International Fertiliser Society
PROCEEDINGS:
Proceedings from the late 1940s
available from this website. Start your search
MEMBERSHIP:
Contact the secretary to obtain
further membership details. Enquire

Events


2018 IFS Agronomic Conference
5 Dec 2018 - 7 Dec 2018
MEMBER LOGIN: USERNAME:   PASSWORD:   Forgot password? Privacy Statement
Header4 Overlay

2018 IFS Agronomic Conference

5 Dec 2018 - 7 Dec 2018

Robinson College, Cambridge, United Kingdom

The theme of this year's Conference will be 'Soils and Fertilisers: Management to Improve Nutrient Use Efficiency'.

The Conference will feature eleven papers, covering topics such as soil structure and fertility management, the effect of soil condition on dairy grassland productivity, soil carbon, the 4 per mille approach, soil calcium, practical soil health management, and an evaluation of soil testers. We are particularly pleased to host a presentation from Achim Dobermann, CEO of Rothamsted Research, covering his views on the need for a new approach to innovation in soil and nutrient management. 

The presentations will again be augmented by a varied display of posters, while the Conference will host the final of the 2018  Brian Chambers International Award for Early Career Researchers in Crop Nutrition.

If you would like to submit an abstract of a poster that you wish to display at the Conference, please e-mail this to the Society Secretary at the address in the footer at the bottom of this page.

There will also be ample opportunities for valuable networking, including the Conference dinner.

For those of you in the UK, attendance at this conference is worth ten BASIS FACTS points.

To help you with your travel plans, many delegates consider the Conference to start on the evening of Wednesday 5th December, when an informal dinner provides excellent opportunities for networking.  The formal proceedings start at 09.00 on Thursday 6th December, and finish at lunch time on the 7th.  The dinners on both the Wednesday and Thursday evenings are both inclusive of wine and thus provide excellent value.

Registration for the conference is now open.  This can be done either by downloading the registration form as a Word document, and then sending this to the Secretary, or by completing the online version of the form.

Information on the presentations for this year's Conference is shown below. 

 

Achim Dobermann, Rothamsted Research, UK

Accelerating innovation in soil and nutrient management - the need for a new approach

This presentation will provide a vision for speeding up innovation in soil and nutrient management. The new Sustainable Development agenda requires tailored, integrated solutions that ensure greater precision and efficiency in managing soils and nutrients along the whole food chain. Despite incremental progress made in past decades, the general paradigms and methods for how we assess soils and translate that information, along with other data, into recommendations for nutrient management have changed little. Limitations that are inherent to this approach constrain its future applicability, particularly also for making faster progress in developing countries.

New thinking and new diagnostic technologies now provide an opportunity to shift the traditional paradigms towards data-driven know-how solutions for nutrient management. Exploiting these opportunities will require a leaner, faster science and innovation culture that can take full advantage of advances in many disciplines. It will also require new models for public-private partnership, generally following a more collaborative and open innovation culture.

 

Gerard Govers, KU Leuven, Belgium

Soil erosion in the EU and its implications for soil fertility management

Sloping agricultural land is, anywhere in the world, subject to soil erosion and it has long been established that this also leads to significant nutrient losses. While it is relatively easy to compensate for the on-site effect of these losses, in the context of intensive agriculture the magnitude of these losses at a continental/global scale is economically very significant.  Furthermore, nutrient losses have detrimental effects on aquatic environments downstream of agricultural land. In this paper I briefly revise the magnitude of nutrient losses from agricultural land and their implications. However my main focus is on the development of a vision on how these losses can be reduced, which is a prerequisite for the development of a sustainable agricultural system.

While the necessary agricultural technology to reduce erosion to near-natural levels on agricultural land does exist, it is also clear that simply promoting the application of measures such as conservation agriculture is not sufficient, as the uptake of these techniques by farmers often remains limited. Reducing nutrient losses from erosion cannot only be achieved through erosion control at the field scale, however. Two key observations are important here : (i) Soil loss is generally most important on steep slopes and (ii) agricultural yields are generally lower on sloping land. Thus, erosion at the regional/continental scale can be greatly reduced by setting aside the steepest land and concentrating arable crops in the flatter areas. Also, within Europe there is considerable scope for such an approach as, in many regions, yields are still well below what is attainable. It is therefore possible to achieve the same agricultural output while using significantly less arable land.

