mohammad hasan rashed mohasel

Purslane (Portulaca oleracea L.) is an annual and C4 plant that belongs to the family of Portulacaceae. The plant is drought- and salt-tolerant which contains high amounts of beneficial omega-3 fatty acids and antioxidant vitamins. Nitrogen is the key element in soil fertility and crop production. Attention to the soil quality and health has increased in recent years, especially for sustainable production of medicinal crops. So that, for production of healthy food in industrialized countries, using natural and on-farm inputs has been considered. One of the practical ways to achieve this goal is organic and biofertilizers. Given the importance of Purslane as a medicinal plant and due to the fact that there is not detailed information about the nitrogen requirement for this plant, this study was conducted to effect of organic, biological and chemical fertilizers on yield,  N and P use efficiency Purslane (Portulaca oleracea L.) in Birjand, Iran 

In order to investigate the effect of organic, biological and chemical fertilizers on the yield and yield components of purslane seed, an experiment was conducted in a factorial randomized complete block design with three replications in Birjand University Research Farm in crop years 2015-2016 and 2017- 2018. Experimental treatments were based on a combination of four sources of nitrogen supply: cow manure, vermicompost, fertilizer (NPK) and control (without any fertilizer application), and four types of biofertilizer including: nitroxin (including azotobacter and azospirillum), mycorrhiza (Glomus intraradices), Biosulfur (including thiobacillus with sulfur) and control (without any fertilizer). The traits studied in this experiment included: biomass yield, grain yield, nitrogen and phosphorus biomass percentage, nitrogen and phosphorus biomass content, nitrogen and phosphorus uptake efficiency, seed based nitrogen and phosphorus uptake efficiency, agronomic efficiency of nitrogen and phosphorus based They were. 

The results showed that the effect of nitrogen sources on all studied traits (except physiological grain nitrogen efficiency) was significant. The highest grain yield (1959.99 kg.ha-1) and biomass yield (9782.43 kg.ha-1) were obtained from NPK treatment with no significant difference with cow manure. Also, the most nitrogen efficiency indices were obtained from NPK treatment. However, no significant difference was observed between agronomic efficiency of grain and cow manure. The highest phosphorus content and biomass phosphorus content were obtained from NPK treatment. However, with the use of organic and chemical fertilizers, the efficiency of phosphorus use decreased. The effect of biofertilizers on most of the studied traits (except biomass P percent) was not significant. Interaction of nitrogen sources and biofertilizers was significant on most of the studied traits (except grain yield, agronomic efficiency of N and P). 

Based on the results of this experiment, considering the environmental effects and increasing the efficiency of nitrogen use for sustainable production of purslane seed in Birjand region can be used as fertilizer replacement (NPK).

To investigate the effects of summer cultivation of crops on weeds densities and biomass as well as yield and performance of following planted wheat, field studies were carried out in Shavoor Research Station (Ahvaz, Khuzestan) over 3 years (2013-2016) using 5 treatments in a randomized complete block design. Treatments included rice-wheat, corn-wheat, sesame-wheat, mung bean-wheat and fallow-wheat rotations. The crops and weed densities and types had been observed during the year before the experiment, and no herbicides were used in all experiments to understand the pure effects of treatments. The main crop (wheat) was planted after autumn harvesting of above-mentioned crops. Densities and types of weeds were recorded 15 and 30 days after wheat primary tillering stage, and weed dry weights and grain yield were measured at the end of experiment. Results of this study indicated that considering the indices of weeds number and biomass (55-90%) as well as wheat yield (80-220%), wheat might not require to any herbicides after rice cultivation. Moreover, in the grain or forage corn planted fields, herbicide application is declined significantly, due to several and irrigations and frequent tillage. The whole three-years outcome of the experiments demonstrated that summer cultivation of crops might lead to sharp decline in the seed banks of important weeds such as wild oat (Avena ludoviciana), wild barley (Hordeum spantaneum) and some main broad leaf weed.

