scholarly journals Weed infestations in soybean grown in succession to cropping systems with sorghum and cover plants

Author(s):  
Joilson Sodré Filho ◽  
Ricardo Carmona ◽  
Robélio Leandro Marchão ◽  
Arminda Moreira de Carvalho

Abstract: The objective of this work was to evaluate the influence of sorghum and cover plant cropping systems before soybean cultivation on the occurrence of weeds during soybean growing in the Brazilian Cerrado. The experiment was carried out in a randomized complete block design, with four replicates. The treatments comprised six cropping systems before soybean: sorghum (Sorghum bicolor), palisade grass (Urochloa brizantha), and Congo grass (Urochloa ruziziensis) as cover plants, alone or intercropped, in addition to fallowing. Weeds were evaluated as to: density, dry matter mass, diversity, importance value, and similarity. The greatest similarity of weeds ocurred in single crops of sorghum, palisade grass, and Congo grass, in comparison with their intercroppings. Congo grass before soybean promoted a greater reduction in weed diversity overtime, when compared with palisade grass. The absence of cover crops before soybean cultivation increased weed infestation during the soybean cycle. The cropping systems with sorghum intercropped with cover crops before the soybean cultivation affect the diversity and the importance value of weed species.

Author(s):  
G. C. Michael ◽  
H. Tijani-Eniola ◽  
F. A. Nwagwu ◽  
O. W. Olaniyi

Aim: Competition from weeds is an obstacle to profitable maize production. Knowledge of weed species limiting productivity is essential for sustainable management. A two years field experiment was conducted to evaluate the effect of a leguminous cover crop, akidi (Vigna unquiculata sub-sp sequipedalis) and two non-leguminous cover crops (melon and sweet potato) planted at three densities on weed flora composition and shift in maize at Jalingo, North-eastern Nigeria. Study Design: There were 11 treatments replicated three times in a randomized complete block design. Methodology: Low, moderate and high densities (20,000, 30,000 and 40,000 stands/ha respectively) of Akidi, Melon and Sweet potato (A1, A2, A3, M1, M2, M3, S1, S2, S3) with weeded (C1) and unweeded (C2) checks constituted the treatments laid out in a randomized complete block design replicated three times. Weed flora abundance, percentage density, percentage frequency, frequency index and percentage contributions were determined from a 50cm x 50cm quadrat thrown twice per plot at various phases of maize growth. Results: Thirteen weed families made up of 11 broad leaves, one grass and one sedge were identified. The abundance was in the order Broad leaf > Grass > Sedges. The most abundant weed species were: Imperata cylindrica L (3.8), Mucuna utilis (3.0), Oldenlandia herbacea L. (2.6) Sida acuta Burm F, Tridax procumbens L. (2.5 each), Leucas martinicensis, Pennisetum pedicellatum (2.3 each). Commelina benghalensis, Cyperus difformis (3.5), Digitaria horizontalis, Fimbristylis littoralis (2.8 each). The influence of selected cover crops on individual weed percentage the contribution shows: Commelina benghalensis ( C2<C1 < M <S< A), Euphorbia hyssopifolia (C2<M/S < A<C1), Euphorbia heterophylla (M<S<A), Leucasmartinicensis (C1<C2<M<A<S), Mucunautilis (S<M<C1<C2<A) and Sida acuta (M<S<A<C2<C1) while grassy weeds, Imperata cylindrical (A<C2<S<M), Pennisetum pedicellatum (A<C2), Digitaria horizontalis (C1/ C2< A < M <S), Kyllinga squamulata (M/S <C2<A <C1). Commelina spp. increased in status from an accessory (21.2%) to abundance (66.7%) while others increased from rare to accessory (from 0.0 to 20-40%). Conclusion: Akidi was more effective on broad-leaved weeds while melon and sweet potato were more effective on grasses and Commelina benghalensis need to be monitored.


