Mass Of Weeds Research Articles

Combination of Halauxifen - Methyl + Florasulamwith Other Grassy Herbicides Against Complex Weed Flora in Wheat (Triticumaestivum)

Two field experiments were carried out in Alexandria and El-Beheira governorates in Egypt to evaluate the biological efficacy of a ready mix herbicide Paradigm (Halauxifen-methyl + Florasulam) with application rate 21 gm/fed combined with Pyroxsulam (160 ml/fed), Pinoxaden (550 ml/fed), Clodinafop-propargyl (140 gm/fed) and Diclofop-methyl (1000 ml/fed) compared to Pyroxsulam (Pallas), Atlantis (Iodosulfuran + Mesosulfuron) and unweededcheck on winter wheat in 2014, herbicides were applied at tillering stage in both regions. Paradigm with its combinations with grassy weed herbicides showed excellent control onMedicagohispida, Beta vulgaris, Malvaprviflora, Anagallisarvensis, Coronopussquamatus, Sonchusoleraceusand Brassica nigra .On the other hand, the best efficacy on grassy weed mass, visual weed estimation and percentage of grassy seed heads were obtained from Paradigm combinations with Pyroxsulam and Pinoxaden only at tillering stage in Alexandria region, while its combination with Clodinafop-propargyl and Diclofop-methyl did not improve grassy herbicidal activity in both trials compared to standard herbicides, Generally the combinations showed good control for broad weed leaves in both locations, while in grassy leaves it showed better control in Alexandria than in El-Beheira governorate.

Мульчування як захист енергетичної верби від бур'янів

Species composition of weeds in energy willow plantations was under the effect of such factors as current land use, soil conditions and weed seeds stock. Thus, in control treatment dominated the following species (number of plants per m 2 ): (i) dicots – goosefoot ( Chenopodium album L.) 13.8 and green amaranth ( Amaranthus retroflexus L.) 10.4, with their proportion in total weeds of 30.5%; (ii) monocots – barnyardgrass ( Echinochloa crus-galli L.) 7.6 and foxtail grey ( Setaria glauca L.) 11.5. Together these four weed species accounted for 64.0%. Other dicot species presented in the field were field pennycress ( Thlaspi arvense L.) 5.1 (6.4%), catchweed ( Galium aparine L.) 4.2 (5.3%), black nightshade ( Solanum nigrum L.) 3.4 (4.3%), wild buckwheat ( Polygonum convolvulus L) 7.4 (9.3%), spotted ladysthumb ( Polygonum persicaria L.) 3.2 (4.0%), other 5.3 (6.7%). Total number of weeds in the control treatment made up about 79.6. When using winter wheat straw as a screening material (layer thickness 5 cm) the total number of weeds decreased significantly to 16.8. High efficiency of the mulching marked sprouts of goosefoot, green amaranth (within 90%) and monocots species (85-86%). Whereas the number of black nightshade sprouts (2.6) and field pennycress (1.9) decreased by only 49 and 44%, respectively. The number of spotted ladysthumb (1.3) decreased by 60%. In a treatment with 10 cm of mulching straw, weed sprouts number decreased to 3.3. Dicots reduced their number by 87.5-97.3% and monocots by 97.4-99.1% compared with control treatment. Under these conditions, the number of field pennycress plants was 0.9, green amaranth, barnyard grass and spotted ladysthumb 0.4. When applying 15 cm of mulching straw there were few sprouts of green amaranth, field pennycress (0.1 and 0.2, respectively) left, which impose no significant damage to energy willow plantations. Green mass of weeds on 20-91 July in the control treatment made up 2418 g/m 2 . To this, the most contributing species were wild buckwheat (417 g/m 2 ), black nightshade (336 g/m 2 ) and barnyardgrass (324 g/m 2 ). When applying 5 cm straw, green mass of weeds decreased by 7.7 times (to 314 g/m 2 ). Goosefoot produced the above-ground mass of 117 g/m 2 , which exceeded all other species by more than 3.0 times as much. Covering inter-row space with 10 cm straw reduced weed green mass to 116 g/m 2 , whereas 15 cm straw ­­ to 3 g/m 2 . Treatment with 5 cm straw provided reducing weeds number 4.7 times compared to the control treatment. However, the number of weeds in the growing season made up 16.8 per m 2 . Better results provided screening with 10 and 15 cm of straw, which significantly reduced both the number of weeds and their weight, which makes it possible to prevent energy willow plantations from weed infestation.

