Integration of Living Mulch and Stale Seedbed for Weed Management in Maize (Zea mays L.)

Application of living mulch and stale seedbed has been proposed for weed management in crop production. Field experiment was carried out at the Research Farm of university of Zanjan in 2013 as split block based on  randomized complete block design to assess integration of living mulch and stale seedbed for weed management in maize. The main plot was stale seedbed preparation (6 April, 3 May, and 24 May), and sub plot three different living mulch included Vicia villosa, Trifolium alexandrinum, and Lathyrus sativus. Cover crops were planted in the space between two rows at the recommended densities. Weed free and weed infestation, were also included. The results showed that 100-seed weight, biomass and seed yield of maize significantly affected by the time of stale seedbed preparation. However, this treatment had no effect on traits such as plant height, ear diameter, seed row number per ear and weed biomass. The highest maize grain yield (8.7 t.ha-1) was obtained when seedbed prepared on 6 April. Living mulch had significant effects on maize and weed growth. The highest maize grain yield was obtained in weed free plots. The lower weed biomass was produced when T. alexandrinum was used as a cover crop. The interaction of the stale seed bed and living mulch was not significant. These results suggest that living mulch or stale seedbed alone or in combination could not provide reliable weed control in maize; therefore, these methods should be integrated with other efficient weed control measures

A State of the Art on Railway Simulation Modelling Software Packages and Their Application to Designing Baggage Transfer Services

There is a new baggage transfer service suggested in Newcastle Central Station. In order to prove that this service is feasible, a simulation model can be developed to test the concept and operating pattern behind. For the purposes of this paper, we intend to organize a literature review on simulation modelling software packages employed to study service design. Specifically, this paper has compared five different simulation software packages used by the railway industry to study service-related challenges. As a result, it is suggested that SIMUL8, a macroscopic discrete event-based software package, should be used among the five compared ones because of its simplicity and the ability to give practical results for the design and performance of such a baggage transfer system

Track maintenance scheduling and its interactions with operations: Dedicated and mixed high-speed rail (HSR) scenarios

HSRs are a complex system not only in terms of technical specifications, but also with respect to operations and maintenance over the track structure. Also, track structure is basically considered as the most important and costly railway asset. Its maintenance is vital to assure safety and operating practices are also of great importance to assure that a good level of service is provided. Considering track maintenance considerations over a new HSR line, one important and critical feature is the operational regime and the question of whether the line will be operated as mixed (passenger and freight) or dedicated only to passenger traffic. This can influence the maintenance patterns: preventive maintenance planning, maintenances scheduling and assignment issues. This will be different for the dedicated and mixed HSR traffic scenarios. In this research, the main approach is focused on the interactions between track maintenance planning and operational concerns and influences in these two scenarios. With this aim and within the current paper, a model of the preventive maintenance scheduling problem (PMSP) has been selected initially from Budai (2006) and then an upgraded revision of this model (Multi-segment assignment and scheduling of preventive maintenance problem) is introduced. Furthermore, the upgraded model of PMSP has been run over a given HSR line (Tehran-Qom HSR corridor in Iran) based on the comparison between the two scenarios of dedicated HSR and upgraded mixed HSR patterns. The main requirements, similarities and differences between these two scenarios are analyzed based on preventive maintenance scheduling and assignment requisites and interactions over the operating restrictions and considerations such as track possession patterns for maintenance activities. We conclude that decision making between these two scenarios through PMSP modeling are quite complicated and depends on the technical and operational specifications of the given HSR corridor, although some general comments on tradeoffs are possible

