Biochar improves fertility of a clay soil in the Brazilian Savannah: short term effects and impact on rice yield

The objective of this study was to report single season effects of wood biochar (char) application coupled with N fertilization on soil chemical properties, aerobic rice growth and grain yield in a clayey Rhodic Ferralsol in the Brazilian Savannah. Char application effected an increase in soil pH, K, Ca, Mg, CEC, Mn and nitrate while decreasing Al content and potential acidity of soils. No distinct effect of char application on grain yield of aerobic rice was observed. We believe that soil properties impacted by char application were inconsequential for rice yields because neither water, low pH, nor the availability of K or P were limiting factors for rice production. Rate of char above 16 Mg ha^(−1) reduced leaf area index and total shoot dry matter by 72 days after sowing. The number of panicles infected by rice blast decreased with increasing char rate. Increased dry matter beyond the remobilization capacity of the crop, and high number of panicles infected by rice blast were the likely cause of the lower grain yield observed when more than 60 kg N ha^(−1) was applied. The optimal rate of N was 46 kg ha^(−1) and resulted in a rice grain yield above 3 Mg ha^(−1)

Nutrient cycling by cover crops and yield of soybean and rice in no-tillage

O objetivo deste trabalho foi avaliar a ciclagem de nutrientes por plantas de cobertura e a sua influência sobre o desempenho da rotação entre arroz de terras altas e soja. As culturas foram implantadas sob plantio direto, em Latossolo Vermelho distroférrico, na região do Cerrado de Goiás. As plantas de cobertura foram semeadas mecanicamente, também em plantio direto, após a colheita da soja (25/3/2008) e do arroz (7/4/2009). Utilizou-se o delineamento de blocos ao acaso, com parcelas subdivididas no tempo e quatro repetições. Os tratamentos consistiram das seguintes espécies de plantas de cobertura, além do pousio: Urochloa ruziziensis, U. brizantha, Pennisetum glaucum e U. ruziziensis + Cajanus cajan. A avaliação dos nutrientes remanescentes na palhada foi feita aos: 0, 15, 30, 60, 90 e 120 dias a partir da data da dessecação das plantas de cobertura. Urochloa ruziziensis e U. brizantha apresentaram maior eficiência no acúmulo e na liberação de nutrientes, principalmente quanto ao potássio. Urochloa ruziziensis é a espécie mais indicada como planta de cobertura antecessora à cultura do arroz de terras altas, em plantio direto. No entanto, nenhuma espécie de cobertura afeta significativamente a produtividade de grãos da soja.The objective of this work was to evaluate nutrient cycling by cover crops and its influence on the performance of the rotation between upland rice and soybean. The crops were sown under no‑tillage, in a Rhodic Haplustox, in the Cerrado region of the state of Goiás, Brazil. The cover crops were sown mechanically, also under no‑tillage, after the harvest of soybean (3/25/2008) and rice (4/7/2009). A randomized complete block design was used, split‑plotted in time, with four replicates. The treatments consisted of the following cover crop species, besides fallow: Urochloa ruziziensis, U. brizantha, Pennisetum glaucum and U. ruziziensis + Cajanus cajan. The evaluation of the remaining nutrient in straw was performed at 0, 15, 30, 60, 90, and 120 days from the desiccation date of the cover crops. Urochloa ruziziensis and U. brizantha were the most efficient in the accumulation and release of nutrients, especially potassium. Urochloa ruziziensis is the most suited species for use as a cover crop previous to upland rice cultivation under no‑tillage. However, none of the cover crop species significantly affect soybean grain yield

Electrical conductivity mapping in relation to clay of a Ferralsol under no tillage system