Allelopathic Influence of Residues from Sphagneticola trilobata on Weeds and Crops

The allelopathic effect studied in many cultures has currently generated great expectations that displayed a natural and environmentally friendly tool for weed management using bioherbicides. The objective of this work was to assess allelopathic influence of residues of S. trilobata on the germination and growth of weeds, as well as their relation with some crops and effects on soil properties. Results show that residues from S. trilobata have inhibited the germination of weeds (31.6 - 72%), increasingly with the applied dose. All residue doses of this specie have inhibited dicotyledonous germination, but only maximum concentration has affected monocotyledons. The residues did not affect onion germination, but stimulated it in radish and tomato, while the dose applied at 50% produced tomato stimulation and inhibition of cabbage. The effects of residues on hypocotyl growth in different crops showed changes in species response. For onion, the three doses had negative effects on the growth of hypocotyl, while tomato was stimulated. For radish, the growth was hindered by any dose applied, and were only different (50 and 100%) compared to control. For cabbage, only hypocotyl length was stimulated, when maximum dose (100%) was applied. For the radicle growth, in onion and radish no differences were found compared to control. While the tomato radicle growth was inhibited, in cabbage, all doses encouraged the elongation of the radicle. The dry mass of weed was affected by increased dose of residue (0.49 - 8.8 g m-2), however the soil microflora was stimulated, while the population of Azotobacter spp. was not affect. Some soil properties were affected, the level of organic material, Na+ and electrical conductivity were increased, while pH (H2O) decreased a bit, however it remained basic.

Non-chemical weed control systems in organically grown spring oilseed rape

This study aims to determine the impact of different non-chemical weed control systems on organically grown spring oilseed rape ( Brassica napus L.) crop weediness and yield of seeds. Non-chemical weed control systems: 1) thermal (water steam), 2) mechanical (inter-row loosening), and 3) smothering (self-regulation). Thermal (1.5–1.8 times) and mechanical (2.5–6.8 times) weed control systems significantly reduced the number of weed seedlings in spring oilseed rape crop, compared with the weed smothering system. The most effective system of weed control in rape crop was mechanical (efficiency 30.9–75.5 %). Efficiency of thermal weed control system, compared with mechanical, was lower, 28.4–40.0 %. Before rape harvesting in plots where mechanical weed control was applied, compared with plots where weed smothering was used, the number of weeds was significantly 3.2–4.4 times lower, and dry matter mass of weeds was 2.2–3.1 times lower. The yield of rape seeds increased with increasing efficiency of thermal and mechanical weed control. In 2014, the yield of rape seeds depended on number of weed seedlings and dry matter mass of weeds before rape harvesting. Keywords: spring oilseed rape, weed control systems, weed, yield, organic farming

Effect of herbicides on yield and quality of straw and homomorphic fibre in flax (Linum usitatissimum L.)

Fibre flax (Linum usitatissimum L.) is a very poor competitor with weeds, and to obtain acceptable yields, weeds should be effectively controlled. Very little information is available on the tolerance of flax to herbicide applications. Types of applied herbicides determine not only the yield of flax but can also affect yield of fibre, its quality and may affect processes (physical, chemical and enzymatic) used in the refining of homomorphic fibres to increase their thinness and divisibility. Presented basic field research was carried out in the years 2011–2012. In the studies the impact of three herbicides (with a.i. linuron, bentazon and chlorsulfuron) was examined on the control of weeds, course of vegetation and yield and quality of flax homomorphic fibre. The applied herbicides had a significant impact on the weed control, the length of the vegetation, straw yield, the percentage of fibre in the straw, weight and length of the fibre and its thinness and divisibility. The lowest number and mass of weeds and the highest flax straw yield and fibre quality was obtained after chlorsulfuron application. Bentazon, despite its high herbicidal effectiveness, reduced both the amount and quality of fibre yield when compared to chlorsulfuron, due to its phytotoxic effect on flax. Pre-emergence linuron application resulted in the longest fibres and highest fibre content in flax straw.