Evaluation of Annual Clover Ecotypes by Using Drought Tolerance Indices

To evaluate clover ecotypes by using  drought tolerance indices, 17 annual clover ecotypes were tested in a split-plot experiment by using randomized complete  block design with three replications, under two irrigated and rain-fed conditions in the Saatlo Research Station in Urmia, Iran. In this study, based on the dry matter yield in stressed (Ys) and non-stressed (Yp) conditions, quantitative values of drought tolerance indices of mean productivity index (MP), tolerance index (TOL), geometric mean productivity index (GMP), harmonic mean index (HM), stress susceptibility index (SSI), and stress tolerance index (STI) were calculated. There was a significant difference among the ecotypes as to their yields under irrigated and rain-fed conditions, which indicated the existence of genetic diversity and the possibility of selection for drought tolerance and using them in breeding programs for further genetic. The correlations among drought indices and Yp and Ys showed that MP, GMP, HM, and STI were highly correlated with Yp and Ys. Cluster analysis categorized tolerant ecotypes No. 11, 2, 13, 8 and 10 in the same group and the others in the sensitive one. Based on the values of indices and higher dry matter yield, in both stress and non-stress conditions, ecotype No. 11 (T.resupinatum L.) was recognized to be as the most tolerant ecotype against drought

The Study Efficiency of Reduced Rate of Pendimethalin Integrated with Mulch and Hand-Weeding in Fennel (Foeniculum vulgare Mill.).

Introduction: Fennel has been cultivated as a medicinal and spice plant for a long time in different areas of Iran. However, its characterizes such as slow-growing, weak establishment, owning low LAI index and long seasonal plant, make it a poor competitor against weed, therefore, protection from weed is essential for successful cropping. The combination of management practices, such as mulching with herbicide could improve weed control efficacy of reduced rates. Limited information is available on control of weeds in fennel as important medicinal plant. Using a combination of physical control and herbicides at reduced rate may increase the efficacy of both treatments while reducing the cost of the weed control program and environmental impact of over reliance on herbicide applications. Therefore, the objective of this study was to evaluate the effects of reduced rates of the pendimethalin alone and in combination with wheat straw mulch and one hand-weeding on the growth of weed and grain yield of cultivated fennel. Materials and Methods: this experiment was carried out at the Research Farm of Faculty of Agriculture, University of Zanjan in the spring 2012 to introduce an integrated weed control method in fennel. In this experiment the efficacy of different rates of pendimethalin alone and with combination with one hand weeding and straw mulch for selective control of grass and broadleaf weed species were evaluated. Field experiment was laid out as factorial based on randomized complete block design with three replications. Factors were application dose (0, 660, 990 and 1320 g a.i. ha-1) and supplemental weed control (none, one hand-weeding, mulching). A plot with whole season hand weeding was also included as control. The recommended doses of pendimethalin were 1320 g ai ha-1. Fennel was planted at 10 seeds m-2, at 0.5 m row spacing, on May 6, 2012. Pendimethalin was applied pre-emergence soon after planting. In the mulch treatments, wheat straw were spread evenly after fennel planting at the rate of 2 kg m-2. In the weed control treatments which one hand weeding used as supplemental physical control, a hand-weeding was performed at 50 days after planting. At fennel maturity, weeds were harvested from a 0.5 m2 area and dried in an oven for 48 h at 75 oC and biomass was recorded. For assessing the effect of the treatments on fennel seed yield a 2 m2 centre area of the plots was harvested manually. Data were subjected to an analysis of variance using PROC GLM in SAS Software. The means were compared using a Fisher's Protected Least Significance Difference test (P< 0.05). Results and Discussion: Biomass of broad leaf weeds was significantly affected by herbicide doses and supplemental control. However, application dose and supplemental control interaction were not significant on broad leaf weeds biomass. Maximum broadleaf weed biomass control (85.9%) was recorded by recommended dose of pendimethalin. For a given dose of herbicide, weed control efficiency was higher when the physical methods were used as supplemental control and generally one hand-weeding was effective than mulching. All weed management treatments reduced biomass of grass weeds compared to weedy control. No differences were observed between the grass weed biomass in plots which received 75% and 100% of the labeled recommended rate of pendimethalin. Significant differences (p < 0.05) among herbicide rates and 50% of the labeled recommended rate (660 g a.i. ha-1) was observed for grass weed biomass. Biomass of grass weeds was also significantly affected by physical control. Maximum grass weed control (86%) was observed with one hand-weeding than the mulch. Same to broadleaf, the interaction effect of application dose × supplemental control treatments was not significant for grass weeds biomass. Total weeds biomass was significantly affected by herbicide. The interaction effect of application dose × supplemental control treatments were significant for total weeds biomass. Maximum weed biomass (1837.5 g.m-2) was recorded in weedy control. When herbicide combined with one hand-weeding, the rate of 660 g a.i. ha-1 of pendimethalin was sufficient to provide 81% total weed control, which was statistically similar to the best control achieved for all dose and physical combination treatments. Fennel seed yield and yield component was significantly affected by application dose and physical control. The greatest seed yield loss (97.6%) was recorded in no weed control plots. and the lowest seed yield loss (13%) was seen in the recommended dose of pendimethalin + one hand-weeding plot. When one hand-weeding was used as a supplemental control, increased herbicide application rates from 990 to 1320 g a.i. ha-1 did not significantly influence the level of fennel seed yield. Conclusions Overall, results of this study showed that pendimethalin in labeled recommended rate and applied alone was not sufficient to provide season long weed control. The recommended dose in combination with one hand weeding could not prevent of economic yield loss. As a result, it is recommended to test efficient herbicide or other methods of weed management of this plant. To improve the level of weed control with mulch, application of herbicides at the same time as the mulch or supplemental hand-weeding could be suggested as a part of integrated weed management in fennel

