The Amazon and the Atlantic Forest are Brazilian biomes that suffered an intense land use and land cover change, marked by the loss of native forest and expansion of agriculture and livestock. This article aims to analyze land use and land cover change history and to propose a sustainable alternative for agriculture and livestock as an opportunity for rural development in these biomes. The statistics of the platform from the Annual Mapping Project for Land Use and Land Cover in Brazil (MapBiomas) were used in an annual historical series from 1985 to 2020. The analysis of land use and land cover changes indicates that the Amazon native forest was reduced by 44.53 million hectares (Mha), while pasture, agriculture and planted forest increased by 38.10, 6.06 and 0.26 Mha, respectively, over the 35 years (1985 to 2020). In the Atlantic Forest, for the same period, forest and pasture reduced by 0.99 and 11.53 Mha, respectively, while agriculture expanded by 8.06 Mha and planted forest by 2.99 Mha. Sustainable land use strategies, such as the Integration Crop-Livestock-Forest (ICLF), can support the increase in agricultural production while recovering and preserving the environment. Policies and programs should consider regional particularities and barriers for more significant adoption of this strategy.

Although agriculture and livestock systems represent important sources of N 2 O from the soil, they may also aid in emissions mitigation, mainly when integrated systems are taken into account, such as crop-livestock-forest, for food production. This work assessed the soil N 2 O emissions from a tropical Oxisol under row-crop, livestock, forest monocultures, and an integrated crop-livestock-forest system in the Southern Amazon-Brazil. Soil N 2 O emissions were measured using static chambers from November 2014 to October 2016 in four soil use systems [row-crop, livestock, forest, and integrated crop-livestock-forest (CLF)], and in a reference area under native forest fragment. For the whole period, the average of soil N 2 O fluxes was 16.9, 12.2, and 15.4 µg N 2 ON m-2 h-1 , to row-crop, livestock, and CLF systems, respectively, all with a similar average among them. The lowest fluxes were observed in the forest system and native forest fragment, with average fluxes of 4.0 and 6.3 µg N 2 ON m-2 h-1 , respectively, both lower than the agricultural systems. The largest soil N 2 O fluxes were observed throughout the rainy seasons in the row-crop, livestock, and CLF, mostly after N-fertilizer application to the soil surface or in the planted row. As a consequence, the cumulative emissions were greater in row-crop, livestock, and CLF systems, which in the averages of two cycles emitted respectively 1.40, 1.15, and 1.27 kg N 2 ON ha-1 yr-1 , all different of the forest system and native forest fragment (0.33 and 0.52 kg N 2 ON ha-1 yr-1 , respectively). Nitrogen fertilization and soil moisture influenced soil N 2 O emissions of all systems assessed in the Southern Amazon. The N 2 O emissions took place after both factors were met, corroborating the hole-in-the-pipe model. Even with more soil use intensification, once in the same area there were three cultures in succession during a year and perennial trees, CLF did not lead to greater N 2 O emissions from the soil than row-crop and livestock. Thus, CLF represents a good option for N 2 O mitigation for the edaphic and climatic conditions of the Southern Amazon.

O objetivo deste trabalho foi avaliar o potencial de mitigação de óxido nitroso (N₂O) em sistema de integração lavoura-pecuária-floresta (ILPF), em comparação ao monocultivo, e identificar os principais fatores que regulam as emissões deste gás. O experimento foi realizado em Sinop, MT, entre as safras 2012/2013 e 2013/2014, e avaliou os seguintes tratamentos: floresta, lavoura e pastagem, além do ILPF. Durante a realização do experimento, não houve presença de bovinos nas áreas com pastagem. Amostras de óxido nitroso foram coletadas semanalmente, com uso de câmaras estáticas, modelo topo-base. As concentrações do gás foram determinadas por meio de cromatografia gasosa. A precipitação pluvial e a disponibilidade de N foram os principais fatores reguladores das emissões de N₂O. O sistema de ILPF apresenta potencial promissor para mitigar as emissões de N₂O, com emissão acumulada de 0,367 kg ha^-1 de N, em comparação a de 1,401 kg ha^-1 emitidas pela lavoura; de 0,298 kg ha^-1, pela pastagem; e de 0,165 kg ha^-1, pela floresta.