems that produce cereals, maize, grain legumes, and rice, which are the dietary powerhouses crucial to delivering the calories and protein for human diets (see Figure 1.4). The sustainable or continued production of these crops is extremely important to global agricultural production, and IPNS will be a key component of achieving agri-sustainability in these systems.

The use of long-term data from the global long-term experiments such as those of the Morrow Plots in the United States and those at Rothamsted in England have provided important lessons for the sustainability of grain-based production systems by demonstrating how it can be achieved. These experiments are over 100 years old, and they have shown that using the optimal rate of nutrient inputs generally corresponds to obtaining the optimal yield of a crop. This, combined with the use of crop rotations and break crops, can improve nutrient use efficiency, soil organic matter content (SOM), and reduce disease pressure as compared with continuous cropping.26 The impact of weed pressures has also been investigated in the long-term agricultural experiments and provides important data that describe the emergence of herbicide resistance in weed species, which is now having serious impacts on cereal yields.27 The interaction between crop yield limitations and crop varieties has also been explored by benchmarking modern varieties to older varieties so that yield benefits observed as a result of introducing new varieties and crop breeding can be identified to be between 10% and 30% of current yields.28

2.8    Long-Term Field Experiments Hold Critical Data That Provide Our Understanding of Nutrient Flows in Farming Systems So That Sustainable Food Supply Chains Are Developed

The global long-term experiments have provided valuable data on the soil organic matter (SOM) content of agricultural soils, which are critical to understanding global carbon and nutrient cycles. It has been found that cultivation of the soil will decrease organic matter content of most soils, and this decrease will reach an equilibrium level that is associated with the particular soil and cultivation system being investigated.29 This equilibrium level will largely depend upon agronomic, climatic, and soil structural factors. Conservation of SOM can be achieved by optimal soil cultivation methods (such as minimal tillage or no till where possible), managing animal manure, and organic matter inputs utilising crop rotations effectively. The correlation between optimal soil organic matter, soil type, and long-term fertility is a strong one but very difficult to define in many field situations. Farm-recorded data collected over many rotations and several seasons are important in assessing the optimal organic matter content for a given soil because it is a means to maintain soil fertility and conserve the GHG emissions associated with farming. This is one of the reasons record keeping over long-term time series is essential to determining what sustainable production is.

How major plant nutrients interact with the soil and SOM is also critical to their bioavailability and accumulation by crops. Nitrogen is a major nutrient that is usually added at amounts of 100–250 kg/ha/ yr to supplement soil supplies that are made available by mineralisation.30 Mineralisation is the result of microbial metabolism whereby organic forms of nitrogen that include proteins and amine compounds in the soil are converted to inorganic forms, such as ammonium and nitrate ions, which are soluble, and nitrate ions are both soluble and mobile in soils.31,32

Phosphate and potassium are the other major nutrients most important to establishment of crops in soils. Large amounts of these nutrients can be available over varying timescales because they are less mobile and soluble in water than nitrate ions. In general, there are ‘nutrient pools’ in the soil for P and K that are immediately available, and those that are available over several growing seasons, decades, and even hundreds of years. Thus, the soil fertility with respect to phosphate and potassium can be either accumulative over many years or just maintained by addition of fertilisers. This type of ‘nutrient banking’ in soils has been shown at the Rothamsted Hoos Field long-term experiment in the United Kingdom, where phosphate additions over 100 years ago still present yield benefits because of the slow release of phosphate from fertilisers added over many years.33

Changes in soil pH can radically change the mobility of nutrients in soils, and most soils will decrease in pH over time unless they have a limestone bedrock that is disturbed or alkaline water flows through them.34 Knowing how to manage these pH changes and pools of nutrients with respect to timescale represents an important management strategy for productive and sustainable farming. Components of the physical breakdown of soils by erosion and weathering will be important in releasing P and K from less available pools but these releases are generally too low to support productive crop production. However, where land has been extensively manured with mineral or organic fertiliser, the long-term value of phosphorus and potassium can be considerable. Many trials have definitively shown that these nutrients can be released to crops over many decades with the Hoos Field at Rothamsted being of highest profile.

