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Pondweed is a rhizomatous perennial weed of aquatic habitats that recently adapted to rice ecosystems in northern Iran. Two field experiments were conducted at the Rice Research Institute of Iran to determine the impact of pondweed on rice yield and identify effective herbicides for pondweed control. The focus of the first study was to evaluate the herbicides commonly used in Iranian rice, including butachlor, pretilachlor, oxadiargyl, pendimethalin, thiobencarb, and bensulfuron-methyl. None of these herbicides effectively controlled pondweed, except bensulfuron, which reduced pondweed biomass by ≥95% and produced 26% higher rough rice grain yield than the nontreated plots. The second experiment evaluated the performance of acetolactate synthase–inhibiting herbicides on pondweed control, rough rice yield, and pondweed regrowth. Herbicide efficacy on pondweed varied from 36% to 100%. Five preemergence herbicides, bensulfuron at 45 g ai ha−1, flucetosulfuron at 30 g ai ha−1, triafamone plus ethoxysulfuron at 40 g ai ha−1, and metsulfuron-methyl at 15 g ai ha−1, provided ≥98% control of pondweed. Use of postemergence herbicides penoxsulam at 35 g ai ha−1, bispyribac-sodium at 30 g ai ha−1, and pyribenzoxim at 35 g ai ha−1provided 36%, 89%, and 93% pondweed control, respectively. Rough rice yields ranged from 107% to 124% in herbicide-treated plots compared with the nontreated plots. Soil-applied herbicide treatments produced higher (≥119%) yield than the hand-weeded control or foliar-applied herbicides. Pondweed regrowth was affected by herbicides and was variable. Soil-applied residual herbicides metazosulfuron, flucetosulfuron, and metsulfuron provided complete control of pondweed and prevented regrowth. In contrast, pondweed regrowth in other soil- and foliar-applied herbicide treatments occurred, indicating their lesser translocation to underground vegetative rhizomes. This study shows that although most sulfonylurea herbicides can control pondweed effectively to achieve high rough rice yield, only a few soil-applied herbicides were able to prevent pondweed regrowth.

Intercropping and bio-fertilizer application play important roles in sustainable agro-ecosystems. A two-year field experiment was conducted at Astaneh-ye Ashrafiyeh, Northern Iran, to evaluate the effect of Azotobacter (Azotobacter chroococcum) inoculation on the growth and yield of a peanut/maize intercropping system. The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were Azotobacter application [control (non-inoculated) and inoculation (with Azotobacter chroococcum) and different maize (Zea mays L.)/peanut (Arachis hypogaea L.) intercropping pattern (100% peanut + 100% maize, 100% peanut + 50% maize, 50% peanut + 100% maize, 50% peanut + 50% maize, 67% peanut + 33% maize, and 33% peanut + 67% maize). Sole cropping of peanut and maize were also used. Results showed that averaged across years and intercropping patterns, grain yields of peanut and maize were significantly increased by 10% and 16%, respectively, in inoculated plots compared to non-inoculated ones. Azotobacter also had a positive significant effect on nitrogen concentration of grain, while it had no significant effect on oil concentration of peanut grain and significantly decreased the oil concentration of maize grain. Land equivalent ratio (LER) ranged from 1.05 to 1.70, indicating more efficient and productive use of environmental resources by intercrops. Results also showed that inoculated intercropped plots had 12-16% grater LER that non-inoculated ones. The highest LER was observed for inoculated plot with 100% peanut + 50% maize intercropping pattern (1.70), while the lowest one was recorded for non-inoculated plot with 50% peanut + 50% maize intercropping pattern (1.05). Based on the result of this experiment, intercropping pattern of 100% peanut + 50% maize along with Azotobacter application is recommended to obtain the highest productivity in maize/peanut intercropping system.