Vermicomposting of Mucuna bracteata – a Fast Spreading Troublesome Weed in Kerala, India

Mucuna bracteata DC. is one among the common weeds spreading rapidly in Kerala. The spread of this weed becomes an environmental nuisance and a threat to the local biodiversity. Conversion of this troublesome weed into nutrient rich manure through vermicomposting with native earthworm species of Perionyx ceylanensis was attempted in this study. The phytomass of M. bracteata was subjected to precompost along with cattle dung in the ratio of 6:1 for a period of 15 days. The resulting precompost – partially decomposed phytomass – was fed into vermireactors. The vermireactors fed with 37.5 g (dry weight) precomposted weed mass and 10 adult earthworms were operated for 15 days. These experiments were repeated for six times. The vermireactors performed with 14–21.3% recovery of vermicast with a C/N ratio of 23.7, which is comparable with the reported values in the literature. The findings of this study indicate that the earthworm species P. ceylanensis is potential enough to convert the phytomass of M. bracteata into nutrient rich manure. Also, the worms multiplied and grew well by gaining weight. Hence, these reactors with precomposted phytomass of M. bracteata can be operated sustainably. DOI: http://dx.doi.org/10.5755/j01.erem.70.4.8552

English

The millet crop in recent decades has shown an increase in planted area, mainly in the Cerrado region. However, there are few studies related to the management and phytossociology of weeds in this culture. Thus, the objective of this research was to perform a phytosociological survey in millet under different soil managements in Savanna Sul-Mato-Grossense region. The experiment was conducted in the experimental area of Universidade Estadual de Mato Grosso do Sul – Unit of Aquidauana (UEMS/UUA), in Aquidauana-MS. The area is cultivated to five years with soybeans in first crop and corn in second. The experimental design was randomized complete block in a split-plot design consisting of four blocks with four replications. In the plots were used soil preparation systems (minimum tillage and no-tillage) and in the subplots was utilized the nitrogen fertilization at 50 kg ha -1 and absence of nitrogen on millet at 25 days after emergence (DAE). Were evaluated the parameters number of species (NS), total number and dry mass of weeds (TN and DMW, respectively), dry mass of millet (DMM) and frequency (F), density (D), abundance (A) and Importance Value (IV) of weeds. The no-tillage system provided greater dry mass of weeds, whereas the nitrogen resulted in a smaller total number of weeds (TN). Cynodon dactylon and Commelina benghalensis were the most predominant species on area.

Soil properties and crop yield under different tillage methods for rapeseed cultivation in paddy fields

A two-year research was conducted to investigate the effect of different tillage methods on some soil physical characteristics and crop yield in rapeseed cultivation after rice harvesting. Five tillage treatments including: (i) using rotavator, once to depth of 10-15 cm (T1), (ii) using rotavator, twice to depth of 10-15 cm (T2), (iii) using moldboard plow to depth of 25 cm + rotavator, once to depth of 10-15 cm (T3), (iv) no-till planting through removing rice stubbles from plots (T4), and (v) no-till planting without removing rice stubbles from plots (T5), were evaluated under randomized complete block design (RCBD) in three replications. The biannual results revealed that the effect of tillage methods was significant (p<0.01) on soil bulk density, surface residues after tillage, dry mass of weeds, seed germination, and grain yield. T2 and T3 made considerable reduction in soil bulk density compared to other treatments for the 15- to 30-cm tillage depths. In T1, T2, T3, and T4, surface residues after tillage decreased in comparison with T5 by up to 35.37, 50.71, 69.92, and 75.75%, respectively. Having 71.48 g m-2, T5 had the maximum dry mass of weeds while T3 had the minimum one with 37.50 g m-2. Means comparison represented that in T2 and T3, seed germination reached the shortest length of 6.4 days in average. The highest and lowest grain yields were acquired in T3 (1,571 kg ha-1) and T5 (1,339 kg ha-1), respectively. Statistically, there was no significant difference between T1 (1,432 kg ha-1) and T2 (1,537 kg ha-1) compared with T3 in terms of grain yield.