O objetivo deste trabalho foi mapear e avaliar a variabilidade espacial da condutividade elétrica do solo (CE), obtida por meio de sensor de contato de campo, num Latossolo Vermelho distroférrico, sob plantio direto de grãos, e relacionar a CE com os teores de argila medidos pelo método do densímetro, em amostras georreferenciadas de solo. As amostras foram coletadas numa área de 13 ha, por meio de uma grade de 40x40 m e de grades de 20x20 m, 10x10 m e 5x5 m. A continuidade espacial da CE e do teor de argila foi modelada com o uso de semivariogramas. A CE variou de 1,9 a 13,7 mS m-1, com valor médio de 5,2 mS m-1 e coeficiente de variação de 48%. O mapa interpolado mostrou tendência de aumento da CE com o aumento dos teores de argila. Os coeficientes de determinação foram de 0,78 e 0,77 entre CE e teor de argila, camadas 0–5 e 5–10 cm, respectivamente. O mapa da CE reflete suficientemente a variação espacial dos teores de argila para uso na delimitação de zonas de manejo.The objective of this work was to map and evaluate the spatial variability of the soil electrical conductivity (EC), measured with a contact sensor in a Rhodic Ferralsol under no till grain crops. The values of soil EC were related to soil clay content, measured by the densimetric method in georreferenced samples collected at 0–5 and 5–10 cm, in a 13 ha field. Soil samples were collected using a 40x40 m grid and densed grids of 20, 10 and 5 m spacing. Spatial continuity of EC and of clay content was modeled using semivariograms. Soil EC ranged from 1.9 to 13.7 mS m-1 with an average of 5.2 mS m-1 and coefficient of variation of 48%. The kriged map of soil EC pointed out a tendency of increase where clay levels were higher. Determination coefficients between soil EC and clay content were 0.78 and 0.77, respectively for 0–5 and 5–10 cm depth. The EC map adequatly reflects the spatial variation in soil texture for establishing the limits of management zones

Resposta da transpiração de arroz de terras altas ao deficit hídrico modificado por diferentes doses do “biochar” de eucalipto

Submitted by Luciana Ferreira ([email protected]) on 2018-03-01T14:54:39Z No. of bitstreams: 2 Artigo - Rogério Gomes Pereira - 2012.pdf: 669495 bytes, checksum: c54f913ec5ee37a58d9b0fb8da750844 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira ([email protected]) on 2018-03-05T13:14:18Z (GMT) No. of bitstreams: 2 Artigo - Rogério Gomes Pereira - 2012.pdf: 669495 bytes, checksum: c54f913ec5ee37a58d9b0fb8da750844 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2018-03-05T13:14:32Z (GMT). No. of bitstreams: 2 Artigo - Rogério Gomes Pereira - 2012.pdf: 669495 bytes, checksum: c54f913ec5ee37a58d9b0fb8da750844 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2012-05O objetivo deste trabalho foi avaliar os efeitos do “biochar” de eucalipto na resposta da taxa de transpiração do arroz de terras altas 'BRSMG Curinga', como alternativa para minimizar os efeitos da seca no desenvolvimento e crescimento das plantas. Dois experimentos em vasos foram realizados, em delineamento inteiramente casualizado, em parcelas subdivididas, com seis repetições. As parcelas principais foram constituídas pela deficiência hídrica (WS) e a não deficiência hídrica (NWS), e as subparcelas pelas doses de “biochar” a 0, 6, 12 e 24% adicionadas ao substrato (areia). A quantidade de água transpirável no solo (TTSW), o fator de depleção (p) – definido como a fração de TTSW que pode ser retirada da zona radicular, antes de a deficiência hídrica limitar o crescimento –, e a taxa de transpiração normalizada (NTR) foram determinados. A adição do “biochar” aumentou a TTSW e o fator p, e reduziu a NTR. Consequentemente, a adição do “biochar” foi capaz de modificar o limiar de umidade (fator p) do substrato, até 12% de concentração máxima, e retardar o ponto em que a transpiração declina e afeta a produtividade.The objective of this work was to evaluate the effect of eucalyptus biochar on the transpiration rate of upland rice 'BRSMG Curinga' as an alternative means to decrease the effect of water stress on plant growth and development. Two‐pot experiments were carried out using a completely randomized block design, in a split-plot arrangement, with six replicates. Main plots were water stress (WS) and no‐water stress (NWS), and the subplots were biochar doses at 0, 6, 12 and 24% in growing medium (sand). Total transpirable soil water (TTSW), the p factor – defined as the average fraction of TTSW which can be depleted from the root zone before water stress limits growth –, and the normalized transpiration rate (NTR) were determined. Biochar addition increased TTSW and the p factor, and reduced NTR. Consequently, biochar addition was able to change the moisture threshold (p factor) of the growing medium, up to 12% maximum concentration, delaying the point where transpiration declines and affects yield