Adapting such an approach will not solve all erosion problems, as some erosion-prone land use, such as vineyards, cannot be simply moved to flatter land. Effective erosion control will therefore require a general implementation of soil conservation technology, in combination with the intensification of arable production on the best suited arable land, while setting aside erosion-prone land. By doing so, we will reap important additional benefits in terms of soil carbon storage, water use efficiency and biodiversity conservation, because the spared arable land can be used for other purposes, such as nature conservation. Indeed, soil erosion is far from the only negative environmental effect of agriculture that can be reduced by smart intensification.

 

Anne Bhogal1, Paul Newell Price1, Paul Hargreaves2, Joanna Cloy2 and John Williams3

1ADAS Gleadthorpe, Mansfield, UK; 2SRUC Edinburgh, UK; 3ADAS Boxworth, Cambridge, UK

Structural condition of agricultural soils in the UK

The maintenance of good soil structure is central to the delivery of resilient, sustainable and economically productive cropping systems.  Soil structure, consistence and porosity influence crop root proliferation (and hence water and nutrient use efficiency) and the movement of air and water through soils. Consequently, poorly structured and compacted soils are often associated with lower crop yields, higher inputs (nutrients, energy) and an increased risk of flooding, run-off and erosion, leading to soil and diffuse pollution to watercourses. 

Damage to soil structure largely arises due to compaction as a result of vehicle and livestock trafficking, particularly when soils are wet. Late-harvested crops are particularly susceptible, as are soils with low organic matter content. Compaction can be identified through field assessments of soil bulk density or penetrometer resistance, but visual soil evaluation (e.g. Visual Evaluation of Soil Structure - VESS) provides an overall assessment of soil structural condition and is a useful tool for guiding soil management. Visual evaluation techniques should be practical and accessible for farmers and advisers and can be used to quantify soil structural condition and aid decision making at the field level.

This paper considers the importance of soil structure to crop productivity and nutrient use efficiency and looks at the use of visual soil evaluation techniques for assessing soil structural condition. We report on the current condition of agricultural soils in UK, summarising the key issues identified by recent surveys of arable, horticultural and grassland soils. Finally we explore ways of restoring and maintaining good soil structure in order to improve root growth, nutrient use efficiency and water infiltration.

 

Paul Hallett, Aberdeen University, UK

Management of soil structure to improve Nutrient Use Efficiency

This talk will focus on soil physical constraints to nutrient use, and how these can be mitigated through better soil management and crop traits.  Soil structure degradation is widespread, leading to poor root growth and losses of nutrients.  In a broad survey of commercial farms in Scotland, we found about 20% had severely degraded soil physical structure that was easily detected visually. More in-depth analysis in another survey found a third of farms had mechanically impeded topsoils.  In such compacted soils, plant roots rely on macropores as growth pathways, having a large impact on root architecture that we found varied between crop genotypes.  Compaction decreases the effectiveness of fertilisers as poorer aeration accentuates denitrification, and physically constrained roots can explore less soil for available nutrients. Crops bred to root deep to capture leached fertilisers may remain restricted above the plough pan.

Plants have a great capacity to re-structure degraded soils, thereby altering the physical environment at the root-soil interface to improve nutrient capture.  Root exudates have well-known chemical and biological impacts to nutrient capture and cycling, but we have also found they can mechanically disperse soils, potentially aiding the release of immobile nutrients bound to soil.  By dropping the surface tension of pore water, exudates may ease capture of water and entrained nutrients, and they can act as hydrogels that mediate water stresses.  Over time, microbial decomposition of exudates and the hydromechanical action of the plant root creates a thin zone at the root-soil interface termed the rhizosphere.   Root hairs permeate into the rhizosphere, capturing nutrients and creating a highly aggregated pore structure that improves oxygen transport and biological habitats.