In order to study the seed germination and dormancy of three weed species (Chenopodium album, Convolvulus arvensis and Setariaviridis) of pistachio orchards in Rafsanjan, Iran, three separate factorial experiments (with 2 factors) were conducted based on a completely randomized design with four replications, at the faculty of agriculture, Vali-E-Asr university of Rafsanjan, Iran, in 2014. Weed seeds were collected from five different regions of Rafsanjan, including Markazi, Anar, Koshkoiyeh, Kabotarkhan and Nogh. Dormancy breaking treatments for Chenopodium album included distilled water (control), KNO3 (at 500 and 1000 ppm), chemical scarification by sulfuric acid (for 5 and 10 min), and cold stratification (for 1, 3 and 5 weeks). Treatments for Convolvulus arvensis included distilled water (control), scarification by sandpaper, chemical scarification by sulfuric acid (20 and 30 min), and boiling water (for 15 and 30 min). Treatments for Setaria viridis included distilled water (control), gibbereilic acid (250, 500 and 1000 ppm), KNO3 (500 and 1000 ppm), and cold stratification (for 1, 3 and 5 weeks). Results showed that seed germination percentage (SGP) and mean germination time (MGT) of three weed species were significantly different among weed populations and dormancy breaking methods. For Chenopodium album, 5 weeks cold stratification resulted in highest SGP (97%) in Nogh population. For Convolvulus arvensis and Setaria viridis, highest SGP obtained after scarification by sandpaper (98% in Kabotarkhan population), and using 1000 ppm gibbereilic acid (60% in Kabotarkhan population), respectively. Also, SGP increased as increasing 1000 seed weight in three weed species.

This study was conducted to investigate the efficiency of three artificial neural network algorithms employed to identify seeds of 20 weed species from their scanned images. A total of 15 features related to seed shape and size were extracted from the images using an image-editing program these image-extracted data were fed as inputs into three neural networks of Multilayer perceptron (MLP), RBF/GRNN/PNN Network and Generalized Feed Forward (GFF) neural network employed for seed identification purposes. RBF/GRNN/PNN network is a combined network of Radial Basic Function (RBF), General Regression Neural Network (GRNN) and Probabilistic Neural Network (PNN). After the training stage, each network was tested. The results of testing stage indicated that Generalized Feed Forward network had the highest identification accuracy (90%). This network was able to identify 8 out of twenty species by 100% accuracy. The least seed identification accuracy, using this network, was 52%. The accuracy of RBF/GRNN/PNN network was found to be 61% and this network could accurately identify only 4 species with 100% accuracy. The least precision percentage using this network was zero. The Multilayer perceptron network with 71% identification accuracy had an intermediate efficiency among the three networks. The overall results showed that GFF had the highest efficiency in identifying the studied weed seeds among the three networks.

This research was carried out to investigate the population structure of the plant flora of weeds in two different microclimates. To perform this experiment, two pieces of lands located in Mashhad, with dimensions of 95 × 20 m were selected; one of them was an abandoned agricultural land and the other was an abandoned garden. Both areas were without maintenance for about 8 years but the garden was irrigated just for grazing sheeps and goats. Sample taking from intersections of regular grids of 5 × 5 m by 1 × 1 m quadrates was conducted. After fitting the theoretical models of empirical variogram with interpolation of points, the maps of the species were drawn. To study the vegetative cover in both regions the α and β diversity indicators, the relative frequency, species richness, uniformity, Shanon-Veiwer and Simpson indices, and also similarity indicators, Ashtyn house, Jaccard and Sorenson similarity coefficient was determined. Totally 35 species which were belonged to 12 plant families were found, 15 species of which were found in the abandoned agricultural land but Alhagi pseudalhaji and two species of Lactuca genus were common in both lands. In the survey conducted, 31 species were dicots and 4 species were monocots. Climate conditions causes that in each region ecotype of plant species vary in terms of the number and families, thus effects on the diversity and distribution in the region.

To study weed species diversity and community structure in wheat fields of Khorasan province, a four-year field trial was conducted from 2003-2006 in Khorasan province, Iran. during jointing stage to heading stage of wheat. Density, frequency and homogeneity of weed species in 5-10 randomly dropped 0.5×0.5 quadrates in 259 fields of 21 cities were determined. Data were analyzed by principal component analysis and clustered by hierarchical complete linkage method. The results showed that weeds of wheat fields were belong to 26 families and 120 species. The majority of weed species were of Asteraceae (20 species) and Poaceae (25 species) amongst dicotyledonous and monocotyledonous, respectively. Nishabour and Nehbandan had the most and the least diversity by 52 and 4 species respectively. Mashhad and Quochan showed the highest similarity index (70%) for weed diversity. Esfarayen had the highest shanon-weiner (2.93) and simpson (1) indices between the cities. however, Nehbandan had the lowest shanon-weiner (0.57) and simpson (0.71) indices. Biplot of the first two principal components (covered 61.4%, and 24.8% of variances, respectively) showed that weed homogeneity and frequency had more correlation with each other than weed density. By considering 75% similarity, cities were grouped in two clusters for weed density, homogeneity and frequency in wheat fields. Nehbandan was located in one cluster and the rest of the cities were placed in another. Nehbandan had low weed density compare to the other cities because of the warm and dry climatic conditions.