Dirvos paruošimo įtaka žolinių augalų vystymuisi miško želdiniuose žemės ūkiui naudotuose plotuose ir kirtavietėse

The influence of soil preparation on the development of ground vegetation during the establishment of forest plantations was studied. It was found that in the first-year plantations on former farmland the least biomass of ground vegetation develops on furrows. Complete soil tillage to the depth of 22-27 cm, ploughed in berms or elimination of weeds with Roundup Bio may reduce the biomass of ground vegetation by up to two times. Soil ploughing in berms or piles always reduced the mass of weeds. In the second year of plantations' growth, differences in the biomass of weeds among different soil preparation treatments decreased. On fresh clear-cut areas of fertile mineral soils any mechanical method of soil preparation reduced the biomass of ground vegetation. With increasing soil preparation depth (down to 40 cm) and the width of the strip (up to 100 cm), the biomass of ground vegetation decreased. The least (4-9 times less compared with unprepared soil) ground vegetation biomass was observed when the soil had been prepared in furrows, berms or piles. Soil preparation method affected also the height of ground vegetation. It depended on soil fertility and moisture content, weed species, spring and summer weather conditions. The shading class of seedlings and the volume of plantation tending depended on soil preparation method too. Seedlings planted on wide (100 cm) furrows and on 30 cm high piles were the least shaded, while those growing on unprepared, completely ploughed soil or on inverted humus mounds experienced the greatest suppression.

Controle químico de Talinum paniculatum em três estádios de desenvolvimento

Talinum paniculatum é uma espécie pertencente à família Portulacacea, conhecida popularmente como maria-gorda, planta daninha em culturas como a cana-de-açúcar, feijão comum, soja, milho e cenoura, além de áreas não agrícolas. Com este trabalho objetivou-se estudar a eficácia de herbicidas no controle de T. paniculatum, assim como seu efeito na massa fresca e seca destas plantas em três estádios de desenvolvimento. O delineamento experimental utilizado foi o inteiramente casualizado, com nove tratamentos e quatro repetições, posicionados em três estádios: 4-6 folhas, 10-12 folhas e florescimento. Para avaliar a eficácia dos tratamentos aferiu-se a porcentagem de controle das plantas, além de sua massa fresca e seca. Houve maior controle para alguns tratamentos dentro das fases de desenvolvimento das plantas daninhas, com aplicação de isoxaflutole, diuron+hexazinone, ametryn e imazapic no primeiro estádio, glyphosate na dose de 2000 g e.a. ha-1, diuron+hexazinone e 2,4-D no segundo estádio e 2,4-D, glyphosate na dose de 2000 g e.a. ha-1 e amônio glufosinato no terceiro estádio. A massa fresca e seca das plantas daninhas foi afetada, seguindo o comportamento obtido para o controle. O uso de herbicidas se mostrou eficiente na minoria dos arranjos testados para o controle de T. paniculatum. O estádio de desenvolvimento da planta influencia a eficácia de controle dos tratamentos.