Great scope exists in crop breeding to exploit plant root traits like hairs, exudates and architecture to improve nutrient use efficiency.  Coupled with improved soil management, exploiting these traits could help mitigate the widespread soil structure degradation that has been found globally. 

 

David Wall, Teagasc, Ireland

Nutrient balances and soil condition: effects on dairy grassland productivity

 

Davey Jones, Bangor University, UK

Evaluating soil sensors to inform fertiliser rates, using a nitrogen case study

Typically, 40-60% of the nitrogen (N) fertiliser added to the soil does not end up in the crop but is lost to the wider environment. Improving N use efficiency in both arable and grassland systems therefore represents a key industry challenge. This can be achieved in a range of ways including: (i) improving fertiliser formulation, (ii) precision fertiliser placement, (iii) use of more N use efficient plant genotypes, (iv) better management of the soil microbiome, and (v) adoption of sensor technologies allowing measurement of soil and plant N status in real-time.

Theoretically, deployment of N sensing technologies will allow us to better match N fertiliser application to plant demand, thereby enhancing efficiency. While a range of plant canopy sensors are available for estimating foliar N status, ranging from hand-held devices through to airborne drones and satellite imagery, no sensors are commercially available for in situ soil N monitoring. It is possible that soil-based sensors are superior to canopy-based sensors as they provide a better indicator of when soil N reserves are running low, well before N deficiency symptoms become evident in the crop. In this paper, we will critically evaluate the robustness of soil N sensors in guiding N fertiliser management in cereal cropping systems. We will focus on the laboratory- and field-based testing of a range of integrated sensors for predicting N supply and demand. Further, we will provide an overview of the pros and cons of each technology and knowledge gaps that need to be addressed to promote technology adoption.

 

Philip White and and Jonathan Holland, James Hutton Institute, UK 

Calcium in plant physiology and its availability from the soil

Soils vary greatly in their calcium (Ca) content. The Ca content of soils affects the adsorption and release of exchangeable cations and the pH of the soil solution. Thus, soil Ca content influences the availability of both nutrients and toxic elements to plants and soil biota, affecting community composition and biological activities. Calcium also influences soil physical properties through its effects on soil aggregation and dispersion processes. Soils with a large Ca content are described as calcareous and their properties differ from non-calcareous soils. Calcareous soils are mainly located in arid regions and are generally slightly alkaline, often containing >15% CaCO3. However, their agricultural productivity can be high when adequate water and nutrients are supplied. Most non-calcareous soils contain sufficient Ca for crop production, particularly if calcareous lime is applied to correct the pH of the soil solution. However, Ca deficiencies can occur in crops grown on acidic sandy soils with low Ca content and are often observed when plants are grown hydroponically.

Calcium is one of the fourteen mineral elements required by plants. It has unique roles in maintaining the expansion and structural integrity of cell walls and lipid membranes and as a cytosolic signal coordinating cellular responses to developmental and environmental stimuli. It also has nonspecific roles in maintaining cation-anion balance and osmoregulation under particular environmental conditions. Plant species vary greatly in their tissue Ca concentration, and Ca requirement, which is largely determined by the cation exchange capacity of their cell walls. Calcium enters the root from the rhizosphere and much Ca is thought to move apoplastically (extracellularly) across the root to the stele, where it is loaded into the xylem for transport to the shoot. In the shoot, Ca follows the transpiration stream and is not re-translocated from leaves in the phloem. Thus, Ca deficiency symptoms occur in developing tissues when the immediate Ca supply from the root is insufficient for growth.

This article will describe the occurrence and properties of soils with contrasting Ca contents, the uptake and movement of Ca within plants, the roles of Ca in plant physiology, and the requirements of Ca by different crops. It will then focus on the management of Ca availability in soils for greater crop production and produce quality. 