2017 ◽  
Vol 52 (8) ◽  
pp. 592-598 ◽  
Author(s):  
Alvadi Antonio Balbinot Junior ◽  
Julio Cezar Franchini Dos Santos ◽  
Henrique Debiasi ◽  
Anderson Hideo Yokoyama

Abstract: The objective of this work was to evaluate the effect of roots and straw of palisade grass (Urochloa brizantha) and Ruzi grass (U. ruziziensis), used as cover crops in autumn-winter, on soybean performance. Seven treatments were evaluated in a randomized complete block design, with four replicates: fallow, during autumn-winter; straw of U. ruziziensis or U. brizantha 'BRS Piatã', distributed in plots kept under fallow in the winter, without roots; plots only with roots of U. ruziziensis or U. brizantha, without straw; and plots with straw and roots of U. ruziziensis or U. brizantha. The grass species were planted during the 2014/2015 crop season, and treatments were evaluated at the end of the 2015/2016 crop season, without drought during the soybean cycle. The oil and protein contents of soybean grains were not affected significantly by the treatments. However, the cultivation of grass species during autumn-winter increased soybean grain yield in comparison with fallow. Grass root effects are more expressive than those of straw. The combined presence of roots and straw confers a better performance to soybean than the isolated presence of roots or straw.


2018 ◽  
Vol 36 (0) ◽  
Author(s):  
C.T. FORTE ◽  
L. GALON ◽  
A.N. BEUTLER ◽  
F.W. REICHERT JR. ◽  
A.D. MENEGAT ◽  
...  

ABSTRACT: Phytosociological studies are groups of methods that aim at the identification, composition and distribution of plant species in a community. The objective of this study was to identify and quantify the main weeds found in beans, maize and soybean cultivated in no-tillage and conventional systems. The experimental design was a randomized block one, with four replications. Experiments were conducted during three consecutive years, with summer crop (bean, maize and soybean) treatments, no-tillage system (NTS) composed by the covers, black oat, vetch and forage radish, in addition to their intercrop. In the conventional planting system (CTS), the area was left fallow in the off-season. The shoot dry matter of the covers was evaluated in each crop. The evaluated variables were: frequency, density, abundance, dry matter and the importance value index of the species in the area. Eighteen species of weeds and 12 families were identified, with Asteraceae and Poaceae families showing the highest number of individuals. The shoot dry matter production presented a difference among the covers; the cover black oat alone and intercrop with radish and vetch stood out, with the highest averages in the 3 years of the experiments. Cropping systems and different cover crops within the no-tillage system interfered in the number of encontered species. The emergence of Euphorbia heterophylla was favored, while the emergence of Lolium multiflorum was inhibited. E. heterophylla was the most encountered in the NTS areas, and its germination was negatively influenced by soil mobilization. The intercrop of black oat and vetch provided maximum weed control in soybean.


2014 ◽  
Vol 32 (4) ◽  
pp. 665-674 ◽  
Author(s):  
G. Concenço ◽  
I.S. Motta ◽  
I.V.T. Correia ◽  
S.A. Santos ◽  
A. Mariani ◽  
...  

We aimed with this study to compare weed infestation in coffee under two different cropping managements: conventional coffee grown alone, or intercropped with banana plantation in a year-round basis (late spring, late summer, late fall and late winter). The experiment was installed in 2009 under field conditions at the Escola Municipal Rural Benedita Figueiró de Oliveira, in the city of Ivinhema in the state of Mato Grosso do Sul, Brazil. Assessments of weed occurrence were made three years after employment, on both cropping systems, and density, frequency, dominance and the importance value for each plant species in each system and season were quantified. Plant diversity within each system was estimated by Simpson and Shannon-Weiner indexes. Similarity between cropping systems were also assessed by the binary asymmetric similarity coefficient of Jaccard. Absolute infestation and spontaneous species differed between the two cropping systems in all seasons. Overall species diversity is higher in the monocrop compared with the intercrop, and it is associated in this study with the higher incidence of troublesome species. Areas were similar in terms of weed composition only in the Fall. Shading provided by the banana trees shows to be an efficient culture management aiming to suppress weeds in agro-ecological planting systems.


2017 ◽  
Vol 52 (8) ◽  
pp. 652-662
Author(s):  
Bárbara Cardoso da Mata e Silva ◽  
Norberto Mario Rodriguez ◽  
Mirton José Frota Morenz ◽  
Marco Antônio Sundfeld da Gama ◽  
Carlos Eugênio Martins ◽  
...  