THE EFFECT OF DIFFERENT TYPES OF STRAW MULCHES ON WEED-CONTROL IN VEGETABLES CULTIVATION

The experiment was carried out in 2010–2012. The effect of different kinds of straw and its dose applied to soil mulching on the amount and fresh mass of weeds and yield level of broccoli and tomato was investigated. The type of straw mulch applied to the soil mulching influenced number and fresh mass of weeds. This effect could be the re sult of the properties of the mulch (colour, structure, etc.) or the allelopathic effect on the germination and growth of individual weed species. The most efficient for limiting infestation was mulch from buckwheat and rye straw. Soil mulching, regardless of its kind, causes a decrease in the number and mass of weeds at the beginning of growing period of vegetables. The application of straw at a dose of 20 t∙ha -1 had higher weedsuppressing effect than at a dose of 10 t∙ha -1 . When assessing the infestation before harvest the influence of straw mulch was lower but still significant. The application in higher dose of rye and buckwheat straw in broccoli, corn and rape in tomato cultivation reduced a number of weeds compared to dose of 10 t∙ha -1 . The better yielding effect in both vegetable species had soil mulching with straw at a dose of 10 t∙ha -1 .

Época de emergência de azevém e nabo sobre a habilidade competitiva da cultura da cevada

Objetivou-se com o trabalho avaliar os efeitos de épocas de emergência das plantas daninhas, azevém e nabo, sobre a cultura da cevada. O experimento foi conduzido em delineamento de blocos casualizados, arranjado em esquema fatorial 2x5, com três repetições. No fator A, foram alocadas as plantas competidoras (azevém e nabo) e no B as épocas de emergência (14 e 07 dias antes, no mesmo dia, 07 e 14 dias depois da emergência da cultura). No início da floração da cevada, foram mensuradas as variáveis: estatura das plantas, número de colmos ou caules, área foliar e matéria seca da parte aérea da cultura e das plantas daninhas. Todas as variáveis avaliadas da cevada apresentaram aumento de valor com o atraso da emergência das plantas daninhas. As espécies, cultivada ou daninhas, que emergiram antes, apresentaram maior habilidade competitiva, dominando o ambiente quando emergiram 14 dias antes uma da outra. Quanto mais tarde ocorrer a emergência das plantas daninhas com relação à cultura, menor é a interferência e, desse modo, maior é a habilidade da cevada em competir com a espécie daninha pelos recursos disponíveis no meio.

The effect of soil mulching with organic mulches, on weed infestation in broccoli and tomato cultivated under polypropylene fibre, and without a cover

Abstract An investigation was done on the effect of different types of organic mulches that were applied in form of straw to the soil mulching process, on the weed infestation, number, and fresh mass of weeds in broccoli cv. Milady F1 (Brassica oleracea L. var. italica Plenck) and tomato cv. Polfast F1 (Lycopersicon esculentum Mill.) grown under polypropylene fibre as a covering, or grown without a covering. The different types of organic straw mulches were: rye (Secale cereale L.), corn (Zea mays L.), rape (Brassica napus L. subsp. napus), and buckwheat (Fagopyrum esculentum Moench.). All the organic mulches were applied at a dose of 10 t/ha. The effect of the mulches was compared to a control plot which had no mulch. The type of organic mulch applied to the soil mulching process influenced species composition, number, and fresh mass of weeds. This effect could be the result of the properties of the mulch (colour, structure, etc.) or the allelopathic effect on the germination and growth of individual weeds species. Irrespective of the investigated factors, 24 and 25 weeds species, respectively, were observed immediately after cover removal and before broccoli and tomato harvest. In the first date of estimation Chenopodium album L., Echinochloa crus-galli (L.) P. Beauv., Fallopia convolvulus (L.) Á. Löve, Stellaria media (L.) Vill., and Viola tricolor L. dominated, however, before the vegetables were harvested Ch. album, V. tricolor, Veronica arvensis L., and E. crus-galli dominated. An application of polypropylene fibre contributed to an increase in the number and fresh mass of weeds in both vegetables in the first date of estimation (after cover removal). During this period, vegetables cannot compete with weeds. It is important to note, though, that before the vegetables were harvested, a decrease was found in the number and fresh mass of weeds in the covered plots. The most efficient weed limiter, both after cover removal and also before the broccoli and tomatoes were harvested, was buckwheat and rye straw, respectively.

Impact of plant density on the canopy area index and weed infestation depending on different cultivars of winter oilseed rape (Brassica napus L., ssp. oleifera Metzg.)

