JOURNAL OF CROP PRODUCTION RESEARCH (ENVIRONMENTAL STRESSES IN PLANT SCIENCES)
Year:2014 | Volume:5 | Issue:4|Papers Count:9

Due to investigate the efficiency of some herbicides to control cruciferous weeds in canola fields an experiment was done during 2010- 2011 in the basis of completely randomized blocks design with 4 replications and 18 treatments which included isoxaben (Cent 7 12.5% EC) at 0.45 L/ha (with and without wetting agent), trifluralin (Treflan 48% EC) at 2.5 L/ha with and without isoxaben (with and without wetting agent), Metazachlor+Quinmerac (Butisan Star 41.6%) preemergence and at cotyledon stage of canola growth at 2.2 L/ha with and without Isoxaben (with and without wetting agent), ethametsulfuron (Master 75% WG) at 20 and 30 g/ha postemergence +wetting agent with and without trifluralin butisan star or isoxaben, and weedy check. The results indicated that pre-emergence of 2.2 L/ha Butisan Star and 20 and 30 g/ha postemergence of ethametsulfuron alone or with 2.2 L/ha Butisan Star were the best treatment for broadleaf control.

Application of organic materials, such as humic acid, prevent from environmental pollution and also increases sustainability by decline the harmful impacts of industrial fertilizers in agroecosystems. In order to study the effect of different levels of foliar application of humic acid on yield and yield components of maize (Zea mays L.) an experiment was conducted at Research Station, Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, in year 2009. The experiment was conducted with different levels of humic acid (0,200, 500, 1000, 1500 and 2000 mg/l) based on a completely randomized blocks design with three replications. The results showed that different levels of humic acid impose a significant effect on leaf area index, leaf area duration, grain yield, biomass, kernel number per row and ear length, but there were no significant effects on harvest index, 1000 grain weight, ear diagonal, and rows number in ear due to humic acid application. According to the results, the highest and lowest grain yield belonged to 1000 mg/l humic acid and control treatments respectively. The highest biomass production gained in 2000 mg/l humic acid treatment, while the highest rows number and ear length gained in 1000 mg/l humic acid treatments. Generally, it seems that, application of humic acid improves maize performance and reduces environmental pollution and it could be used as an organic material to increase crop production and yield sustainability in field conditions.

A filed experiment was conducted to determine the effects of nitrogen starter fertilizer and post emergence herbicide effects on weed frequency in early season production and some agronomic traits of cotton plants, in Gorgan during 2008. Plots were arranged in factorial design based on Randomized Complete Block Design (RCBD) with four replications. First (factor A) and second (factor B) treatment factors were four levels of weed management (Early post emergence application of Methazole + Envoc in early cotton growth, late post emergence application of Methazole + Envoc in 15-20 cm cotton plant height period, early hand weeding and late hand weeding in cotton growth season) and four levels of starter fertilizer (0, 50, 100 and 150 percent of Urea starter fertilizer recommended). Cotton cultivar was Siokra which is one of the commercial Golestan province verities. The results showed that late hand weeding and herbicide application had the highest amounts of whole weed biomass after 10 day weed control levels (W1) and a month after weed control levels (W2). In this research, W1 decreasing and W2 increasing was seen when starter fertilizer levels has been added. The highest cotton yield was produced by early hand weeding and herbicide application with 3903 and 3917 kg/ha, respectively and among nitrogen fertilizer levels, 50% Urea starter recommended was gained the highest cotton yield (3897 kg/ha). The highest total cotton yield (First + second picking lint yield) has produced by early weed control levels with 50% nitrogen starter recommended (5364 kg/ha). Among yield components, the maximum and significant correlation coefficient of first picking was seen with number of boll and total cotton yield were observed with number of bolls per plant.

Silicon (Si) is the second most abundant elements in soil and increase biotic and abiotic tolerance in plants. In order to evaluate the effect of silicon on increasing tolerance to limited irrigation, an experimentas was done as factorial based on completely randomized block design with three replications at university of Zabol research farm. Experimental factors were irrigation water deficit stress (%75, %50 and 25% of field capacity) and Si spraying (0, 1 and 2 mM) at flowering stage. Limited irrigation reduced plant height, one thousand grain weight, biological yield, grain yield, harvest index, numbers of grain per capitul and chlorophyll content, while enhanced catalase and peroxidase. It's worth mentioning that drought had no significant effect on grain oil percentage. Silicon application increased plant height, one thousand grain weight, biological yield, grain yield, numbers of grain per capitula and chlorophyll content, while decreased catalase and peroxidase. Also, harvest index and grain oil percentage did not influenced by Si foliar application. These results suggested that 2 mM of Si sprying resulted in the greatest one thousand grain weight, plant height, biological and grain yield, numbers of grain per capitula and chlorophyll content.