 

Jens Blomquist, Uppsala University, Sweden

Calcium, soil structure and nutrient availability

The structural improvement of soil, following the application of lime, affects aggregate stability, aggregate size distribution, crop yield and micro nutrient availability.  Structurallime in the form of calcium oxide (CaO) and hydroxide (Ca(OH)2) can react with clay minerals in soils, thereby influencing the physical properties and modifying aggregate formation. The effect is often attributed to a series of reactions such as cation exchange, flocculation, lime carbonation and pozzolanic reactions (cementation).

One of the desired consequences of increased aggregate stability is reduced losses of particulate phosphorus. For this reason structural liming has been subsidised in environmental programmes in Sweden since 2009/10. The aim is to encourage measures to prevent losses of phosphorus from clay soils. The commercial products used are mainly mixes of calcium carbonate (CaCO3) and slaked lime (Ca(OH)2).

Aggregate stability is often estimated through measurements of turbidity (clay dispersion) on leachates from aggregates after rain simulation or after immersion of aggregates in water. In different studies over the last few years structural lime has demonstrated the ability to significantly decrease turbidity, indicating increased aggregate stability.

Also linked to changes in aggregate stability are variations in the aggregate size distribution. Measurements in the seed bed show that structural lime can lead to a higher proportion of fine aggregates and a lower proportion of coarse aggregates, thereby improving the soil tilth. This means in turn an improved protection against evaporation, assisting rapid crop emergence under dry conditions.

The yield response to structural lime varies with different crops. Field trials with sugar beet often show consistent and significant yield increases for lime amendments of any type. Positive yield responses can be interpreted as coupled with soil physical changes, such as improved aggregate size distribution or less slaking/crusting. Negative crop responses can be attributed to soil chemical changes, such as decreased availability of micro nutrients (eg Mn, Zn, Fe, Cu) which has been measured both in top soil and in barley grain after treatment with structural lime.

 

David Powlson, Rothamsted Research, UK

4 per mille: - a way of sequestering soil carbon?

The quantity of carbon (C) held in organic matter in the world's soils to a depth of 1m is estimated at about 1500 Gt, about twice the amount currently in atmospheric CO2. Soil organic carbon (SOC) has declined over several centuries due to clearance of natural vegetation and conversion of land to agriculture, thus releasing additional CO2 to the atmosphere. If some of this C could be restored to the soil it would slow the current rate of increase in atmospheric CO2 concentration - a process termed climate change mitigation through soil C sequestration. Over some 30 years, estimates have been made of the extent to which such C sequestration is feasible; a recent expression of the idea is the "4 per mille" initiative launched at the Paris Climate Conference in 2015. The initiative proposes that, if the global SOC stock was consistently increased at the rate of 0.4% (4 parts per 1000, 4‰) of the current value annually this would offset all CO2 emissions from fossil fuel burning. The initiative has provoked considerable debate over whether this rate of increase is possible over significant areas of the globe.

At Rothamsted Research we recently re-analysed SOC data from our long-term experiments, providing 114 treatment comparisons on 3 soil types over 7 to 157 years. We found that, with drastic changes to soil management or land use, the annual 4‰ rate of SOC increase was met or exceeded, in some cases over many years. But within management practices that are more easily adopted in practice it is very difficult to reach this rate of increase. Most farmers do not have access to sufficient manure. In addition, the large applications that would be required would cause serious pollution of water by nitrate and phosphate and are not be permitted within Nitrate Vulnerable Zones. For these, and other, reasons we consider that the 4‰ annual rate of SOC increase is unachievable in most agricultural situations and cannot be regarded as a major contributor to climate change mitigation. Smaller increases in SOC will improve soil quality and functioning, especially as small increases can have disproportionately large beneficial impacts, though not necessarily translating into increased crop yield. 

 

Renske Hijbeek1*, Hein ten Berge2, Martin van Ittersum1 and Andy Whitmore3

Evidence review indicates a re-think on the impact of organic inputs and soil organic matter on yield

In recent years, a number of studies have reviewed existing evidence of the additional yield effect of soil organic matter or organic inputs (such as compost, animal manure or crop residues). The additional yield effect is considered as any effect on crop yields not related to supply of macro-nutrients (N,P,K), by improving soil structure, water holding capacity, disease suppression or supply of micro-nutrients. Mentioned studies often used meta-analyses, thereby combining data from multiple field experiments into one response variable. Understanding the additional yield effect is necessary to contextualize current policy proposals on soil carbon sequestration and for farmers' recommendations on soil management.   

