Repositório RCAAP

The study of green manure species secking the soil protection, improvement of your chemical conditions, as well a weed control, has crucial imponance to reach the balance in a production system. An experiment was deve loped to evaluate the behavior of different green manures in soil covering and competition with weed species. The statistical design was complete randomized blocks with three replications. The treatments consisted of nine summer green manures, Crotalaria juncea, Vigna unguiculata, Canavalia ensiformis, Cajanus cajan (dwarf), Caj anus cajan, Lablab purpureum, Stizolobium deeringianum, Stizolobium cinereum, Stizolobium aterrimum. The percentage of soil covering, green manure population and weeds, the relationship between soil covering and plant population, were evaluated. The production of biomass (green and dry matter) during the flowering, were evaluated. Canavalia ensiformis was the specie that presented the major velocity and soil covering percentage along the period. Crotalária juncea, cajanus cajan (dwarf) and Stizolobium deeringianum, provided an increase in the weeds and soil covcring percentage along the time. Stizolobium cinereum tended to result in the smallest weeds population.

One of the difficulties faced for the development of the fish farming is the lack of studies about theadversities of this activity, as wel I as of researches that guide the formulation of actions and of public politics andprivate for the sector. The present work seeks to characterize the fish fanning of the northwest area of the State ofRio Grande do Sul, aiding in the development of the activity and guiding rescarch demands and appropriatetechnical attendance. The information were obtained through applied questionnaire in 250 fish farmers, being theanswers analyzed in tables of double entrance. h was verificd that most of the producers do not have the fishfarming as the main activity, small fish farmers that use the technology in a reduced way prevailing. Thecommercialization concentrates on the Easter week, presenting a little market in other periods of the year. Theprincipal identified problem was the market lack consolidated to absorb the production, hindering the permanenceof the producers in the activity.

The present paper compares and characterizes the said conventional and organical cultivation systems implanted in july, 2001, in two orchards with a quarter hectar each in which Valência' orange trees were budded on Poncirus trifoliata rootstock, at Centro de Formação de Montenegro - RS. The orchards were installed at the distante of 300 m between them, with spacing among trees of 2,5 m and among tines of 5,5 m. Around each orchard a line of Cameroon grass was planted, as well as a line of Pinus elliotti to protect the trees against winds. In each orchard were applied in five blocks, with 5 trees each, from which were collected preliminary data in relation to growth, fruit bearing and attacks of certain plagues and diseases. The management of the conventional orchard comprehended activities accomplished for convencional system of cultivation of oranges, while organical proces- ses, which were commended by Cooperativa de Citricultores Ecológicos do Vale do Caí (ECOCITROS), were used in the organical system. Tree years after the stablishment of the orchards, we are able to asseverate that in the convencional orchard, trees grcw plus, but they were more suscetible to citrus canker attacks. In organical orchards, fru its bore less and there were no records of citrus canker attacks.

This work was carricd out at Depressão Central/RS (alt.46m, lat.30°05"S, long.51°40'0), to determine the effect ofsoil tillagc systems on the persistente of Desmodium incanum DC. in field crops established on natural grassland. In arandomized complete block design three tillage methods were used as plots: direct drill (DD), minimum tillage (MT) andconventional tillagc (CT). Surveying of cover-abundance, frequency and soil secd bank (soil core samples and germination) of D.incanum were carricd in: autumn and spring of 2002 and 2003, and autumn of 2004. A very low amount of seeds was registered.D. incanum frequency and cover-abundance were higher in the DD than MT and CT, of which the latter shówed ver> , Iow valucs.In DD and MT, the relationship between frequency and cover-abundance with vegetation sampling dates were described bynegative linear regressions. Positive linear regressions were recorded between frcquency and cover-abundance with pH andorganic mattcr of soil surface. In solte of the gradual reduction in persistente, D. incanum showed ability to persist for unti I fouryears, in soil tillagc systems under Iow disturbancc such as direct drill.

With thc objective to evaluate the effects of pruning and hand fruit thinning to control altemate bearing and ameliorate fruit quality of 'Montenegrina' mandarins (Citrus deliciosa Tenore), buddcd on 'Caipira' Orange, was conducted the present study in a seven-year old private orchard, located in Butiá-RS, southem Brazil (29°57'S - 51°40W). The following treatmcnts were applied: A) Control I (trees with heavy fruit load); B) Control 2, trees not bearing fruits; C) Hand thinnig in February of 66% of fruits on heavy loaded trees; D) Pruning in December, of heavy loaded trees; E) Pruning in December of heavy loaded troes plus hand thinning of 33% of the fruits; F) Pruning in December, of no bearing trees.The treatmcnts were applied in a randomized block design with four replicatcs and 3 plants as experimental unit. Thc averagc time required for pruning, thinning and harvesting the fruits of each tree, and weight of fruits classified in three categories were determined. An average price of R$ 0.38/kg for fruits of first plus second category and R$ 0.08/kg for the fruits of third category was considered. We concluded that pruning and hand thinning of 33% of the fruits, on heavy loaded trees, enhances growers income and reduces altemate beteing.

