Total and labile organic carbon content in agroecological system.

In an intercropping lettuce-carrot system submitted to crescent dosages of organic compost (0; 12; 24; 48 Mg ha-1) were monitored carbon from soil microbial biomass (MBC), labile carbon in fumigated soil (LCF), in non-fumigated soil (LCNF), in autoclaved soil (LCA) and total organic carbon (TOC) at 0-10 cm of depth. Pasture and forest areas surrounding the experiment were used as reference. Five samples from soil were evaluated at 8 days before the beginning of the experiment, 0; 6; 60 and 114 days after manuring (dam). LCF was the attribute that presented the most consistent correlation with TOC that is usually utilized to detect changes in soil organic matter. Increasing dosages of organic compost caused the increase of MBC, LCF, LCNF, LCA and TOC. From 60 days after planting and forward, MBC and LCF presented decrease of their levels according to the quality of organic compost. Pasture and forest soils behave as contrasts, holding lower and higher content of carbon of soil, respectively

Determinação do nitrogênio da biomassa microbiana do solo (BMS-N).

Materiais e equipamentos necessários; Para fumigação; Para extração; Para determinação do nitrogênio microbiano; Amsotra; Limitações do método; Procedimento; Preparação da amostra; Determinação da umidade na capacidade de campo do solo; Procedimento analítico; Determinação da umidade do solo; Fumigação; Extração; Determinação do nitrogênio microbiano; Cálculo da molaridade exata da solução de ácido sulfúrico (H2S04) 0,015M; Cálculo do teor de N nos extratos (Equação 4); Cálculo da BMS-N; Equação 5.bitstream/CNPAB-2010/34388/1/cot096.pdfParceria: UFRR

Pseudomonas fluorescentes associadas à olerícolas sob sistema de produção orgânico.

Avaliou-se a diversidade de populações de Pseudomonas spp. fluorescentes associadas à alface, cenoura e pepino, cultivados em sistema orgânico. O delineamento experimental foi de blocos inteiramente casualizados, com três repetições. Foi incorporado ao solo anterior ao plantio, 20 t/ha de esterco bovino curtido e 1,5 t/ha de termofosfato. As amostras de solo foram separadas em ectorizosfera, rizoplano, endorizosfera e filoplano por olerícola. Os isolados bacterianos que apresentaram fluorescência sob luz UV foram selecionados e caracterizados conforme a morfologia de suas colônias, sendo que um isolado, de cada um dos grupos mais representativos quantitativamente, foi identificado pelo Sistema API 20NE. Foram selecionados 25 isolados, identificados como P. putida, das culturas de alface e cenoura para caracterização por RAPD. A análise fenotípica permitiu a identificação de alguns grupos de isolados associados à alface, cenoura e pepino. Existe uma alta diversidade de estirpes, revelada pela caracterização fenotípica e genotípica, associada às olerícolas estudadas, sob sistema orgânico de produção

Observatório de Conflitos Urbanos de Curitiba: metodologia e categorias de análise

Urban conflicts, as an expression of social conflict, are significant phenomena and represent a prominent object for reflection on social dynamics and relations. The aim of this paper is to present categories and methodology that help to broaden knowledge on urban social struggles and their insertion into the most general range of social conflict based on the experience of building research instruments and theoretical contributions that contribute to the Curitiba Observatory of Urban Conflict. The global analysis of the 707 documented protests delivers elements with which to assess the theoretical-methodological potential of the proposal, thereby indicating that the protests, in different ways, have triggered demands for the qualification (improvements in infrastructure and services), appropriation (recognition of uses) and transformation (modification in production processes) of urban spaces.Os conflitos urbanos, como expressão da conflitualidade social, são fenômenos importantes e objeto destacado para a reflexão sobre as dinâmicas e relações sociais. A proposta deste trabalho é apresentar categorias e metodologia que contribuam para aprofundar o conhecimento sobre as lutas sociais urbanas e sua inserção na dinâmica mais geral da conflitualidade social, com base na experiência de construção de instrumentos de pesquisa e aportes teóricos que subsidiam o Observatório de Conflitos Urbanos de Curitiba. A análise global dos 707 protestos registrados traz elementos para avaliação do potencial teórico-metodológico da proposta, evidenciando que os protestos acionam, de diferentes maneiras, demandas pela qualificação (melhorias em infraestrutura e serviços), apropriação (reconhecimento de usos) e transformação (modificação dos processos de produção) dos espaços urbanos

