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No-tillage (NT) has been one of the main advances related to soil management in Brazilian agriculture in the last 30 years. However, its full adoption in lowland areas that are traditionally cultivated with flooded rice is still incipient (

Phenotyping is the major bottleneck in the effort to develop varieties of rice (Oryza sativa L) suitable for grow under a water saving irrigation management, such as alternate wetting and drying irrigation technique (AWD). In order to analyze if the genotypic variability for carbon isotope discrimination (CID) in rice leaves could be used as a relatively high-throughput tracer to early select superior genotypes highlighting improved root architecture traits when submitted to AWD, a set of twenty varieties grown under semi-natural conditions were submitted to two water irrigation regimes, continuous ooding (CF) and AWD cycles. Coecients of genetic variance (π2g) obtained for root architecture, micro-morphological and physiological traits were signicant for all of them regardless of adopted irrigation system, except to mean root diameter. The three signicant principal components (PCs) with eigenvalue > 1, explain the most of the total variation across cycles and water regimes. For most of analyzed traits, the values of heritability coecients were higher regardless of adopted irrigation management and trait category; for CID, the magnitudes of broad heritability at individual level (greater than 0.80) were similar in the two irrigation techniques, evidencing that the success of selection is independent of irrigation management. The higher CID values after three AWD cycles are associated to varieties with higher total root length and volume. To our knowledge, this is the rst study demonstrating the potential application of CID as tracer to select root architecture traits in rice when water-saving irrigation management are of concern. Made available in DSpace on 2022-06-12T04:01:14Z (GMT). No. of bitstreams: 1 Artigo-Research-Square.pdf: 5156220 bytes, checksum: e76033d923ea8789d5bbeae401bf9a15 (MD5) Previous issue date: 2022 Accepted: 28 June 2021 / Published online: 5 August 2021.

Breeding programs aim to increase grain yield and quality through selection oriented mostly by morphological and productive traits. Although morphoanatomical traits are preponderant for plant performance, they are usually time-consuming, demanding specific equipment and trained personnel. The aim of the study is to establish relationships among morphological, micromorphological and anatomical traits of rice genotypes, to support rice breeders in choosing variables to be assessed in the search for superior rice genotypes. We assessed morphological (2nd leaf and root lengths, tiller and root number), micromorphological (vein density, intervein distance, stomatal density and opening width) and anatomical (area of sclerenchyma, xylem and phloem vessels, and percentage of aerenchyma) traits. Root number and length, area of sclerenchyma and xylem and phloem vessels are proposed to be the most efficient traits to be assessed in detailed studies aiming to identify superior genotypes in rice breeding programs, from the morphophysiological point of view. Made available in DSpace on 2021-10-06T02:12:00Z (GMT). No. of bitstreams: 1 Artigo-Contribution-For-Improvement-Of-Rice-Breeding-Prog.pdf: 1546878 bytes, checksum: 6b6eb3524b050aaeb8bd3c5ac7d26c16 (MD5) Previous issue date: 2021

Paddy fields are significant anthropogenic sources of methane (CH4) emissions. In southern Brazil, rice is grown in lowland flooded areas once a year, followed by a long fallow period. This study aimed to measure CH4 fluxes in a rice paddy field in southern Brazil during the rice-growing season of 2015/2016 and the following fallow period. The fluxes were estimated using the eddy covariance (EC) technique and soil chamber (SC). Diurnal and seasonal variations of CH4 fluxes and potential meteorological drivers were analyzed. The CH4 fluxes showed distinct diurnal variations in each analyzed subperiod (vegetative, reproductive, pre-harvest, no rice, and land preparation), characterized by a single-peak diurnal pattern. The variables that most influenced methane emissions were air and surface temperatures. In the growing season, the rice vegetative stage was responsible for most of the measured emissions. The accumulated annual emission estimated was 44.88 g CH4 m?2 y?1, being 64% (28.50 g CH4 m?2) due to the rice-growing season and 36% (16.38 g CH4 m?2) due to the fallow period. These results show the importance of including fallow periods in strategies to mitigate methane emissions in flood irrigated rice-growing areas. Made available in DSpace on 2021-10-22T12:01:15Z (GMT). No. of bitstreams: 1 Artigo-The-Fallow-Period-Plays-Sustainability.pdf: 1229550 bytes, checksum: 9f2bc4d78979fa0657a437912e33b256 (MD5) Previous issue date: 2021