Abstract: The objective of this work was to evaluate the milk fatty acid (FA) profile of Holstein x Gyr cows subjected to two different grazing managements (fixed and variable rest periods) of Urochloa brizantha 'Marandu' pastures. A randomized complete block design was used, with two replicates of pasture areas (blocks) per treatment and four cows per block. Milk production and composition were not affected by grazing strategies. No treatment effects were observed on the proportions (g 100 g-1 of total FA) of the main FAs (palmitic, linoleic, and α-linolenic) of the pasture, but their intakes (grams per day) were affected by differences in forage dry matter intake. The concentrations of FAs in milk plasma and fat were not affected by the treatments. Milk fat contents of rumenic, vaccenic, oleic, and α-linolenic acids varied from 0.71 to 0.93, 1.40 to 1.50, 19.40 to 19.70, and 0.39 to 0.43 g 100 g-1 total FAs, respectively. Grazing strategies of U.brizantha 'Marandu' cause no changes on the milk fatty acid profile of cows.


2018 ◽  
Vol 53 (5) ◽  
pp. 566-574
Author(s):  
Alexandre Cunha de Barcellos Ferreira ◽  
Ana Luiza Dias Coelho Borin ◽  
Julio Cesar Bogiani ◽  
Fernando Mendes Lamas

Abstract: The objective of this work was to evaluate the dry matter yield of cover crops and their suppressive effects on weeds. The experiment was carried out during three years in a cerrado area of the state of Goiás, Brazil, and consisted of 16 treatments with fallow and cover crops cultivated in single cropping and intercropping. Fallow allowed high weed infestation. Cover crops affected the composition of weeds, which showed greater diversity in fallow, followed by the Pennisetum glaucum 'BRS 1501' and Cajanus cajan crops. In the average of the three experimental years, the highest dry matter yield was observed for the treatments Panicum maximum (10,857 kg ha-1), Urochloa brizantha 'Piatã' (11,437 kg ha-1), U. ruziziensis (9,463 kg ha-1), and U. ruziziensis intercropped with Crotalaria spectabilis (9,167 kg ha-1), which prevented weed infestation. Pennisetum glaucum 'BRS 1501' had a low dry matter yield (<5,000 kg ha-1) and did not suppress weeds. Panicum maximum, U. brizantha 'Piatã', U. ruziziensis, and U. ruziziensis intercropped with C. spectabilis provide high dry matter yield and suppress weed infestation in the cerrado area.


2016 ◽  
Vol 29 (4) ◽  
pp. 885-891 ◽  
Author(s):  
LUAN CUTTI ◽  
FABIANE PINTO LAMEGO ◽  
ADALIN CEZAR MORAES DE AGUIAR ◽  
TIAGO EDU KASPARY ◽  
CARLOS ALBERTO GONSIORKIEWICZ RIGON

ABSTRACT The establishment of commercial crops in succession to winter cover crops that leaves a dense straw layer provides significantly suppression of weeds. The objective of this work was to evaluate the suppressive potential of winter cover crops on weed infestation in maize and its effect on the yield of the maize sown in succession. The experiment was conducted in the 2012/2013 crop season, in an area of the UFSM Campus Frederico Westphalen, State of Rio Grande do Sul. Four different species of cover crops (black oat, ryegrass, vetch and forage radish) were seeded and a fallow area was used as control. Evaluations to quantify the dry matter and chemical desiccation were performed at the full flowering period of the cover crops. Maize was sown in no-tillage system, in succession to the cover crops. The incidence and shoot dry matter of weeds (g 0.25 m-2) was evaluated 15 days after the maize emergence. The main weed species in the area were: morning-glory (Ipomoea grandifolia), wild poinsettia (Euphorbia heterophylla), large crabgrass (Digitaria sanguinalis) and purple nutsedge (Cyperus rotundus). In general, vetch and ryegrass were the winter cover crops that better suppressed the weeds evaluated. The best maize yield was found in the area previously covered with ryegrass, inferring a relation between the cover crop and suppression of weeds and crop yield.