One way to increase the competitiveness of crop plants against weed infestation is to adjust crop density. Introduction of new (“semi-dwarf”) cultivars of winter oilseed rape triggers a need for research in this field. A two-factor experiment evaluated the effect of plant density and winter oilseed rape (WOSR) cultivars on the canopy architecture and weed infestation of a WOSR crop as well as on the correlation between these traits. During the 2010–2012 study period, the average plant density was 38.0; 29.4; and 22.9 plants m-2 (three row spacings were used: 33, 44, and 55 cm). The oilseed rape cultivars were as follows: conventional, hybrid and “semi-dwarf” hybrid. Experimental factors did not cause significant differences in the number of weeds and their mass. However, there was a clear trend of decreasing total number of weeds in the span of 33 cm spacing than in the 44 and 55 cm. Hybrid cultivar resulted in increasing of total number of weeds in comparison to the conventional one. The differences in the assimilation area of WOSR plants per unit of ground area were significant between row spacings until the end of the flowering stage and between cultivars until the flower bud development stage. During the growth stages from the beginning of flowering until the end of pod development significant negative correlations were found between the assimilation area and the number of weeds, while the correlations between the assimilation area and the weed weight were insignificant. Insignificant correlations also occurred between the number of oilseed rape plants per unit area and the mass of weeds. The results indicate the possibility of reducing the demand for seed sowing, without requiring additional costs for weed control.

Allelopatic potential of weeds under the minimalization of soil treatment

The content of water-dispersible phenol substances in rhizosphere both of annual and perennial species of weeds ( Cirsium arvense, Sonchus arvensis ) increases under soil treatment minimalization. The higher content of phenol substances of researched weeds is defined in rhizosphere of Common Couch ( Agropyrum repens ). The absence of intensive anthropogenic treatment of plowing layer which accumulates the significant mass of weed’s roots in the cause of much more higher allelopathic potential of some species’ of weeds. The high level of saturation by weeds in agrophytocoenosis under non-tillage soil treatment is defines the competitiveness between certain sepsis’ of weeds, especially, at the beginning of the vegetation. In this case, increasing the secretion of phenol substances is one of the physiological screenings of such competitiveness.

Influence of Italian ryegrass (Lolium multiflorum Lam.) as intercrop with spring barley (Hordeum vulgare L.) on the diversity of weed communities

<p class="abstracttekst">The paper presents results of 3 years of studies (2009–2011) on the influence of Italian ryegrass on the development of weed communities in spring barley (without chemical weeds control) cultivated after potato, spring wheat and spring barley. The reaction of spring barley to the choice of the forecrop was compared with identical plots with pure stand of that cereal where herbicides were applied for weeds control. Evaluation of infestation with weeds was conducted during barley tillering and before harvest. That evaluation considered the number and composition of weed species. During harvest, the dry mass of weeds was also considered. The results were used for determination of Shannon-Wiener diversity index and species homogeneity coefficient, Simpson’s index of dominance as well as Sørensen similarity index.</p>Spring barley weeding was significantly higher in case of cultivating it in mixed stand with Italian ryegrass (without chemical control), than in pure stand (with control). In the plots with mixed crop, lower diversity and homogeneity of weeds’ communities were recorded than in pure stand. Barley in mixed crop sown after spring barley, during both times of evaluation (spring and before harvest), increased the value of the index of dominance according to the number of species the most. As concerns the composition of species, number and biomass, the communities of pure stand and mixed crop with Italian ryegrass on the plot after potato were the most similar.

Interference of Grasses on the Growth of Eucalyptus Clones

This experiment aimed to study the interference of Urochloa decumbens, Brachiaria plantaginea, Brachiaria ruziziensis and Panicum maximum (100 plants m-2 density), on the initial growth of clones of eucalyptus (Eucalyptus urograndis) clones 1, 2, 3, 4 and 5. Each pot had one plant of eucalyptus and five weed plants. The experimental design was completely randomized with four replications, constituting a 5x5 factorial design. The height and the diameter of eucalyptus plants were evaluated at 0, 15, 28, 41 and 50 days after weeds transplanting (DAT). At 50 DAT was measured the foliar area of eucalyptus plants, as well as the dry mass of eucalyptus plants (leaves and stem) and the dry mass of weeds. The five clones suffered negative interference during the coexistence with weeds. The clones showed different behaviors through the interaction with weeds. For the more susceptible characteristics to interference – leaves and stem dry mass – eucalyptus clones 3, 4 and 5 were more sensitive to the presence of weeds.