Variabilidade genética da simbiose Centrosema-Rhizobium

A greenhouse study carried out with 11 Centrosema sp. genotypes and three Rhizobium sp. strains, for the purpose of obtaining more efficient genetic combinations in the fixation of N2. Five of the progenies studied carne from two F2 plants, and three were F2 plants of interspecific hybridization C. pubescens x C. virginianum. IPEACS line 5.1/64, one Australian cultivar and the common material of C. pubescens were also included. Statistical differences were obtained, between genotypes and between strains in nodule number, the dry weight of nodules and the dry weight of plants, per cent N and total N per plant. The study permitted an analysis of the segregation of genetic combinations, between host and strain with highest N2 fixation.Foi realizado em Itaguaí, RJ, um estudo em casa de vegetação, utilizando onze materiais de Centrosema sp. e três estirpes de Rhizobium sp., no sentido de selecionar combinações de maior eficiência quanto à fixação do N2 atmosférico. Dos materiais testados, cinco eram filhas de duas plantas F2, resultantes do cruzamento de linhagens de C. pubescens, três eram plantas F2 do cruzamento interespecífico de C. pubescens x C. virginianum, e os demais eram a linhagem IPEACS 5.1/64, um cultivar australiano e o material original do trabalho de melhoramento (cultivar Deodoro). Houve diferenças estatisticamente significativas, entre genótipos e entre estirpes, quanto ao número de nódulos, peso seco das plantas, peso seco dos nódulos, N percentual e N total das plantas. O fato de terem sido utilizadas gerações F2 e F3, dos diferentes cruzamentos, permite esperar que, com a segregação das gerações seguintes, apareçam combinações gênicas com simbiose mais eficiente do que as observadas no presente trabalho

Deficiência de micronutrientes em solo Podzólico Vermelho-Amarelo e sua correção com "pellet" de F.T.E

Three greenhouse experiments were conducted with a Red Yellow Podzolic soil (pH 5.1) that commonly occurs on the steep hills used for pastures in the state of Rio de Janeiro. The purposes of the study were to observe the effects of F.T.E. on the growth of four species of tropical legumes and the symbiotic fixation of nitrogen. Plant response to four different F.T.E. formulations was measured in terms of root nodule numbers and weight, plant dry matter production, and total N content. From the differencial effects of the 4 F.T.E. formulae it was deducted that Mn or Fe were suspect as being limiting in the legume - Rhizobium symbiosis, although other micronutrients may also have been involved. Plant responses to applications of a F.T.E. containing all micronutrients. Crude protein production by Centrosema pubescens, Phaseolus atropurpureus, Glycine wightii, and Stylosanthes guyanensis, was doubled by these treatments. Except in the case of Stylosanthes guyanensis, similar increases in crude protein when the F.T.E. formulations were applied as pellets consisting of various combinations of F.T.E., lime, rock phosphate, and peat inoculum. Increases in legume dry matter production were less than those in crude protein content, but still highly significant. Applications of F.T.E. in pellets initially induced chlorosis in the legume seedlings. The chlorosis was almost completely eliminated by pelleting with F.T.E. mixed with lime or by layering the pellets with F.T.E. and lime. In culture medium, Rhizobium was not inhibited by any of the four F.T.E. formulations.Foram feitos três experimentos em casa de vegetação com solo Podzólico Vermelho-Amarelo, de relevo acidentado, normalmente usado como pastagem, para estudar problemas de estabelecimento de leguminosas forrageiras. Verificou-se que deficiência de manganês e de outros micronutrientes limita a fixação de nitrogênio e o desenvolvimento destas leguminosas. O uso do F.T.E. ("Fritted Trace Elements") duplicou a produção de proteína de Centrosema pubescens, Phaseolus atropurpureus, Glycine wightii e Stylosanthes guyanensis, quando aplicado no solo, e das três primeiras, quando aplicado em forma de "pellet". O F.T.E., quando usado puro, na forma de "pellet", induziu uma clorose nas plantas novas; no entanto, quando misturado ou em camadas com calcário, este efeito foi quase eliminado. Testes em meio de cultura mostraram que o Rhizobium não foi inibido pelas diversas fórmulas do F.T.E

Performance of roquette crop fertilized with cattle and green manure using two planting densities.