2016 ◽  
Vol 51 (9) ◽  
pp. 1633-1642 ◽  
Author(s):  
Claudio Hideo Martins da Costa ◽  
Carlos Alexandre Costa Crusciol ◽  
Jayme Ferrari Neto ◽  
Gustavo Spadotti Amaral Castro

Abstract The objective of this work was to evaluate the long-term effects of the surface application of lime on soil fertility and on the mineral nutrition and grain yield of soybean, and of black oat and sorghum in crop succession. The experiment was carried out on a clayey Oxisol, in a randomized complete block design, with four replicates. Treatments consisted of lime the rates of 0, 1,000, 2,000, and 4,000 kg ha-1, applied in October 2002 and November 2004. Soil samples were collected at five soil layers, down to 0.60-m depth. Surface liming was effective in reducing soil acidity and increasing Ca2+ and Mg2+ contents in the subsurface. Moreover, it increased available phosphorus contents and soil organic matter in the long term (48 to 60 months after the last lime application). Surface liming improved plant nutrition, mainly for N, Ca, and Mg, and increased dry matter production and grain yield of the crops, even in years with regular distribution of rainfall. The greatest productivities of soybean, black oat, and sorghum were obtained with the respective estimated lime doses of 4,000, 2,333, and 3,281 kg ha-1, for shoot dry matter, and of 2,550, 3,555, and over 4,000 kg ha-1, for grain yield.


2004 ◽  
Vol 22 (4) ◽  
pp. 529-537 ◽  
Author(s):  
P.S.L. Silva ◽  
Z. Barbosa ◽  
O.F. Oliveira ◽  
R.P. Antonio ◽  
P.I.B. Silva

Weeds have a negative influence on several fruit tree characteristics, such as yield, making it difficult to management practices in orchards. Alternative weed management methods, aiming to reduce the use of herbicides, have become attractive since herbicides are costly and cause environmental degradation. The use of cultivars with greater competitive ability against weeds has attracted international attention. The objective of this work was to evaluate the floristic composition and growth of weeds under the canopies of irrigated custard apple tree progenies. Twenty halfsibling progenies around three years of age were evaluated in a random block design with five replicates and four plants per plot. A circle with a 0.5 m² area was established around the trunk of each plant. Floristic composition, fresh matter, and dry matter mass of the above-ground part of the weeds, were evaluated in this area. Root collar and canopy diameters, as well as leaf area of the progenies were also evaluated. Fifty-eight weed species were recorded. The five weed families with the most species were Leguminosae, Convolvulaceae, Euphorbiaceae, Malvaceae and Sterculiaceae, in decreasing order. The number of weed species per plot ranged from 6 to 18, but there was no difference between the mean percentages of different weeds under the canopies of the progenies. The lowest weed fresh and dry matter masses occurred in progenies JG1 and SM8, respectively. There were no differences between progenies with regard to root collar diameter and leaf area; however, one of the lowest weed dry matter yields was observed under the canopy of progeny FE4, which showed the largest canopy diameter.


2017 ◽  
Vol 35 (3) ◽  
pp. 425-427
Author(s):  
Jana Koefender ◽  
André Schoffel ◽  
Diego P Golle ◽  
Candida E Manfio ◽  
Alice PB Dambróz ◽  
...  

ABSTRACT The purpose of this work was to evaluate the influence of cutting the apex of the main stem of marigold plants on floral capitula yield. The experiment was carried out in a randomized complete block design, with five replicates. The following removal stages of the main stem apexes were studied: control (without pruning), up to 10 leaves, up to 15 leaves and visible flower bud. Three harvest periods were also evaluated: July, August and September, composing a factorial experiment in a 4x3 arrangement. The diameter, number, fresh matter and the dry capitula were evaluated. The most significant effect of cutting the apex of the main stem on fresh and dry matter of the capitula was obtained when the technique was performed at the time the plants had up to 15 leaves and visible flower bud. The harvesting performed in September showed to be the most promising, since it presented the larger diameter, higher number and higher fresh matter and the dry capitula.


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