A Fronteira Oeste do Rio Grande do Sul (RS) vem se destacando pela diversificação produtiva e pelo desenvolvimento do setor frutícola. A adequada nutrição dos pomares é um dos fatores essenciais para garantir o sucesso da atividade nessa nova região produtora. Devido à escassez de dados referentes à citricultura da região da Fronteira Oeste do RS, objetivou-se, neste trabalho, avaliar o estado nutricional de laranjeiras ?Lane late?, ?Navelina?, ?Salustiana?, ?Valência?, ?Valência Midknight? e ?Valência Delta Seedless? enxertadas sob Poncirus trifoliata nas condições edafoclimáticas da região. Os pomares em que se realizaram as amostragens foram constituídos por plantas adultas. Os pomares de laranjeiras da Fronteira Oeste do RS apresentam, de forma geral, deficiência foliar em N, Ca, Mn e Zn, apresentando, ainda, excesso foliar de Cu e P, indicando necessidade de adequação do manejo do solo e da adubação, visando o aumento no conteúdo de matéria-orgânica do solo, o parcelamento da adubação nitrogenada e o aprimoramento da adubação com Mn e Zn. Made available in DSpace on 2020-12-09T09:04:35Z (GMT). No. of bitstreams: 1 Artigo-Diagnostico-nutricional-de-pomares-de-laranjeiras.pdf: 602695 bytes, checksum: 715586aa76db12af8fe51887f0b23bdf (MD5) Previous issue date: 2020 Edição está em andamento, na modalidade de publicação contínua.

Made available in DSpace on 2018-02-27T00:40:59Z (GMT). No. of bitstreams: 1 WalkyriaBuenoRevistaBrasileiradeGeografiaFisica.pdf: 1411172 bytes, checksum: f06657b43682994138269dc613913642 (MD5) Previous issue date: 2018-02-26

Made available in DSpace on 2018-01-15T23:19:11Z (GMT). No. of bitstreams: 1 RobertoPedrosoLEDsculturadetecidos.pdf: 266367 bytes, checksum: 8af0e72717e7f93e4ea39e77a2cca491 (MD5) Previous issue date: 2018-01-15

The objective of this work was to evaluate the response of irrigated rice to phosphate fertilization using triple superphosphate (TSP) and Arad phosphate rock (APR), and the phosphate residual effects of upland crops in no-tillage system on the following rice crop. Also, it aimed to evaluate the efficiency of Mehlich-1 and anion exchange resin as soil P extractors. Two experiments were conducted in Albaqualf soil under irrigated conditions in the southern region of Rio Grande do Sul State. The experiments were designed as random blocks with four replications and the treatments were displayed as a 2 × 2 factorial (TSP and APR, with and without annual P application as TSP). No yield responses to phosphate were observed. Phosphate fertilization performed on upland crops (maize and soybeans) presented a residual effect on the rice crop even after four years of consecutive cropping under no-tillage. The extractors Mehlich-1 and AER were equally efficient in the evaluation of P availability for the rice crop. P content values obtained by both methods did show a significant correlation with accumulated plant P. The APR presents a similar performance as the TSP in regard to phosphate nutrition in irrigated rice when rotated with upland crops under no-tillage system.