For increasing the effectiveness of weed management and more understanding of weed population dynamics, spatial distribution needs to more attentions. Infestation levels and spatial distributions of Amaranthus blitoides, Chenopodium album and Solanum nigrum were studied in four 10x30 m corn fields. N-fertilizer was applied in two method of whole application at the time of corn planting (T1 and T2) and equal split application at the time of corn planting and at six-leaf stage (T3 and T4). One of either fields with the same method of N-fertilizer application, received herbicide too (T1 and T3). Weeds Samples were taken four times at the intersection of 2.5m square grids with 23days interval. The first sample was taken June 24, before top-dressing and herbicide application in related plots. For studying weed spatial distribution, the parameters of appropriate semivariogram model were calculated and weed contour maps were constructed by using kriging. The weed semivariograms fitted spherical and exponential models, over four sampling times and fields and spatial autocorrelation during growing season, was moderate to strong. In early growing season, Amaranthus blitoides was the dominant weed species in all fields, but lower density was recorded for Chenopodium album and Solanum nigrum. At the first sampling time, mean density of A. blitoides and S. nigrum in fields with split application of N-fertilizer was respectively more- and less than fields with whole application of N-fertilizer. In the case of C. album an evident difference wasn’t observed. Herbicide application in related plots considerably reduced the density of three mentioned species; however density never became zero. In the majority of cases the lack of herbicide application causes to increase in population density at the second sampling time. Spatial structure was observed in all three species and study on contour maps confirmed the existence of patches that the density was high in their center, but decreasing gradually toward edges. In general, despite of some displacement, structure and location of patches were kept and possibly these places were the locations for weed emergence in next year. So site-specific herbicide application and exploitation of its advantages may be possible; however, more researches are necessary.

The exotic plant, Swallow- wort, a twining perennial of the Milkweed family, has become increasingly invasive in some place of Iran, especially orchards. Increased knowledge of wort germination biology would facilitate development of an optimum control program. Germination of Swallow wort seeds as affected by environmental factors was studied under controlled-environment growth chamber conditions. The following studies were conducted in plant Pests & Diseases Research Institute during the years 2003-4: 1- Effect of constant temperature on germination that including 10, 15, 18, 20, 25, 30, 35 and 40˚C; 2- Effect of light on constant germination; 3- Effect of temperature fluctuations on seed germination: 15/7, 20/12, 25/17 and 30/22˚C. All experiments were conducted with 8 replications. Swallow wort seeds showed no dormancy when detachment from mother plant. Seed germination was strongly influenced by temperature. Light did not play a crucial role on seed germination of this weed. Therefore Swallow wort seeds were not photoblastic and temperature fluctuations did not increase seed germination of Swallow wort. The above characteristics are very important in making swallowwort an invasive weed. Having precise information of these traits enables us to a better management and control of this troublesome weed.

Interest has increased towards hemp (Cannabis sativa L.) fibre production due to renewed demand for natural fibre in the world. A Study was conducted in 2005 at Shirvan in Northern Khorasan province, Iran, to determine the effects of three plant populations (30, 90 and 150 plant per m2) and three rates of nitrogen application (50, 150 and 250 kg N per ha) on final stand, stalk height, basal stalk diameter, total stalk yield as well as fibre content from stalk and fibre yield in male and female plants. A split plot experimental with three replications was used. The result indicated that due to enhanced competition for light at higher population on density and N2 level plant mortality was higher than other treatment Morphological characteristics were highly correlated with plant sexual, plant population and nitrogen fertilizer. Highest stem, leaf and inflorescence yield were obtained at 250 plant m-2 when 150 kg N ha-1 was used. Lowest plant density did not show self-thinning but reduced above ground dry matter. Shoot dry matter increased with increasing plant density and nitrogen supply. Apparently, fibre content was greater at medium density and lowest nitrogen fertilizer, however, fibre yield was greatest at highest plant population and nitrogen fertilizer. In terms of fibre yield, approximate 31.7% of the fibre was located in the bottom parts, 22.4% in the middle and only 9.9% in the top part of the stem. The results suggest that hemp can yield large quantities of useful fibre at Shirvan when planted in proper plant densities and suitable nitrogen fertilize

