The study “Agroecological measures and circular economy strategies to ensure sufficient nitrogen for sustainable farming“, developed by Técnico/MARETEC researchers Tiago Morais, Ricardo Teixeira and Tiago Domingos, in collaboration with colleagues from Austria, concludes that organic farming alone, as presently practiced, could not feed the world by 2050. The study was recently published in Global Environmental Change and highlights that organic farming, which prohibits the use of synthetic fertilizers, cannot provide enough nitrogen to crops and be viable at the global level.
“The results clearly demonstrate that the complete transition to organic production in 2050, as presently practiced, leads to a lack of nutrients to produce the food needed to feed the world’s population regardless of dietary changes”, says Tiago Morais.
This limitation can be resolved by 2050, but only through investments in agricultural innovation and animal production, food waste reduction, diversification of organic fertilizer sources and renewable energy use.
The study also highlights the important role of livestock in organic farming since animals facilitate sustainable organic production, either by improving and maintaining the fertility of the soil or by animal waste.
In this study, the scientists used a model called “BioBaM” – developed by the Austrian scientists – which allows to track biomass on a global scale. The nitrogen fluxes associated with the biomass fluxes, as well as the nitrogen balance in crops were added to the model.
The researchers also studied several measures such as: improving the efficiency of agricultural and animal production; improving biological nitrogen fixation and optimizing crop rotations (only in organic farming scenarios); reduction of food waste; the use of organic fertilizer obtained from municipal urban waste and human waste; decarbonization of the synthetic fertilizer manufacturing process; and the use of biogas produced from animal waste. The results achieved show that the sustainability of agricultural production will necessarily have to pass through measures aimed at improving production systems.
Tiago Morais stresses “the results show that individually, none of the measures considered is sufficient to overcome the nitrogen limitation – this effect being verified for all human diet alternatives”. “The agroecological and circular economy improvements are the most significant measures. Increasing the efficiency of the use of nitrogen in both agricultural and animal production, combined with waste reduction, will ensure global food supply”, adds the researcher.
The study also allows us to draw some conclusions about human diets. As for conventional agriculture, the one with the least impact is vegan – that is, without any use of animal products. However, as Tiago Morais highlights, “the continuous consumption of livestock products, namely meat, makes organic farming closer to being successfully done”. “However, meat diets require more agricultural land and emit more greenhouse gas emissions, compared to diets without meat or even without animal products”, highlights the researcher.
“This study confirms some partial results that already existed – the organic farming, as presently practiced, cannot feed the world”, highlighted Tiago Morais.