Natural events such as the deposition of sulfur and nitrogen nutrients from the atmosphere or from flood waters is a slow process with around 45 kg/ha nitrogen being available and less than 1 kg/ha of phosphorus and potassium being deposited in any year. Flooding can enrich soils significantly with phosphate if there are regular flooding periods, and this will result in considerable spatial variation in nutrients across landscapes and fields. Manure and slurry either from grazing animals or from spreading of stored material is the most important source of plant nutrients from non-industrially produced mineral fertilisers. The purpose of fertilisers and manures are to supplement the natural supply of nutrients required for optimal yield by using fertiliser recommendations. Fertiliser recommendations supplement the nutrition requirement of crops and can be described using principles of nutrient balance, that is, what is removed from land is maintained by fertilisers to meet yield demands.

2.9    The Sustainable Production of Livestock and Long-Term Data

The nutrient balance of sustainable livestock systems deserve special attention, and there are also long-term experiments that consider grassland systems, which include the Park Grass experiment at Rothamsted in England. Park Grass demonstrates interactions between species on long-term grass sward development with different lime and nitrogen, phosphorus, and potassium inputs.35 This trial has been permanent grass since 1856 and provides a case study for developing species diversity and understanding responses of natural grasslands to lime and nutrient management. An important impact of the experiment has been to show that decreased soil pH on natural grassland is a natural process that can be increased by manure and nitrogen applications.

Liming practices are therefore extremely important in order to produce optimal biomass. In manipulating pH and nutrient status, the species composition of swards can change, and this is an important consideration for biomass production and development of biodiversity. Experiments such as Park Grass show us that the effects of soil pH at nitrogen, phosphorus, and potassium applications must be looked at as a whole to assess the value of a particular management regime. This is a particularly important consideration when considering indicators of biodiversity and environmental quality.

Livestock production system long-term data are somewhat harder to find but trials do exist, such as those of the Palace Leas trials at Newcastle University in England.36 This trial demonstrates the importance of integrating nutrient inputs from fertiliser, manure, and livestock into nutrient programs, as well as the type of grazing or grass conservation management used. Management, storage, and distribution of organic manure will be an important consideration in any livestock system. Innovative methods of utilising manures are becoming available, including the production of dry manures (particularly from poultry production).37 The development of efficient manure handling can result in more efficient nutrient use, and the production of forages and conserving grass biomass for feed can result in less nutrients being imported into the grazing system.

Stocking density for particular enterprises will be an essential consideration to prevent overgrazing and erosion of top soil. The management of nutrient inputs must be assessed with the production goals of the farming enterprise in mind, and this is not necessarily the optimal yield. Production and the ensiling or storage of forages produced on farm also reduces the need to import feeds and nutrients onto the farm. The aim of the IPNS system for livestock is to reduce the reliance on nutrient imported into an enterprise. The use of these nutrient budgets can be drawn for livestock enterprises and can be an essential management tool that can be integrated into a nutrient management plan for a given enterprise.38

2.10    The Historical Proof of the Value of Agricultural Innovations in Providing Food Security

The history of agronomic breakthroughs shows us that for innovations to be successful, there is often a convergence of investment and technology that results in market entry. Nowhere was this more apparent than the development of the plant nutrient and fertiliser industries in nineteenth-century England.39,40 The specifics of what occurred are important in the context of deploying any new technology in agriculture since then. The mid-nineteenth century was a time of rapid industrialisation and urbanisation. The problems faced by a growing population were reflected in Sir John Bennett Lawes and Sir Joseph Henry Gilbert's aim of understanding crop production so as to optimise the use of plant nutrients and agronomic techniques to provide food security. They realised that providing increasing population numbers with a sufficient food supply would require an efficient agricultural industry and this increased efficiency could only be reliably demonstrated by agricultural trials.41