Effect of arbuscular mycorrhizal fungi on the accumulation of secondary metabolites in roots and reproductive organs of Solanum nigrum, Digitaria sanguinalis and Ipomoea purpurea

Background: The application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, thus impacting their allelopathic potential. Materials and methods: The objective of this study was to determine the effect of three AMF species (Rhizoglomus intraradices, Funneliformis mosseae, Rhizoglomus fasciculatum) on photosynthetic pigments and secondary metabolites content in roots and reproductive organs of Ipomoea purpurea L., Digitaria sanguinalis L., and Solanum nigrum L. as a problematic weed species. Results: Among compared weeds, the roots of D. sanguinalis associated with AMF accumulated the highest level of phenols. Higher content of flavonoids was obtained in roots of S. nigrum (7.46 mg g(-1) FW) following colonization with R. intraradices. Berries of S. nigrum inoculated with R. intraradices had a higher concentration of terpenoids (21.45 mg 100 mL(-1) of extract) than reproductive organs of D. sanguinalis and I. purpurea. Colonization with R. intraradices improved total phenolics in seeds of D. sanguinalis compared to the reproductive organs of other weeds. These compounds released from seeds help defend against pathogen infection, consequently increasing seed production. In addition, phenylalanine ammonia lyase enzyme activity in leaves of D. sanguinalis colonized by R. fasciculatum and F. mosseae was 55% and 67%, respectively, higher than I. purpurea plants, grown in the same condition

Mycorrhizal impact on competitive relationships and yield parameters in Phaseolus vulgaris L. — weed mixtures

Arbuscular mycorrhizal fungi (AMF) are known to improve plant growth and nutrition and therefore are likely to afect the competitive relationships between crops and weeds. In this study, we evaluated whether AMF (Funneliformis mosseae, Rhizoglomus fasciculatum, Rhizoglomus intraradices) change plant competition between Phaseolus vulgaris and the weeds Solanum nigrum L., Digitaria sanguinalis L., and Ipomoea purpurea L. Mycorrhizal colonization, aggressivity index, photosynthetic rates, and yield parameters were measured. While the presence of AMF reduced the total biomass of D. sanguinalis and S. nigrum when grown in competition with P. vulgaris, it increased the total biomass of I. purpurea when grown with P. vulgaris. Signifcantly, elevated mycorrhizal growth responses (38–44%) improved the competitive ability of I. purpurea. In contrast, the competitive ability of S. nigrum was increased only when plants colonized by R. intraradices. The total protein content of P. vulgaris pods when in competition was negatively afected by AMF, thus leading to low nutritional quality. The results suggest that AMF have the potential to afect the outcome of weed—P. vulgaris competition. We demonstrate that not only colonization with AMF but also AMF species can afect the competitive relationships between crops and weeds, and thus, AMF represent key soil organisms to be taken into account in sustainable weed management strategies

