Strip cropping, autonomous vehicles and regenerative agriculture. Can crop productivity and resilience be improved through combining technology with traditional techniques?

Secondary Supervisor(s): Dr Ed Dickin, Dr Simon Jeffrey

University of Registration: Harper Adams University

BBSRC Research Themes: Sustainable Agriculture and Food (Plant and Crop Science)

Project Outline

One way to help achieve sustainable intensification of agriculture is to improve resilience of crops to biotic and abiotic stresses such as pest outbreaks and weather extremes. Monocultures can be vulnerable to extreme shocks as all individuals are at similar risk from weather, disease, pests and weeds. Crop diversification can build resilience in agricultural systems. Intercropping or polyculture (growing several crops together) offers advantages in control of pests, disease and weeds, while providing greater diversity, for example for natural pest control and soil protection (Brooker et al. 2015).

Mixed intercropping requires species that can be grown together and harvested at the same time. The crops are separated post-harvest. In contrast, in a strip intercropping system, crops can be sown and harvested at different times (relay cropping) meaning there is no need for post-harvest separation.

Strip intercropping introduces spatial and genetic diversity, disrupts the lifecycles of weeds, pests and diseases, and increases resilience. Relay crops also benefit from temporal complementarity (Wang et al, 2023) in their use of resources (light, water and nutrients). For example, growing winter barley with spring beans allows each plant best access to available resources at the most appropriate time (late spring for winter barley when the neighbouring spring bean plants are small, and mid-summer for the beans). Relay cropping also avoids having the whole field bare at the same time, achieving two principles of Regenerative Agriculture – living roots in the soil for much of year, and cover of the soil.

Narrower strips (1 to 2m) may provide greater benefits, as a higher proportion of plants are in edge rows, but conventional farm machinery imposes a minimum strip width of at least 4m (narrowest commercial combine header width). Autonomous vehicles such as small robots offer a solution, perhaps several working as a swarm to replace one larger manned vehicle. Autonomous vehicles at Harper Adams University enable us to utilise 2m strips. Use of smaller, lower mass machines operating in a controlled traffic farming strip cropping system, may also contribute to greater soil health.

Aim and Objectives

The aim of this PhD is to investigate the potential of narrow strip cropping for improving the agronomic and environmental aspects of crop production systems. The project will investigate multiple aspects of the system.

The key objectives are to:

1. Investigate:

a) the impact of strip cropping on resource use (e.g. light, nutrients and water) by arable crops.

b) the agronomic impacts of strip cropping on weed, pest and disease control, and soil health within arable systems.

2. Evaluate the overall plant productivity impacts of strip cropping, and the associated effect on yield and on land equivalent ratio (LER).
3. Evaluate the potential of strip cropping to deliver temporal complementarity.
4. Make recommendations for practice, policy and research on the future potential for strip cropping in productive systems.

To achieve the objectives we anticipate using:

• A desk review (systematic map) of existing research to collate existing evidence relating to the relevant impacts of strip cropping.
• Field plot experiments to include: crop measurements using standard techniques.
• Biodiversity measurements (beneficial and pest invertebrates, weed counts), soil testing (nutrients, water, soil biodiversity).
• A cost/benefit analysis combining primary research from the field trial with desk studies/expert elicitation on the potential costs and wider benefits of strip cropping.
• Farmer engagement activities to support the experimental findings and inform outputs/advice to farmers/policy makers/commercial companies on the establishment and management of strip cropping in order to maximise productivity and practical implementation.

References

Brooker, et al., 2015.New Phytologist,206(1), pp.107-117.

Wang, et al., 2023.Field Crops Research,291, p.108757.

The potential of waste wool as a soil amendment to improve plant productivity and agricultural resilience

Secondary Supervisor(s): Dr Laura Vickers, Dr Samuel Eze

University of Registration: Harper Adams University

BBSRC Research Themes: Sustainable Agriculture and Food (Plant and Crop Science)

Project Outline

Increases in frequency and severity of extreme weather events such as drought and waterlogging adversely affect agricultural productivity. Regenerative agriculture or agroecological practices are being encouraged to deal with some of these issues. Reducing or re-using waste products in agricultural systems may help support these approaches.

Over 1 million tonnes of wool are produced globally each year, of which up to 30% is wasted during sorting and processing. Use as a soil amendment may offer an alternative for waste wool. Previous studies have indicated that wool-amended soils have higher nutrient and water holding capacity than controls¹. Also, wool dust in soil can delay the onset of drought conditions by up to 3 days².

Existing research is limited in productive systems. Pilot studies at Harper Adams University investigating the potential of raw sheep wool as a biological soil amendment for lettuce plants indicated that it may help reduce the impacts of water stress on crop yield, but the mechanisms are unknown.

Aims and Objectives

The aim of this PhD is to investigate the potential of waste wool as a soil/substrate amendment to improve the water and nutrient use efficiency of plant species in productive systems.

