Guilherme Braga Pereira Braz

Fitorremediação de solo contaminado com picloram por capim-pé-de-galinha-gigante (Eleusine coracana)

The long-term residual effect of the herbicide picloram poses risks of leaching and phytotoxicity to successive crops. Phytoremediation can abbreviate the long carryover effect. This research was carried out from September 2006 to February 2007, under green house conditions, in Rio Verde, Goias, Brazil, to study the influence of Eleusine coracana population density on phytoremediation of soil contaminated with picloram. The treatments consisted of the combination of four Eleusine coracana population densities (0, 7, 14 and 21 plants per pot, corresponding to 0, 172, 344 and 516 plants m-2, respectively) and three picloram rates (0, 80 and 160 g ha-1 - applied directly to the pots, simulating soil contamination levels). After growing the phytoremediation species on substrate during 100 days, soybean was sown as a bioindicator species in the same pot. E. coracana was able to remediate soils contaminanted with picloram. At densities above 172 plants m-2, there was no further reduction of the carryover effect to soybean sown in succession.

Seleção de plantas para fitorremediação de solos contaminados com picloram

To initiate a phytoremediation program, the first step is to evaluate the tolerance of selected species to its contaminant. Registered for use in Brazil, picloram may cause carryover and underground water contamination problems due to its high persistence on soil. Thus, this work aimed to select species tolerant to picloram in soil contaminated with this herbicide for posterior use in phytoremediation programs. The experiment was carried out in a greenhouse, in Rio Verde-GO, from October to December of 2005. The treatments consisted of combinations of 19 plant species [Brachiaria brizantha (cv. Marandu); Brachiaria brizantha (cv. MG-5 Vitoria); Brachiaria brizantha (cv. Mulato); Brachiaria decumbens; Brachiaria humidicola; Brachiaria ruziziensis; Panicum maximum (cv. Massai); Panicum maximum (cv. Mombaca); Panicum maximum (cv. Tanzânia); Pennisetum purpureum x Pennisetum glaucum (cv. Paraiso); Eleusine coracana; Pennisetum glaucum (cv. ADR-300); Pennisetum glaucum (cv. ADR-500); Sorghum bicolor x Sorghum sudanense - Cover Crop; Sorghum bicolor x Sorghum sudanense (cv. Jumbo); Paspalum atratum; Zea mays (hibrid Coodetec 208); Canavalia ensiformis; and Stizolobium aterrimum] and five rates of picloram (0, 80, 160, 320 and 640 g ha-1), in 95 treatments. The experiment was arranged in a randomized block design in a factorial scheme 19 X 5, with four replications. Samples of eutroferric Red Latosol were used as substrate to plant growth, with the herbicide applied after filling and humidifying the pots, and after 15 days, seeds from the plant species were sown. After analyzing the results, Zea mays (hybrid Coodetec 208), Sorghum bicolor x Sorghum sudanense - Cover Crop, Eleusine coracana, Brachiaria brizantha (cv. MG-5 Vitoria), Pennisetum glaucum (cv. ADR-500), Brachiaria decumbens, Brachiaria ruziziensis, Brachiaria humidicola, Pennisetum glaucum (cv. ADR-300), Brachiaria brizantha (cv. Mulato), Sorghum bicolor x Sorghum sudanense (cv. Jumbo), Panicum maximum (cv. Tanzânia), Panicum maximum (cv. Mombaca) and Panicum maximum (cv. Massai) showed tolerance to herbicide carryover on soil, thus these species may be initially evaluated in phytoremediation programs of this herbicide.

Emergência de plantas daninhas em lavouras de feijão e de trigo após o cultivo de espécies de cobertura de solo

This study aimed to evaluate Euphorbia heterophylla and Bidens pilosa emergence in common bean- and wheat-producing areas, after cultivation of coverage plants. The experiment was carried out under a no-tillage system in straw, during five years, at Capivara Farm of Embrapa Arroz e Feijao, located in Santo Antonio de Goias, GO. The local soil is classified as dystrophic Oxisol. The treatments combined seven coverage plants (Brachiaria brizantha - cv. Marandu; Brachiaria brizantha intercroping with corn (Zea mays) - hybrid HT BRS 3150; Cajanus cajan; Pennisetum glaucum - cv. BN-2; Panicum maximum - cv. Mombaca, Sorghum bicolor - cv. BR 304 and Stylosanthes guianensis - cv. Mineirao and two crops cultivated successively in the areas (common bean - cv. Perola and wheat - Embrapa 42. All coverage plants were cut together by using a straw crusher and left on the ground; 60 days after being cut, the common bean and wheat plants were sowed. The number of plants obtained from Euphorbia heterophylla and Bidens pilosa was counted twice and the plants were separated into three growth stages (less than two leaves, from two to four leaves and more than four leaves). Brachiaria brizantha and Panicum maximum coverages were efficient in reducing weed emergence, mainly E. heterophylla in subsequent cultivation of common bean and wheat. No differences were observed in relation to common bean and wheat crop capacity of reducing E. heterophylla and B. pilosa population.