Effect of arbuscular mycorrhizal fungi on the accumulation of secondary metabolites in roots and reproductive organs of Solanum nigrum, Digitaria sanguinalis and Ipomoea purpurea

Background: The application of arbuscular mycorrhizal fungi (AMF) can induce the synthesis and accumulation of secondary metabolites in the tissues of host plants, thus impacting their allelopathic potential. Materials and methods: The objective of this study was to determine the effect of three AMF species (Rhizoglomus intraradices, Funneliformis mosseae, Rhizoglomus fasciculatum) on photosynthetic pigments and secondary metabolites content in roots and reproductive organs of Ipomoea purpurea L., Digitaria sanguinalis L., and Solanum nigrum L. as a problematic weed species. Results: Among compared weeds, the roots of D. sanguinalis associated with AMF accumulated the highest level of phenols. Higher content of flavonoids was obtained in roots of S. nigrum (7.46 mg g(-1) FW) following colonization with R. intraradices. Berries of S. nigrum inoculated with R. intraradices had a higher concentration of terpenoids (21.45 mg 100 mL(-1) of extract) than reproductive organs of D. sanguinalis and I. purpurea. Colonization with R. intraradices improved total phenolics in seeds of D. sanguinalis compared to the reproductive organs of other weeds. These compounds released from seeds help defend against pathogen infection, consequently increasing seed production. In addition, phenylalanine ammonia lyase enzyme activity in leaves of D. sanguinalis colonized by R. fasciculatum and F. mosseae was 55% and 67%, respectively, higher than I. purpurea plants, grown in the same condition

Allelopathic interactions between seeds of portulaca oleracea L. and various crop species

Allelopathy is described as the interference to plant growth resulting from chemical interactions among plants and other organisms mediated through the release of bioactive secondary metabolites. Since only a few studies have been reported about the role of seed allelopathy, an experiment was designed to evaluate the interactions among seeds of Portulaca oleracea L. and the crop species common bean (Phaseolus vulgaris L.), onion (Allium cepa L.), sugar beet (Beta vulgaris L.), broad bean (Vicia faba L.), and pea (Pisum sativum L.) on seed and seedling growth parameters. The results indicated that P. oleracea seeds had a negative effect on the germination of P. vulgaris and A. cepa. Conversely, germination of P. oleracea in the presence of P. vulgaris, A. cepa, and B. vulgaris seeds was strongly reduced with a higher inhibitory effect found for the seeds of A. cepa. The highest negative effect on root and shoot length was observed in P. vulgaris. Seedling vigor of all crop species decreased in the presence of P. oleracea. Our results suggest that seeds of P. vulgaris, A. cepa, and B. vulgaris exhibited high allelopathic effects against seeds of P. oleracea and can be used as potential bio-herbicides in future screening programs

Allelopathic interactions between seeds of portulaca oleracea L. and various crop species

Allelopathy is described as the interference to plant growth resulting from chemical interactions among plants and other organisms mediated through the release of bioactive secondary metabolites. Since only a few studies have been reported about the role of seed allelopathy, an experiment was designed to evaluate the interactions among seeds of Portulaca oleracea L. and the crop species common bean (Phaseolus vulgaris L.), onion (Allium cepa L.), sugar beet (Beta vulgaris L.), broad bean (Vicia faba L.), and pea (Pisum sativum L.) on seed and seedling growth parameters. The results indicated that P. oleracea seeds had a negative effect on the germination of P. vulgaris and A. cepa. Conversely, germination of P. oleracea in the presence of P. vulgaris, A. cepa, and B. vulgaris seeds was strongly reduced with a higher inhibitory effect found for the seeds of A. cepa. The highest negative effect on root and shoot length was observed in P. vulgaris. Seedling vigor of all crop species decreased in the presence of P. oleracea. Our results suggest that seeds of P. vulgaris, A. cepa, and B. vulgaris exhibited high allelopathic effects against seeds of P. oleracea and can be used as potential bio-herbicides in future screening programs