Manejo de plantas daninhas na cultura da melancia nos sistemas de plantio direto e convencional

Foram avaliadas estratégias de manejo de plantas daninhas sobre a produção de melancia, nos sistemas de plantio direto e convencional, em cultivo sucessivo ao meloeiro. O experimento foi conduzido em blocos casualisados com quatro repetições, no esquema de parcelas subdivididas. Nas parcelas foram avaliados dois sistemas de plantio (direto e convencional) e, nas sub-parcelas, nove sistemas de manejo de plantas daninhas [cobertura com filme de polietileno; com capinas aos 14 dias após o transplantio (DAT); aos 14 e 28 DAT; 14 e 42 DAT; aos 14, 28 e 42 DAT; aos 28 DAT; aos 28 e 42 DAT; aos 42 DAT e testemunha sem capinas]. Antes da implantação do experimento, a área foi cultivada com meloeiro nos respectivos sistemas de plantio, tendo-se reutilizado a palhada nos tratamentos com sistema de plantio direto e o filme de polietileno nos tratamentos com uso desse material nos dois sistemas de cultivo. Aos 14, 28 e 42 DAT e por ocasião da colheita da melancia (80 DAT), foram realizadas avaliações de densidade e massa seca de plantas daninhas. Para a melancia, foram avaliados o número de frutos comercializáveis por planta; número total de frutos por planta; massa média de frutos comercializáveis por planta; massa média de frutos (totais) por planta; produtividade comercializável e total. O sistema de plantio direto induziu redução da densidade e da massa seca das plantas daninhas, com necessidade de realização de uma única capina entre 28 e 42 DAT, enquanto que no plantio convencional foram necessárias duas capinas, aos 14 e 28 DAT. Quando a cultura conviveu com as plantas daninhas durante todo o ciclo, houve redução de 100 e 35,7% na produtividade de frutos comercializáveis para os sistemas de plantio convencional e direto, respectivamente. O sistema de plantio direto e o filme de polietileno no plantio convencional permitem a realização do cultivo da melancia em sucessão ao meloeiro, reduzindo a interferência de plantas daninhas e proporcionando produtividade satisfatória.

Fitossociologia de plantas daninhas do cafezal consorciado com leguminosas

O objetivo deste trabalho foi avaliar a fitossociologia de plantas daninhas em cafezais sob diferentes períodos de consórcio com leguminosas em dois anos de cultivo. Os tratamentos corresponderam à combinação fatorial entre as leguminosas feijão-de-porco (Canavalia ensiformis) e lablabe (Dolichos lab-lab) e períodos de consorciação com cafeeiros aos 30, 60, 90 e 120 dias após o plantio, mais uma testemunha sem leguminosa. O experimento foi composto por nove tratamentos em delineamento de blocos casualizados com quatro repetições. As leguminosas foram semeadas em dezembro de 2007 e outubro de 2008 e cortadas conforme os períodos de consorciação, sendo removidas da entrelinha, para ficarem sob a copa dos cafeeiros. As plantas daninhas foram amostradas nas entrelinhas e na projeção das copas dos cafeeiros, em outubro de 2008 e em outubro de 2009, refletindo o efeito dos tratamentos após um e dois anos de consorciação, respectivamente. As avaliações constaram da similaridade da comunidade, do índice do valor de importância e da importância relativa das plantas daninhas mais frequentes. Nos dois anos agrícolas foram identificadas 17 espécies de plantas daninhas, distribuídas em dez famílias botânicas, sendo mais frequentes as espécies Cyperus rotundus, Paspalum conjugatum, Amaranthus retroflexus e Oxalis latifolia. No primeiro ano, o feijão-de-porco (2,65 t ha-1) produziu mais massa que a lablabe (1,89 t ha-1), e no segundo ano a lablabe produziu mais massa (4,21 t ha-1) que o feijão-de-porco (2,73 t ha‑1). Nas entrelinhas, a diferença da flora de plantas daninhas em relação à testemunha foi maior do que na projeção da copa dos cafeeiros, no final dos dois anos. Em 2008, quando a lablabe ficou por 90 ou 120 dias nas entrelinhas, houve crescimento da importância da tiririca, enquanto em 2009 a importância relativa desta foi mais elevada na testemunha. As entrelinhas do cafeeiro apresentaram massa de matéria seca de plantas daninhas maior do que a projeção da copa, possivelmente devido ao sombreamento proporcionado pelos cafeeiros. A espécie Cyperus rotundus foi a de maior importância nos dois anos, seguida de Paspalum conjugatum, que teve sua importância aumentada de 2008 para 2009, devido à sua adaptação às condições de baixa luminosidade.

