Resumen

BOCCHIO, Verónica; REQUESENS, E.  y  MESTELAN, S.. Tendencias y equitatividad de los principales cultivos extensivos en el centro de la provincia de Buenos Aires. RIA. Rev. investig. agropecu. [online]. 2019, vol.45, n.2, pp.196-203. ISSN 1669-2314.

The processes of agricultural expansion and loss of productive diversity have been linked to an increase in environmental costs in terms of soil degradation, water and air pollution, loss of biodiversity and deterioration of essential ecological services. This study aims to analyze such processes in a sector of the center of the Buenos Aires province, dominated by the orographic system of Tandilia. The study area comprises the counties of Azul, Benito Juárez, Olavarría and Tandil, it has rolling piedmont terrains around the sierras, and inter sierras plains that concentrate most of the agricultural activity, surrounded by environments with soil limitations for agriculture corresponding to the Depressed Pampa. The study was based on data of sowing area of the main crops of the region contributed by the Integrated System of Agricultural Information of the Ministry of Agriculture and Industry of Argentina. Information analyzed corresponds to wheat, corn, sunflower, soybean, brewing barley and oats. Twenty growing seasons (campaigns) were analyzed, starting in the mid-1990s, when the launch of transgenic soy accelerated the agricultural expansion in the country. The main variables analyzed were the area allocated to the different crops in each season and the productive diversity associated with the number and relative area of ​​the latter. Given that the number of crops was previously established by virtue of their regional relevance, the productive diversity was estimated by the Shannon Equitability Index (J’) in order to evaluate exclusively the degree of uniformity among the relative surfaces of the crops analyzed. The combined surface of the studied crops registered an increase of 93% during the study period. This increase was accompanied by different dynamics among the surveyed crops, highlighting the replacement of wheat by soybean as the dominant crop. Despite these changes, equitability was shown as a relatively stable variable with high values that ranged between J’= 0.76 and J’= 0.86. These results and their discussion in terms of the relationships among environmental heterogeneity, biodiversity and sustainability, support the convenience of conserving and, if possible, further increasing the levels of equity registered for the study area. The latter could be achieved from a greater relative participation of non-dominant crops, especially those that, like corn and wheat, have a better soil carbon balance as compared to soybeans.

Palabras clave : Sown area; dominant crops; planned diversity.