Search

A serapilheira é um importante meio de contribuição ao estoque de nutrientes em ambientes com árvores, especialmente, em sistemas integrados de produção, que apresentam significativo crescimento em termos de área produtiva no país. O objetivo do estudo foi avaliar a influência da sazonalidade climática, face de exposição e da posição dos coletores na deposição e estoque de nutrientes da serapilheira em sistemas integrados de produção. A deposição e o estoque de nutrientes da serapilheira foram avaliados em cultivo de eucalipto dos 47 aos 58 meses, em consórcio com cultivos agrícolas (ILF) e pastagem (IPF) na Embrapa Agrossilvipastoril, Sinop, MT. Avaliou-se também a correlação da deposição com as variáveis climáticas. Os dados entre os sistemas foram comparados pelo teste F e a comparação de médias pelo teste de Tukey, a 5% de probabilidade. A deposição total média acumulada de serapilheira foi de 0,63 t ha-1 no ILF, 0,47 t ha-1 no IPF. A maior deposição e estoque de nutrientes ocorreu no consórcio com cultivos agrícolas comparado a pastagem. A produção de serapilheira apresentou padrão sazonal, com maior deposição no período de seca. Valores superiores de deposição e estoque de nutrientes ocorreram na linha central das faixas das árvores sem variação significativa da deposição quando comparado a face norte e sul entre si. Os fatores de sazonalidade climática, face de exposição e a posição dos coletores influenciaram na deposição e no estoque de nutrientes da serapilheira de eucalipto entre os sistemas de cultivo. Influence of climatic and spatial factors on Eucalyptus litter production in integrated system Litter is an important way to contribute to nutrients stock in environments with trees, especially to the current integrated production systems, which show significant growth in terms of production area in Brazil. The objective of this study was to evaluate the climatic influence of seasonality, the face of solar exposure, and the litter collector's position and nutrient stock in integrated production systems. The litter deposition and nutrient stock was evaluated in eucalyptus cultivation from 47 to 58 months old, cultivated in a consortium with agricultural species (ILF) and pasture (IPF) at Embrapa Agrossilvipastoril, Sinop, MT. The deposition correlation with climatic variables was also evaluated. The data between both systems were compared by the F test, the means were compared by Tukey test, at 5% probability. The accumulated mean total litter deposition was 0.63 t ha-1 in the ILF, 0.47 t ha-1 in the IPF. The greatest deposition and nutrients stock occurred in the ILF system. The litter production presented a seasonal pattern, with the highest deposition occurring in the dry season. Higher deposition and nutrient stock values occurred in the central line without significant variation in the deposition when compared to north and south faces. The factors of climatic seasonality, exposure face and the position of collectors influenced the deposition and nutrient stock of eucalyptus litter between the cropping systems. Made available in DSpace on 2022-08-08T14:19:37Z (GMT). No. of bitstreams: 1 AFS-2022-FatoresClimaticosSerapilheiraEucalipto.pdf: 403667 bytes, checksum: 23fcffbbb390e1b5ecec5b8d79d3940b (MD5) Previous issue date: 2022

Leaching and nitrous oxide (N2O) emissions can represent substantial nitrogen (N) losses from chemical fertilizers, and slow-release fertilizers (SRFs) can mitigate these effects. Thus, biochar can be an alternative from an agronomic and environmental point of view to synthesize SRFs due to its physicochemical characteristics. We investigated the effect of nitrogenous organomineral fertilizers (OMF-N) formulated based on activated biochar on N losses by leaching and N2O emissions. The OMF-N were developed from a dry mechanical pelleting process with different biochar and urea proportions (2:1; 1:2, and 1:4). Three experiments were conducted using four fertilizer sources (urea, OMF-N 2:1, OMF-N 1:2, and OMF-N 1:4): i. to analyze the kinetics of N release from OMF-N at times: 5, 15, 30, 60, 90, and 120 min; ii. for N2O emission analysis determined at 3, 6, 10, 14, 24, 44, 54, 64, 74, 84, 104, and 118 days after application to the soil; and iii. for a double factorial design that was adopted to analyze N leaching, consisting of the combination of applying 160 kg N ha−1 of fertilizers in PVC columns at different depths (20, 40, 60, and 80 cm) and analyzed at five times (1, 7, 14, 21, and 28 days). FTIR spectroscopic analysis, specific surface area, porosity, and surface morphology showed physicochemical interactions of N of the OMF with biochar; the N from the OMF interacts physically and chemically binds to the functional surfaces of biochar, delaying the dissolution flow. The OMF-N proved capable of retaining 48% to 60% more NH4 + and reduced the release of Ntotal from urea from 27% to 60%, as well as reduced N2O emissions from 47% to 66%. Although absolute CO2 emissions intensified with the application of OMF-N, its use provides C sequestration in the soil to due to the recalcitrant C of the biochar, which results in a positive input-output balance in the system. The NO3 − concentration profiles revealed that the OMF-N application was able to reduce leaching in the soil to a depth of 80 cm. These studies enabled better understanding of the processes involved in the biochar:urea interaction and revealed that biochar can be used as an organic matrix in the synthesis of SRF. Made available in DSpace on 2022-10-25T20:08:20Z (GMT). No. of bitstreams: 1 Pereira-et-al.-2022.pdf: 2979494 bytes, checksum: d406a3fb58b766b905c85253128f0140 (MD5) Previous issue date: 2022