Rice cultivation in Iran has a special place and its cultivation area is about 640,000 ha. Soil salinization is one of the most factor in reducing of grain yields and cultivation of paddy rice. Currently, half of Iran's cultivated lands (9.5 million ha) are affected by salinity, which has a major impact on crop yields. For this purpose, an field experiment conducted with the use of microorganisms ( Pseudomonas putida strain S34, Pseudomonas fluorescens strain R167, Arbuscular mycorrhizal fungi (AMF) ( Rhizophagus irregularis ), co-inoculation of P.putida + P.fluorescens + AMF, and a non-inoculated treatment as control) on two rice cultivars (Hashemi and Gilane) in saline and normal soil in north of Iran during the 2018 and 2019. The results showed interactions of microorganisms and soil condition could alleviate the adverse effects of salinity by decreasing H 2 O 2 (14-71% in normal soil and 44-281% in saline soil) and increasing catalase (CAT) activity (39.5-65% in Gilane and 45-61% in Hashemi), proline (17-46% in Gilane and 13.5-52% in Hashemi) and nitrogen (N) concentrations (12-27% in normal soil and 7-23% in saline soil) of leaves. Also microorganisms significantly increased tiller, panicle and grain number plant -1 , and biological and grain yield (23-44.5% and 32.5-56% in normal and saline soil, respectively). Furthermore, the greatest mitigating effects were observed in treated by P.putida + P.fluorescens + AMF plants. This study indicated that P.putida + P.fluorescens + AMF synergistically mitigate harmful impacts of soil salinity in rice cultivars.

Sustainable development of food production depends on damping the environmental impacts of agricultural production. The aim of this study was to investigate the environmental performance of rice production in single crop and ratooning (main rice + ratoon crop) agro-systems through life cycle assessment (LCA) methodology in Guilan province, Northern Iran, in 2015. The flooding irrigation regime was the dominant irrigation method for single cropping system and main crop rising in ratooning agro-system. The data were gathered through a face to face interview with 215 single crop and 115 ratoon breeder paddy farmers. The environmental risks were determined in six impact categories including global warming, terrestrial eutrophication, acidification, and depletion of fossil fuels, phosphate, and potash resources. The functional unit (FU) was set as 100 kg protein. Results indicated that the CO2, N2O, and CH4 emissions of the rice ratooning agro-system (661.44, 1.96, and 5.42 kg 100 kg−1 protein) were less than the corresponding values in the rice single cropping agro-system (1341.63, 2.88, and 9.20 kg 100 kg−1 protein, respectively). Among all the environmental impact categories, the terrestrial eutrophication had the widest negative environmental effect followed by depletion of phosphate resources in single cropping agro-system with weighted indices of 0.51 and 0.41, respectively. Moreover, the terrestrial eutrophication had the largest negative environmental effect followed by acidification in rice ratooning agro-system with weighted indices of 0.48 and 0.29, respectively. Overall, the results highlighted that the rice ratooning ago-system is more environmentally beneficial than the single cropping system, particularly in terms of depletion of fossil fuels, global warming, and depletion of phosphate and potash resources categories. This priority may be improved through adopting proper management of agronomic practices for main and ratoon rice in ratooning agro-system.

Bioethanol is one of the most widely used biofuels worldwide and rice (Oryza sativa L.) is a feedstock for bioethanol production. This study aimed at evaluating the energy use efficiency of rice single cropping and ratooning agro-systems in terms of brown rice production as a feedstock for bioethanol production. Moreover, the possibility of bioethanol production from Iranian rice was studied and a potential atlas, regarding the possibility of bioethanol production across the country, was also presented. The results demonstrated that the total energy consumption for producing 2.4 kg of brown rice as the feedstock unit for 1 L bioethanol production in rice single and ratooning agro-systems were 54.24 and 29.98 MJ, respectively. The results clearly highlighted that the bioethanol feedstock production in ratooning agro-system was more energy-efficient than the single cropping system. Substitution of low-yielding paddy variety of Hashemi with high-yielding cultivars and compensating some of the crop's nitrogen requirement using biological alternatives are proposed to enhance energy productivity in both agro-systems. The annual potential of bioethanol production from rice in Iran was estimated to be 648 million liters. Overall, developing a macro-plan is recommended to produce rice to be used as food and bioethanol feedstock based on the ratooning agro-system in Northern Iran.

