Cover Image: https://ptes.org/hedgerow/hedge-structure/
Citation: Devereux, E.J., (2025), “Why Hedgerows Yield Big Results in Sustainable Food Systems”, EcoFoodDev, https://www.ecofooddev.com/why-hedgerows-yield-big-results-in-sustainable-food-systems/
Introduction
Hedgerow biodiversity is increasingly gaining attention in mainstream agricultural science – and with good reason. The biodiversity contained within hedgerows, and the ecosystem services hedgerows provide:
- are acknowledged as key in fighting climate change (for example the capacity of hedgerows for carbon sequestration and storage);
- from a future food security perspective, are central to the transition to sustainable, pro-environmental methods of modern agriculture.
We are aware that intensification of agriculture over the course of the 20th and 21st centuries was designed to boost food production for increasing populations. This was achieved by:
- the development of dwarf crop varieties;
- the advancement of agrotechnology and adoption of bigger, faster machinery;
- the consolidation of land into large high output industries,;
- intensive crop fertilisation;
- and pesticide use.
However, this has come at a cost to many aspects of the environment and has resulted in a stark reduction of farmland biodiversity.
Biodiversity in Agriculture
Farmland biodiversity provides multiple functions, and our hedgerows are key sources of this valuable biodiversity. Quantifying these multiple services provided by farmland hedgerows (shelter for livestock, pest control, soil health, reducing runoff, carbon capture and storage, genetic reservoir for crop research etc.) will be essential in the move towards a fully sustainable farming future. These services are not only vital for nature and our climate but are also vital to ensure that sustainable farming is economically viable for our farmers. Future sustainable farm management practices will look to hedgerows in the quest to find methods to increase soil fertility, crop yield, and reduce the dependency of farmers on chemical inputs.
Hedgerows have long been part of traditional farming systems around the world. “Traditional farming” generally refers to subsistence farming (that is farming for one’s own survival and not large scale, economically driven production) that use “primitive” agricultural techniques like animal power, indigenous tools, and organic manures (Hamadani et al., 2021) and incorporate indigenous ecological knowledge into the farming practices (for indigenous ecological knowledge please see https://www.ecofooddev.com/traditional-ecological-knowledge-indigenous-wisdom-global-climate-change/).
Hedgerows in Agriculture: Intercropping
In some agricultural systems, hedgerows are used for “intercropping”, also known as “alley cropping”. Intercropping is the sustainable farming practice of growing two or more crops in the same field at the same time (Andrews and Kassam, 1976). With hedgerows, this involves planting one or two rows of perennial trees or shrubs in close proximity in order to form hedges. These hedges are spaced 4–8 meters apart, and crops are cultivated concurrently in the spaces between the hedgerows. The hedges act as barriers prevent soil erosion and water run-off. Regular pruning of the hedges allows the trimmed material to be used as mulch, which aids in soil erosion control, reduces evaporation, reduces weeds, and adds nutrients to the soil. The intercropping system ultimately leads to better crop growth and increased productivity in a pro-environmental farming context (Kaushal et al., 2021).
Intercropping increases biodiversity, improving the ability of an agricultural system to deal with changes, such as extreme weather. Benefits of intercropping include improved yields and yield stability, enhanced use of water and nutrients, increased weed suppression, increased pest and disease resistance, reduced soil erosion and improved forage quality. A study from South America looked at intercropping of annual crops between Inga edulis (Ice-cream-bean) hedgerows in South America (García De León, et al., 2021) and found that:
- farmland with hedgerows supported significantly higher biodiversity than comparable farmland without hedgerows,
- that hedgerows significantly increased provisioning services linked to food and forage production in those systems,
- that biodiversity in farmland with hedgerows was broadly comparable to nearby natural habitats overall.
Commercial & Organic Farming
Hedgerows are gradually more focused upon in research into pro-environmental diversification on modern commercial farms. A Danish study compared hedgerows on organic farms and conventional/commercial farms, investigating their species richness, species composition, and soil factors. The results showed significant differences in pH, conductivity, and total nitrogen between farm types. The project indicates that organic hedgerows have higher species richness and a species composition more similar to semi-natural communities, making them more suitable habitats for declining species in the agricultural landscape (Aude et al., 2004).
Land Use Change & Biodiversity Loss
The shift towards intensive agriculture and mechanization throughout the 20th century brought significant impacts to hedgerows and their biodiversity. With the adoption of intensive agriculture, there was a trend towards creating larger and more consolidated/simplified fields. Traditional small-scale farming with diverse crops gave way to large monoculture fields. To accommodate larger machinery and optimize field operations, farmers removed hedgerows that impeded the movement of machinery and maximised the available land (Précigout & Robert, 2022).
This consolidation was, and is, driven by economic pressures of maximising profits, particularly as the costs of farming rise, as well as the pressure to conform with such government agri schemes such as REPs. This has resulted in habitat modification and loss, including the loss of hedgerows (Holden et al., 2019; Pelletier-Guittier et al., 2020).
