JOURNAL OF CROP ECOPHYSIOLOGY
Year:2011 | Volume:3 | Issue:1|Papers Count:12

Growths of cover crops between main crops have a potential to act as an important approach in ecological weed management. To study the effect of winter cover crops on biomass, plant density and population diversity of weeds, an experiment was carried out at the research farm of Agriculture faculty, Bu-Ali Sina University, in 2009. The trial was done as a randomized complete block design with 3 replications. The experimental treatments were cover crops of rye, barley and rape seed, each one at normal and three times of normal density, with a UN weed control treatment. The results showed rye and barley with 3 times plant density produced 1503.5 and 1392.2 g/m-2, respectively were more biomass than other treatments. live mulch of rye, barley and rape seed with 3 times plant density, reduced biomass of control treatment weeds equal 788.26 g/m2 was 20.65, 27.58 and 41.72 g/m2, respectively so reduced total biomass of weeds, 97%, 96% and 94%, respectively at 230 days after planting in compared with control treatment. In addition above mentioned cover crop treatments reduced plant population of weeds, by 82%, 66% and 81%, respectively. These treatments decreased weeds species diversity of control treatment which species was 19.33 diversity/m2 to 7.66, 10.33 and 10 diversity/m2, respectively. In general, live mulch of cover crop can reduce weed competition with the main crops in the spring and it was decreased weed seed bank in the soil probability.

In order to evaluation of 18 sunflower hybrids with different growth characteristics under water deficit stress, three separate experiments were conducted as randomized completly block design with three replications at the experimental field of Seed and Plant Improvement Institute in 2006-Karaj, Iran. The first experiment conducted at optimum conditions and plants were irrigated after 60 mm evaporation from evaporation pan, whereas the second and third experiments were irrigated after 120, 180 mm evaporation from evaporation pan, class A, respectively, and those were considered as mild and sever water deficit stress. The results indicated that water deficit stress had not significant effect on days to star like stage, but caused to delaying the %75 flowering. Also, plant dry weight, seed yield, productivity effort, harvest index and oil yield decreased under water deficit stress treatments. Among the sunflower hybrids, Allstar with the highest leaf area index at flowering had the maximum seed yield, harvest index and oil yield. Under normal irrigation, late maturity hybrids showed greatest leaf asrea index in comparison with early maturity hybrids and leaf asrea index decreased across sunflower hybrids, in water deficit stress. However Maximum plant dry weight belonged to late maturity hybrids and Allstar (as early maturity hybrid), under normal irrigation conditions wherease, in water deficit stress early maturity hybrids were superior to others.

To evaluate the effect of drought stress on antioxidant enzymes and proline accumulation in sorghum, experiment as a split plot design in randomized complete block in the city area Shahr-e-Qods carried this experiment were studied, four genotypes of sorghum varieties. The results showed that proline under stress conditions compared to more normal conditions. Figures of proline accumulation at 5% probability was significant.Also enzymes SOD, Dihydroxy, malondialdehyde stress conditions compared to normal irrigation increased significantly.

For investigation of potassium application on moderating of drought stress effects in corn, an experiment was performed in Split-Split Plot in the basis of Randomized Complete Block Design in the Agricultural Farmland Research Station of Khoy in 1387. irrigation in main plot involves three levels (Irrigation after 70 mm, 105 mm and 140 mm evaporation from the pan class A), varieties in sub factors involve two factors (704 and 666), and potassium consumption in sub sub factor involve three levels (potassium non consumption, consumption in the base of fertilizer recommendation and double consumption of fertilizer recommendation.The results showed that there was significantly difference between irrigation levels, in number of grains in row, number of seed row and biological yield. Of the above mentioned properties water treatment excelled after 70 mm evaporation and drought stress cause decreased of their. Among of the experimental varieties, variety 704 was the best considering variety 666. Among of fertilizer levels, equal consumption of fertilizer recommendation and double consumption of fertilizer recommendation (380 kg/ha) was better than of non potassium consumption, in the biological yield. Interaction effect of experimental factors had significantly effect on 1000 seed weight.

