فهرست مطالب soheila dastborhan

The aim of this study was the determine effects of nitrogen fertilizer sources (biological, chemical and integrated) and weed interference on the yield and yield components of chickpea cultivars in Khorramabad conditions.

The experiment was conducted as split-split-plot based on randomized complete block design with three replications at the Experimental Farm of Pole Baba Hossein, Khorramabad during the 2017-2018 growing season. Nitrogen fertilizer as main factor (control (without fertilizer), Rhizobium bio-fertilizer, 100% required chemical fertilizer and integration of Rhizobium + 50% nitrogen chemical fertilizer), chickpea cultivars (Adel, Mansour and Arman) as sub-factor and weed interference (weed control and full-season weed interference) as sub-sub-factor were considered.

The effect of nitrogen fertilizer (especially integration of Rhizobium + 50% nitrogen chemical fertilizer) on all evaluated traits was positive and significant. The mean comparisons of cultivar × fertilizer showed that the highest number of pods with one seed, number of pods per plant, number of seeds per plant, straw yield and grain yield were achieved by Arman cultivar and with integrated application Rhizobium + 50% nitrogen chemical fertilizer. In weed control conditions, the highest plant height, number of pods with one seed, number of pods per plant and grain yield was related to Arman cultivar.

Arman cultivar can be considered as the best cultivar in Khorramabad climate conditions. Seeds inoculation with Rhizobium along with consuming 50% of the required nitrogen fertilizer and weeds control can significantly increase the yield of chickpea cultivars.

Intercropping is one of the most common practices used in sustainable agricultural systems which have an important role in increasing the productivity and stability of yield in order to improve resource utilization and environmental factors. Intercropping is an option for reducing weed problems through non-chemical methods. Dragon’s head (Lallemantia iberica Fish. et Mey.) is an annual herb from the Lamiaceae family. This plant mainly cultivated for its grains that contain about 30% (even 35-38%) siccative oil with iodine value between 163 and 203, which is used in foods, but especially in dye and varnish industry. Despite the positive effects of intercropping on weed control and the increment in crop yield and the very important role of dragon’s head in sustainable agriculture in arid and semi-arid regions of Iran, information on the effects of these factors on this medicinal plant is scarce. Therefore, in this research, the effect of cumin-dragon’s head additive intercropping in the improvement of the dragon’s head yield and weed control was investigated.

To evaluate the effect of cumin and dragon’s head additive intercropping on weed control and yield of dragon’s head, a factorial experiment based on a randomized complete block design with three replications was carried out at the Research Farm of the Faculty of Agriculture, University of Tabriz, Iran in 2014. Treatments were two levels of weed control (complete control and no weed control) and sole cropping of two crops as well as three additive intercropping ratios including of 100% cumin + 20% dragon’s head, 100% cumin + 40% dragon’s head, 100% cumin + 60% dragon’s head. At the maturity time, plants of 1 m2 in the middle part of each plot were harvested and biological yield, grain yield per unit area as well as harvest index of dragon’s head were determined. Land equivalent ratio (LER) and relative value total (RVT) were used to quantify the efficiency of the intercropping treatments.Data were analyzed by MSTAT-C requires and SPSS 16 softwares and the means were compared using Duncan multiple range tests at p ≤ 0.05. Excel software was used to draw figures.

The effect of planting pattern was significant on the dry weight of weeds. Intercropping of 100% cumin + 20% dragon’s head had the lowest weed biomass. The highest biological and grain yields of dragon’s head under weedy and weed-free conditions were obtained from the monoculture of the dragon’s head. However, among different intercropping treatments, the highest biological and grain yields of dragon’s head were related to 100% cumin + 60% dragon’s head in both conditions of weed treatment. The maximum harvest index was also recorded for monoculture of dragon’s head under weed-free conditions. The land equivalent ratio was more than 1 in intercropping patterns (LER>1) that shows the positive effect of intercropping on yield. Although weed biomass in 100% cumin + 60% dragon’s was higher than that other planting patterns, the maximum LER (1.42) based on seed yield were observed in this planting system under weedy condition. In weed-free conditions, increasing of dragon’s head density reduced LER, while in the weedy conditions, the increment in dragon’s head density was associated with improved LER, indicating the higher efficiency of intercropping of these two plants under no weed control conditions.

The results of this research showed that the combination of 100% cumin + 60% dragon’s head, especially under weedy condition, was the superior treatment, because of the highest land equivalent ratio (1.42). In general, intercropping of cumin and dragon’s head, especially 100% cumin + 60% dragon’s head, is recommended for the creation of variety and production stability and increasing land-use efficiency under weedy condition.

