Recebido para publicação em 24/02/2015 Aceito para publicação em 03/09/2015 RESUMO: O manjericão (Ocimum basilicum L.) atualmente encontra-se distribuído por todos os continentes e foi introduzido no Brasil com a chegada da colonização italiana. As principais partes utilizadas para comercialização no Brasil são as folhas frescas ou secas. O presente trabalho teve como objetivo avaliar o efeito de doses da adubação nitrogenada, durante o cultivo na primavera e outono, nas características produtivas e na produtividade de manjericão, Alfavaca basilicão vermelho, em casa de vegetação. O delineamento utilizado foi em blocos casualizados, em esquema fatorial 6 x 2, com cinco repetições, onde o primeiro fator foi constituído de cinco doses de nitrogênio e uma testemunha (0,0; 45,0; 90,0; 135,0; 180,0 e 225,0 kg ha -1 de nitrogênio) e o segundo, pelas épocas de cultivo (primavera e outono). Para as características produtivas da cultivar de manjericão Alfavaca Basilicão vermelho, verificou-se que as doses de nitrogênio entre 90,0 a 135,0 kg ha -1 foram mais adequadas, elevando todas as características produtivas avaliadas, do cultivo de primavera. Quando observado o cultivo no outono, teve-se ajuste apenas para a projeção de copa, massa fresca de parte aérea e área foliar. Quando se obteve ajuste significativo, a dose de aproximadamente 110,0 kg ha -1 de nitrogênio foi a que promoveu maior desenvolvimento da cultura. Em relação às épocas de cultivo na primavera recomenda-se o uso de adubação mineral nitrogenada, porém quando esse cultivo é realizado outono, a adubação nitrogenada não é responsiva. Palavras-chaves:Fertilização, características produtivas, cultivo protegido.ABSTRACT: Effect of nitrogen fertilization on the production and productivity of Basil, red basil (Ocimum basilicum L.) in spring and autumn seasons. The basil (Ocimum basilicum L.) currently is distributed to all continents and was introduced in Brazil with the arrival of Italian colonization. The main parts used for commercialization in Brazil are the fresh or dried leaves. This study aimed to evaluate the effect of doses of nitrogen fertilization for cultivation in spring and fall, the yield characteristics and the productivity of basil, Basil red in the greenhouse. The experimental design was a randomized block, in a factorial 2 x 6 with five replications, where the first factor constituent of five nitrogen doses and one control (0.0; 45.0; 90.0; 135.0; 180.0 and 225.0 kg ha -1 of nitrogen) and by the second, the growing seasons (Spring and Autumn). For the productive characteristics of the cultivar red Basil, it was found that the nitrogen rates between 90.0 to 135.0 kg ha -1 were better, bringing all tested productive characteristics, the spring crop. When observed growing in the autumn, was only fit for the crown projection, fresh weight of shoot and leaf area. When there was significant adjustment, the dose of approximately 110.0 kg ha -1 of nitrogen was that promoted further development of culture. Regarding the growing seasons in the spring we...

Allelopathy contributes to the sustainable management of weeds in growing areas, due to its ability to inhibit the development of weed species. This study aimed to evaluate the allelopathic effect of Pachyrhizus erosus extract on Euphorbia heterophylla and Bidens pilosa germination. The experiment was carried out in a completely randomized design, in a 2 x 2 x 4 factorial scheme, with four replications. The first factor corresponded to the plant portion (shoot and tuberous root), the second to the extract preparation method (water at room temperature and boiling) and the third to the extract concentrations (0 %, 25 %, 50 % and 100 %). Phytochemical analyses were performed to identify the presence of secondary metabolites. The variables germination percentage, germination rate index and dry biomass decreased with increasing aqueous extract concentrations for both E. heterophylla and B. pilosa. When applied a P. erosus crude shoot extract (boiling), decreases of 18 % and 92 % were observed in the E. heterophylla and B. pilosa germination, respectively, with a decrease of 91 % in the dry biomass of E. heterophylla seedlings. The tuberous root extract (boiling), on the other hand, reduced the germination percentages for E. heterophylla and B. pilosa in 18 % and 80 %, respectively. The phytochemical evaluation indicated the presence of flavonoids, coumarins and saponins in the shoot and tuberous root extracts, while tannins were only observed in the shoot extract. Thus, it can be concluded that P. erosus extracts display an allelopathic effect on the weed species evaluated.

Recebido para publicação em 16.7.2015 ABSTRACT -Weeds have the potential to dramatically interfere in cassava cultivation, reducing its productive potential; however, there are few studies on the selective herbicides in this crop. Therefore, the objective was to evaluate in this work the selectivity and efficiency of sulfentrazone in cassava crops grown in sandy and clayey soils. Two experiments were carried out: The first one was carried out in sandy soil conditions in the conventional system; and the second one was carried out in clayey soil conditions in the no-tillage system. The experimental design was a randomized block with four replications. The treatments consisted in doses of 250, 500, 750 and 1,000 g ha -1 of sulfentrazone, and weeded and non-weeded controls. Sulfentrazone application in cassava crops has linearly reduced the production of roots in a proportion of 0.0153 and 0.0107 t ha -1 at each increment in grams of the active ingredient, respectively. It was concluded that sulfentrazone was not selective for cassava crops grown both in sandy and in clayey soil; however, it was highly effective in weed control in both soils.