The burgeoning demand for rice in Latin America and Caribbean (LAC) exceeds supply, resulting in a rice deficit. To overcome this challenge, rice production should be increased, albeit sustainably. However, since rice production is associated with increases in the atmospheric concentration of two greenhouse gases (GHGs), namely methane (CH4) and nitrous oxide (N2O), the challenge is on ensuring that production increases are not associated with an increase in GHG emissions and thus do not cause an increase in GHG emission intensities. Based on current understanding of drivers of CH4 and N2O production, we provide here insights on the potential climate change mitigation benefits of management and technological options (i.e., seeding, tillage, irrigation, residue management) pursued in the LAC region. Studies conducted in the LAC region show intermittent irrigation or alternate wetting and drying of rice fields to reduce CH4 emissions by 25–70% without increasing N2O emissions. Results on yield changes associated with intermittent irrigation remain inconclusive. Compared to conventional tillage, no-tillage and anticipated tillage (i.e., fall tillage) cause a 21% and 25% reduction in CH4 emissions, respectively. From existing literature, it was unambiguous that the mitigation potential of most management strategies pursued in the LAC region need to be quantified while acknowledging country-specific conditions. While breeding high yielding and low emitting rice varieties may represent the most promising and possibly sustainable approach for achieving GHG emission reductions without demanding major changes in on-farm management practices, this is rather idealistic. We contend that a more realistic approach for realizing low GHG emitting rice production systems is to focus on increasing rice yields, for obvious food security reasons, which, while not reducing absolute emissions, should translate to a reduction in GHG emission intensities. Moreover, there is need to explore creative ways of incentivizing the adoption of promising combinations of management and technological options EEA Corrientes Fil: Chirinda, Ngonidzashe. Centro Internacional de Agricultura Tropical (CIAT); Colombia Fil: Arenas, Laura. Centro Internacional de Agricultura Tropical (CIAT); Colombia Fil: Katto, María. Centro Internacional de Agricultura Tropical (CIAT); Colombia Fil: Loaiza, Sandra. Centro Internacional de Agricultura Tropical (CIAT); Colombia Fil: Correa, Fernando. Centro Internacional de Agricultura Tropical (CIAT); Colombia Fil: Isthitani, Manabu. Centro Internacional de Agricultura Tropical (CIAT); Colombia Fil: Loboguerrero, Ana María. Centro Internacional de Agricultura Tropical (CIAT); Colombia. Consultative Group on International Agricultural Research (CGIAR) Research Program on Climate Change, Agriculture and Food Security (CCAFS); Colombia Fil: Martínez-Barón, Deissy. Centro Internacional de Agricultura Tropical (CIAT); Colombia. Consultative Group on International Agricultural Research (CGIAR) Research Program on Climate Change, Agriculture and Food Security (CCAFS); Colombia Fil: Graterol, Eduardo. Fondo Latinoamericano para Arroz de Riego (FLAR); Colombia Fil: Jaramillo, Santiago. Fondo Latinoamericano para Arroz de Riego (FLAR); Colombia Fil: Torres, Carlos Felipe. Instituto de Hidrología, Meteorología y Estudios Ambientales (IDEAM); Colombia Fil: Arango, Miguel. Corporación Colombiana de Investigación Agropecuaria (CORPOICA); Colombia Fil: Guzmán, Myriam. Federación Nacional de Arroceros (FEDEARROZ); Colombia Fil: Avila, Ivan. Federación Nacional de Arroceros (FEDEARROZ); Colombia Fil: Hube, Sara. Instituto de Investigaciones Agropecuarias (INIA); Chile Fil: Kurtz, Ditmar Bernardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Corrientes; Argentina Fil: Zorrilla, Gonzalo. National Agricultural Research Institute (INIA); Uruguay Fil: Terra, Jose. National Agricultural Research Institute (INIA); Uruguay Fil: Irisarri, Pilar. Universidad de la República. Facultad de Agricultura. Department of Plant Biology; Uruguay Fil: Tarlera, Silvana. Universidad de la República. Facultad de Química y Ciencia. Department of Biosciences; Uruguay Fil: LaHue, Gabriel. University of California, Davis. Land, Air and Water Resources. Department Plant Sciences; Estados Unidos Fil: Scivittaro, Walkyria Bueno. Embrapa Clima Temperado (CPACT); Brasil Fil: Noguera, Aldo. Paraguay. Ministerio de Agricultura y Ganadería (MAG); Paraguay Fil: Bayer, Cimelio. Universidad Federal de Río Grande del Sur. Department of Soil Science; Brasil

O objetivo deste trabalho foi determinar a influência da tensão de água e de atributos físicos e químicos do solo sobre a produtividade do arroz irrigado por aspersão, em terras baixas no Rio Grande do S l. Na safra 2011/2012, foram avaliados os efeitos das tensões de água no solo de 20 e 40 kPa, durante todo o ciclo da cultura, bem como as de 40 e 20 kPa nas fases vegetativa e reprodutiva, respectivamente. Na safra 2012/2013, foram avaliadas as tensões de 10, 20 e 40 kPa, durante todo o ciclo da cultura, e as de 40 e 10 kPa nas fases vegetativa e reprodutiva, respectivamente. Em ambas as safras, utilizou-se a cultivar de arroz irrigado BRS Pampa. O gasto com água na irrigação por aspersão representou 48% do gasto com a irrigação por inundação. A produtividade do arroz correlacionou-se positivamente com a microporosidade e com os teores de fósforo e potássio disponíveis no solo; e negativamente com a macroporosidade e a saturação por alumínio. A avaliação conjunta da tensão de água e de atributos físicos e químicos do solo permite avaliar com mais propriedade a variabilidade na produtividade de arroz irrigado por aspersão em terras baixas no Rio Grande do Sul. A irrigação por aspersão possibilita melhor uso da água proveniente da precipitação pluvial, com efeitos positivos sobre a economia de água. Made available in DSpace on 2017-04-12T12:47:14Z (GMT). No. of bitstreams: 1 WalkyriaProdutividadedearrozirrigado.pdf: 648665 bytes, checksum: 6219a06dc97fd5958f4a718d5d34e471 (MD5) Previous issue date: 2017-04-12

Made available in DSpace on 2013-07-24T23:33:25Z (GMT). No. of bitstreams: 1 RobertoPedrosoa20313cr20121069.pdf: 213593 bytes, checksum: e8d602fbf2f485f024443f039478ffdf (MD5) Previous issue date: 2013-07-24

Made available in DSpace on 2013-08-29T23:35:03Z (GMT). No. of bitstreams: 1 WalV37N3a15impresso.pdf: 141621 bytes, checksum: c856b7a66dc655196aaeac17378a24d3 (MD5) Previous issue date: 2013-08-29

Made available in DSpace on 2014-02-20T23:24:53Z (GMT). No. of bitstreams: 1 14092625581PB.pdf: 270175 bytes, checksum: 1a6bf1ad4ed0a248ba90cbf5d74e86d8 (MD5) Previous issue date: 2014-02-20 Resumos do VIII Congresso Brasileiro de Agroecologia - Porto Alegre/RS - 25 a 28/11/2013.