John Bennet Lawes is the founder of the long-term experiments and the Rothamsted Experimental Station. He was the owner of the Rothamsted estate that he inherited from his parents. Lawes was also one of the first people to manufacture and patent superphosphate, initially using bones that were reacted with sulfuric acid. Lawes developed the superphosphate production into an industry, which generated a substantial fortune for his family. Although he made his fortune producing mineral fertiliser, he advocated the value of recycling nutrients by rotations and the efficient use of organic manure in much of his work. Joseph Henry Gilbert was an experimenter and chemist who provided the technical excellence for the development of Lawes' programs of agronomic research at Rothamsted. Gilbert was driven to obtain indisputable proof and experimental data on which the current understanding of biomass production in the agricultural industry is based.

Gilbert and Lawes worked in partnership for nearly 60 years, laying the foundations for the scientific understanding of crop rotation, soil fertility, and the sustainable use of plant nutrients. By establishing the long-term agricultural experiments at Rothamsted in the United Kingdom during the 1850s, they provide an important step in understanding what sustainable agriculture is. The scientific- and trial-based approach to understanding the soil, water, and atmosphere relationships also led to the development of superphosphate industry in England during the mid-nineteenth century. Phosphate was known to be a limiting factor for crop production on many soils in England, and prior to the production of phosphate fertilisers, the only source was organic manures. In the 1830s and 1840s, John Lawes and others experimented with reacting bone materials with sulfuric acid to make the bone phosphate more available to crops. This resulted in the production of superphosphate, for which Lawes had a patent made in 1843. At this time, around 40 000 tonnes of bones were being imported into England, with a further 26 000 tonnes being produced in England each year for industrial uses. Lawes successfully developed the first fertiliser product with superphosphate, a mixture of calcium phosphate and sulfate, and developed factories by the River Thames in London for their production.42 Bones were soon replaced with rock phosphates in the manufacturing process, and this had led to overmining guano rich deposits derived from bird droppings and the current debate around the criticality of ‘peak phosphate’ reserves.

Where Lawes and Gilbert were particularly innovative in their approach was to relate fertiliser products to field trial evidence so that the benefits of using fertilisers responsibly could be clearly seen by farmers. The trials set up at Rothamsted first showed clear crop yield benefits, but in time, further aspects of the plant, soil, and atmosphere system were understood. For example, the way in which plant nutrients became mobile in soils was determined by Lawes and Gilbert when they constructed field drain experiments to determine water balance and nutrient balance of crops. These experiments determined that nitrate remained soluble in soils and it was therefore mobile and leached from soils. This laid down the first understanding of potential nutrient pollution, and at the end of the twentieth century, nitrogen applications to crops are regulated in European Union member countries to reduce nitrate enrichment of water supplies.43 The field drain experiments at Rothamsted also determined how phosphate and potassium interacted with the water and soil system, providing the first understanding of readily available and slowly available nutrient pools in the soil due to the action of cation exchange.44 Thus, the Rothamsted trials that Lawes and Gilbert started were not only about demonstrating to farmers the worth of using Lawes fertilisers produced in his factories in East London, but they also established the foundation of understanding nutrient sustainability and innovation in farming systems.

