Produção de sementes por picão-preto e guanxuma em função de densidades das plantas daninhas e da época de semeadura da soja

Fleck, Nilson Gilberto; Rizzardi, Mauro Antônio; Agostinetto, Dirceu; Vidal, Ribas Antônio

doi:10.1590/s0100-83582003000200004

Cited by 10 publications

(7 citation statements)

References 19 publications

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“…rhombifolia occurs in annual and perennial crops, being highly competitive due to its radicular system, which can reach 50 cm in depth (Kissmann and Groth, 2000;Lorenzi, 2008). Reports indicated that this plant can yield up to 28.2 thousand seeds per m -2 in only a cycle in the summer as a weed in soybean fields (Fleck et al, 2003). Within the species of -guanxuma‖ that occur in Brazil, it is considered the most disseminated species and its control is the most problematic, regardless the agricultural environment (Constantin et al, 2007).…”

Section: Resultsmentioning

confidence: 99%

Effect of weeds on yield loss of cassava plants in response to NPK fertilization

Soares¹,

Neto²,

JosÃ©³

et al. 2016

Afr. J. Agric. Res.

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The objective of this study was to assess yield loss of weed-infested cassava and the degree of interference of weeds on the crop productivity in response to the fertilization of NPK. The study was conducted at the Universidade Estadual do Sudoeste da Bahia, in the municipality of Vitória da Conquista, BA, with two different treatment groups that were evaluated in parcels with and without fertilizer. The treatments of the first group consisted of initial coexistence periods in which the cassava plants and weeds were put to live together: 35, 70, 105, 140 and 175 days after planting (DAP); in the second group, the cassava plants, initially, remain free from weeds during the same periods. Weeds were assessed every 35 days, from the 35 to 525 days after planting of cassava, determining the fresh mass of the identified species in the evaluated treatments with and without fertilizers. The characteristics of root yield, shoot weight, harvest index, dry mass of roots, starch content and flour production were evaluated 18 months after plantation. The predominant weeds in the experimental area were: Panicum maximum, Brachiaria plantaginea, Sida rhombifolia, Pavonia cancellata, Portulaca oleracea, Cynodon dactylon and Setaria parviflora. The interference of the weeds in the cassava yield was bigger when the crop was subjected to fertilization, in coexistence periods from the 35 days after planting; however, when cassava plants were kept in the absence or in coexistence with weeds up to 35 DAP, fertilization provided increase in crop productivity factors. The competition with weeds resulted in high losses in root yield of the cassava plant, thus, being necessary the control of the invading plants in the period between 35 and 175 DAP.

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Section: Resultsmentioning

confidence: 99%

Effect of weeds on yield loss of cassava plants in response to NPK fertilization

Soares¹,

Neto²,

JosÃ©³

et al. 2016

Afr. J. Agric. Res.

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show abstract

“…rhombifolia is found in annual and perennial crops, being highly competitive because of its root system that can reach 50 cm depth (Lorenzi, 2008;Kissmann and Groth, 2000). There are reports showing that this plant is able to produce up to 28.2 thousand seeds m -2 in a single summer season infesting soybean crop (Fleck et al, 2003). Among "guanxuma" species found in Brazil, this is considered most widely spread and hard to be controlled at various farming environments (Constantin et al, 2007).…”

Section: Resultsmentioning

confidence: 99%

Weed dry mass accumulation in response to the application of NPK fertilizers in cassava crop

Soares¹,

Neto²,

José³

et al. 2015

Afr. J. Agric. Res.

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Fertilizers can be used to change competition relationships between crop and weed by promoting crop species growth, since rival species has a differentiated response to nutrients. We aimed to evaluate weed dry mass accumulation when or not NPK (nitrogen, phosphorus and potassium) fertilizers were applied to cassava crop. Therefore, weed samples were collected every 35 days, from 35 to 525 days after cassava planting, by randomly throwing a 0.25 m 2 metal square (0.5 m × 0.5 m) within useful area of the plots with and without fertilization. After each thrown, it was removed weed shoot, separated by species, then counted and weighed to determine number of plants and shoot dry mass. Fertilization did not influenced the weed population during most part of the crop cycle; however, promoted greater weed dry mass accumulation in the second crop year, 350 days after planting. Panicum maximum, Brachiaria plantaginea, Sida rhombifolia, Pavonia cancellata, Setaria parviflora and Cynodon dactylon, which were the most abundant weeds, had different responses to fertilization. P. maximum and B. plantaginea have outstood because of their shoot dry mass increase of 41.59 and 36.25%, respectively, when comparing fertilized and non-fertilized treatments.

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“…Average values of phytomass production of the B. pilosa plants are between 3,000 and 6,000 kg ha -1 (Fleck et al, 2003). P. major can produce levels of 2,000 kg ha -1 of phytomass (Nascimento et al, 2007), once P. lanceolata can produce higher levels of phytomass than P. major.…”

Section: Copper Phytoremediationmentioning

confidence: 99%

Evaluation of two Brazilian indigenous plants for phytostabilization and phytoremediation of copper-contaminated soils

et al. 2015

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Indigenous plants have been grown naturally and vigorously in copper contaminated soils. Thus, the aim of this study was to evaluate the phytoremediation ability of two indigenous plants naturally grown in two vineyard soils copper contaminated, and in a copper mining waste. However, it was evaluated the macro and micronutrient uptake and the potential of phytoremediation. So, a greenhouse study was carried out with Bidens pilosa and Plantago lanceolata in samples of vineyard soils (Inceptisol and Mollisol) copper contaminated, and in a copper mining waste. Plant growth, macro and micronutrient up take, tolerance index (TI), translocation factor (TF), metal extraction ratio (MER), bioaccumulation factor (BCF), plant effective number of the shoots (PENs), and plant effective number of the total plant (PENt) were analyzed. Both plants grown in vineyard soils showed high phytomass production and TI. P. lanceolata plants cultivated in the Inceptisol showed the highest copper concentrations in the shoots (142 mg kg -1 ), roots (964 mg kg -1) and entire plants (1,106 mg kg -1 ). High levels of copper were phytoaccumulated from the Inceptisol by B. pilosa and P. lanceolata with 3,500 and 2,200 g ha -1 respectively. Both B. pilosa and P. lanceolata plants showed characteristics of high copper hyperaccumulator. Results showed that both species play an important role in the natural copper phytoaccumulation in both vineyard soils contaminated with copper, being important to its phytoremediation. , respectivamente, quando cultivadas em Neossolo. Ambas as espécies apresentaram características hiperacumuladoras de cobre. Os resultados mostraram que estas espécies desempenham um papel importante na fitoacumulação de cobre naturalmente em ambos os solos de vitivinicultura contaminados com cobre, sendo importantes para a fitorremediação. KeywordsPalavras-chave: Bidens pilosa, areas contaminadas com cobre, fitoacumulação de cobre, Plantago lanceolata.

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Produção de sementes por picão-preto e guanxuma em função de densidades das plantas daninhas e da época de semeadura da soja

Cited by 10 publications

References 19 publications

Effect of weeds on yield loss of cassava plants in response to NPK fertilization

Effect of weeds on yield loss of cassava plants in response to NPK fertilization

Weed dry mass accumulation in response to the application of NPK fertilizers in cassava crop

Evaluation of two Brazilian indigenous plants for phytostabilization and phytoremediation of copper-contaminated soils

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