Identification of high-yielding stable promising rice lines and determination of suitable areas for rice lines would be done by additive main effects and multiplicative interaction (AMMI) model. Seven promising rice genotypes plus two check varieties Shiroudi and 843 were analyzed using a randomized complete block design with three replications in three consecutive years (2012, 2013 and 2014). Homogenous error variance was indicated in the nine environments for grain yield. The combined analysis of variance indicated significant effects of environment, genotype and genotype × environment (GE) interactions on grain yield. The significant effect of GE interaction reflected on the differential response of genotypes in various environments and demonstrated that GE interaction had remarkable effect on genotypic performance in different environments. The application of AMMI model for partitioning the GE interaction effects showed that only the first two terms of AMMI were significant based on Gollob's F-test. The lowest AMMI-1 was observed for G7, G2 and G6. G7 and G6 had higher grain yield. According to the first eigenvalue, which benefits only the first interaction principal component scores, G1, G6, G2 and G9 were the most stable genotypes. The values of the sum of first two interaction principal component scores could be useful in identifying genotype stability, and G6, G5 and G2 were the most dynamic stable genotypes. AMMI stability value introduced G6 as the most stable one. According to AMMI biplot view, G6 was high yielding and highly stable genotype. In conclusion, this study revealed that GE interactions were an important source of rice yield variation, and its AMMI biplots were forceful for visualizing the response of genotypes to environments.

Double cropping is an essential strategy for increasing crop productivity, promoting employment, satisfying food demands, and enhancing sustainability of production. However, much of the evidence on which farmers double crop (and if so, how often) is anecdotal. Factors affecting the adoption of double cropping were explored in Rasht County of Guilan Province in northern Iran. Most farmers (58.3%) practiced double cropping with one crop (i.e., ratoon rice, vegetables or pulses). Leafy vegetables, such as coriander (Coriandrum sativum), parsley (Petroselinum crispum), spinach (Spinacia oleracea), and garden cress (Lepidium sativum) as well as root vegetables, such as garlic (Allium sativum), carrot (Daucus carota subsp. sativus), and radish (Raphanus sativus) were the most common vegetables. Cranberry bean (Phaseolus vulgaris) and faba bean (Vicia faba) were the most common pulses. Almost a third of the farmers (32.5%) practiced double cropping with a combination of two crops (i.e., ratoon rice plus vegetables or ratoon rice plus pulses). Adopters of double cropping had a more positive attitude for this cropping practice (as expressed by perceptions of high profitability and sufficient satisfaction of household food demands), higher levels of social participation (i.e., participation in cooperatives, associations, unions) and cooperation with other farmers, more use of communication tools (i.e., TV, radio, internet, magazines), and higher income from rice farming than the non-adopters. A logistic regression model with predictive ability 72.8% showed that farmers’ attitude towards double cropping had the greatest role in the prediction of its acceptance followed by attendance of education courses and farming experience. The results are of practical significance for policy-makers who seek the best options for greater farm productivity and well-being in developing countries. Training courses and discussion meetings, particularly targeted to young farmers, as well as the establishment of cooperatives to foster social participation could motivate adoption of double cropping.

Herbicides, as a major part of weed control strategy in paddy fields, have different impact on growth and activity of soil-beneficial bacteria such as Azospirillum species. A field experiment was conducted at Sefid Rood Livestock and Agricultural Company, northern Iran, to investigate the possibility of chemical weed control in paddy fields inoculated with Azospirillum lipoferum. The experiment was designed in a factorial arrangement based on a randomized complete block with three replicates. The factors were Azospirillum application (inoculation with or without Azospirillum lipoferum) and weed management regime (butachlor application with supplementary hand-weeding, bensulfuron methyl application with supplementary hand-weeding, combination of butachlor and bensulfuron methyl application with supplementary hand-weeding, hand-weeding at 15, 30, and 45 days after transplanting, and no weeding [not weeded during the rice-growing period). The results showed that plants inoculated with A. lipoferum produced 19% higher grain yield compared to plants that were not inoculated. The highest grain yields were recorded for plots treated with butachlor with supplementary hand-weeding (4,512 kg ha-1) and for those treated with a combination of butachlor and bensulfuron methyl with supplementary hand-weeding (4500.5 kg ha-1). The lowest yield (3494.3 kg ha-1) was recorded for weedy plots. No significant interaction was detected between A. lipoferum application and weed management regime for grain yield, indicating that the