Nutrient cycling by cover crops and yield of soybean and rice in no-tillage

Submitted by Luciana Ferreira ([email protected]) on 2018-06-05T15:13:07Z No. of bitstreams: 2 Artigo - Leandro Pereira Pacheco - 2013.pdf: 483384 bytes, checksum: eb3a729684ab203014d07e101f72537a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira ([email protected]) on 2018-06-06T11:18:51Z (GMT) No. of bitstreams: 2 Artigo - Leandro Pereira Pacheco - 2013.pdf: 483384 bytes, checksum: eb3a729684ab203014d07e101f72537a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2018-06-06T11:18:51Z (GMT). No. of bitstreams: 2 Artigo - Leandro Pereira Pacheco - 2013.pdf: 483384 bytes, checksum: eb3a729684ab203014d07e101f72537a (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2013-09O objetivo deste trabalho foi avaliar a ciclagem de nutrientes por plantas de cobertura e a sua influência sobre o desempenho da rotação entre arroz de terras altas e soja. As culturas foram implantadas sob plantio direto, em Latossolo Vermelho distroférrico, na região do Cerrado de Goiás. As plantas de cobertura foram semeadas mecanicamente, também em plantio direto, após a colheita da soja (25/3/2008) e do arroz (7/4/2009). Utilizou-se o delineamento de blocos ao acaso, com parcelas subdivididas no tempo e quatro repetições. Os tratamentos consistiram das seguintes espécies de plantas de cobertura, além do pousio: Urochloa ruziziensis, U. brizantha, Pennisetum glaucum e U. ruziziensis + Cajanus cajan. A avaliação dos nutrientes remanescentes na palhada foi feita aos: 0, 15, 30, 60, 90 e 120 dias a partir da data da dessecação das plantas de cobertura. Urochloa ruziziensis e U. brizantha apresentaram maior eficiência no acúmulo e na liberação de nutrientes, principalmente quanto ao potássio. Urochloa ruziziensis é a espécie mais indicada como planta de cobertura antecessora à cultura do arroz de terras altas, em plantio direto. No entanto, nenhuma espécie de cobertura afeta significativamente a produtividade de grãos da soja.The objective of this work was to evaluate nutrient cycling by cover crops and its influence on the performance of the rotation between upland rice and soybean. The crops were sown under no‐tillage, in a Rhodic Haplustox, in the Cerrado region of the state of Goiás, Brazil. The cover crops were sown mechanically, also under no‐tillage, after the harvest of soybean (3/25/2008) and rice (4/7/2009). A randomized complete block design was used, split‐plotted in time, with four replicates. The treatments consisted of the following cover crop species, besides fallow: Urochloa ruziziensis, U. brizantha, Pennisetum glaucum and U. ruziziensis + Cajanus cajan. The evaluation of the remaining nutrient in straw was performed at 0, 15, 30, 60, 90, and 120 days from the desiccation date of the cover crops. Urochloa ruziziensis and U. brizantha were the most efficient in the accumulation and release of nutrients, especially potassium. Urochloa ruziziensis is the most suited species for use as a cover crop previous to upland rice cultivation under no‐tillage. However, none of the cover crop species significantly affect soybean grain yield

Biomass production and nutrient cycling of cover crops in upland rice and soybean