Those hedgerows that remain are also being slowly degraded on most “conventional” (or commercial) farms through inappropriate management, neglect, and a lack of training available for farmers on hedgerow maintenance. Traditional grazing practices that allowed livestock to roam and graze along hedgerows were replaced by more intensive and confined livestock systems. With reduced grazing pressure, many hedgerows have become overgrown, leading to their decline.
Agri-environment Policy & Hedgerows
Throughout the twentieth century and continuing into the 21st, government policies and agricultural subsidies were established that unfortunately resulted in the removal of hedgerows to increase the available area for cultivation. Subsidies were often tied to the size of cultivated land, providing financial incentives to farmers to remove hedgerows and expand their fields- a difficult choice for many farmers, but one which could not be avoided due to the economic realities of farming for most. This was related to the single farm payment (SFP or BPS for basic payment scheme), which maps out “productive” land on individual farms. The subsidy is paid by the hectare; and so the more land you have, the higher your payment will be. But to get the full amount, the land must be so-called ‘agricultural land’ used to grow grass and crops.
In this way, the retention of features such as hedgerows would result in a loss of subsidy to the farmer. Hence, apart from not being incentivized to promote nature on farms, for many years, farmers have been penalised to do so. The Common Agricultural Policy, which contains the single farm payment, is an EU-wide policy, but each individual member state acts as the competent authority and dictates how the subsidy is paid at a national level. There is now a significant shift towards agri-environmental schemes and pro-environmental diversification on farms, which include a focus on hedgerow retention and management (pers. obs; Mooney, S., Carter, A, Hynds, P., Macken-Walsh, A., Henchion, M., O’Brien, D., Devereux, E.J., Markiewicz-Keszycka, M., 2023, On-farm pro-environmental diversification: Actions taken to diversify, challenges encountered. A thematic analysis of narrative interviews with Western-European farmers. Journal of Agroecology and Sustainable Food Systems).
Despite their prevalence and multi-functionality, the full extent of hedgerow biodiversity remains inadequately quantified and understood. Conservation policies in Ireland are primarily enshrined in national legislation, particularly in agriculture-focused schemes and County Development Plans. However, the mere existence of legislation does not guarantee hedgerow conservation, as they continue to face removal for purposes of agricultural intensification and urban development. Furthermore, the lack of adequate training in hedgerow monitoring, assessment, and conservation contributes to poor hedgerow management practices. All this needs to change.
This post has provided a high level introduction to the potential for hedgerows in a sustainable farming and future. In the upcoming posts we will delve more deeply into this potential, and the value of hedgerows in achieving our climate targets and paving the way for a pesticide-free food future.
References
Hamadani, H., Rashid, S.M., Parrah, J.D., Khan, A.A., Dar, K.A., Ganie, A.A., Gazal, A., Dar, R.A. and Ali, A., 2021. Traditional farming practices and its consequences. Microbiota and Biofertilizers, Vol 2: Ecofriendly Tools for Reclamation of Degraded Soil Environs, pp.119-128.
Andrews, D.J. and Kassam, A.H., 1976. The importance of multiple cropping in increasing world food supplies. Multiple cropping, 27, pp.1-10.
Kaushal, R., Mandal, D., Panwar, P., Kumar, P., Tomar, J.M.S. and Mehta, H., 2021. Soil and water conservation benefits of agroforestry. In Forest resources resilience and conflicts (pp. 259-275). Elsevier.
García de León, D., Rey Benayas, J.M. and Andivia, E., 2021. Contributions of hedgerows to people: a global meta-analysis. Frontiers in Conservation Science, 2, p.789612.
Aude, E., Tybirk, K., Michelsen, A., Ejrnæs, R., Hald, A.B. and Mark, S., 2004. Conservation value of the herbaceous vegetation in hedgerows–does organic farming make a difference? Biological conservation, 118(4), pp.467-478.
Précigout, P.A. and Robert, C., 2022. Effects of hedgerows on the preservation of spontaneous biodiversity and the promotion of biotic regulation services in agriculture: towards a more constructive relationships between agriculture and biodiversity. Botany Letters, 169(2), pp.176-204.
Holden, J., Grayson, R.P., Berdeni, D., Bird, S., Chapman, P.J., Edmondson, J.L., Firbank, L.G., Helgason, T., Hodson, M.E., Hunt, S.F.P. and Jones, D.T., 2019. The role of hedgerows in soil functioning within agricultural landscapes. Agriculture, ecosystems & environment, 273, pp.1-12.
Mooney, S., Carter, A, Hynds, P., Macken-Walsh, A., Henchion, M., O’Brien, D., Devereux, E.J., Markiewicz-Keszycka, M., 2023. On-farm pro-environmental diversification: Actions taken to diversify, challenges encountered. A thematic analysis of narrative interviews with Western-European farmers. Journal of Agroecology and Sustainable Food Systems.