herbicides had no adverse effect on the efficiency of A. lipoferum in promoting growth and grain yield of rice. There was no significant difference in the dry weights of weed between inoculated and non-inoculated plots. The dry weights of weed in hand-weeded and herbicide-treated plots were significantly lower than that of the weedy plot. In conclusion, the result of this experiment confirms the possibility of chemical weed control in paddy fields inoculated with A. lipoferum. RESUMO: Os herbicidas, como uma parte importante da estratégia de controle de plantas daninhas em arrozais, têm diferentes impactos no crescimento e atividade de bactérias benéficas para o solo, como as espécies de Azospirillum. Um experimento de campo foi realizado no Sefid Rood Livestock and Agricultural Company, norte do Irã, para investigar a possibilidade de capina química em campos de arroz inoculados com Azospirillum lipoferum. O experimento foi desenvolvido em esquema fatorial, com base em blocos casualizados com três repetições. Os fatores foram a aplicação de Azospirillum (inoculação com ou sem Azospirillum lipoferum) e o regime de manejo de plantas daninhas (butaclor - aplicação com capina manual suplementar; bensulfuron-methyl - aplicação com capina manual suplementar; combinação de butaclor e bensulfuron-methyl - aplicação com capina manual suplementar, capina manual aos 15, 30 e 45 dias após o transplante e sem capina [não eliminados durante o período de cultivo de arroz). Os resultados mostraram que plantas inoculadas com A. lipoferum apresentaram rendimento de grãos 19% superior em comparação com aquelas que não foram inoculadas. As maiores produções de grãos foram registradas para parcelas tratadas com butaclor com capina manual suplementar (4.512 kg ha-1) e para aquelas tratadas com uma combinação de butaclor e bensulfuron-methyl com capina manual suplementar (4.500,5 kg ha-1). O menor rendimento (3.494,3 kg ha-1) foi registrado nos lotes que não foram capinados. Não houve interação significativa entre a aplicação de A. lipoferum e o regime de manejo de plantas daninhas para produção de grãos, indicando que os herbicidas não tiveram nenhum efeito adverso sobre a eficiência de A. lipoferum na promoção do crescimento e produtividade de grãos de arroz. Não houve diferença significativa nos pesos secos de plantas daninhas entre parcelas inoculadas e não inoculadas. O peso seco de plantas daninhas em parcelas capinadas manualmente e tratadas com herbicidas foi significativamente menor do que o do lote que não foi capinado. Em conclusão, o resultado desta experiência confirma a possibilidade de capina química em campos de arroz inoculados com A. lipoferum.

espanolEl experimento de campo fue llevado a cabo en Lihijan, Iran en 2013 con el objetivo de evaluar el efecto de la aplicacion de fosforo (P) y Pseudomonas fluorescens en el desarrollo y rendimiento de un cultivo de haba. El diseno experimental fue de bloques completos al azar con arreglo factorial 2x3, con tres repeticiones. Los factores experimentales fueron la aplicacion de fosforo (0 y 25 kg ha-1) y cepas de P. fluorescens cepas (no inoculados, cepa 136 y cepa 168). El ANOVA mostro un efecto interactivo significativo de P y cepa de P. fluorescens en altura de la planta, numero de vainas por planta, peso del 100 granos, longitud de vaina y el rendimiento de vaina y grano. SE observo que el numero de granos por vaina se vio afectado significativamente por la aplicacion de fosforo y cepa de P. fluorescens cepa, mientras que el rendimiento del tallo solo fue significativamente afectada por la cepa de P. fluorescens. En ausencia de P, el rendimiento de grano de plantas inoculadas fue igual que en plantas no inoculadas. Enpresencia de P (25 kg ha-1), la cepa 168 mostro un aumento en el rendimiento de grano de 42% y 65%, en comparacion a las plantas inoculadas con la cepa 136 y las plantas no inoculadas, respectivamente. Los resultados sugieren que la aplicacion de fosforo (25 kg ha-1) y la inoculacion de semillas con P. fluorescens cepa 168 se puede recomendar para incrementar el rendimiento de vainas y grano en un cultivo de habas. EnglishA field experiment was conducted in Lihijan, Iran in 2013 to evaluate the effect of phosphorus fertilization (P) and Pseudomonas fluorescens strain on the growth and yield of the faba bean. The experiment used a randomized complete block design with a factorial treatment arrangement and three replicates. The experimental factors were phosphorus application (0 and 25 kg ha-1) and P. fluorescens strains (non-inoculated, strain 136, and strain 168). ANOVA showed a significant interaction effect of P and P. fluorescens strain on plant height, pod number per plant, 100 grain weight, pod length, and pod and grain yield. ANOVA also showed that grain number per pod was significantly affected by P application and P. fluorescens strain, while haulm yield was significantly affected only by P. fluorescens strain. In the absence of P, the grain yield of inoculated plants was not significantly different from that of non-inoculated plants. In the presence of P (25 kg ha-1), strain 168 showed an increase in grain yield of 42% and 65% over strain 136 and non-inoculated plants, respectively. The results indicated that application of phosphorus (25 kg ha-1) and seed inoculation with P. fluorescens strain 168 can be recommended to increase grain/pod yield significantly.