The intensive use of glyphosate can select resistant populations. This study aimed at evaluating the occurrence of glyphosate resistance in populations of D. insularis in agricultural areas. Three experiments were conducted in randomized block experimental design with four replications. The Resistance Degree (RD) was determined by a dose-response curve in the evaluated populations: Experiment 2012, São Camilo (R01 and R02) and Palotina (R03, R04 and S05-susceptible); Experiment 2013 Palotina (R06 and R12), Katueté/Paraguay (R07), Toledo (R08 and R10), Cascavel (R09), São Miguel do Iguaçu (R11), Dom Eliseu/Pará (S13-susceptible); Experiment 2015 Nova Aurora (R14), Iracema do Oeste (R15 and R16), Jesuitas (R17 and R18), Tupãssi (R19), Jotaesse (R20), Espigão Azul (R21) and Palmitopolis (S22- susceptible). In 2012, it was possible to confirm a moderate resistance (RD = 1.1 to 5.0) only in R03; and populations R01, R02 and R04 were highly resistant (RD>5.0). In 2013, populations R09, R10, R11 and R12 showed resistance, while R06, R07 and R08 were highly resistant. In 2015, the R14, R16, R18, R19 and R20 populations showed moderateresistance, and R15 and R18 were highly resistant. Only R21 was susceptible. It was found that 83% of producers use the no-tillage system, 100% use the succession soybean/corn with 90% transgenic varieties, 45% of producers cannot explain the procedure regulation/sprayer calibration. Around 62% use practices to prevent the selection of resistant biotypes. Resistance was confirmed in 89.5% of the populations. The adopted agronomic practices may explain these results.

Selecting glyphosate-resistant Digitaria insularis may cause changes in the biological cycle of the species. Therefore, the objective of this study was to evaluate the biological cycle of susceptible and glyphosate-resistant D. insularis biotypes in two growth periods (summer/autumn and autumn/winter). Seeds were collected in the municipality of Alagoa Grande (07o02’59" S 35o37’01,5" W), and were considered susceptible (S1), in Cascavel (24o55’27" S 53o27’54.6 ”W) considered as resistant 1 (R1), Entre Rios do Oeste (24o40’44" S 54o17’05" W) considered as resistant 2 (R2) and Marechal Cândido Rondon (24o42’30" S 54o21’10" W) considered as resistant 3 (R3). Evaluations were carried out in the summer/autumn and autumn/winter periods. The collection periods of plants were: 14; 21; 28; 35; 42; 49; 56; 63; 70; 77; 84; 91; 98; 105; 112 and 119 days after emergence (DAE). The selection of glyphosate-resistant D. insularis biotypes in agricultural areas affected the biology of the species, in relation to the original population of the susceptible biotype. In the summer/autumn period (mean temperature 24.6 oC), the S biotype started the emission of tillers and flowering at 14 and 21 DAE on an average, respectively, before the resistant biotypes. However, in the autumn/winter period (mean temperature 19.0 oC) only the R1 biotype was able to develop and complete the biological cycle. The evaluated biotypes presented differences during the development, mainly between the phenological stages, so that the susceptible biotype was the most precocious and with a high reproductive potential. The physiological evaluations showed no differences among the S, R1, R2 and R3 biotypes, as verified in the TCR.

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The objective of this work was to evaluate the effect of weed competition on the accumulation of nitrogen and phosphorus in the leaves and on the dry weight of the roots of cassava (Manihot esculenta) in the conventional and no-tillage systems, in two crop cycles. The experiments were carried out in a randomized complete block design, with split-split plots and four replicates. The plots consisted of conventional tillage or no-tillage; the split plots, of the competition or not with weeds; and the split-split plots, of the evaluation periods (0, 25, 50, 75, 100, 125, 150, 175, 200, and 225 days after planting/pruning). In the first cycle, weed competition reduced the accumulation of nitrogen in 82.6 and 81.3% and of phosphorus in 65.7 and 85.3% under conventional tillage and no-tillage, respectively. In the second cycle, the reductions in the accumulation of nitrogen were of 41.1 and 52.4% and of phosphorus of 44.1 and 52.6%, in conventional tillage and no-tillage, respectively. The root dry weight of cassava grown with weed competition showed reductions of 15.8 and 11.2% under conventional tillage and no-tillage, respectively, only in the second cycle. Weed competition reduces the accumulation of nitrogen and phosphorus in the leaves of cassava in the conventional and no-tillage systems in both crop cycles, but reduces the dry matter of cassava roots only in the second cycle.

The use of strategies such as sequential applications and mixtures may increase the control spectrum and the residual effect of chemical control of weed in the cassava crop. Thus, the objective was to evaluate the selectivity and efficacy of sequential applications and tank mixture of herbicides in the control of weed in the cassava crop cultivar 'Baianinha'. The experimental design was of randomized blocks, with eleven treatments and four replicates. The treatments consisted in: harrowed control, control without harrow, clomazone, mesotrione, S-metolachlor, clomazone+S-metolachlor, mesotrione+S-metolachlor, clomazone+mesotrione, sulfentrazone/clomazone, clomazone/[mesotrione+S-metolachlor], S-metolachlor/[mesotrione+clomazone]. The doses used for clomazone, mesotrione, sulfentrazone and S-metolachlor in the single applications, in sequence and in tank mixture were of 1.25, 0.24; 0.6 and 1.92 kg ha -1 , respectively. The first application of the sequential treatments occurred 50 days after planting (DAP) and the second at 92 DAP. The applications of mesotrione, mesotrione+clomazone and mesotrione+S-metolachlor, were carried late, at 92 DAP. Based on the data obtained, it is concluded that the mixture mesotrione+S-metolachlor and the sequential application of clomazone/ [mesotrione+S-metolachlor] were selective to cassava 'Baianinha' and efficient in the weed control (over 80% up to 148 days after planting).