Adapting to Climate Change:
Conventional Agriculture Vs. Agro-ecology
The vulnerability of agriculture puts global food security at stake. It is therefore necessary to increase its resilience to both slow-onset and abrupt changes in climate and related conditions.
Conventional agriculture, and particularly intensive, homogeneous monocultures (Figure 1), are highly susceptible to disturbances. A stressor that affects one plant will affect all the rest in the plantation, as they are no other than its clones. For instance, a pest can rapidly spread across these farms, as it can infect all of its surrounding plants; as it happened in the famous Irish potato famine in the 1840s, where monocultures of genetically identical potatoes collapsed with the spread of the pest P. infestans and put over 1 million people to starvation. Moreover, the lack of structural complexity and diversity of homogeneous croplands makes them more vulnerable to being destroyed by extreme events, and it reduces their self-regulation of factors like heat and moisture. Intensive farming also requires more polluting and expensive resources, such as fertilizers, pesticides and machinery, and crops become physiologically dependent on human inputs.
Ecosystem-based adaptation techniques may be necessary to avoid crop collapses under imminent and unpredictable climate changes. Diversification of crops (Figure 1), spatial and temporal rotation of crops, and the inclusion of trees can buffer climatic variability and extremes and limit pests. Moreover, planting cover crops between growing seasons limits soil loss, and naturally fertilizes it, reducing the need for synthetic fertilizers. And agro-ecosystems control pest insects without using chemical pesticides, with naturally found predatory or parasitoid insects that perform this function.
Conventional agriculture, and particularly intensive, homogeneous monocultures (Figure 1), are highly susceptible to disturbances. A stressor that affects one plant will affect all the rest in the plantation, as they are no other than its clones. For instance, a pest can rapidly spread across these farms, as it can infect all of its surrounding plants; as it happened in the famous Irish potato famine in the 1840s, where monocultures of genetically identical potatoes collapsed with the spread of the pest P. infestans and put over 1 million people to starvation. Moreover, the lack of structural complexity and diversity of homogeneous croplands makes them more vulnerable to being destroyed by extreme events, and it reduces their self-regulation of factors like heat and moisture. Intensive farming also requires more polluting and expensive resources, such as fertilizers, pesticides and machinery, and crops become physiologically dependent on human inputs.
Ecosystem-based adaptation techniques may be necessary to avoid crop collapses under imminent and unpredictable climate changes. Diversification of crops (Figure 1), spatial and temporal rotation of crops, and the inclusion of trees can buffer climatic variability and extremes and limit pests. Moreover, planting cover crops between growing seasons limits soil loss, and naturally fertilizes it, reducing the need for synthetic fertilizers. And agro-ecosystems control pest insects without using chemical pesticides, with naturally found predatory or parasitoid insects that perform this function.
Figure 1 - A homogeneous monoculture corn field (above) and a diverse farm with agroforestry (below)
Agro-ecological management can hence offer greater resilience of crops to the upcoming environmental changes than do current intensive systems. Why aren't they more implemented then? There is a common belief that intensive monocultures using abundant fertilizers and pesticides are more productive. Consequently, there are more economic incentives for these intensive practices, and for the production of a few crops only than for agro-ecological approaches that benefit resilience, yields and biodiversity simultaneously.
Diego Garcia-Vega - December 11th 2017
Diego Garcia-Vega - December 11th 2017