To evaluate the effect of planting date and spatial pattern on common bean yield under weed-free and weed-infested conditions, an experiment was conducted in Kelachay, Northern Iran, in 2013. The experimental design was a randomized complete block in a factorial arrangement with three replicates. Factors were planting date (10 August and 20 August), spatial pattern (square and rectangular planting pattern, with a planting distance of 30 x 30 cm and 45 x 20 cm, respectively), and weed management regime (weed-free and weedy conditions, weeded and not weeded throughout the growing season, respectively). Results showed that the main effect of planting date was significant only for pod number per plant and seed number per pod. At the same time, pod number per plant, seed number per pod, pod length, and grain yield were influenced significantly by spatial pattern. Results of ANOVA have also indicated that all traits, except pod length, were influenced significantly by weed-management regimes. Moreover, effect of planting date and spatial pattern were nonsignificant for weed dry weight. Mean comparison has expressed a significant increment in seed yield for square planting arrangement (1,055 kg ha-1) over rectangular (971 kg ha-1). Weeding has also presented an overall 12% and 8% improvement in grain and pod yield over control (weedy check), respectively. Based on the results of this study, weed control, as well as square planting pattern, are recommended for obtaining the highest seed yield in common bean. RESUMOUm experimento foi conduzido em 2013 em Kelachay, no norte do Irã, para avaliar o efeito da época de semeadura e do arranjo espacial na produtividade do feijoeiro com e sem infestação de plantas daninhas. O delineamento experimental foi de blocos casualizados, em esquema fatorial, com três repetições. Os fatores foram época de plantio (10 de agosto e 20 de agosto), arranjo espacial (sistema de plantio quadrado e retangular, com espaçamento de plantio de 30 x 30 cm e 45 x 20 cm, respectivamente), e sistema de manejo de plantas daninhas (ausência e presença de plantas daninhas, com ou sem roçada durante todo o período de crescimento, respectivamente). Os resultados mostraram que o principal efeito da época de semeadura foi significativa apenas para número de vagens por planta e número de sementes por vagem. Ao mesmo tempo, número de vagens por planta, número de sementes por vagem, comprimento de vagem e produtividade de grãos sofreram influência significativa do padrão espacial. Os resultados de análise de variância indicaram também que todas as características, exceto comprimento de vagem, sofreram influência significativa dos sistemas de manejo de plantas daninhas. Além disso, o efeito da época de plantio e do padrão espacial foram nãosignificativa para massa seca de plantas daninhas. A comparação das médias indicou um aumento significativo na produtividade de sementes no sistema de plantio quadrado (1.055 kg ha-1) em comparação ao retangular (971 kg ha-1). A roçada de ervas daninhas também indicou um aumento geral de 12% e 8% no rendimento de grãos e vagem em comparação ao controle, respectivamente. Com base nos resultados deste estudo, recomenda-se o controle de plantas daninhas, bem como o sistema de plantio quadrado, para a obtenção de maior rendimento de sementes de feijoeiro comum.