Influência do oeríodo de cultivo de Panicum maximum (cultivar Tanzânia) na fitorremediação de solo contaminado com picloram

The objective of this study was to evaluate the influence of cultivation time of Panicum maximum (cv. Tanzania) on phyto-remediation of soil contaminated with picloram. The experiment was carried out under greenhouse conditions from September 2006 to February 2007, using euthroferric Red Latosol samples as substrate for plant growth. The experiment was arranged in a completely randomized design, with four replicates, with treatments in a 4 x 3 factorial scheme. The treatments comprised twelve combinations of four periods of soil cultivation with the species Panicum maximum (cv. Tanzania) (0, 60, 80 and 100 days) and three doses of picloram (0, 80 and 160 g ha-1). At the end of each pre-established time of soil cultivation with the phyto-remediating species, seeds of tomato and soybean plants, used as bio-indicators of picloram presence, were sown on soil. The bio-indicators showed high sensitivity to picloram in soil, as their cultivation was not feasible without a prior phyto-remediation procedure. The previous cultivation of Tanzania for 60 days ensured a satisfactory initial growth of both soybean and tomato plants when the initial contamination level was lower than 80 g ha-1 of picloram. Above this dose, phyto-remediation provided by Tanzânia plants provide a lower soybean and tomato plants growth, indicating that a longer period of decontamination is required.

Influência do período de cultivo do capim-pé-de-galinha-gigante (Eleusine coracana) na fitorremediação de solo contaminado com picloram

The objective of this study was to evaluate the influence of Eleusine coracana cultivation period on phytoremediation of soil contaminated with picloram. The experiment was carried out at a greenhouse from September 2006 to February 2007, in 12 treatments combining four Eleusine coracana cultivation periods ((0, 60, 80 and 100 days) and three picloram rates (0, 80 and 160 g ha-1), arranged in a completely randomized design, in a factorial scheme 4 x 3, with four replicates and Eutroferric Red Latosol samples used as growth substrate. The bioindicators tomato (cultivar Santa Clara) and soybean (cultivar Monsoy 6101) were sowed at the end of the time established for the phytoremediation species to act. The bioindicators showed high sensitivity to picloram on soil, rendering impracticable the cultivation of those crops in areas contaminated with this herbicide without remediation. Prior cultivation of four Eleusine coracana for 60 days provided a satisfactory initial growth of soybean and tomato cultivated in soil that had previously received the application of up to 160 g ha-1 picloram; however; these bioindicators showed visible symptoms of herbicide intoxication.The objective of this study was to evaluate the influence of Eleusine coracana cultivation period on phytoremediation of soil contaminated with picloram. The experiment was carried out at a greenhouse from September 2006 to February 2007, in 12 treatments combining four Eleusine coracana cultivation periods ((0, 60, 80 and 100 days) and three picloram rates (0, 80 and 160 g ha-1), arranged in a completely randomized design, in a factorial scheme 4 x 3, with four replicates and Eutroferric Red Latosol samples used as growth substrate. The bioindicators tomato (cultivar Santa Clara) and soybean (cultivar Monsoy 6101) were sowed at the end of the time established for the phytoremediation species to act. The bioindicators showed high sensitivity to picloram on soil, rendering impracticable the cultivation of those crops in areas contaminated with this herbicide without remediation. Prior cultivation of four Eleusine coracana for 60 days provided a satisfactory initial growth of soybean and tomato cultivated in soil that had previously received the application of up to 160 g ha-1 picloram; however; these bioindicators showed visible symptoms of herbicide intoxication.

Fitorremediação de solo contaminado com o herbicida picloram por plantas de capim pé de galinha gigante

This study aimed to evaluate the influence of different water depths in the soil on phytoremediation of soil contaminated with picloram by Eleusine coracana plants. The experiment was carried out under greenhouse conditions with samples of Oxisol. The treatments consisted of the combination of four daily levels of water replacement (80, 90, 100 and 110% of evaporated water) and three picloram rates (0, 80 and 160 g ha-1), arranged in a completely randomized design, in a factorial scheme 4 x 3, with four replications. The phytoremediation specie was sowed 48 h after applying the herbicide. At 90 days post emergence, the plants were desiccated and cut and the bioindicator specie (soybean - Monsoy 6101 cultivar) was sowed. The results indicated that the highest evaporated water replacemente depth contributes to the remediation of soil contaminated with picloram, by using Eleusine coracana plants. This phytoremediation improvement only is significant when soil contamination is not over 80 g ha-1.