In order to examine the effect of desiccation and freezing on Russian knapweed,s (Acroptilon repens) root regrowth, two experiments on basis of completely randomized design were conducted in Weed Research Department, Plant Pests and Diseases Research Institute of Tehran in 2003.To examine the effect of desiccation, the first experiment was a factorial arrangement with 4 replications. First factor (A) was desiccation length time (control, 24, 48, 96 and 192 hours), and second factor (B) was desiccation temperatures (5, 15 and 25˚C). To examine the effect of freezing, second experiment was also a factorial arrangement with 4 replications. First factor (A) was the freezing length time (control, 24, 48 and 96 hours) and second factor (B) was freezing temperatures (-1, -3 and -5˚C). In the effect of desiccation experiment on root regrowth, factors A and B were significant on all of measured characters (water loss percent, shoot numbers, dry weight, leaf number and shoot length). Increasing in temperature and length time of desiccation, leads to low regrowth. The interaction effect (AB) on water loss percent, shoot number and shoot length was significant. Regrowth stopped in 5˚C after 96 hours desiccation and in 15˚C and 25˚C after 24 hours. In freezing experiment, factors (A), (b) and their interaction were significant on all of measured characters (shoot number, leaf number and shoot length).Decreasing in temperature and increasing of freezing length time, leads to low regrowth. Regrowth reduced in -1˚C after 96, 48 and 24 hours respectively. But stopped in -3˚C and -5˚C after 48 and 24 hours freezing, respectively.

To study the effect of plant density on growth indices of four grain sorghum cultivars an experiment was conducted as factorial based on Compelete Randomized Block Design with 3 replications at Experimental Field of Birjand Azad University in 2003 growing season. In this study 4 grain sorghum cultivars including Sepideh, Saravan local, Payam and Kimia and 3 plant densities 100000, 180000 and 260000 plant/ha were investigated. The results showed superiority of Saravan local compare to other cultivars because of having maximum total dry matter, leaf area index, crop growth rate, relative growth rate, and net assimilation rate. The highest amount of leaf area ratio and specific leaf area were in Kimia and Payam cultivars, respectively. All of the above mentioned growth parameters were increased by increasing population denseity with exception of relative growth rate and net assimilation rate. From the obtained results Saravan local cultivar in density of 260000 plant /ha had the highest grain yield. The maximum relative growth rate and net assimilation rate were obtained in lowest density.

In recent years, allelopathy has received special attention by scientists in integrated weed management (IWM). To study the effect of different amount of Knotweed residue on emergence and growth of tomato and corn seedlings, two experiments were conducted at Ferdowsi University of Mashhad. The type of design was completely randomized, with 5 and 4 replications for tomato and corn, respectively. The Knotweed residues (zero, 0.33, 0.67, 1 and 1.33 %(W/W) were added to the pot soil. Seedlings showed different response to different amount of Knotweed residues. Increasing residues increased the emergence percentage of tomato but decreased corn emergence. Increasing residues resulted in increasing 33.9% and 39.3% of leaf area in tomato and corn, respectively. Knotweed residues resulted in 36.5% and 46.7% increase in shoot dry matter of tomato and corn, respectively. Increasing dry matter resulted in increasing up to 67.2% and 54.5% root dry matter of tomato and corn, respectively. Different doses of Knotweed had stimulatory effect on emergence of tomato but had inhibiting effect on corn. Knotweed residues had stimulating effect on seedling growth of corn and tomato. Root dry matters of both species were more influenced by Knotweed residue than foliage.