Polyclonal antisera against Pectobacterium carotovorum subsp. atrosepticum (Pca), P carotovorum subsp. carotovorum (Pcc) and P chrysanthemi (Pch) were produced from intact, untreated cel Is. Bacterial suspensions with 6 to 7 x CFU/ml (2 ml), emulsified with an equal volume of complete Freund's adjuvant were used as antigens to immunize rabbits. The antigens were injected four times at weekly intervala. The antisera obtained (1:640 titer) were specific against the antigens used and did not exhibit any reaction toward other phytopathogenic bacteria, vírus and fungi, as well as potato, tomato, and tobacco plant extracts. Only antigens presents in the cellular structures of Pca, Pcc and Pch are identified by the antibodies and that the latex agglutination test can be used with di I utions of the antigens in order of 1:1 and 1:10 of the initial concentration (50% T, 550 nm).

Antisera produced against intact and untreated cells of Pectobacterium carotovorum subsp. atrosepticum (Pca), P carotovorum subsp. carotovorum (Pcc) and P chrysanthemi (Pch) were used to index several plants of potatoe that exhibited syntoms of blackleg disease. The stalk samples were better than the root and leave samples for the serological evaluation of Pectobacterium spp. Elowever, only several samples with blacleg syntoms had enough antigens for the visualization in the latex agglutination test. Of 66 plants with blackleg syntoms, collected in the field and indexed by serological methods, only 23 were considered as not typical for Pectobacterium by biochemical tests and did not react positively in the serological tests. Twenty six out of 43 isolates of Pectobacterium spp. were considered as Pca and 17 as Pcc by the biochemical and physiological tests. Flowever, only 17 isolates reacted with the antisera for ? carotovorum (Pca and Pcc) and, not all of them correspond to the previous biochemical characterization. The low number of positive serological reactions with the bacterial isolates indicate that has occurred an involuntary selection of strains for different serotypes. No one of the isolates react with the antisera against Pch. The results allow to conclude that the latex agglutination test can be used for the preliminary identification of bacteria of the genus Pectobacterium, specially when associated with biochemical and physiological tests.

Five cultivars of different types of melon (Ctecumis melo 1.) were evaluated in protected environment in vertical trai ni ng system, with fertilization and irrigation by dropping, during summer time. The results showed that production of the cultivars was similar, with si gnificant differences in the number and weigt of fruits. A negative correlation between number of fruits and fruit weight was observed. The cultivar of cantaloupe type and the cultivars of gal ia type exhibited low conservation after harvest, confirming the need of an accurate system for identification of harvest point to allow fruit commercialization. 

A aplicação de herbicidas pode afetar a microbiota do solo como um todo e. mais especificamente, as bactérias do gênero Bradyrbizobiwn, responsáveis pelo processo de fixação biológica do nitrogénio em simbiose com a soja. Em função de sua variabilidade genética. as estirpes de Bradyrbizobitun podem apresentar diferenças na sensibilida- de aos diversos herbicidas utilizados na cultura da soja. Com o objetivo de testar a sensibilidade de diferentes estirpes dc Brodyrhizobium, <span style="font-wei

The objective of this work was evaluate the water soil availability for com mon bean (Phaseolus yulgarisL.) crops in the region of Planalto Médio —Rio Grande do Sul, Brazil, in different sowing times, during the period 1975 —2002, considering different values of water availability in the soil. Crop water requirements were determined at different periods, using crop coefficients obtained from the relation between the maximum crop evapotranspiration (ETm) and the reference evapotranspiration estimated by penman's formula. The average values of total evapotranspiration in the entire crop cycle ranged from 337 mm, for crops sown in November in Cruz Alta to 384 mm for crops sown in September and November, in Julio de Casti lhos. The highest averaged values of evapotranspiration were obtained at Julio de Castilhos, followed Passo Fundo and Cruz Alta. Frequent water deficits were detected in the three local it ies, with mean total values in the entire cycle rangi ng from 38mm to 97mm. The highest mean values of water deficiency were verified in Julio de Castilhos for the water availability in the soil of 50mm, and the lowest values occurred in Passo Fundo for a soil water availability of 70mm, with intermediary values in Cruz Alta. For the three places the highest estimated water deficits correspond to the sowing date of October, from the beginning of flowering to the beginning of grain filling stages as wel I as from the beginning of grain filling to the physiological maturity. The lower ri sk to grain production was obtained in sowing date of September.

