This paper is relevant to the impact areas in the following areas:
| Crops | Maize |
| Traits | Insect Res. (BT), Insect Resistance |
| Countries | Spain |
| Regions | Europe |
| Tags | carbon fixation, irrigation, land management, pesticide use |
The Bt maize area in Spain has increased since its introduction in 1998. This increase in the Bt maize area has accentuated since 2010. The adoption of Bt maize during the 18 year period has brought a number of advantages in agronomic, economic and term, as well as for the International trade and the environment.
From an agronomic point of view, Bt maize resistance to the corn borer leads to higher yields than the conventional maize. According to some studies, the average yield differences vary between 7.38% and 10.53% depending on the geographical area analysed as well as the pest incidence. The adoption of this crop provides benefits associated with the quality of the crop as a consequence of its relatively low content in fumonisins (mycotoxins).
The high yields of Bt maize lead to higher economic benefits for the farmer, due to a higher gross margin compared to the conventional maize. This difference in gross margins varies between 3.17 and 147 euros/ha depending on the geographical area and the year in which the study was conducted. Apart from the economic benefits, farmers also consider other reasons to adopt Bt maize such as its greater flexibility and simplicity in crop management. Amongst these reasons farmers highlight the reduction in time spent in scouting and spraying fields to address weed problems.
Apart from the direct economic benefits for the farmer, Bt maize has also yield benefits for the Spanish international trade. Thus, Bt maize has allowed Spain to fulfil its internal demand for maize with domestic production, making it less dependent to additional maize imports. More specifically, the value of the avoided maize imports as a consequence of Bt maize adoption in Spain during the 18 years is almost 193 million euros.
It is worth noting that besides the benefits for farmers and the trade balance associated with Bt maize adoption, there have been other non-monetary benefits related with the environmental function of agriculture.
Thus, there are benefits associated with a lower use of insecticides, a lower use of irrigation water per tonne of maize produced, and a higher carbon fixation. Thus, biodiversity benefits 18 The value of averted imports in each year has been updated for 2013. To do this we used the coefficients provided by the INE (based on 2011 figures), and we have taken the rate of inflation for 2013 until the October 2013. 19 are obtained by optimising the use of insecticides. As pointed out above, Bt maize produces higher yields than conventional maize, which leads to a lower irrigation water consumption per tonne of maize produced. Such irrigation water savings has been estimated to be 615,778,000 m3 for the 18 year period of Bt maize cultivation in Spain, which is equivalent to the provision of water for 746,000 people per year (equivalent to the Spanish cities of Lérida, Tarragona and Badajoz all together). Taking into account the whole production process of grain maize and its impact on hydrological resources at a global level, the adoption of Bt maize in Spain has avoided a hydrological footprint of almost 1,335 million m3 . Bt maize in Spain has also contributed to lower pressure on land use, since by keeping the same level of maize production would have meant an increase of 106,775 ha of maize. Finally, considering maize capability as a natural drain for CO2, Bt maize cultivation in Spain has yield a net fixation of additional carbon of 849,935 t CO2 eq., which makes up for the emissions associated with 25,004 cars in Spain for a year.
Benefits of Bt maize in Spain (1998-2015). Benefits from an economic, social and environmental viewpoint. (held on an external server, and so may require additional authentication details)
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