To assess the additional yield effect, studies have used different response variables (e.g. assessing effects on agronomic nutrient use efficiencies, on attainable crop yields or comparing yields at equal nutrient supply), included different crops and/or focused on different geographical regions. Some studies had global coverage, while others focused on a specific continent or country. Not surprisingly, outcomes of these studies therefore differ. Some general trends can however be observed. Especially cereals cultivated in temperate climates seem to benefit relatively little from soil organic matter or organic inputs while most crops cultivated in tropical climates benefit more. This contribution to the IFS conference explains current available methodologies to assess the additional yield effect of soil organic matter and highlights the most relevant results and implications.

1Plant Production Systems, Wageningen University and Research

2Agrosystems Research, Wageningen University and Research

3Sustainable Soils and Grassland Systems, Rothamsted Research

* renske.hijbeek@wur.nl 

 

Elizabeth Stockdale1 Bryan Griffiths2, Paul Hargreaves3 and Anne Bhogal4 

Developing a practical and relevant soil health measurement toolkit

Soil physics, chemistry and biology are interlinked and all play a role in maintaining productive agricultural and horticultural systems. While physical and chemical properties of soil are relatively well understood, the same is not necessarily true for soil biology. In recent years, interest in soil health has increased and a range of indicators for soil biology has been developed. These indicators, however, often have not been produced in parallel with the necessary guidance and tools to allow them to be exploited on farm. At the same time, farmers and growers have taken the initiative to understand the health of their own soils and a great deal of work is being done on-farm to experiment with ways to optimise soil biology and health. Within a five-year cross-sector programme of research and knowledge exchange (AHDB and BBRO, Soil Biology and Soil Health Partnership, 2017-2021), we are working to support farmers and growers to maintain and improve the productivity of UK agricultural and horticultural systems, through better understanding of soil biology and soil health. The Partnership will work closely with farmers, growers and advisers to draw together and build on knowledge and experience to create accessible guidance and tools to help farmers improve soil health.

This paper will describe some of the initial steps taken, and challenges faced, in the development and testing of a rotational soil health scorecard for routine use on farm. We have compiled a list of 45 of the most relevant biological, physical and chemical indicators for soil health that had been studied. These indicators were then scored using a logical sieve approach to ensure an objective outcome. The criteria used considered relevance to both agricultural production and environmental impact and practical aspects including sample throughput, sample storage, necessity of single or multiple visits for sampling, ease of use, ease of interpretation, sensitivity, cost, standardisation and UK availability. We were thus able to reduce the potential list of indicators to 12 (pH, routine nutrients, loss-on-ignition, microbial biomass, respiration, nematodes/earthworms, visual assessment of soil structure (VESS), bulk density, water infiltration) that will be used, in a provisional soil health scorecard during the Programme. Working with feedback from the industry, we have developed a provisional scorecard that uses a 'traffic light' system to give a visual overview of the status of each indicator drawing on existing knowledge of threshold values to delineate the categories. So, green - amber - red representing low - moderate - high risk of reduced yield and sub-optimal soil conditions We recommend that the indicator results be benchmarked for comparison over time and across pedoclimatic zone. Soil health monitoring from existing medium- and long-term trials and on-farm will be used throughout the programme to validate and optimise the scorecard. Some initial results from the 2018 cropping season will be presented.

  1. NIAB, Huntington Road, Cambridge, CB3 OLE
  2. SRUC Edinburgh Campus, King's Buildings, West Mains Road, Edinburgh, EH9 3JG
  3. SRUC, Dairy Research Centre, West Mains Road, Edinburgh, EH9 3JG, UK
  4. ADAS Gleadthorpe, Meden Vale, Mansfield, Notts, NG20 9PF, UK

 

We are grateful for the support being provided for the Conference by these organisations. 

 2018 Ag Conf sponsor logos