Evaluation of sustainability of cropping sequences on production systems: agricultural intensification indices

Abstract

In recent decades, agriculture has undergone intensification and diversification processes to improve productivity, the economic income and to face the climate variability. However, concerns about environmental problems associated with agricultural practices are increasing. In this way, effects such as soil erosion, changes in soil carbon stock, fertility losses, eutrophication and aquatic-biotic integrity degradation have been reported. Although several methodological frameworks have been developed to assess the environmental performance of farms and to support the decision-making process, these frameworks normally rely on indicators that measure a particular characteristic of an agricultural system. The aim of this work was to propose an integrated index considering (a) sequence diversification, the area occupied by crops in winter and summer, and the participation percent-age of each crop and (b) two weighting factors to reflect the differential contributions of cropping sequences to environmental performance. The study was carried out between 2008 and 2020 in a commercial farm in northwest Uruguay with cropping sequences that included rice, soybean, corn, sorghum and pastures. Our results show that the proposed index is suitable for assessing the intensification degree and allowing the selection of agricultural sequences that present the highest environmental performance. The optimal spatial scale for applying the index is on farms no larger than 1000 hectares; this threshold includes approximately 90% of Uruguayan farms. Due to the similar physical characteristics, weather conditions and management practices in farms in southern Brazil and central-eastern Argentina, the index is suitable for applications in these regions as well.