Din?mica da mat?ria org?nica, fertilidade e agrega??o do solo em ?reas sob diferentes sistemas de uso no Cerrado goiano.

• Main Author: Loss, Arc?ngelo
• Other Authors: Pereira, Marcos Gervasio
• Format: Others
• Language: Portuguese
• Published: Universidade Federal Rural do Rio de Janeiro 2016
• Subjects: Edaphic indicators; Integrated production system; Seasonality; Indicadores ed?ficos; Sistema integrado de produ??o; Sazonalidade; Ci?ncias Agr?rias
• Online Access: https://tede.ufrrj.br/jspui/handle/jspui/1233

Submitted by Leticia Schettini ([e-mail]) on 2016-10-04T15:54:19Z No. of bitstreams: 1 2011 - Arcangelo Loss.pdf: 3517882 bytes, checksum: 70d6fb3cef54e289b9abe89818c070c1 (MD5) === Made available in DSpace on 2016-10-04T15:54:19Z (GMT). No. of bitstreams: 1 2011 - Arcangelo Loss.pdf: 3517882 bytes, checksum: 70d6fb3cef54e289b9abe89818c070c1 (MD5) Previous issue date: 2011-06-10 === Funda??o Carlos Chagas Filho de Amparo ? Pesquisa do Estado do RJ, FAPERJ, Brasil === The Integrated Agriculture and Cattle-raising System (IACRS) is an excellent option for Cerrado soils, since the association with grasses (Brachiaria) intensify biomass production, especially in the year dry season. The No-till System (NTS) interspersed with brachiaria (Urochloa ruziziensis) and in consortium with maize (IACRS), when compared to the IACRS without brachiaria provides the best balance between distribution of C in the more labile and recalcitrant fractions of soil organic matter (SOM), and increases C and N stock, and soil aggregation. The general objective of this study was to evaluate the contribution of IACRS system on soil fertility, in chemical and physical fractions of SOM, in the distribution of oxidized carbon fractions, in soil aggregation, and C and N stocks in different land use systems in Cerrado, Goias State. Two areas with crop rotation were evaluated in Montividiu municipality, Goias State, identified as: IARCS (Brachiaria + corn/bean/cotton/soybean) and NTS (sunflower/millet/soy/corn). A natural area of Cerrado was taken as natural soil reference. Soil was sampled at 0.0-5.0; 5.0-10.0; 10.0-20.0 and 20.0-40.0 depths, and also up to 100.0 cm, in a randomized design. In Chapter I it was evaluated bulk density (BD), mineralogy properties, and soil fertility. Due to the animal range used in the IACRS, it was not observed increase in BD in comparison to the area without cattle (NTS). The values of SiO2/Al2O3 (ki) soil ratio indicate dominance of gibbsite in the Cerrado natural area, and kaolinite in the cultivated areas. The IACRS, associated with crop and pasture fertilization, resulted in higher soil fertility and nutrient stocks, compared with the NTS. In Chapter II physical and chemical indicators of SOM were evaluated. The total organic carbon (TOC), stocks of C in the humic acid fraction (C-HAF) and oxidizable carbon, and the physical indicators, particulate organic carbon (POC), light organic matter (LOM) and free light fraction (FLF), allowed inferring that IACRS increased these SOM fractions when compared with the NTS. The IACRS also provided a balanced distribution of C labile forms (F1) and recalcitrant (F4) in the soil, a higher degree of SOM humification, and better stratification of POC than the NTS area. In chapter III it was evaluated the soil aggregation, distribution of C and N, natural abundance of 13C and 15N in aggregates and C-CO2 (mineralization carbon) from soil aggregates incubation. IACRS increased: soil aggregation indexes (0-5 and 5-10 cm), TOC and N (0-5 cm), formation of water stable aggregates (5-10 cm), and also had higher accumulation of C-CO2 than NTS. In Chapter IV the distribution of TOC, N total, natural abundance of 13C and 15N were assessed, and quantified the TOC and nitrogen values. The usage of Urochloa ruziziensis associated with IACRS, increased the TOC levels (0-30 cm) and N (0-20 cm), when compared with NTS. It was possible to conclude that IACRS was more efficient to