Future plant nutritional research within a world context

– The perspective of a South African-based fertiliser company
 

DR KOOS BORNMAN; GENERAL MANAGER STRATEGIC AGRICULTURAL SERVICES, OMNIA FERTILISER

The understanding of plant nutrition has come a long way since the definition of plant nutrients as a “peculiar terrestrial matter” by the pioneers of plant nutritional research, Von Helmont (Flemish) and Woodward (British) during the mid-sixteen hundreds.

However, the world is facing a new challenge today in having to feed 2 billion more people by 2050 while there are more than a billion hungry people today. The requirements for more protein by the world, especially in the form of meat and the increase in mass production of crops for biofuel, have added to the complexity of the challenge.

Agricultural production will have to increase by 60% and 90% of that increase will lie in enhancing production efficiency and intensity. Such enhancement of production will include better understanding and management of plant nutrition as a primary objective, as 50% of the world is currently fed from produce off fertilised fields.

As Per Pinstrup-Anderson, the then director general of International Food Policy Research Institute (IFPRI), put it in 2000: “As long as agriculture remains a soil-based industry, major increases in productivity are unlikely to be attained without ensuring that plants have an adequate and balanced supply of nutrients.”

From 1960 to 2020, the world population will have tripled and the available land for food production will have halved. To add to the dilemma, world per capita cereal production, despite for instance the current steady growth of maize production of 120 kg per ha per year, did not increase. It actually decreased from 374 kg/capita in 1985 to 340 kg/capita in 2007 (Graph 1 and Graph 2).

Another dimension has been added over recent time and that is the concept of farming for health – not only to improve yield, soil fertility, profitability and to reduce environmental impact, but also to enhance human health. The new objective is food security (calories) as well as nutrition security (supply of all essential elements).

In an African context, it is ironic that sub-Saharan Africa that is looked at as the base for future additional food production (some argue that 70% of the growth in production will have to come from this continent), only uses on average approximately 6 kg of fertiliser per hectare and is regarded as containing the largest area of physical and economic water scarcity.

Against this background and its huge challenges, a fertiliser company needs to be strategically positioned and committed to investment in plant nutritional and agronomical research in order to contribute to meet said challenges and to gain and maintain a competitive advantage in a harsh commercial international environment by contributing in real terms on farm.

Omnia Fertiliser currently invests approximately R30 million in plant nutritional research per annum to meet the aforementioned challenges. In the following paragraphs, the primary research fields relating to plant nutritional requirements for the immediate future, as identified by world organisations and Omnia Fertiliser, with specific reference to grain crops, will be briefly mentioned.

Water use efficiency

Enhanced water use efficiency is by far the aspect most identified by international researchers as being able to make a difference to food production. Certain forms of fertiliser, for instance nitrates, enhance water use efficiency. The correct management of fertiliser can too enhance the water use efficiency of crops. One example is the fact that efficient fertilisation of pasture can halve the water requirement for the production of a unit of beef.

The other side of the coin is that nutrient use efficiency is substantially enhanced by effective irrigation and soil moisture management.

Nutrient use efficiency, especially nitrogen

The second most important factor emerging from international publications to make a difference in food production is nutrient use efficiency, especially that of nitrogen. It has been shown that nitrogen use efficiency is approximately 40% commercially in developed countries, but field trials done by the same countries have shown that efficiency rates of higher than 80% is possible.

Ohio State University in the US has shown that nitrogen use efficiency in maize could be enhanced from 45% to 80% by applying higher potassium levels than is accepted as the usual norm. The US has shown the efficiency of nitrogen use on maize as currently being 70 kg of maize grain produced per kg nitrogen applied (Graph 3). Omnia Fertiliser trials have proved in South Africa that it is possible to produce 113 kg of maize grain per kg of nitrogen applied on a sandy soil by using differential application.

It is clear that there is no silver bullet regarding nitrogen management, but that an integrated approach should be followed accommodating a magnitude of factors.

Best management practices and fully balanced nutrition

This age old, but still developing field of research is based on the often quoted 4R approach, meaning to apply the right product at the right rate, time and place. Sound practices of the past, such as fully balanced nutritional and liming programmes need to be built on (Graph 4), but more nutritional elements and their interaction should be considered. For instance, there are now officially 17 elements regarded as essential for plant nutrition.

Chloride and nickel have been added to the well-known list. In addition, there are so called beneficial elements, namely aluminium, cobalt, sodium, selenium and silicon that need to be considered. Plant nutritional elements do have an impact on soil life, which is a most important aspect in sustainable systems. New methods of plant and soil analysis and element detection are emerging that need to be utilised to their full extent. Moreover, new cultivars bred for drought tolerance and enhanced nitrogen use efficiency, will for instance become more prominent and will have to receive special attention regarding nutrition.

Nutrition strategies for conservation tillage systems

Linking to the previous point, good management includes the use of cover crops and soil conservation measures, the addition of organic matter to the soil and the judicious use of chemical fertilisers, pesticides and farm machinery.