The key objectives are to:

a) Conduct an evidence review to establish the optimal integration of wool into substrates, and quantify and test the findings

b) Develop protocols for the evaluation of the potential of wool as a soil amendment.

c) Develop protocols to quantify the impact of water stress on the plant physiology and performance in different growing substrates.

d) Evaluate the interactions between wool, substrates, water conditions, and their combined impacts on plant physiology and productivity

e) Compare potential costs and benefits of utilising wool as an amendment within commercial production systems and evaluate how best to utilise wool and/or other natural waste products, within plant growing systems

f) Make recommendations to the farming community for the use of wool with substrates

To achieve the objectives we anticipate using:

• A systematic evidence map (desk study) of research into the impacts of wool amendments on parameters of relevance to plant production potential (eg. yield, water content, essential plant processes such as transpiration and photosynthesis).
• Nutrient/pollutant testing of washed/unwashed raw wool & processed wool (eg pellets).
• Methods for incorporation of wool into growing substrates.
• Controlled experiments (glasshouse/polytunnel/semi-field) into

a) water stress conditions, and their impact on the productive potential of model plant species (yield, biomass, biochemistry, water potential)

b) interactions between wool and environmental factors (eg. soil/substrate type, watering regime, temperature, method of application of wool etc.) and relevant outcomes (eg. nutrient use efficiency, plant quality and yield components, water use efficiency, and postharvest quality and longevity.)

• Desk studies/expert elicitation on the potential costs and wider benefits of wool/other natural waste products (eg. reducing reliance on peat, impacts on soil community diversity, enhanced nutrient/ water holding capacity or nitrogen fixation ability), and used to inform a cost/benefit analysis.

The findings will be used to provide advice to farmers/policy makers/commercial companies on the use of wool (or other waste products) as a soil amendment. Advisory notes, infographics, farmer events and our farmer networks will be used to disseminate findings.

References

1. Abdallah A et al. (2019) The potential of recycling wool residues as an amendment for enhancing the physical and hydraulic properties of a sandy loam soil. International Journal of Recycling of Organic Waste in Agriculture 8 pp.131-143.
2. Gabryś T and Fryczkowska, B. (2022) Using Sheep’s Wool as an Additive to the Growing Medium and its Impact on Plant Development on the Example of Chlorophytum comosum, Journal of Ecological Engineering 23(6) pp.205-212.

Sainfoin as an alternative legume forage to support livestock health, biodiversity, and reduced emissions

Secondary Supervisor(s): Dr John Reade, Dr James McCaughern

University of Registration: Harper Adams University

BBSRC Research Themes: Sustainable Agriculture and Food (Animal Health and Welfare, Plant and Crop Science)

Project Outline

Climate change scenarios suggest that alternative forage plants may help meet policy requirements to reduce the environmental impact of agriculture, whilst also increasing the resilience of farmland areas to environmental change.

Sainfoin (Onobrychis viciifolia) is a perennial forage legume. In the UK, it is not commonly used outside of thin alkaline soils in the South of England, but like other legumes, Sainfoin offers soil benefits due to nitrogen fixing properties. Sainfoin contains proteins, and also tannins which are thought to a) reduce the amount of methane provided by ruminants, and b) reduce bloating. Tannins can also result in rapid liveweight gains by aiding protein absorption. Potential additional benefits of Sainfoin are drought resistance and ability to grow on poor soils, which may be a good choice for regenerative agriculture systems. Sainfoin is good for encouraging pollinators. It has been shown to disrupt the lifecycle of parasitic worms in Europe.

Preliminary desk reviews at Harper Adams investigated the establishment and nutritional value of Sainfoin, and early stage experiments indicate that Sainfoin establishes well under a variety of soil types although water availability appears to be a limiting factor.

These findings indicate that Sainfoin may have the potential to be more widely used in forage than previously thought.

Aims and Objectives

The aim of this PhD is to investigate the potential of Sainfoin to support diversification of forage legumes for improved animal health and to support environmental sustainability.

The key objectives are to:

a) Investigate the opportunities and limitations for expansion of Sainfoin into forage systems in the UK.

• Glasshouse and field experiments will evaluate the impact of environmental factors for the establishment and growth of Sainfoin. Factors to be investigated may include, soil type, watering regime, temperature, variety of Sainfoin, associated plant communities/sward diversity etc.

b) Investigate how best to utilise Sainfoin within ruminant diets to improve weight gain and reduce emissions intensity.

• Different varieties and lifestages of Sainfoin/Sainfoin forage within broader mixes (and controls) will undertake a full proximate analysis to determine their feeding value within a variety of farm animal production systems. The resulting values will be introduced into dietary formulation models in order to predict animal performance, costs of production, and emissions intensity.

c) Compare the potential costs and environmental benefits of Sainfoin with other forage crops.

• Primary research from a) and b) will be combined with desk studies/expert elicitation on the potential costs and wider benefits of Sainfoin (such as pollinator support nitrogen fixation ability) compared with other forage plants, and used to inform a cost/benefit analysis. Where specific research gaps are found, further primary research (eg pollinator visits, soil sampling in field experiments) may be carried out to investigate the environmental parameters.

d) Make recommendations to the farming community for the use of Sainfoin within forage, and the potential benefits that may be gained.

• Findings from Objectives a and b will be used to provide advice to farmers/policy makers/commercial companies on the best varieties of sainfoin to use, and how to manage it, in order to maximise it’s establishment under local conditions, and nutritional benefits to livestock, particularly ruminants. Advisory notes, infographics, farmer events and our farmer networks will be used to disseminate findings, and will also include advice on potential benefits of Sainfoin.

We anticipate findings will inform farmers/policy makers considering diversification of their forage, particularly where they want to:

• Establish mixed species into existing lays to reduce the need for fertiliser and to improve drought resilience.
• Improve forage quality.
• Reduce methane emissions.
• Move to more resilient/regenerative systems.