espanolSe realizo la evaluacion economica de huertos de olivos cultivados bajo sistema organico y convencional. Aleatoriamente, se distribuyeron 305 cuestionarios entre los olivicultores de Rudbar, provincia de Guilan, Iran, durante 2014. Los huertos se dividieron en tres grupos segun la superficie de cultivo: 5 ha. Los datos obtenidos fueron procesados con el software Excel 2010 para calcular los indicadores economicos: valor total de la produccion; beneficio neto; relacion costo-beneficio y eficiencia economica. Los resultados para el valor total de la produccion se estimo en 3.316,44 $ ha-1 y el costo total de produccion fue de 1.806,21 $ ha-1, independientemente del tamano de la huerta. La eficiencia economicafue de 2.937kg $-1 y la relacion costo-beneficio fue de 1,79 para la produccion en huertos de olivo ecologico. Para los huertos convencionales la eficiencia economica y relacion beneficio-costo fue de 3.036 kg $-1 y 1,84; respectivamente. Los resultados sugieren que no hay diferencia significativa para la eficiencia economica y relacion costo-beneficio entre huertos organicos y convencionales. Se concluye que se debe incentivar la produccion organica en huertos de olivo. EnglishThe present study investigated the economic performance of olive orchards in Rudbar in the province of Guilan in Iran in 2014 using the results from 305 questionnaires that were randomly distributed to regional olive growers. The orchards were divided into three groups of 5 ha in size as small, medium, and large olive orchards, respectively. The information was analyzed using Excel software and the means of the economic indices of total production value, net benefit, benefit-to-cost ratio and economic productivity were calculated. The total production value was estimated as 3316.44 $ ha-1 and total cost of production was 1806.21 $ ha-1, regardless of size of orchard. Calculation of economic indices indicates that the best total production values were recorded for small- and medium-sized orchards. The economic efficiency was 2.937 kg $-1 and the benefit-to-cost ratio was 1.79 for organic olive production. These values were 3.036 kg $-1 and 1.84, respectively, for non-organic orchards. The figures show that there was no significant difference between organic and non-organic olive production in terms of economic efficiency and benefit to cost ratio in Guilan province, Iran. With the ever-increasing tendency toward organic production of agricultural products, the olive producers and agricultural authorities of Guilan province are recommended to consider seriously non-chemical/ organic methods for olive production as the best economic and environmental alternative.

Effects of the foliar application of methanol on the yield and growth of rice (Oryza sativa cv. Shiroudi). Cien. Inv. Agr. 43(1):17-24. Approximately two decades have passed since it was reported that the foliar application of methanol increased plant biomass and yield. Many subsequent reports have been published concerning the ability or inability to reproduce these initial observations. To evaluate the effect of methanol on rice (Oryza sativa cv. Shiroudi) yield and rice components, a field experiment was conducted at the Tonekabon Rice Research Station in Iran in 2012 and 2013. The experiment had a randomized complete block design (RCBD) with three replicates. The plants were treated with aqueous methanol solutions (0, 6, 12, 18, and 24% (v/v)). Methanol was sprayed on the rice foliage three times during the experimental period at two-week intervals. The results indicated that, in general, the methanol did not affect rice growth or yield and seemed to be ineffective as a growth enhancer, so foliar spraying of aqueous methanol cannot be recommended for rice. The negative results could be due to the absence of Methylobacterium sp. or that the effects are cultivar-specific because positive effects on the growth and yield of rice have been reported in other cultivars. Efectos de la aplicación foliar de metanol en el rendimiento y el crecimiento de arroz (Oryza sativa cv. Shiroudi). Cien. Inv. Agr. 43(1):17-24. Hace aproximadamente dos décadas se informó que la aplicación foliar de metanol produce aumento de la biomasa y el rendimiento de las plantas. Desde entonces, muchos informes han sido publicados describiendo la capacidad o incapacidad de reproducir estas observaciones iniciales. Con el fin de evaluar el efecto de metanol en el arroz (Oryza sativa cv. Shiroudi) en el rendimiento y sus componentes, se desarrolló un experimento de campo en la Estación de Investigación del Arroz de Tonekabon, Irán, durante 2012 y 2013. El diseño estadístico usado fue de bloques completamente aleatorios (DBCA), con tres repeticiones. Los tratamientos estudiados fueron soluciones acuosas de metanol (0, 6, 12, 18 y 24% (v / v)). El metanol se pulverizó sobre partes de follaje de arroz tres veces durante su período de crecimiento, con intervalos de dos semanas. Los resultados de estos experimentos indicaron que, en general, el metanol no afectó el crecimiento y el rendimiento del arroz y, por lo tanto, parecía ser ineficaz como un promotor de crecimiento, en cambio, no se pueden recomendar pulverizaciones foliares de metanol acuoso para el arroz. Esto podría ser debido a la ausencia del Methylobacterium sp. o que el cultivar no ha sido adecuada, ya que otros cultivares de arroz se produce un efecto positivo en el crecimiento y rendimiento de arroz. Se otorgan mayores comentarios en las conclusiones finales del estudio.