Submitted by Luciana Ferreira ([email protected]) on 2018-06-06T13:15:28Z No. of bitstreams: 2 Artigo - Leandro Pereira Pacheco - 2011.pdf: 2100050 bytes, checksum: 1ee9336cabfb8efb358e10cebb4c6d9f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Approved for entry into archive by Luciana Ferreira ([email protected]) on 2018-06-08T11:37:17Z (GMT) No. of bitstreams: 2 Artigo - Leandro Pereira Pacheco - 2011.pdf: 2100050 bytes, checksum: 1ee9336cabfb8efb358e10cebb4c6d9f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5)Made available in DSpace on 2018-06-08T11:37:17Z (GMT). No. of bitstreams: 2 Artigo - Leandro Pereira Pacheco - 2011.pdf: 2100050 bytes, checksum: 1ee9336cabfb8efb358e10cebb4c6d9f (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2011As plantas de cobertura em sistema de plantio direto pode contribuir na formação de palhada e ciclagem de nutrientes para as culturas em sucessão. O objetivo deste trabalho foi avaliar a produção de matéria seca e ciclagem de nutrientes por plantas de cobertura semeadas em safrinha no desempenho do arroz de terras altas e da soja semeados em rotação, em sistemas plantio direto e preparo convencional, em Latossolo Vermelho do município de Rio Verde, Goiás. O estudo foi realizado no período de abril de 2008 a abril de 2010. Utilizou-se o delineamento em faixas com fatorial 2 x 5 com quatro repetições. Nas faixas horizontais foram testados os dois sistemas de manejo do solo (plantio direto e convencional) e nas faixas verticais, as plantas de cobertura. As avaliações de matéria seca, taxa de cobertura do solo e ciclagem de nutrientes foram realizadas apenas nos tratamentos plantio direto, em que as parcelas foram subdivididas em seis épocas de coletas de matéria seca após a dessecação das plantas de cobertura, o que ocorreu aos 0, 15, 30, 60, 90 e 120 dias a partir da dessecação de manejo das plantas de cobertura, perfazendo um fatorial 5 x 6. As plantas de cobertura, semeadas em safrinha, foram as seguintes: Brachiaria brizantha, B. ruziziensis, Pennisetum glaucum e B. ruziziensis + Cajanus cajan e o pousio. Avaliaram-se a produção de matéria seca, a taxa de cobertura do solo, o acúmulo e liberação de nutrientes pelas plantas de cobertura e a produtividade do arroz na safra 2008/09 e da soja na safra 2009/10, semeados em rotação. As espécies B. ruziziensis e B. ruziziensis + C. cajan destacaram-se na produção de matéria seca, taxa de cobertura do solo e acúmulo de nutrientes no final do período de entressafra. Os nutrientes com mais acúmulos nas matérias secas foram N e K, e as maiores taxas de liberação no solo foram observadas nos elementos K e P. As maiores produtividades de arroz sob plantio direto foram obtidas sobre palhadas de P. glaucum e B. ruziziensis, enquanto a cultura da soja não apresentou diferenças em sua produtividade nos tratamentos estudados.The cover crops in no-till system can contribute to the formation of mulch and nutrient cycling to annual crops in succession. The objective of this study was to evaluate biomass production and nutrient cycling of cover crops sown in the second growing season, in crop rotation after upland rice and soybean, in no-tillage and conventional tillage systems, on a Red Latassol of Rio Verde, state of Goiás, from April 2008 to April 2010. The experiment was evaluated in randomized strips, in a 5 x 6 factorial design, with four replications. In the horizontal strips two soil management systems (after three years of no-tillage and conventional systems) were evaluated and the cover crops in the vertical strips. Biomass and ground cover and nutrient cycling rates were only evaluated in the no-till treatments, in a 5 x 6 factorial arrangement, where the plots were subdivided, corresponding to six harvest dates of dried biomass 0, 15, 30, 60, 90 and 120 days after cutting of the cover crops. The following cover crops were sown in the second growing season: Brachiaria ruziziensis, Pennisetum glaucum and B. ruziziensis + Cajanus cajan and a fallow treatment as reference. Biomass production and the rates of soil cover and nutrient accumulation and release by cover crops as well as rice and soybean yield were evaluated. B. ruziziensis and B. ruziziensis + C. cajan performed best in biomass production, ground cover and nutrient accumulation at the end of the cover crops. The nutrients N and K had the highest concentration in the biomass, and the highest nutrient release to the soil was observed for K and P. The highest rice yield was observed when grown in no-tillage on crop residues of P. glaucum and B. ruziziensis, while soybean yields did not differ in the treatments