In order to study, the effect of drought stress on vascular system in wheat rachis (var. Bahar) this experiment was conducted in the research farm of Islamic Azad University of Saveh in 2009-2010 years in 4 replications. This experiment was arranged in randomized complete blocks design with drought stress factor in two levels including: 1- Control (without drought stress, 2- drought stress (from stem elongation stage to complete anthesis). The number, size and distribution of vascular bundle in different parts of spike were checked. The results have shown that, in both samples (control and drought stress), number and size of central vascular bundle acropetally decreased along the rachis from proximal to distal part of spike as the most decreasing number and size dedicated in central part. Samples under drought stress condition revealed that the number and size of vascular bundles decreased as compare to control and it was the result of drought stress. The size of vascular bundles decreased along the rachis in both the treatments as the biggest size of vascular bundles revealed in the middle of spike and then in the proximal and distal of spike respectively. There was a positive relation between the number and weight of grains with the number and size of vascular bundles for each spikelet along rachis of spike. The spikelets of middle part of spike rachis had the most average of weight and number of grains in both treatments as compare to other parts. However there are less weight and number of grains in the spike under drought stress in compare with the same parts in control situation. As the results revealed, the weight and the number of grains in drought stress conditions decreased because of decreasing in number and size of vascular bundles along the rachis of spike.

To study the impact of the growing season and drought on the quantitative and qualitative features advanced varieties of rapeseed in a field trial plan to split plot randomized complete block design with three replications Zaray year 1388-1387 research Draystkah Qazvin, Iran was. Tested in dry conditions stress the growing season at two levels and four varieties of rapeseed traits such as pod length to calculate the number of seeds per pod, seed weight and biological yield was organized. After sampling various stages of development indicators to measure the results showed that traits test result farm management operations such as planting season drought stress can be corrected.The simple result of the growing season and irrigation on pod length, number of seeds in pod, seed weight was significant biological function and interaction as the growing season and irrigation on grain number, and satchel were a significant biological function, but on the pod length and seed weight was not significant and strong negative relationship between irrigation flowering stage to the next planting season and winter (10/12/87) was tested with the characters. Leading to decreased pod length, seeds per pod, seed weight was biological function. While the fall planting season (10/7/87) and typical irrigation (control) increased pod length, seeds per pod, weight biological function in seed traits were tested.

To evaluate the effect of planting date on dry weight and physiological characteristics of rice cultivars (Oryza sativa L.) in direct Seeding, Four seeding date as 30 April and 10, 20, 30 May and three cultivars as Hashmi, Tarom and Elpaso were arranged in a split plot design as base of RCBD with four replications. Seeding dates and cultivars were set as Main and sub plots, respctvely. The results showed a significant effect of planting date traits days to tillering period, growth period, leaf chlorophyll content, seed number hollow, grain 1000 weight, grain length, yield and harvest index found.The first seeding date 36.75 days highest days to tillering and 110.5 was the highest growth period. The second seeding date with 38.16 mg g fresh weight to the highest leaf chlorophyll won. Of all the traits of the figure mentioned was significant. Elpaso cultivar highest with 32.69 per day for tillering and 113.8 days, the highest growth period won. Hashemi cultivar 39.69 mg g fresh weight had the highest leaf chlorophyll content. Interactions between seeding date and cultivar on seed traits hollow, grain 1000 weight, grain length, yield and harvest index was significant. Elpaso cultivar in the second seeding date 5582, the highest number of hollow seeds. Hashemi cultivar seeding date the third highest weight of 23.83 grams and 10.73 mm grain 1000 weight highest seed during seeding date and this cultivar fourth highest harvest index of 50.49% won.