storage TOC than the natural Cerrado area in the 10.0-20.0 and 20.0-30.0 cm layers, and for the sum of the layers 0.0-40.0, and 0.0-60.0 cm. The use of legumes in the crop systems resulted in higher values of 15N compared to Cerrado area. The replacement of the original Cerrado vegetation by agriculture resulted in changes in 13C, as proven after 17 years of cultivation, by incorporation of carbon from grasses in areas of NTS and IACRS. === O sistema de Integra??o Lavoura-Pecu?ria (ILP) ? uma excelente op??o de uso para solos do Bioma Cerrado, pois a associa??o com esp?cies po?ceas (braqui?ria) intensifica a produ??o de palhada, principalmente no per?odo seco do ano. O Sistema Plantio Direto (SPD) intercalado com braqui?ria (Urochloa ruziziensis) e consorciado ao milho safrinha (ILP), comparado ao SPD sem braqui?ria, pode conduzir a equil?brio entre a distribui??o do C das fra??es da mat?ria org?nica do solo (MOS) mais l?beis e recalcitrantes e aumentar estoques de C e N e a agrega??o do solo. O objetivo geral do estudo foi avaliar contribui??es do sistema de ILP na fertilidade do solo, nas fra??es qu?micas e f?sicas da MOS, na distribui??o das fra??es de carbono oxid?vel, na agrega??o do solo e nos estoques de C e N em diferentes sistemas de uso do solo no Cerrado goiano. Foram avaliadas duas ?reas com rota??o de culturas em Montividiu, GO: ILP (milho+braqui?ria/feij?o/algod?o/soja) e SPD (girassol/milheto/soja/ milho). Uma ?rea de Cerrad?o natural foi tomada como condi??o original do solo. Foram coletadas amostras de terra nas profundidades de 0,0-5,0; 5,0-10,0; 10,0-20,0 e 20,0-40,0 cm, e, tamb?m at? 100 cm, em delineamento inteiramente casualizado. No Cap?tulo I foram avaliadas a densidade do solo (Ds), caracteriza??o mineral?gica e fertilidade do solo. Devido a lota??o animal utilizada no ILP n?o foram constatados aumentos da Ds em compara??o ? ?rea sem pisoteio animal (SPD). Os valores da rela??o SiO2/Al2O3 (ki) no solo indicam predom?nio de gibbsita na ?rea de Cerrad?o e de caulinita nas ?reas cultivadas. O sistema de ILP, mais ?s aduba??es das culturas e na braqui?ria, acarretou maior fertilidade do solo e estoques de nutrientes comparados ao SPD. No Cap?tulo II foram avaliados indicadores f?sicos e qu?micos da MOS. Os indicadores carbono org?nico total (COT), estoques de C da fra??o ?cido h?mico (C-FAH) e C oxid?vel e, os indicadores f?sicos, C org?nico particulado (COp), mat?ria org?nica leve (MOL) e fra??o leve livre (FLL), permitiram inferir que o sistema de ILP aumentou essas fra??es da MOS comparado ao SPD. No sistema de ILP a distribui??o das formas de carbono l?beis (F1) e recalcitrantes (F4) no solo foi mais equilibrada, com maior grau de humifica??o da MOS e melhor estratifica??o do COp, comparado ao SPD. No cap?tulo III foram avaliados os ?ndices de agrega??o do solo, a distribui??o dos teores de C e N e a abund?ncia natural de 13C e 15N dos agregados e o C-CO2 (carbono mineraliz?vel) proveniente da incuba??o de agregados do solo. A ILP aumentou os ?ndices de agrega??o do solo (0-5 e 5-10 cm), os teores de COT e N (0-5 cm), a forma??o de agregados est?veis em ?gua (5-10 cm) e tamb?m o ac?mulo de C-CO2, comparada ao SPD. No Capitulo IV foi avaliada a distribui??o do COT, N total, abund?ncia natural de 13C e 15N, e quantificados os estoques de COT e N do solo. A utiliza??o da Urochloa ruziziensis com rota??o de culturas (ILP) aumentou os teores de COT (0-30 cm) e N (0-20 cm), comparada ? rota??o de culturas (SPD). Conclui-se que o sistema de ILP foi mais eficiente em estocar COT no solo que a ?rea de Cerrad?o nas camadas de 10,0-20,0 e 20,0-30,0 cm e, na soma das camadas de 0,0-40,0 e 0,0-60,0 cm. O uso de leguminosas nas ?reas cultivadas acarretou em maiores valores de 15N em compara??o a de Cerrad?o. A substitui??o da vegeta??o original de Cerrad?o para implantar lavouras acarretou mudan?as do 13C, sendo comprovada, ap?s 17 anos de cultivo, a incorpora??o de C das po?ceas nas ?reas de SPD e ILP.