Brazil, which hosts 60% of the Amazon Rainforest and the Cerrado, the two largest biomes of South America, has experienced rapid land cover/use change in the last decades, mainly caused by human activities such as deforestation and fires. According to PRODES, the government deforestation monitoring system in the primary forest, from 2001 to 2018 21.5 Mha are loss in the Amazônia Legal, while 202 Mha are burned mainly in secondary forest and grassland; during the same period soybean harvested area expanded from 14 Mha to 35 Mha. After the Soy Moratorium commitment in 2006 the direct deforestation for soybean decreased but, despite the measure, Brazil has become a leader in the sector. The analysis is intended to identify the spatiotemporal dynamics of this change, investigating the role of cattle ranching and soybean expansion which constitute the major drivers, both through direct conversion and indirectly by land use displacement, quantifying the hectares involved in the land cover change and the relation with data from deforestation and burned area. Results confirm the hypothesis of cross-biome leakage: soybean expansion were displaced to the Cerrado biome causing a conversion of native savanna vegetation, at the same time pasture for cattle ranching has become the direct driver of deforestation in Amazonia biome. The beginning of a shift in last years of cattle herd from pasture to feedlot is another way to free up space for soybean plantations, that find its efficiency in the double-crop production in the tropics. Another important implication of this change, analyzed in this work, is the consequence on water resources. Cropland expansion required a constant increase in blue water, in particular double-cropping needed approximately 10 km3 of irrigation water. This water demand, added to the increasingly frequent occurrence of drought years, affected the water availability. This implies a worsening in water supplies in the country, from abundance to moderate scarcity.
Il Brasile, che comprende il 60% della Foresta Amazzonica e il Cerrado, i due più estesi biomi del Sud America, ha sofferto negli ultimi decenni di un rapido cambiamento di uso e copertura del suolo, causato principalmente da attività umane come deforestazione e incendi. Secondo i dati di PRODES, il programma di monitoraggio governativo della foresta primaria, dal 2001 al 2018 sono stati deforestati 21.5 Mha nell’Amazzonia Legale, mentre circa 202 Mha sono stati bruciati principalmente nella foresta secondaria e nelle praterie; durante lo stesso periodo gli ettari coltivati a soia sono passati da 14 Mha a 35 Mha. Dopo l’accordo sulla Moratoria della Soia nel 2006 la deforestazione diretta per soia è diminuita ma, nonostante i provvedimenti, il Brasile è comunque diventato leader nel settore. L’analisi ha come scopo quello di identificare le dinamiche spazio-temporali di questo cambiamento, indagando sul ruolo dell’allevamento bovino e dell’espansione di soia, che sono i maggiori responsabili, sia tramite conversione diretta che di spostamento indiretto di uso del suolo, quantificando gli ettari interessati e la loro relazione con i dati di deforestazione e area bruciata. I risultati confermano l’ipotesi di uno scambio di perdita tra i biomi: l’espansione di soia si è spostata nel Cerrado causando la conversione della vegetazione di savana nativa, mentre allo stesso tempo il pascolo per allevamento bovino è diventato la causa di deforestazione diretta nel bioma Amazzonico. L’inizio dello spostamento degli allevamenti bovini in sistemi intensivi negli ultimi anni è un altro espediente per liberare aree da coltivare a soia, metodo che trova la sua efficienza nello sviluppo della doppia coltivazione ai tropici. Un’altra importante implicazione di questo cambiamento, analizzata in questo elaborato, è la conseguenza che si ha sulle risorse idriche. L’espansione agricola richiede infatti un continuo aumento di acqua blu, in particolare la doppia coltivazione necessita di circa 10 km3 di irrigazione. Questa richiesta d’acqua, aggiunta all’aumento della frequenza di anni particolarmente siccitosi, incide sulla disponibilità della stessa. Questo implica un peggioramento sulla fornitura d’acqua nel Paese, passando da abbondante a moderatamente scarsa.
Dynamics and potential environmental implications of soybean expansion and beef production in Brazil : fires, deforestation and water scarcity
GOVONI, CAMILLA
2018/2019
Abstract
Brazil, which hosts 60% of the Amazon Rainforest and the Cerrado, the two largest biomes of South America, has experienced rapid land cover/use change in the last decades, mainly caused by human activities such as deforestation and fires. According to PRODES, the government deforestation monitoring system in the primary forest, from 2001 to 2018 21.5 Mha are loss in the Amazônia Legal, while 202 Mha are burned mainly in secondary forest and grassland; during the same period soybean harvested area expanded from 14 Mha to 35 Mha. After the Soy Moratorium commitment in 2006 the direct deforestation for soybean decreased but, despite the measure, Brazil has become a leader in the sector. The analysis is intended to identify the spatiotemporal dynamics of this change, investigating the role of cattle ranching and soybean expansion which constitute the major drivers, both through direct conversion and indirectly by land use displacement, quantifying the hectares involved in the land cover change and the relation with data from deforestation and burned area. Results confirm the hypothesis of cross-biome leakage: soybean expansion were displaced to the Cerrado biome causing a conversion of native savanna vegetation, at the same time pasture for cattle ranching has become the direct driver of deforestation in Amazonia biome. The beginning of a shift in last years of cattle herd from pasture to feedlot is another way to free up space for soybean plantations, that find its efficiency in the double-crop production in the tropics. Another important implication of this change, analyzed in this work, is the consequence on water resources. Cropland expansion required a constant increase in blue water, in particular double-cropping needed approximately 10 km3 of irrigation water. This water demand, added to the increasingly frequent occurrence of drought years, affected the water availability. This implies a worsening in water supplies in the country, from abundance to moderate scarcity.| File | Dimensione | Formato | |
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https://hdl.handle.net/10589/164733