Autoria: CARVALHO, A. M. de; SANTOS, D. C. R. dos; RAMOS, M. L. G.; MARCHAO, R. L.; VILELA, L.; SOUSA, T. R. de; MALAQUIAS, J. V.; GONÇALVES, A. D. M. de A.; COSER, T. R.; OLIVEIRA, A. D. de

Resumo: Abstract: Nitrous oxide (N2O) emissions resulting from nitrogen (N) fertilization have been docu- mented. However, no data on the effects of other nutrients, such as phosphate (P) and potassium (K), on N2O emissions in integrated crop?livestock systems are available so far. In the 2015/2016 and 2016/2017 growing seasons, we measured N2O emissions from a long-term system, established in 1991 in the Cerrado biome (a tropical savanna ecoregion in Brazil), fertilized with two P and K levels. The studied no-tillage farming systems consisted of continuous crops fertilized with half of the recommended P and K rates (CC-F1), continuous crops at the recommended P and K rates (CC-F2), an integrated crop?livestock system with half of the recommended P and K rates (ICL-F1), and an integrated crop?livestock at the recommended P and K rates (ICL-F2). The cumulative N2O emissions (603 days) and soil chemical properties were analyzed as a 2 × 2 factorial design (long-term agricultural systems x fertilization). The cumulative N2O emissions from CC-F2 and ICL-F1 were 2.74 and 1.12 kg N ha−1, respectively. The yield-scaled N2O emissions from soybean were 55.5% lower from ICL-F1 than from CC-F2 in the 2015/2016 growing season. For off-season sorghum, the mean yield-scaled N2O emissions were 216 mg N2O m−2 kg−1 (in a range from 79.83 to 363.52 mg N2O m−2 kg−1, for ICL-F2 and CC-F1, respectively). The absence of pasture and the presence of soybean and sorghum promoted the highest cumulative N2O emissions, favored by the recommended rate in relation to half of the P and K. In the total evaluation period (603 days), the presence of grazed land in the years prior to this study and land fertilized with half the recommended P and K rates in an integrated crop?livestock system reduced the resulting cumulative N2O emis- sions by 59%. Thus, we conclude that crop?livestock systems can be beneficial in reducing P and K applications and also in mitigating N2O emissions in comparison with continuous cropping systems fertilized with the full recommended P and K rates. In view of the global fertilizer crisis, this aspect is extremely relevant for agriculture in Brazil and around the world.

Ano de publicação: 2022

Tipo de publicação: Artigo de periódico

Unidade: Embrapa Cerrados

Palavras-chave: Agricultura Sustentável, Efeito Estufa, Gás