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Plant breeding reduces the genetic diversity of plants and could influence the composition, structure, and diversity of the rhizosphere microbiome, selecting more homogeneous and specialized microbes. In this study, we used 16S rRNA sequencing to assess the bacterial community in the rhizosphere of different lines and modern cowpea cultivars, to investigate the effect of cowpea breeding on bacterial community assembly. Made available in DSpace on 2022-05-19T18:12:54Z (GMT). No. of bitstreams: 1 GeneticallyRelatedGenotypesCowpeaSR12.2022.pdf: 3969211 bytes, checksum: e6aa59f5e56a237a0a51c50fc3548f5f (MD5) Previous issue date: 2022

The aim of this study was to assess the carbon pools of a tropical soil where the native forest was replaced with different pasture systems. We studied five pasture production systems, including four monoculture systems with forage grasses such as Andropogon, Brachiaria, Panicum, and Cynodon, and an agroforestry system as well as a native vegetation plot. Greater availability of fulvic acid was detected in the agroforestry system as compared with that in the other systems. Higher lability of C was detected in the Andropogon system during the dry and rainy seasons and during the dry season in Cynodon. During the dry season, all pastures systems showed deficits in the net removal of atmospheric CO2. The structure and practices of the agroforestry system enables more carbon to be sequestered in the soil as compared with the monoculture pasture, suggesting that it is an important practice to mitigate climatic change and to improve soil quality.

Made available in DSpace on 2015-03-18T15:56:27Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-12-01Bitstream added on 2015-03-18T16:28:18Z : No. of bitstreams: 1 WOS000346393700031.pdf: 53483 bytes, checksum: cf040adc391f339601b980cd132f2f6c (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Tannery industry releases high amounts of tannery sludge which are currently composted and used in agricultural soils. The consecutive amendment of such composted tannery sludge (CTS) may affect soil microrganisms, such as rhizobia. In this study, we evaluated the effects of 5-year repeated CTS amendment on growth, nodulation, and yield of cowpea (Vigna unguiculata L.) CTS was applied in different amounts (0, 2.5, 5, 10 and 20 Mg ha(-1)) to a sandy soil. Amendment of CTS increased soil pH, electrical conductivity (EC), sodium and chromium content. Plant growth, nodulation, N accumulation, and cowpea yield increased up to 10 Mg hat however, above this rate, these variables decreased. After 5 years of CTS amendment, the increase in soil chemical properties, particularly EC and Na content, exerted negative effects on the growth, nodulation, and yield of cowpea. Univ Fed Piaui, Agr Sci Ctr, Soil Qual Lab, BR-64000000 Teresina, PI, Brazil Sao Paulo State Univ UNESP, Fac Agr Sci & Vet FCAV, BR-18000000 Jaboticabal, SP, Brazil Sao Paulo State Univ UNESP, Fac Agr Sci & Vet FCAV, BR-18000000 Jaboticabal, SP, Brazil

Objetivou-se, com este trabalho, quantificar os efeitos dos Sistemas Agroflorestais com diferentes tempos de adoção e a agricultura de corte e queima sobre os atributos químicos de um Argissolo Vermelho-Amarelo em áreas de cerrado do estado do Piauí. Em duas épocas climáticas foram estudados quatro sistemas: sistemas agroflorestais com seis e treze anos de adoção, agricultura de corte e queima e uma floresta nativa do cerrado. As amostras de solo foram coletadas em quatro profundidades para determinação dos atributos químicos. No solo sob os Sistemas Agroflorestais foram observados, em todas as camadas avaliadas, redução dos teores de Al³+ e H++Al 3+ e aumento do pH, dos teores dos nutrientes e do carbono orgânico total em relação aos demais sistemas. No solo sob agricultura de corte e queima, verificou-se que apenas nas camadas superficiais a cinza depositada sobre o solo promoveu aumento dos nutrientes, exceto para o P, que foi maior em todas as camadas. Nos demais sistemas houve diminuição dos teores dos nutrientes no período chuvoso. Os sistemas agroflorestais promoveram aumento dos teores de nutrientes do solo e garantiram melhoria da qualidade química do solo em áreas de cerrado no estado do Piauí.