In order to evaluate seed germination, seedling emergence and changes in growth indices of borage in response to seed priming and water limitation, laboratory tests were laid out as completely randomized design with four replicates and field experiment was carried out as split plot based on randomized complete block design with three replications in 2012. Irrigation treatments (I1, I2, I3 and I4: irrigation after 60, 90, 120 and 150 mm evaporation from class A pan, respectively) and seed priming methods (P0: unprimed, P1: hydro-priming, P2: priming with 100 mM KNO3, P3: priming with 100 mM KH2PO4 for 8 h at 15±1°C) were allocated to main and sub plots, respectively. Results indicated that seed hydro-priming increased germination rate and seedling dry weight of borage by 15.9% and 22.6%, respectively. Emergence rate of borage seedlings was also improved about 7% under different seed treatments. At vegetative stage, leaf area index of plants from seeds primed with water, KNO3 and KH2PO4 was 22.8, 39.7 and 16.1% higher than that of unprimed seeds. At flowering stage, water loss of the plants decreased under water deficit conditions by reducing the leaf area index. All priming techniques, especially hydro-priming, improved leaf area index, particularly under well watering, through increasing seedling emergence rate. Dry matter accumulation, relative growth rate and crop growth rate decreased with increasing irrigation intervals. However, growth duration of plants from primed seeds was longer than those from unprimed seeds, leading to the production of larger plants under well watering.

The effect of different interference and weed control period on morphological traits, yield components, oil and mucilage contents of Dragon’s head, studied by field experimental based on randomized complete block design with three replicates and 15 treatments at the Agricultural Research Station, University of Tabriz. The treatments were six periods of weed interference, six periods of weed control, weed free and weed infected during the growing season and, pure weed (without crop). The results indicated that weed dry weight significantly increased with increasing duration of infection and decreasing weed free period. Number of leaves per plant, plant height, number of capsules and seeds, 1000-seed weight, biological and grain yield reduced with increasing weed interference period. Among the yield components, number of seeds per plants decreased by 46.8% related to weed free control and so it was the most sensitive component. The effect of treatments on percentage and yield of essential oil and seed mucilage was not significant. Weed infested control with 1200 kg.ha-1 and weed free control with 2289 kg.ha-1 had the lowest and the highest grain yield, respectively. Evaluation of Dragon’s head performance under weedy conditions with 1200 kg.ha-1 grain yield indicated the high competitive potential of medicinal plant of Dragon’s head in front of natural weeds of field. This capability embosses success of this plant in competition with weeds accompanied by acceptable level of grain yield.

Nutrients management, especially nitrogen, influences the weed-crop competition. Thus, to evaluate the effect of nitrogen and weed interference on yield and yield components of winter barley (Hordeum vulgare L. Var. Makoei), a field experiment was arranged as split-plot based on randomized complete block design with three replications at the Research Farm of the Faculty of Agriculture, University of Tabriz, Iran. The treatments included four levels of nitrogen (0, 40, 60 and 120 kg ha-1) and 10 weed interference periods in two sets (weed free and weed infested periods), that allocated to the main and subplots, respectively. Results indicated that increasing nitrogen supply increased spikes per area, grain and biological yields and decreased grain number per spike. Weed interference had significant effect on number of spike per m2, grain number per spike, and grain and biological yields. Increasing duration of weed interference led to significant decrease of spikes per m2, biological and grain yields of barley. Based on the results of this research, spike number per m2 was the most sensitive yield component of barley to nitrogen deficiency and weeds interference. Generally, by application of nitrogen up to 80 kg ha-1 and better weeds management by reducing duration of weed interference in barely, high performance in this crop can be obtained in similar conditions.

Salicylic acid (SA) is a phyto-hormone that regulates physiological and biological processes in plants and can be used to improve plant growth under different environmental conditions, including water stress. Thus, a field experiment as split plot factorial based on randomized complete blocks design with three replications was conducted in 2014 to investigate the effects of fertilizer and salicylic acid on growth, chlorophyll content and grain yield of coriander (Coriandrum sativum L.) plants under drought stress. Treatments were three levels of water supply (irrigation after 60, 90 and 120 mm evaporation from class A pan) and four levels of fertilizer application (control, 100 kg ha-1 Urea, Nitrokara (biofertilizer) and 50% Urea + Nitrokara) and foliar spray of salicylic acid (0 and 1 mM). Results indicated that water deficit had a significant reduction effect on leaf area, chlorophyll content, fresh weight of root and leaf and grain yield. Salicylic acid and 50% Urea + Nitrokara resulted in a significant increase of all traits under stress and well watering conditions. Although highest amount of studied traits was observed in plants treated with SA or application of 50% Urea and Nitrokara under well watering, but the changes rate was higher under stress conditions. Therefore, salicylic acid and combination of urea and Nitrokara can be used to promote growth of coriander under different water availabilities, which ultimately can enhance field performance of this plant.