The Rothamsted Classic experiments enabled the development of the fertiliser industry and now they offer important evidence for sustainability landmarks that can be demonstrated by field trials that have collected data since the 1850s. In particular, the development of phosphate fertilisers that not only made the fortunes of the founders but enabled the development of urban populations and reduced the reliance on guano fertilisers mined from South Atlantic islands. Phosphate remains a limiting nutrient globally, and the availability of phosphate reserves is likely to be of increasing importance to the world food production system.45 Field trial-derived innovations do not obtain market entry easily, as can be seen in Figure 2.1; the fertiliser recommendations identified by Lawes and Gilbert were not able to be fully implemented until the late twentieth century. The reasons for this were one of nutrient availability, regulatory considerations, and the ability to manage new fertiliser materials. The current market entry of genetically modified crops such as golden rice have taken over a decade to reach market so far, and it is perhaps not surprising it may take longer when we consider time lags between invention, product development, and market entry. All of the new technologies in the agricultural system, including nutrient use, liming, and pest control have time lags to market entry. Indeed, the questioning of whether delay is appropriate in a world where we need to increase production for security raises many issues.

web_c2-fig-0001
Figure 2.1.    The development of agronomic innovations and their relationship to average wheat yields in the United Kingdom. Red arrows show the recommended N : P : K fertiliser application (the fertiliser recommendation for wheat in kilograms per hectare) at that date, the actual amounts of fertiliser as N : P : K applied is shown with blue arrows (in thousand tonnes). Development of different wheat varieties are shown with black arrows, and new agronomic techniques are shown with green arrows. The graph demonstrates the agronomic development of the wheat crops and the innovations that have made dramatic grain yield increases possible.
Source:  The wheat yield data were obtained from FAO. FAOSTAT (2012). Production, crops (data set). http://faostat.fao.org/ (accessed 22 April 2014). Fertiliser data were adapted from the data presented by Cooke (1977),46 and agronomic practice data were developed by W. Martindale as part of an OECD Cooperative Research Fellowship (2001).47 (For a colour version, please see the colour plate section.)

The long-term data sets developed by these trials can support methods such as total factor productivity (TFP), which is used to assess the value of specific parts of the food supply chain, particularly with respect to economic output.48 These types of methodology can be integrated with measurements of ecosystem services so that they can be applied to the food system globally.49–51 The data from long-term experiments such as those at Rothamsted in the United Kingdom are crucial to the development of such assessments because historical data improve the projection and understanding of current growing season data. Figure 2.1 demonstrates this because wheat yield increases in the United Kingdom can be related to breakthroughs in plant nutrition, plant nutrient availability, and agronomic innovations.

2.11    The Relationship between Field Trials, Investments, and Innovation

The transfer of field trial research into agriculture and the food supply chain is crucial and can be regarded as the innovation process; that is, the transferring research to market-ready application. For this to happen, field trial research must be placed on farms in a user friendly form that can provide an assurance that optimal decisions are being made with regard to crop management and the food supply chain. As an example of research knowledge to market, the amount of protein in the leaf tissue of crops has been shown to relate to both nitrogen supply and the gas exchange of water vapour and carbon dioxide into and out of leaf tissue.52 Specific physiological responses, such as the regulation of water balance within a crop, relate to nitrogen supply and protein content of leaves, as well as how farmers will deploy management decisions such as fertiliser application and irrigation. It is therefore not surprising that attempts are made at using the amount of membrane-bound proteins or soluble proteins as indicators of productivity, disease, and stress in crops.53

Many environmental stresses experienced by crops will influence the amount and activity of these photosynthetic proteins present in leaves that contain pigments such as chlorophyll. The uses of chlorophyll sensors that have become commercially available are becoming routine to assess crop health and nitrogen fertiliser requirements of crops. The amount of chlorophyll in some plants is closely related to the amount of protein present, and thus chlorophyll can be used as an indicator of nutrient or protein status. Relating this to physiological problems with crops such as water stress and disease is now possible, and the use of metabolic markers such as the ‘greenness’ of leaves offers much hope in crop diagnostics and managing crop responses to environmental stresses. The importance of now-available chlorophyll meters is that they standardise measurements made in the field so that actions can be guided by robust research and reproducible measurements.54 These indicators of crop health, such as ‘green index’, do provide important diagnostic tools for crop management, and it is increasingly important that agron­omists have some understanding of crop biochemistry and physiology in order to be able to apply these methodologies.

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