In order to reduce consumption of sulfur-coated urea (main) in three levels (250, 300, 350 kg ha) and potassium fertilizer treatments on the (operating subsidiary) in three levels (1-120 kg ha K 2-sprayed on the concentration of 6 per thousand 3-120 kg ha potassium and sprayed with six concentrations of zinc sulfate in a thousand, based on soil test), on some quantitative and qualitative characteristics of green beans (Phaseolous vulgaris) genotype Sunray, research into split plot with randomized complete block design based on the 1389 crop year, the Agricultural Research Station Varamin was carried out in three. Comparison of results of interactions showed that the highest grain yield, biological yield, protein yield, the percentage of carbohydrates and carbohydrate yield, respectively, with 2/2817 kilograms per hectare, 2/6285 kilograms per hectare, 5/583 kg ha 3/49 percent and 9/1388 kg per hectare consumption of 250 kg ha treatment and the combined application of potassium and the leaves were sprayed and the lowest consumption of all these traits of treatment 350 kg N ha sulfur coated urea and application of 120 kg of potassium was achieved. Highest percentage of protein intake treatment of 350 kg ha of nitrogen and sulfur-coated urea application of combined potassium and zinc sprayed leaves was achieved 93/21 percent and the lowest percentage of protein nitrogen treatment 250 kg ha-coated urea Application of 120 kg of sulfur and potassium, with 20.6 percent to allocate.The highest and lowest nitrate treatment pod in order of consumption of 350 kg ha of nitrogen and sulfur-coated urea application of 120 kg of potassium, with 4/185 mg kg and 250 kg ha treatment intake and combined use of potassium and the leaves sprayed on the 4/76 mg kg was achieved.

This experiment carried out in order to investigate the effect of different methods of biofertilizer application (Nitroxin, barvar-2) included: seed inoculation, foliar spray and application through watering plant, on nitrogen, phosphorous, potasium absobtion and seed yield in white bean var. Daneshkade. Experiment was conducted at research farm of Islamic Azad University-Arak Branch/Iran, in 2009 under randomized complete block design with 4 replications and 14 treatments (includes a compilation of different methods in different stages of growth). Results indicated that the highest amount of seed yield (1807kg/ha) and percent of leaf nitrogen (5.73%) obtained in T8 (seed inoculation+application through watering at seedling stage) and the highest percent of leaf phosphorus (0.26%) obtained in T9 (seed inoculation+application through watering at early flowering stage) that was in a same statistical group with T8. According to the results, it can be concluded that the most effective biofertilizer application time for higher yield and better elements absorbtion in bean was seed inoculation+application through watering seedling.

In order to investigate Effects of nitrogen rates and splitting on physiological and agronomical indices in rice (Oryza sativa L.) Tarom Mahalli variety, an experiment was carried out at split-plot in randomized complete block design with three replications at Qaemshahr region in 2008. Main factor was nitrogen rates in two levels including (46 and 69 kg N ha-1) and subfactor was nitrogen splitting in sex levels on rate of crop requirement in stages of start of planting (based), start of tillering, initial panicle onset and completely panicle. Results showed none traits not significantly (p£0.01; p£0.05) at nitrogen rates. Most of the tiller number per m2 and dry matter accumulation were obtained in nitrogen splitting with application 50% in start of planting stage (based)+50% in start of tillering stage, but least of the total spikelet number per panicle and filled spikelet percentage and minimum of the nitrogen concentration of flag leaf due to in this treatment. The application of 50% nitrogen in start of tillering reason increased tiller number per m2 and application of the 1.3 nitrogen in completely panicle stage due increased filled spikelet percentage.Maximum of the grain yield were produced with nitrogen splitting at four stages of start of planting (based), start of tillering, initial panicle onset and completely panicle. Only nitrogen accumulation in crop significantly (p£0.01; p£0.05) at interaction of the nitrogen rates´nitrogen splitting. Therefore, nitrogen splitting at stages of the start of planting (based), start of tillering, initial panicle onset and completely panicle stages because increased of the physiological and agronomical indices due to an increased of the grain yield as the best studied factors introduced applied.