Zachwaszczenie jęczmienia jarego uprawianego po różnych przedplonach

A field study was carried out between the years 2008–2009 at the Research Station Swadzim that belongs to Poznań University of Life Sciences. The objective of the study was to determine the effect of tillage system and previous crop on the changes in infestation and species compositions in spring barley. As compared to the traditional tillage, direct drilling increased over 100% mass of weeds per unit area. Number of weeds was higher by 60% and more on the plots with direct drilling. There was significant influence of previous crop on number of weeds in spring barley. Number of weeds was 40% higher when spring barley was cultivated after fodder beet compared to the plots where spring barley was cultivated after maize. The dominance species were: Viola arvensis, Chenopodium album, Senecio vulgaris, Geranium pusillum, Anthemis arvensis, Matricaria maritima, Lycopsis arvensis, Brassica napus and Echinochloa crus-galli. There was no significant influence of previous crop on values of dominance index (C). Significant higher value were recorded on the treatments with spring barley cultivated with conventional tillage technology. Higher values of Shannon’s biodiversity index (H) were obtained on the treatments where spring barley was cultivated in direct drill after maize crop and also after fodder beet crop when ploughing cultivation system was applied. Badania przeprowadzono w latach 2008–2009, w Zakładzie Doświadczalno-Dydaktycznym Gorzyń, filia Swadzim należącym do Uniwersytetu Przyrodniczego w Poznaniu. Ich celem była ocena wpływu sposobu uprawy gleby i rodzaju przedplonu na stan i stopień zachwaszczenia jęczmienia jarego. Na obiektach z siewem bezpośrednim obserwowano ponad dwukrotny wzrost masy chwastów na jednostce powierzchni, natomiast wzrost ich liczby w stosunku do tradycyjnej uprawy płużnej wynosił ponad 60%. Rodzaj przedplonu wpływał na liczbę chwastów w łanie jęczmienia jarego. Na obiektach, na których był on wysiewany po kukurydzy charakteryzował się o 40% większą liczbą chwastów w odniesieniu do jego uprawy po buraku pastewnym. W zasiewach szczególnie licznie występowały takie gatunki, jak: Viola arvensis, Chenopodium album, Senecio vulgaris, Geranium pusillum, Anthemis arvensis, Matricaria maritima, Lycopsis arvensis, Brassica napus i Echinochloa crus-galli. Nie stwierdzono istotnego wpływu przedplonu na wartość wskaźnika dominacji (C). Istotnie wyższe wartości tego wskaźnika odnotowano w odniesieniu do zachwaszczenia jęczmienia uprawianego w technologii tradycyjnej. Wyższe wartości wskaźnika bioróżnorodności Shannona (H) wykazano w odniesieniu do zachwaszczenia przy uprawie jęczmienia w stanowisku po kukurydzy w technologii siewu bezpośredniego, natomiast w stanowisku po buraku pastewnym wskaźnik ten przyjmował wyższe wartości, gdy zastosowano płużną uprawę roli.