Grazing and fertilization are cleterminant factors that modify botanical composition and quality of pasture. A grazing experiment with pear) millet grass (Pennisettan american um (L.) Leeke) was conducted at Universidade Federal de Santa Maria, Santa Maria, RS, Brazil, to evaluate lhe effects of nitrogen leveis (0, 150, 300, 450 e 600 kg hal) on botanical composition and quality of pasture components. It was used beef heifers in grazing to maintain the intended forage offer of 10 kg DM 100 kg' LW -1 , according the put-and-take technique (M orr and LUCAS, 1952), in an completely randomized design with two replication. Pasture evaluation were made every 28 days, with cut of pasture at sou' levei, and subsequent hand separation aí components. The nitrogen leveis no had effect about botanical composition, that showed expressive cont ri but ion of Digitaria adscendens and Brachioria plantotinea.Nitrogen increase crude protein (P<0,00 I ) and decrease "in vitro"organic matter digestibility of components (P<0,05).

The objective of this work was to evaluate a pasture of Slack Oats (Avena strigosa) + autuai ryegrass (Loliuni inaltiflonetn)introduced by sodseeding in a nativo pasture with and without herbicide application. and to observe the effect of the herbicides on piam succession. The herbicides used were glyphosate (540. 1080, and 1620 g/ha a.i.) diuron + paraquat ( 300 g/ha a.i. + 600 g/ha a.i.) and paraquat ( 600 g/ha a.i.). The dry matter production (DM) was higher in the treatments with herbicides. and mean crude protein content and in vinn organic matter digestibility (I VOM I)) were similar. The treatments did not affect the occun .ence of Desmodiant incantun. The higher doses of glyphosate increased the participation of Ventania nueliflorn, Eryngiunt horrithun, uncovered.soi I and inter, and reduced Paspaltini notatunt. The herbicides diuron + paraquat, and paraquat increased the presence of Paspalunt notaram, decreased uncovered soi I and litter. and maintained Etyngium horridutn. Paraguai decreased the occurrence of Ventania nurliflora. 

Great relevante on the studies regarding the degree of tolerante of the legumes to shading in the LeyCropping Systems. The behaviour of the legumes Aradas pintoi (Arachis), Craty/ia argentea (Cratil ia), Maeroptilitunatropmpureum (Siratro) and Ptteraria phaseoloides (Kudzu Tropical) was evaluated under 3 leveis of shading 25%, 50%and 75%. The shading effect was obtained by using nylon screens for covering cubic frames seitled over the legume plots.The experiment was carried out at Em bruna Agrobiologia experimental arca at Seropédica, RJ. Shading increased the lengt hof the stems of Kudzu and Siratro in the first cut while leaf dry matter only increased for Kudzu in the shade levei of 25%.In the 2nd cut, Kudzu and Siratro presented the higher root dry matter production ai 25% shading, Arachis at 0% andCratilia presented no response to shading. In the cut dry matter of stems of Kudzu Tropical, Siratro and Cratilia were notaffected by shading, but Arachis presented a reduction of stern dry matter of 94% when shading increased from 50 to 75%.

The objective of this work was to assess different Al leveis in nutrient solution to select Al tolerant tinira and red clover to ticid soils and to compare tilem in different Al leveis. Eight Al leveis were tested: 0; 0,2; 0.3; 0,4; 0,6; 0.9; 1,2; 1.5 mg/L in nutrient soiution continuously aerated, with 10 70 of original ionic strength and phl 4.5. The length of roais and shoots were measured to assess the response to the AI soiution. The evaluation of the moi growt h was more effective than that of the shoot in selecting Al tolerant plants. The red clover showed a better root growth up to 0.6 mg/L AI. The best Al levei to select both species was between 0,4 and 0.6 mg/L Al. The seiection method used was fast (13 days) and simple.

Ten oat genotypes (Avena saliva L.) and twelve environments were tested to evaluate adaptability andstability of grain yield, to discriminate genotypes on different environments to utilize in plant breeding programs. Thebissegmented linear regression was adopted as statistical method. The analysis showed not only that genotype xenvironment interaction was significative, as well that the environment variation contributed with larger portion than thevariability among genotypes for the significance of this interaction. The results showed that the behavior of the analyzedgenotypes was differentiated for the different environments, accepting existence of genetic variability among the testedgenotypes. Except for UFRGS 7, alI the other genotypes expressed grain yield instability.