Field experiment was conducted at Agricultural and Natural Resources Research Center of Golestan Province, Iran, to determine the effects of tillage system and weed management regime on yield and weed populations in soybean ( Glycin max L.). The experimental design was a split plot where the whole plot portion was a randomized complete block with three replicates. Main plots were tillage system: 1- No-till row crop seeding, 2- No-till seed drilling, 3- Tillage with disc harrow and drill planting, 4- Tillage with chisel packer and drill planting. The subplots were weed management regimes: 1-Weed control with herbicide application, 2- Hand weeding, 3- Herbicide application plus hand weeding, and 4- Non-weeding. Results indicated that the main effects of tillage system and weed management regime were significant for seed yield, pod number per plant, seed number per pod, weed density and biomass, while their interaction were significant only for weed density, weed biomass, and seed number per pod. The highest grain yields (3838 kg ha-1) were recorded for No-till row crop seeding. The highest seed yield (3877 kg ha-1) also was recorded for weed control with herbicide and hand weeding treatment, followed by hand weeding (3379 kg ha-1). O experimento foi conduzido no Centro de Pesquisa Agrícola e de Recursos Naturais da Província de Golestan, Irã, para determinar os efeitos do sistema de plantio direto e regime de manejo de plantas invasoras sobre as populações de plantas invasoras em cultivo de soja ( Glycin max L.). O delineamento experimental foi em parcelas subdivididas, em blocos casualizados com três repetições. As parcelas principais foram nos seguintes sistema de plantio direto: 1- Semeadura direta em linha, 2- Plantio direto de sementeira, 3- Plantio direto com grade de disco e plantio em cova, 4- Plantio direto com cinzel e plantio em cova. As subparcelas foram dos seguintes regimes de controle de plantas invasoras: 1- Aplicação de herbicida, 2- Capina manual, 3- Aplicação de herbicida e capina manual, 4- Sem controle químico e sem capina manual. Os resultados indicaram que os principais efeitos do sistema de plantio direto e do regime de manejo de plantas daninhas foram significativos para a produção de sementes, número de vagens por planta, número de sementes por vagem, densidade e biomassa de plantas invasoras, enquanto as interações dos tratamentos foram significativas apenas para densidade de plantas invasoras, biomassa de plantas invasoras e número de sementes por vagem. As maiores produções de grãos (3838 kg ha-1) foram registrados para semeadura direta em linha. O maior rendimento de sementes (3877 kg ha-1) foi observado para o tratamento de controle de plantas invasoras com herbicidas e capina manual, seguido por capina manual (3379 kg ha-1).

