The previous post explored how tropical legumes can contribute to greater agricultural efficiency. Today we will discuss how they can contribute to greater resilience.
State-of-the art climate models have established that (because of anthropogenic emissions) global land and sea temperatures will continue to warm for at least the next two decades regardless of what intervention we collectively take 1. We must therefore tailor our crops to withstand the very high certainty of continued global warming. The tropical zone is particularly vulnerable, where extreme temperatures are already common and the risk of high magnitude events such as tropical storms is high 1.
Since the mid-1970s, the tropics have warmed at an average rate of 0.2°C per decade 2. On this trajectory, we are looking at a total baseline shift of ~1.5°C by 2030 3. As this unfolds, the number of extreme (and potentially dangerous) hot days are expected to increase 1. And as the air temperature rises, the water holding capacity rises with it 4. Intense precipitation events are thus expected to occur more frequently, increasing the risk of flooding, even in places where total precipitation is decreasing 4. Already more than half of the tropical zone is heavily influenced by drought 5 but the continued disruption of global cycles such as the El Niño–Southern Oscillation is driving up their frequency and severity 6.
In terms of food security, adverse impacts are likely to be greatest in regions where both current need and future growth for nutritional demand is greatest 7. Countries with large populations and fast-growing economies – China, India, Indonesia, and Brazil for example – are undergoing periods of major agricultural intensification and moving towards more intense livestock production 8. Protection against the onslaught of climate change in these regions is vital for global food security.
For the major food crops like Wheat, Rice and Maize, substantial progress has been made in breeding climate resilient cultivars. Yet, despite their multitude of environmental and commercial benefits (particularly for livestock) far less attention has been paid to legumes. If we are to buttress our tropical farming systems against climate change, we must rectify this immediately. A first step is finding genes that confer adaptability and resilience.
The problem is that the process of domestication, by design, breeds out genetic variation 9. We select the traits we need and discard those we don’t. As far back as the Neolithic age we have bred crops to be big and fruitful. Over thousands of generations we have selected only the best performing individuals, culminating in our modern day, monoculture crops that produce high yields. The trade off is that they require highly favorable and regulated farming conditions. Thus, of the relatively few domesticated legumes we do have, it is likely they have lost many potentially resilient genes in favor of those that confer a higher yield 9.
In comparison, preserved within wild and uncultivated legumes species (of which there are literally hundreds!) is likely to be a treasure trove of genetic variation. Having not been pushed through the bottleneck of domestication, this wild gene pool will be more diverse 3. Moreover, having adapted to fend for themselves under harsh, unregulated conditions, wild species are expected to display morphology or behavior that confers hardiness and self-sufficiency.
To breed self-sustaining and resilient farming crops, we should exploit self-sustaining and resilient genes 3. This process is far from easy or straightforwards but there are many national and international organizations currently working to do just that. Scientific Institutions like CGIAR, CIAT and ICARDA. In the next installment, I aim to provide a more detailed exploration of their work – past, present and future – towards ‘Climate Proof’ legumes.
Without this vital research in his corner, Mr. Peanut faces a devastating ‘KO’ in the ring….
1 -Hoegh-Guldberg, Ove, Daniela Jacob, M Bindi, S Brown, I Camilloni, A Diedhiou, R Djalante, K Ebi, F Engelbrecht, and J Guiot. 2018. ‘Impacts of 1.5 C global warming on natural and human systems’, Global warming of 1.5 C. An IPCC Special Report.
2 -Malhi, Yadvinder, and James Wright. 2004. ‘Spatial patterns and recent trends in the climate of tropical rainforest regions’, Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 359: 311-29.
3- Mitchell, ML, HC Norman, and RDB Whalley. 2015. ‘Use of functional traits to identify Australian forage grasses, legumes and shrubs for domestication and use in pastoral areas under a changing climate’, Crop and Pasture Science, 66: 71-89.
4 -Trenberth, Kevin E. 2006. ‘The impact of climate change and variability on heavy precipitation, floods, and droughts’, Encyclopedia of hydrological sciences.
5 –Lal, R. 2018. ‘Erosion impact on soil quality in the tropics.’ in, Soil quality and soil erosion (CRC Press).
6 -Moon, J, WK Lee, C Song, SG Lee, SB Heo, A Shvidenko, F Kraxner, M Lamchin, EJ Lee, and Y Zhu. 2017. ‘An introduction to Mid-Latitude ecotone: Sustainability and environmental challenges’, Siberian Journal of Forest Science, 6: 41-51.
7 -Henry, BK, RJ Eckard, and KA Beauchemin. 2018. ‘Adaptation of ruminant livestock production systems to climate changes’, Animal, 12: s445-s56.
8 -Delgado, Christopher L, Mark W Rosegrant, and Siet Meijer. 2001. “Livestock to 2020: The revolution continues.” In
9- Abberton, Michael, Jacqueline Batley, Alison Bentley, John Bryant, Hongwei Cai, James Cockram, Antonio Costa de Oliveira, Leland J Cseke, Hannes Dempewolf, and Ciro De Pace. 2016. ‘Global agricultural intensification during climate change: a role for genomics’, Plant biotechnology journal, 14: 1095-98.