To evaluate the effect of soil tillage systems and crop rotation on com yield an experiment was set up in Passo Fundo, RS, .13razi1, which was monitored over a four-year period. Fiou soil tillage systems — I) no-tillage. during winter and summer seasons, 2) conventional tillage using disk plow and disk harrow, in winter and no-tillage, in summer, 3) conventional tillage using moldboard plow and disk harrow, in winter and no-tillage, in summer, and 4) mini muni tillage, in winter and no-til lage, in summer. — and two crop rotation systems ¡system 1 (wheat/soybean and common vetch/corn) and system II (wheat/soybean, black oats or white oats/soybean, and common vetch/corn)] were compared. An experimental design of blocks at random, with split-plots and three replications, was used. The main plot was formed by soi I tillage systems, while the split-plots consisted of crop rotation systems. The yield of com grown tender to-tillage and minimum tillage was higher than the yield obtained for com grown after conventional tillage using disk or moldboard plow and disk harrow. There were no significant &Tem of crop rotation systems on com yields.

During four years, in Passo Fundo, RS, Brazil, the effects of soil management and crop rotation systems were assessed. Four soil management systems — 1) no-tillage, 2) minimum tillage, 3) conventional tillage using a disk plow, and 4) conventional tillage using a moldboard plow—and three crop rotation systems [system I (wheat/soybean), system II (wheat/soybean and common vetch/sorghum or corn), and system I II (wheat/soybean, common vetch/sorghum or com and wh i te oats/soybean)I were compared. An experimental design of blocks at random with split-plots and three replications was used. The main plot was formed by the soil management systems, while the split-plots consisted of the crop rotation systems. Economic analysis from 1994 to 1997 is presented in this papei. No,til lage (R$ 412.49) and minimum tillage (R$ 389.37) presented higher net returns, while conventional tillage using a disk plow remained in intermediate position (R$ 339.90) and tillage using a moldboard plow showed the lowest net return (R$ 322,18). No significam differences were observed for net return as a result of crop rotation systems. 

Plant arrangement that allow better plant distribuition in the area improve plant growth, resulting in larger grain yield. The experiment was performed at the Agronomic Experimental Station of the Universidade Federal do Rio Grande do Sul, in Eldorado do Sul, Rio Grande do Sul, Brazil, in the 2000/01 growing season. The objectives were to evaluate the soybean growth by canopy stratum in response to plant arrangemnt and the effect in grain yield. The cultivar tested was 'BRS 137', in no-till planting. The treatments were arranged in a split-splitplot randomized complete-block design, with four replications. Water availability (with and without irrigation), row spacing (20 and 40 cm) and population leveis (20, 30 and 40 plants/m 2) were tested. Growth atributes (leaf area index and dry matter), grain yield, by soybean canopy stratum, were determined in samples of ten plants, in sequence in the row, in each sub-subplot. Grain yield was incresead by irrigation and was detected interaction between row spacing and plant population. The plant arrangement of 20 cm row spacing and population of 20 plants/m 2 resulted in greater grain yield. There was a linear decrease in grain yield with the increase in population, with row spacing (20 cm) reduction. The same was also noticed at the medium and botom canopy stratum. These results were consequence of the higher leaf area index and dry matter obtained in the soybean vegetative period, mainly in the medium and botom canopy stratum. 

 In this paper it is presented for the first time the meiotic behavior of microsporogenesis data concerning to fourteen populations of three species of Macroptilium (Benth.) Urban native in the south of Brazil (Rio Grande do Sul). The association and distribution of chromosomes was considered normal in both meiosis 1 and 11. The normal ity for meiotic cells was kept above 91% with exception of M. erytholoma (Benth.) Urban Cacequi population. The meiotic indexes (MI) were kept above 90% with the exceptions of M. heterophyllum(Willd) Maréchal et Baudet from Alegrete and M. herythroloma from Santa Maria populations. The si gnifi cat ve differences among the populations i ns ide each species and between the species shown lhe characteristic genetic variability that each plant has and use to adapt itself to the environment and promote the continuity of the generations. The data obtained shown that the plants were normal regarding to the meiosis and potentially fertile without problems in the inclusion of the species in programs of selection, crossing and viable seed production.

Utilization of red rice as forage plants constitute a control method of this weed along with a gain in animal products. An experiment was carried out at Estação Experimental de Terras Baixas/EMBRAPA CLIMA TEMPERADO, Capão do Leão, RS ,I3razil, to evaluate under, hydromorphic soil conditions, forage production, crude protein and "ia sita" digestibility of dry matter of red rice (Oryza saúva L.). In a split plot complete randomized block design, with four replications. The following variables were compared: a) Five seed densities in the soil (50, 150, 250,350 and 450 seeds/m 2); b) Two cutting times (vegetative and flowering) and c) Two red rice biotypes (straw hull and black hull). Higher forage production was obtained with one cutting in the flowering stage. The density of seeds in the soil influenced maximum forage production. Higher crude protein and "ia sita" digestibility was obtained with cuttings in the vegetative stage.