It is however clear that no matter what conservation tillage system is to be followed, from limited tillage, strip-till to pure no-till or direct seeding, the base of adequate plant nutrition or soil fertility needs to be set with the absolute necessity of having to address any possible soil physical constraints. Defining such fertility thresholds and maintenance in different crop rotational scenarios is a major challenge.

Understanding the dynamics and efficiency of nutrients in increased mulch and trash systems is critical.

Precision farming and risk management

Technology in the field of precision farming is developing at a staggering pace. In most cases the basic understanding and utilisation of this technology, never mind its application, is poorly understood. One aspect is for instance that zone management regarding soil fertility should follow zone identification based on soil physical parameters, water holding capacity and drainage.

Precise and variable rate application of ameliorants, fertiliser and seed, bring more challenges. The biggest task at hand is the management and maximum utilisation of huge databases or “big data” to make a real difference at farm field level. Spatial interpretation of such integrated databases with geographic information systems, especially to identify and quantify risk, not only regarding plant nutrition, will be absolutely crucial.

Proximal and remote sensing is developing fast as well. New sensors (for nutrients too) are emerging on the nanotechnology front and these will be integrated in precision farming systems.

Product efficiency and environmental impact

Each fertiliser company will have to optimise its product efficiency to meet the new challenges, from factory to field. According to international publications, slow and controlled release fertilisers, stabilised fertilisers, fertilisers supplemented with trace elements and soluble/liquid fertilisers will continue to receive primary attention.

With the emphasis on the environmental impact of fertiliser and water use efficiency, renewed attention is given to nitrate based fertilisers. For instance it is a published fact that ammonium nitrate has 25% less impact on greenhouse gas production (CO2) per unit nitrogen, than urea and that nitrates enhance the water use efficiency of plants substantially (see below).

Elicitors and biostimulants

An elicitor is a substance that triggers a resistance and/or hypersensitive response in a plant. Specific nutrients (essential or beneficial), may act as elicitors. Elicitors activate genes involved with the defence response of plants.

Agricultural biostimulants include diverse formulations of compounds, substances and other products that are applied to plants or soils to regulate and enhance the crop’s physiological processes, thus making them more efficient. The important fact is that crop biostimulation is complementary to crop nutrition and crop protection. As the worlds of plant nutrition, stimulants and pesticides move closer to each other, it is important to understand the abovementioned relatively new concepts and their application.

Nanotechnology

This is probably the most misunderstood and misquoted technology under development today.

Nobel laureate, Richard Smalley, presented the benefits of nanotechnology to the US House Committee on Science in 1999. He emphasised that the impact of nanotechnology on the health, wealth, and lives of the people, will be at least equal to the combined influences of microelectronics, medical imaging, computer aided engineering and manmade polymers developed in the 20th century.

The literature pertaining to the role of nanotechnology in plant and soil systems demonstrates that nanomaterials may assist in the controlled release of agrochemicals for nutrition and protection against pests and pathogens, delivery of genetic material, sensitive detection of plant disease and pollutants and the protection and formation of soil structure.

Understanding the “cross talk” between nutrients, plant physiology and soil micro-organisms

This fascinating emerging field of research at molecular level, poses many opportunities and offers explanation to many field-observed phenomena. Recent publications for instance explain why sulphur nutrition of plants generate the plant hormones auxin and jasmonate, and why there is a link between nitrate feeding and iron acquisition as well as several hormones like abscisic acid responsible for the regulation of water in the plant. A part of this front of research is to understand the rhizosphere interaction with soil microbial populations to stimulate nutrient uptake and to generate specific hormones.

Making a difference on the farm

Omnia Fertiliser’s aim is to maximise its customers’ prosperity (reduced risk and increased marketable yield and quality) by leveraging off knowledge. Investing in such knowledge, but not making it practical on the farm, is futile. Producer participation, collaboration with other entities and disciplines and most importantly, technology transfer, is vital. One such example is the current multidisciplinary strip-till trials, where Omnia Fertiliser is involved as co-worker and sponsor with Grain SA.

Omnia Fertiliser strives to bring real, applicable knowledge to the South African producer and to producers in other countries where Omnia is present, by placing multiple feet on the farm and thereby hopefully contribute in a small way to feeding the world of tomorrow.

Primary references

IFPRI/FAO, 2000, Discussion paper 32: Integrated nutrient management, soil fertility and sustainable agriculture: Current issues and future challenges. Publication by IFPRI, Washington DC. ISBN 0-89629-638-5.
Maene, L. 2010, Identifying and examining the current challenges and opportunities faced by the fertiliser industry. An IFA web based publication, www.ifa.com.
Nielson, R.L. 2012. Advanced farming systems and new technologies for the maize industry. FAR conference, Hamilton, New Zealand. Published by Purdue University. 15 pages.
Van Biljon, J.J. 2009. Maize yield and fertiliser research over the last fifty years: An overview. FSSA Journal, June edition p 37 - 50.