Food for Thought: Quantifying agricultural intensification using indicator crops

In just 30-50 years, the number of food shortage crises around the world will dramatically increase. Such a dire prediction is inevitable, given the globe’s finite resources. As a result, it is with a strong sense of urgency that scientists work to improve current agricultural production methods. A 2014 study by a coalition of agricultural researchers attempts to put global sustainability trends into perspective by examining the production processes of four indicator crops: canola, cotton, maize, and soybeans. These kinds of crops are sensitive to production processes or require consistent inputs of water, energy, and land.

Increasing evidence suggests that agricultural intensification, using fewer resources to achieve the same crop yields, can be done sustainably for these four crops. By measuring the utilization of land, water, and energy per unit of production in the decade from 2000–2010, the researchers rank countries by level of intensification.

The study considers the following eco-efficiency metrics to measure a country’s agricultural intensification: land use, irrigation water consumption, energy consumption, and greenhouse gas (GHG) emissions. Land use refers to the harvest land area required per production unit. Irrigation water consumption describes the volume of water used to grow crops. Energy use summarizes the direct (e.g., fuel) and indirect (e.g., production of fuel) energy required for crop production. Lastly, climate change is broadly interpreted as GHG emissions associated with fertilizer consumption and land use change—the highest-emitting agricultural activities. These indicators are presented on timelines that plot each crop’s efficiency level in units of CO₂ produced per kilogram of crop. The results show changes in the relative use of these crops over time, relative to the ability to achieve production demands.

The authors categorize a country’s overall crop intensification as high, medium, or low by summing that country’s intensification levels for three sub-categories: breeding intensity, presence of biotechnology, and agronomic practices. Though greater eco-efficiency corresponds to higher intensification, it is necessary to analyze the breakdown amongst factors. For example, though low-intensity maize production is efficient with respect to energy use and GHG emissions, this comes at the expense of greater land and water use requirements.

The results show maize had the highest eco-efficiency for land, water, and energy categories, followed by canola, soybeans, and cotton coming in last due to its low yield per unit of input. Countries with highest eco-efficiency seem to take yield into account, as they generally all produce maize and canola at high levels relative to soybeans and cotton.

Countries that had the highest gains in eco-efficiency over the decade experienced substantial resource savings as a result of higher-intensification procedures. For example, if high- and medium-intensification countries had operated at the same water-use efficiency in maize harvests as low-intensification countries, approximately four quadrillion additional liters of water would have been used between 2000 and 2010. Such findings are more relevant than ever, given the unprecedented drought affecting areas of the American Southwest—droughts that farmers are trying to combat with smarter irrigation practices. In stark contrast are low-intensification countries, which exhibited no such gains for any of the indicator crops over the decade.

Perhaps most importantly, the authors find that the highest intensification countries did not undergo massive overhauls in any realm of production, but, rather, simply ramped up adoption of their already-effective practices. Such a finding is important to address critiques that better eco-efficiency will require significant monetary investment. Incremental improvements will suffice for progress in low-intensity countries. In order for other countries to mirror these changes, embrace of conservation tillage practices like drip irrigation, better equipment, particularly for soil-bed preparation, and earlier planting dates are suggested.

The researchers acknowledge the limitations of the study, such as short duration and few metrics. However their analysis shows promising trends toward crop intensification. As water resources become increasingly scarce, food demand rises, and GHG emissions warm the planet, it is more important than ever to efficiently manage crops. The authors show that agricultural intensification is rising to meet these needs.

Article Source: “How does agricultural intensification influence global eco-efficiency? The results of an indicator-based study using the world’s four most prevalent indicator crops“, Gustafson et al, International Journal of Agricultural Sustainability, 2013. 

Feature Photo: cc/(Reno1020)