Farmland abandonment in Rio de Janeiro State, Brazil: underlying, proximate causes, and predisposing factors

Abstract

Along the RJ-196 road, where imperial palm trees stand near the ruins of old sugar mills and dirty pastures, the landscape tells a story of change: a story of agricultural abandonment. These abandoned sugarcane fields are the focus of this thesis, which explores the issue of land abandonment in Rio de Janeiro. The transformation of these once-thriving agricultural lands into degraded pastures reflects a broader trend with important consequences for food security, the economy, and the environment. <br /> This thesis examines two key aspects: first, it analyzes the agricultural abandonment in Rio de Janeiro through an established theoretical framework in land-use science; second, it engages with existing studies based on this framework to broaden the discussion. The research focuses on three main categories: underlying and proximate causes, predisposing factors of abandonment, and its occurrence in Northern Rio de Janeiro, where the phenomenon is particularly evident. <br /> The study employs several methodologies to map and analyze the temporal and spatial extent of abandoned farmland. These are structured into four steps: (i) a descriptive analysis of cropping trends and spatial patterns, (ii) a larger-scale investigation of underlying causes, (iii) spatial mapping of sugarcane abandonment, and (iv) an analysis of the proximate causes and biophysical predisposing factors contributing to this abandonment. Interrupted Time Series Analysis (ITSA) was used to test the hypothesis that policy changes such as the end of subsidies and the closure of the IAA played a role in the decline of the sugarcane industry and subsequent land abandonment. Additionally, mapping efforts evaluated whether existing datasets accurately represented the timing and extent of farmland abandonment, particularly for sugarcane. Generalized linear models were employed to explore the biophysical predisposing factors and proximate causes driving farmland abandonment in Rio de Janeiro. <br /> The findings reveal that the primary reason for farmland abandonment in Rio de Janeiro is the decline of sugarcane cultivation in the Norte Fluminense region. Key factors include poor infrastructure, lack of irrigation, urban and industrial development, topographic challenges, uneven rainfall, and policy reforms. This research offers critical insights into the causes and extent of agricultural abandonment in Rio de Janeiro State.