Sumatran Fleabane (Conyza sumatrensis) Control in No-Tillage Soybean with Diclosulam Plus Halauxifen-Methyl

Due to the limited availability of selective herbicides to control Sumatran fleabane after soybean emergence, it is essential to develop new options that provide effective control prior to planting. A new herbicide formulation containing diclosulam + halauxifen-methyl was evaluated for effectiveness at two Sumatran fleabane plant heights (5 to 10 cm, and 10 to 50 cm) and for soybean selectivity when applied at 7 or 3 d before planting. Combined results from the two sites showed that diclosulam+ halauxifen, applied either alone or in a tank mixture with glyphosate, and the tank mixture of diclosulam + 2,4-D amine + glyphosate are effective at all rates tested to control Sumatran fleabane in preplant applications. Crop response was observed with applications 7 days before planting at only one of the sites. A rate-dependent crop response was observed for pre-plant applications performed 3 days before soybean planting. However, crop yield was not significantly affected for either timing across all rates. All rates tested of diclosulam + halauxifen in this study were considered safe to soybean. Nomenclature: Diclosulam; glyphosate; halauxifen, 4-amino-3-chloro-6-(4-chloro-2-fluoro-3-methoxyphenyl)pyridine-2-carboxylic acid; 2,4-D; Sumatran fleabane, Conyza sumatrensis (Retz.) E. Walker; soybean, Glycine max L. Merr.

Plantas daninhas como hospedeiras alternativas para Pratylenchus brachyurus

Uma das acoes indiretas exercidas pelas plantas daninhas na interferencia sob especies cultivadas e o potencial de hospedar agentes causadores de enfermidades. O nematoide das lesoes radiculares (Pratylenchus brachyurus) vem causando uma serie de danos em diversas culturas no Brasil. Para o manejo deste fitoparasita, o cultivo de diferentes especies de crotalarias tem sido empregado. O objetivo deste trabalho foi avaliar a hospedabilidade de plantas daninhas para P. brachyurus, bem como o efeito de supressao de diferentes especies de crotalaria. Para isso, foi instalado um experimento em casa de vegetacao no delineamento inteiramente casualizado em arranjo fatorial (2x17), com seis repeticoes. O primeiro fator consistiu na presenca ou ausencia da inoculacao do nematoide. O segundo correspondeu a dezessete especies vegetais, sendo onze plantas daninhas, quatro crotalarias (C. breviflora, C. juncea, C. ochroleuca e C spectabilis) e duas variedades de soja, as quais serviram como testemunha sendo hospedeiras de P. brachyurus. A inoculacao do nematoide das lesoes radiculares nao influenciou a altura de plantas e massa seca de parte aerea das diferentes especies avaliadas. Portulaca oleracea, Amaranthus viridis e Sida rhombifolia foram as especies com maior numero de nematoides por sistema radicular, e apenas a S. rhombifolia apresentou comportamento semelhante a testemunha (variedade de soja BMX Potencia RR®). Com relacao ao numero de nematoides por grama de raiz, os maiores valores foram observados para A. viridis, seguido por P. oleracea. Excluindo-se a C. juncea, todas as demais especies de crotalaria apresentaram-se como boas opcoes para o manejo em areas infestadas com P. brachyurus.

Growth, Development and Seed Production of Goosegrass1

E. indica is one of the most problematic weeds in the world because it is present in almost every continent, and there are reports of multiple resistance to herbicides by some biotypes. The objective of this paper was to analyze the growth, the development and the production of this plants seeds, in order to generate information about its biology that can be useful for management. The experiment was carried out in a greenhouse from May to September 2015. Sixteen samples were taken during the development cycle of the plant: 3, 10, 17, 24, 31, 38, 45, 52, 59, 66, 73, 80, 87, 94, 101 and 108 days after emergence (DAE). The response variables were based on a leaf area and dry matter of each one of the parts of the plant and the number of seeds produced per plant. At 12 DAE, 80% of the seedlings of E. indica had emerged, and each plant produced more than 120 thousand seeds, closing their cycle at 120 DAE. Between 38 and 43 DAE, the plant had fast emission of new tillers, exponential accumulation of the total dry matter and substantial increase of the absolute growth rate. Due to the data observed here, we concluded that the management of E. indica must be done preferably before 38 DAE due to the exponential growth after this period, preventing the plant from producing seeds and spreading to other places.

SELECTIVITY OF FOMESAFEN TO COTTON

The aim of this work was to evaluate the selectivity of fomesafen alone or in a tank mixture with other preemergent herbicides, with or without S-metolachlor application in early postemergence in cotton plant, cultivar DP 555 BG RR(r). The design utilized was a randomized complete block, organized in a split-plot arrangement, with four replications. For that, 24 herbicides were evaluated with fomesafen (0.45 and 0.625 kg ha-1), prometryn (1.25 kg ha-1), diuron (1.25 kg ha-1), trifluralin (1.8 kg ha-1), and S-metolachlor (0.77 kg ha-1), applied as preemergent, with or without S-metolachlor (0.77 kg ha-1) applied in early postemergence. The variables evaluated were: phytotoxicity, insertion height of the first reproductive branch, plant height, stand, number of reproductive branches per plant, number of bolls per plant, bolls weight, and productivity of cotton seed. Fomesafen alone or in a tank mixture with preemergent prometryn, diuron, trifluralin and S-metolachlor was selective to cotton plant. Preemergent fomesafen isolated application followed by the application of S-metolachlor in early postemergence was also selective. However, on average, preemergent tank mixtures applied in association with preemergent S-metolachlor early application was not selective to cotton crop.