espanolEL objetivo de este trabajo fue evaluar el efecto de la aplicacion de fosfato con una fuente quimica y bio-fertilizante en el crecimiento y rendimiento de judias (Phaseolus vulgaris L.). El experimento se realizo en Khomam, provincia Guilan, al norte de Iran. El diseno experimental fue de bloques completos al azar con arreglo factorial 5X2 con cuatro repeticiones. Los tratamientos fueron aplicacion de fosforo en dosis de 0, 25, 50, 75, y 100 kg ha-1 como superfosfato triple y aplicacion de fosfato bio-fertilizante con semillas inoculadas con Pseudomonas fluorescens y semillas no inoculadas (control). Los resultados indican que la aplicacion de SPT y bio-fertilizantes afecta significativamente la altura de la planta, el numero de vainas por planta, rendimiento y la concentracion de N y P en vainas. Las relaciones entre dosis de fertilizantes fosfatado y bio-fertilizante se expresaron con ecuaciones lineales. Independientemente de la aplicacion de bio-fertilizantes, el numero de vainas aumento significativamente de 55 a 85 vainas por planta cuando la aplicacion de P aumento de 0 a 100 kg ha-1. El rendimiento de vainas aumento a mayor dosis de P de 0 a 100 kg ha-1. El numero de vainas y rendimiento fue significativamente mayor en las parcelas inoculadas con bio-fertilizantes en comparacion con el control, para todas las dosis de fosfato. El numero de vainas por planta y rendimiento se incremento en un 16% y 15%, respectivamente, cuando se aplico bio-fertilizante. Los resultados sugieren que la aplicacion de P en dosis de 100 kg ha-1 y la aplicacion de bio-fertilizante es recomendable para obtener mayor rendimiento de vaina en judias. EnglishA field experiment was conducted at Khomam, Guilan province, northern Iran, to evaluate the effects of phosphorus rate and phosphate bio-fertilizer on growth and yield of green bean (Phaseolus vulgaris L.). The experimental design was a factorial arrangement of treatments based on a randomized complete block with four replicates. Factors were phosphorus fertilizer rates (0, 25, 50, 75, and 100 kg ha-1 as triple superphosphate) and phosphate bio-fertilizer application (seed inoculated with phosphate bio-fertilizer containing Pseudomonas fluorescens strain P5 and strain p13, and non-inoculated (control). Analysis of variance showed that phosphorus rate and phosphate bio-fertilizer had significant effect on plant height, pod number per plant, pod yield and pod N and P concentration. The relationships between phosphorus application rate and pod number per plant and pod yield were well expressed by linear equations. Regardless of phosphate bio-fertilizer application, pod number per plant was significantly increased from 55 to 85 pods per plant as P application rate increased from 0 to 100 kg ha-1. Similarly, pod yield increased linearly with increasing P application rate from 0 to 100 kg ha-1. Regardless of phosphorus rate, pod number per plant and pod yield were significantly higher in plots that received phosphate bio-fertilizer compared to control plots. Pod number per plant and pod yield increased by 16% and 15%, respectively, when phosphate bio-fertilizer was applied. Based on the results of this experiment, P application at the rate of 100 kg ha-1 along with phosphate bio-fertilizer are recommended for obtaining the greatest pod yield in green bean.

espanolEl crecimiento vegetativo y la produccion de cultivos C3 se estimulan por la aplicacion foliar de metanol y mejoran la eficiencia del uso total de agua. El objetivo de este trabajo fue evaluar el efecto de la aplicacion foliar con metanol y la densidad de las pasto dentado en el rendimiento de arroz (Oryza sativa cv. Shiroudi). El experimento se realizo en la Estacion Experimental del Arroz de Tonekabon, Iran en 2012. El diseno experimental fue de bloques completos al azar con un arreglo factorial 5X4, con tres repeticiones. Los factores estudiados fueron soluciones acuosas de metanol en concentraciones de 0, 6, 12, 18 y 24% (v/v) y densidades del pasto dentado (Echinochloa crus-galli) de 0, 16, 24 y 32 plantas m-2.. El metanol se aplico sobre el follaje de arroz cada dos semanas durante su periodo de crecimiento. Los resultados indican que el rendimiento del grano fue afectado por la aplicacion de metanol (P EnglishRecent reports indicate that vegetative growth and yield of C3 crops are enhanced by foliar methanol application and that overall crop water use is reduced by methanol sprays. In order to evaluate the effects of methanol and barnyard grass density on rice (Oryza sativa cv. Shiroudi) yield and its components, a field experiment was conducted at the Rice Research Station of Tonekabon, Iran in 2012. The experiment was carried out as a randomized complete block design with a factorial arrangement in three replicates. Studied factors were aqueous methanol solutions (0, 6, 12, 18 and 24% (v/v)) and barnyard grass (Echinochloa crus-galli) densities (0, 16, 24 and 32 plants m-2). Methanol was sprayed on the foliage of rice three times during its growth period with two-week intervals. Results indicated that effect of methanol was significant for tiller number and grain yield (P