Virtual water trade of maize produced in Buenos Aires, Argentina

MACARENA ARRIEN; CORINA IRIS RODRIGUEZ; MAITE M. ALDAYA

Pamplona

Workshop; 2nd Workshop Water-Energy-Food Nexus; 2020

Universidad Pública de Navarra

Argentina is the second largest maize exporting country in the world after the USA, and the first in Latin America, producing grain in highly productive rain-fed conditions. Green water (soil water originating from rainfall) is by far the largest share of virtual water in Argentinean maize exports (Aldaya et al., 2010). This makes Argentina the second largest green virtual-water exporter related to maize trade (ibid.). The water footprint can be a useful tool to assess the sustainability of water use in maize production. The water footprint of maize refers to the total volume of freshwater used to produce the crop, summed over the various steps of the production chain. Water use is measured in terms of water volumes consumed (evaporated from rain or irrigation) and/or polluted by the processes related to production. The water footprint assessment, coupled with the virtual water trade analysis of maize production in Argentina, make possible to understand the role of the Argentinean maize production in the world, as well as the dependence of others countries on this production. The present study aims at assessing the water footprint and virtual-water exports of maize produced in the province of Buenos Aires (Argentina). The purpose of the study is twofold. First of all, at a local scale, the green, blue and grey water footprints of maize in the central-southeast region of the province of Buenos Aires are analysed, as a result of the Bachelor Degree thesis in Diagnosis and Environmental Management of Macarena Arrien, completed in 2019. Second, the study analyses the green water footprint of maize and related virtual water exports at a provincial level. These are some of the preliminary results of Macarena Arrien?s PhD Degree focused on the water footprint of Argentinian beef cattle productive chain, which have just started in 2020. The green, blue and grey water footprint of maize, both in irrigated and rainfed conditions, were analysed at a local scale for the 2016-2017 campaign following the method of the Water Footprint Assessment Manual (Hoekstra et al., 2011), meanwhile at the provincial level only green water was estimated separately by hydrological region. The green and blue crop water requirements were calculated by estimating the crop evapotranspiration, together with the effective rainfall through the CropWat software (FAO, 2020a) and irrigation application obtained from interviews with producers and agricultural advisers. The green water footprint of maize was estimated as the ratio of the green water use to the crop yield, while the blue water footprint of the crop was taken equal to the ratio of the volume of irrigation water used to the crop yield. The grey water footprint focused on the application of nitrogen fertilizers. The three components of the water footprint were estimated based on local data on precipitation, irrigation, soil type, climatic and hydrogeological data, fertilizer application and agrochemicals. The climatic variables and rainfall data were taken from the closest meteorological stations located throughout the province. Interviews with producers and agricultural advisers were conducted in order to collect data related to the maize crop, its production system and water use. At the provincial level, Buenos Aires is divided in six hydrological regions according to the Water Authority. The average yield for each of the six hydrological regions was taken from official data (Agriculture, Livestock and Fishing Secretariat, 2020). Then, provincial average of green water footprint of rainfed maize production was calculated on the basis of the respective share of each hydrological region to the province production. The international virtual water trade related to maize grain exported by Buenos Aires, Argentina, were assessed taking into account the main destinations of this cereal. Trade data were obtained from the Ministry of Treasury (2017), the Agriculture, Livestock and Fishing Secretariat (2020) and the National Institute of Statistics and Censuses (2010) of the Argentine Republic, and from FAOSTAT (FAO, 2020b). The water footprint of maize in rainfed and irrigated conditions in the central-southeast region of the province of Buenos Aires amounted to 1290 m3/ton and 1736 m3/ton, respectively. In the case of maize produced under rainfed conditions, the green water footprint represented 86% of the total water footprint while the nitrogen-related grey water footprint 14%. Under irrigated conditions, the green water footprint of maize production represented 46% of the total water footprint, the blue water footprint 38% and the grey water footprint 16%. Therefore, and in line with previous studies, one of the main components of the water footprint of maize production, both under rainfed and irrigated conditions, is green water. At the provincial level, the green footprint of maize ranged between 600 and 1,400 m3/ton within the six hydrological regions of Buenos Aires, with an increasing gradient from northern to southern regions. These results were in line with the locally calculated green water footprint values for the central-southeast region of Buenos Aires. Argentina mainly has an agricultural and livestock based economy, which production is located in the Pampean region, comprising the provinces of Santa Fe, Entre Ríos, La Pampa, Córdoba and Buenos Aires. During the 2016/2017 campaign, Argentina produced almost 138 million tons of grains, of which maize represented the 37%. During the same period, Argentina exported 24 million tons of this grain to 120 countries, particularly to the following 7 countries, which add up to 70%: Vietnam, Egypt, Algeria, Malaysia, South Africa, Korea and Brazil. This trade route positions Argentina as one of the main maize exporters. Buenos Aires is the province with the largest weight in exports in the 2016/2017 campaign, being responsible for 25% of the production, equivalent to almost 6 million tons of maize. As regards the virtual water trade, a preliminary value of 4.66 km3 of green water exports related to maize was estimated for the year under study (2017). Taking into account the water volumes needed to produce maize and the quantities exported, it is evident that Argentina, and, in particular, the province of Buenos Aires, exports not only maize, but also thousands of cubic meters of fresh water incorporated in the product that are not considered in its market price. When analysing the global destinations of this product, most of the maize-importing nations present water, territorial or climatic limitations. Through the virtual water imports these countries externalize their environmental impacts and ?save? domestic water. In this context, Argentina has a comparative advantage in the production of maize, as its main water footprint component is green, compared to other nations that base their maize production on blue water.