To study the effects of superabsorbent polymer and irrigation levels on generative traits and yield of sunflower, an experiment was done as split plot based on random complete blocks design with three replications in the research agricultural and natural resources research center of Khoy in 1388-1389. The irrigation as main factor in three levels (Irrigation after 70, 105 and 140 mm evaporation from class A pan) and superabsorbent polymer (Tarawat A 200) as the sub-factor in four levels (Consumption of 100, 200, and 300 kg/ha) were considered. The results of the data variance analysis showed that the irrigation had significant impact on the treated parts. In all evaluated traits, irrigation after 70 mm evaporation was useful and highest diameter of pan, harvest index and oil yield showed 21.4cm, 45.2% and 278 g/m2 alternatively and located in the first statistical group. Regarding the meaningfulness of mutual effect of the two factors on the number of the grain in the pan, 100 grains weight and seed yield, the highest amount of the mentioned traits were attained with the different amounts of superabsorbent factors in the first level of irrigation ( After 70 mm evaporation). The exertion of drought tension and increase of irrigation intervals, led to the reduction of those features, but under the moisture tension conditions, consumption of 200 and 300kg superabsorbent polymers prevented the extreme reduction of treatment segments, and these materials, by preserving and retaining of the soil moisture and its suitable utilization, could become effective in moisture tension conditions.

In order to comparison of growth indices of different soybean cultivars, an experiment was carried out in randomized complete block design with four replicates at Dashte-Naz research farm, Sari in 2011. Three soybean cultivars JK, 033 and Telar were investigated treatments. The results showed that the most total dry matter and LAI in growth stages was observed for JK and Telar and 033 with least difference arrangement in next ranked. CGR increase flow in three cultivars was same. The CGR in soybean cultivars in early growing season has increased, then greater acceleration reached its maximum and reduced finally. The LAD amount for JK in growth period was more than other cultivars and this index for 033 in growth period compare to other cultivars was lowest. BMD for JK in growth stage was more than other cultivars and in Telar and 033 varieties with lowest difference and similar growth pattern located in the next rank. Therfore based on increase in BMD, LAI, LAD, NAR and CGR for JK, this cultivar recommend for Sari climate.

A split-plot experiment using the randomized complete block design with four replications was carried out in the field belonging to the Yadgar-e-Imam Khomeini (RAH) Shahr-e-Rey Branch, Islamic Azad University, Tehran to study the effects of nitrogen fertilizer and winter green manure cover crops on yield and yield components of corn .The treatments included the five winter green manure cover crops of barley, oats, rye, oilseed radish, and Perko in the main plots and the second factor consisted of various rates of nitrogen fertilizer application (Half the recommended rate, the complete recommended rate, and 50% more than the recommended rate) in the sub- plots.The results showed that green manure cover crops had significant effects on biomass performance, 1000 seed weight, seed yield and harvest index of corn. The maximum corn seed yields of 12557 and 11777 kg/ha belonged to the treatments of preplanting Perko and oilseed radish, respectively. Nitrogen fertilizer application significantly increased biomass, number of seeds per cob, number of seeds per row, 1000 seed weight, and seed yield of corn and raising the application rate enhanced these characteristics. However, there were no significant differences between the effects of the recommended rate and those of the 50% more than the recommended rate. The largest and the smallest seed yields of 11834.4 and 8597.8 kg/ha were obtained by applying 50% more and 50% less than the recommended rate of nitrogen fertilizer, respectively. The mutual effects of nitrogen fertilizer and cover crops on the studied characteristics were not significant.

In order to evaluate of biofertilizeres and chemical phosphorus on essence, dry matter, fresh matter and lateral stems in Thyme (Thymus vulgaris) a factorial experiment in randomized complete block design was conducted in pots in field at Shahrekord, Iran in 2012. The factors were 1-biofertilizeres contain phosphate (a), frowzy manure from mutton (b) and Nitroxin (c) (apply and no apply), 2- chemical phosphate from super phosphate triple (d) (0, 20, 40, 60 Kg/ha). The results revealed that there were significant differences among levels of factor a, b, c, d and their combinations in fresh weight, dry weight, number lateral shoots and rate of essence. Results of Duncan comparison showed that the best treatment was the application of phosphate biofertilizer + frowzy manure from mutton+ Nitroxin and 40 Kg/ha application of super phosphate triple (essence production=0.66 percentage of dry matter of plant). In the other hand, the least production of the essence and other parameters of plants made by no application of bio and chemical fertilizers (Control), the essence production in this treatment was 0.047 percentage of dry matter of plant.