In order to study different of velvetleaf (Abutilon theophrasti Medicus) and simultaneous planting date of (Glisine max (L.) Merril) and velvetleaf on yield and yield components of soybean, an experiment was conducted in 2004, at Ferdowsi University of Mashhad, College of Agriculture Experimental Station. The type of experiment was Completely Randomized Design in factorial arrangement with 3 replication in witch velvetleaf density (0, 2, 4, 8, plan/m2) and planting date of soybean and velvetleaf at 3 levels(April 23, May 13 and June 3) were used. Study of grain yield and yield components indicated that increase in velvetleaf density due to significant decrease in pod and grain number of soybean plant caused significant reduction of grain yield. Different planting dates had significant effect on yield and all yield components and delaying planting date, resulted in a significant reduction of yield components and yield. The interaction between density and planting date, was based on number of pod in plant and number of grain in soybean pod but significant effects on grain number per plant, 1000 grain weight and grain yield of soybean.

In order to study the effects of plant density on yield, yield components protein in four grain sorghum varieties an experiment was conducted as factorial based on compeletely randomized block design with three replications in Research Field of Birjand Azad University at year 2003. In this study four varieties including “Sepideh, Saravan local, Payam and Kimia, , and 3 plant densities 100000, 180000 and 260000 plant / ha were investigated. The results indicated that varieties were significantly different for grain yield, protein yield, biological yield, number of seeds per panicle, 1000 kernel weight, harvest index and protein percentage. The highest grain yield, protein yield, biological yield, number of seeds per panicle and 1000 kernel weight were observed in Saravan local and the highest harvest index was belong to Sepideh and the highest protein percentage was in Kimia. Characteristics such as grain yield, protein yield, biological yield and number of seeds per panicle were affected by density. By increaseing of plant density grian yield, protein yield, biological yield increased but seed number per panicle decreased 1000 kernel weigth, harvest index and protein percentage did not affect by density. Also interaction between variety and density was significant on seed number per panicle. According to the results of this experiment, Saravan in 260000 plant / ha density is recommended for maximum grain yield and protein yield.

Effect of 13 planting depths and 6 flooding periods on germination and emergence of swallow wort were investigated under greenhouse conditions. Results showed that swallow wort seeds emerged from up to 6 cm depth. The highest emergence occurred in the first, second, third and fourth week after emergence from 0.5 cm; 0.5, 1 and 1.5 cm; 1.5 cm; and 1.5 cm planting depth, respectively. At the end of the fourth week, 6.5 cm depth treatment had zero emergence. Increasing burial depth resulted in induced secondary dormancy. Increasing flooding period, did not affect germination percentage. However, fresh weight, radicle and hypocotyle lengths under flooding conditions were decreased significantly compared to control. Seeds flooded for 3 and 21 days had the highest and lowest fresh weight, respectively. Hypocotyle length was highest under zero and one day flooding treatments, but lowest under 14 days flooding treatment. Radicle length was highest under 0, 1, 3 and 7 days flooding treatments and lowest under 14 and 21 days flooding treatments.

Weed scouting is an important part of integrated weed management system. In order to evaluate weed emergence pattern and management efficiency on weed populations, a 2 ha sugarbeet field in Mashhad was selected and evaluated during 2002 growing season. Weeds were identified and counted at 441 points at the intersection of a 7m by 7m grid within 0.15 m2 quadrates. The evaluations were done 3 times [pre management (1) and post management (2)]. Geostatistical techniques (kriging) were used to analyze the spatial structure of weeds and dynamics of weed patches. 34 weed species were observed across the field. Wide ranges of weeds were observed during growing season including, winter annual (e. g. Sinapis arvensis and Fumaria officinalis), summer annual (e. g. Echinochloa crus-galli), biennial (Dacus caraota) and perennal (e. g. Convolvulus arvensis). Solanum nigrum, Chenopodium album, Amaranthus spp., Convolvulus arvensis, Polygonum aviculare and Echinochloa crus-galli were the common weeds over growing season. In early growing season, Solanum nigrum with 404.71 seedlings per m2 was present in all samples constituted 81.32% of weed community, but in 2nd and 3rd sampling time, Convolvulus arvensis was the dominant species with 33.29% and 29.26% of weed community. Relative density percentage of perennial and grassy weeds (generally C4 species) was increased over the season but the relative density percentage of broadleaf annual weeds was decreased. Main locations of weed emergence were persisted as elliptical patches east ward and west ward of field over the season. The results of this study indicated that scouting and understanding of weed emergence behavior could be used to design effective strategies of weed management.