This research was conducted to study the direct fertilization combining 0 and 160 kg N ha-1 of cattle manure and green manure as branches of pigeon pea (Cajanus cajan L.) and their residual effects on two population densities of roquette (Eruca sativa Miller) crop, in Seropédica, Rio de Janeiro, Brazil. Yield, number of leaves plant-1, leaf area index, shoot fresh weight, stems dry matter, roots dry matter, leaves dry matter, total dry matter and plant height were measured. The experiment was a randomized block design set as a factorial 2 x 2 x 2, and three replications: 0 and 160 kg N ha-1 of cattle manure, 0 and 160 kg N ha-1 of branches of pigeon pea and 500,000 and 1,000,000 plants ha-1. The results indicate that the population density of 500,000 plants ha-1 showed, in general, better results in terms of yield per plant. However, 1,000,000 plants ha-1 had significantly higher yield per hectare. It was observed that there was no significant difference between the use of cattle manure and branches of pigeon pea on the yield of roquette under directly fertilization and residual effect of fertilization. The replacement of cattle manure by branches of pigeon pea associated with 1,000,000 plants ha-1 showed less loss of roquette yield under the residual effect of fertilization

Influence of surfactant-humectant adjuvants on physical properties, droplet size, and efficacy of glufosinate formulations

Glufosinate efficacy is inconsistent among weed species and under environmental conditions that favor rapid droplet drying. Surfactant-humectant adjuvants could maximize glufosinate efficacy by increasing wetting and penetration into the leaf surface while decreasing evaporation rate (ER). However, there is a lack of information in the literature about the interaction of surfactant-humectants adjuvants with glufosinate. The objective of this study was to investigate the influence of surfactanthumectant adjuvants on the physical properties, droplet size, and efficacy of two glufosinate formulations. Laboratory, greenhouse, and field studies were conducted at the Pesticide Application Technology Laboratory of the University of Nebraska- Lincoln. Treatment design was a 2 × 5 factorial with two glufosinate formulations combined with five adjuvant treatments plus an untreated control. Density and viscosity of glufosinate solutions mostly increased with the addition of adjuvants. However, the influence of the adjuvants on dynamic surface tension (dST), static contact angle (sCA), and evaporation rate (ER) varied by glufosinate formulation, adjuvant, and relative humidity (RH). Under greenhouse conditions, an improvement in efficacy by adding adjuvants was mainly observed for Interline solutions. The addition of adjuvants to Interline solutions increased biomass reduction up to 19 and 35% for common lambsquarters (Chenopodium album L.) and kochia [Bassia scoparia (L.) A. J. Scott], respectively. Also, some of the adjuvants presented null or antagonistic influence on herbicide efficacy. No increase in control, biomass reduction, and mortality of horseweed (Erigeron canadensis L.) and Palmer amaranth (Amaranthus palmeri S. Watson) was observed with the use of adjuvants under field conditions. Herbicide-adjuvant-plant-environment interaction is complex. Thus, the use of surfactant-humectant adjuvants may not increase herbicide efficacy

Fixação de fósforo por um Latossolo e determinação do valor X.

Ensaio conduzido em laboratório para avaliar a capacidade de fixação de fósforo dos horizontes A1, A3 e B22 de latossolo roxo distrófico. Foi também determinado o valor X de WAUGH & FITS (1966) dos três horizontes. Os principais resultados são apresentados a seguir: O horizonte B22 foi que apresentou maior capacidade de fixação de fósforo, seguido pelo A3 e, finalmente, pelo A1. Os valores X encontrados foram 350 ppm225ppm e 175 ppm para os horizontes B22, A3 eA1, respectivamente. Houve uma relação muito estreita entre as quantidades de P adicionadas e as fixadas pelos três horizontes

Microbial soil quality indicators under different crop rotations and tillage management.

An experiment was carried out under field conditions to assess the effects of soil management (no-tillage- NT and conventional tillage- CT) and crop rotation systems on microbial biomass-C (Cmic), basal soil respiration (BSR), metabolic quotient (qCO2), soil organic carbon content (Corg) and microbial carbon to organic carbon ratio (Cmic/Corg). Soil samples were collected on an area cultivated with wheat as winter crop and soybean as summer crop, both in rotation with vetch, maize and oats. Samples were also collected in a secondary forest used as reference. Data of each management system (NT and CT) were compared to forest area by ?t? test (p<0.05) and crop rotations were compared by Tukey test (p<0.05). All data were submitted to multivariate analysis (Principal Component Analysis - PCA). There were observed significant differences (?t? test; p<0.05) for Cmic, BSR, qCO2 and Cmic/Corg between NT and CT, by which NT values resemble those for forest area. For crop rotations significant differences (Tukey test; p<0.05) were found only for BSR and qCO2. The sum of the two first principal components on the PCA explained about 75% of the data variation. PCA showed NT closest to forest area than CT, especially treatments with soybean and vetch as consecutive crops. The forest area-NT clustering was mostly due to Cmic and Cmic/Corg relationship. Results indicate that the NT system is more sustainable than the CT system and can contribute for the accumulation a greater quantity of carbon in soil