Microbial biomass and activity are useful indices for assessing changes in soil ecosystems. The impact of different pastures on microbial biomass and activity was studied in a long-term experiment in Northeast Brazil. For our study the pastures were divided into plots: a) Brachiaria brizantha; b) Leucaena leucocephala; c) Cynodon dactilon; d) Panicum maximum. An adjacent area with native vegetation was used as reference. Soil samples were collected in 0-10 and 10-20 cm depths. No significant differences in soil organic C (Corg) was found among all plots at 0-10 and 10-20 cm depth. Soil microbial C (Cmic) values were higher in native forest and P. maximum when compared to the other plots. The soil basal respiration (CO2) values were similar among all plots evaluated. However, respiratory quotients (qCO2) were significantly lower in native forest and P. maximum when compared to other plots, at 0-10 cm depth. Values of fluorescein diacetate (FDA) hydrolysis were significantly higher in native forest and P. maximum, while values of dehydrogenase activity were found to be signif icantly higher in native forest, C. dactilon and P. maximum. Soil microbial biomass and activity changed when a native forest was converted to pastures. These changes were positive with the inclusion of P. maximum by the high input of C sources., La biomasa y actividad microbiana son índices útiles para identificar cambios en los ecosistemas de suelo. Se estudió el impacto de diferentes pastos en la biomasa y actividad microbiana en un experimento a largo plazo en el nordeste de Brasil. Se dividieron los pastos en parcelas cultivadas con a) Brachiaria brizantha, b) Leucaena leucocephala, c) Cynodon dactilon y d) Panicum maximum, usando como referencia un área adyacente con la vegetación nativa. Se recolectaron muestras de suelo a profundidades de 0-10 y 10-20 cm. No se encontraron diferencias significativas en el C orgánico del suelo (Corg) entre las parcelas a 0-10 y 10-20 cm. Los valores del C microbiano del suelo (Cmic) fueron más altos en la vegetación nativa y en P. maximum que en el resto de las parcelas. Los valores de la respiración básica (CO2) del suelo fueron similares en todas las parcelas evaluadas. Sin embargo, los cocientes respiratorios (qCO2) fueron considerablemente inferiores en la vegetación nativa y en P. maximum que en el resto de las parcelas a la profundidad de 0-10 cm. Los valores de la diacetato de la fluoresceína (FDA) fueron significativamente más altos en la vegetación nativa y en P. maximum, mientras que la actividad deshidrogenasa fue significativamente más alta en la vegetación nativa, C. dactilon y P. maximum. Cuando un bosque nativo fue convertido en pastizales, la biomasa y la actividad microbiana del suelo cambiaron. Estos cambios fueron positivos con la inclusión de P. maximum por el elevado aporte de fuentes de C.

Microbial biomass and activity are useful indices for assessing changes in soil ecosystems. The impact of different pastures on microbial biomass and activity was studied in a long-term experiment in Northeast Brazil. For our study the pastures were divided into plots: a)Brachiaria brizantha; b) Leucaena leucocephala; c) Cynodon dactilon; d) Panicum maximum. An adjacent area with native vegetation was used as reference. Soil samples were collected in 0-10 and 10-20 cm depths. No significant differences in soil organic C (Corg) was found among all plots at 0-10 and 10-20 cm depth. Soil microbial C (Cmic) values were higher in native forest and P. maximum when compared to the other plots. The soil basal respiration (CO2) values were similar among all plots evaluated. However, respiratory quotients (qCO2) were significantly lower in native forest and P. maximum when compared to other plots, at 0-10 cm depth. Values of fluorescein diacetate (FDA) hydrolysis were significantly higher in native forest and P. maximum, while values of dehydrogenase activity were found to be signif icantly higher in native forest, C. dactilon and P. maximum. Soil microbial biomass and activity changed when a native forest was converted to pastures. These changes were positive with the inclusion of P. maximum by the high input of C sources. La biomasa y actividad microbiana son índices útiles para identificar cambios en los ecosistemas de suelo. Se estudió el impacto de diferentes pastos en la biomasa y actividad microbiana en un experimento a largo plazo en el nordeste de Brasil. Se dividieron los pastos en parcelas cultivadas con a)Brachiaria brizantha, b) Leucaena leucocephala, c) Cynodon dactilon y d) Panicum maximum, usando como referencia un área adyacente con la vegetación nativa. Se recolectaron muestras de suelo a profundidades de 0-10 y 10-20 cm. No se encontraron diferencias significativas en el C orgánico del suelo (Corg) entre las parcelas a 0-10 y 10-20 cm. Los valores del C microbiano del suelo (Cmic) fueron más altos en la vegetación nativa y en P. maximum que en el resto de las parcelas. Los valores de la respiración básica (CO2) del suelo fueron similares en todas las parcelas evaluadas. Sin embargo, los cocientes respiratorios (qCO2) fueron considerablemente inferiores en la vegetación nativa y en P. maximum que en el resto de las parcelas a la profundidad de 0-10 cm. Los valores de la diacetato de la fluoresceína (FDA) fueron significativamente más altos en la vegetación nativa y en P. maximum, mientras que la actividad deshidrogenasa fue significativamente más alta en la vegetación nativa, C. dactilon y P. maximum. Cuando un bosque nativo fue convertido en pastizales, la biomasa y la actividad microbiana del suelo cambiaron. Estos cambios fueron positivos con la inclusión de P. maximum por el elevado aporte de fuentes de C.