JOURNAL OF CROP PRODUCTION RESEARCH (ENVIRONMENTAL STRESSES IN PLANT SCIENCES)
Year:2010 | Volume:2 | Issue:2|Papers Count:8

In order to determine the effect of nitrogen levels and time of nitrogen fertilizer application on quantity and quality characteristics of mustard in summer planting, a factorial experiment base on randomized complete plot with three replications, in farming year of 2007 has taken place in research station of Varamin, in Varamin region.In this study, three nitrogen levels (75, 150 and 225 Kg/ha), four splitting patterns (P1: 1.3 at planting time, 1.3 at shooting, 1.3 at bud initiation. p2: 1.3 at four to six leaves, 1.3 at shooting, 1.3 at bud initiation. P3: 1.2 at four to six leaves, 1.2 bud initiations. P4: 1.2 at four to six leaves, 1.2 at shooting) was studied.According to the results maximum seed yield approached in 75 kg/ha nitrogen application and pattern 2 for time of nitrogen fertilizer and maximum biological yield approached in 150 kg/ha nitrogen application with pattern 4 for time of nitrogen fertilizer. Simple effect of amount and split application of nitrogen on grain yield, biological yield and harvest index was significant at 1% level and Interaction between amount and split application of nitrogen on yield and harvest index as well as biological yield at 1% level was significant.

Seed priming could be as a way to improve seed germination behavior and seedling establishment in stress conditions. In order to investigate of seed hydropriming effect on germination components and seedling early growth of rapeseed salinity conditions, a lab experiment was conducted at seed laboratory of faculty of Agricultural, University of Guilan in 2010. The factorial experiment in the form of randomized complete blocks design in four replications was carried out. First factor was seed priming and without priming. Salinity treatments consisted control, 2, 4, 6, 8, 10, 12, 14, 16 and 18 ds/m. Investigated characteristics were consisted: radicle and shoot length, seedling length, radicle fresh and dried weight, shoot fresh and dried weight, seedling dried weight, germination percent, germination rate, alometric coefficient, seedling tissue water percent and vigor index. The results showed seed priming increased investigated characteristics under salinity stress conditions in compared to without priming conditions, as seed could tolerated salinity until 6 ds/m. The result of this experiment is consistent with the hypothesis that under undesirable condition such as dry land areas, hydropriming of canola seeds could be one possible way of enhancing seed germination performance and seedling establishment.

In order to increase organic mater as one of the most effective elements in sustainable agriculture and remove physical and chemical limitation conducted by non useful management as unsuitable seed bed, and bad feeding caused by increase in residual straw C/N, this study was conducted at Karaj Research station to evaluate the six treatments on two succeeding crops, wheat (Triticum aestivum L.)- Corn (Zea maize) rotation. Two experiments were laid out as T-test design. First crop (Wheat) planted then second crop (Corn) planted on residual wheat straw by sex treatments. Treatments included: T1: Burning residual straw +Conventional tillage (Moldboard plow + disk tiller); T2: Chopping total residual straw by Rototiller + Disk tiller: T3: Chopping total residual straw by stone burier + Disk tiller; T4: Removal straw + Stone burier; T5: Reducing C/N Ratio below number 30 + Stone burier; T6: Reducing C/N Ratio below number 30 + Rototiller. After removal corn forage wheat planted on the corn stubble with six treatments included: T1: Removal corn stubble + Conventional tillage; T2: Conventional tillage; T3: Chopping stubble by rototiller; T4: Chopping stubble by stone burier; T5: Conventional tillage; T6: Conventional tillage. The result showed that, using chopping equipments such as stone burier and rototiller were more effective on increasing wheat and corn yield, but stone burier equipment was more effective on the chopping wheat straw, so using stone burier and reducing C/N Ratio method together were the best. Single application of stone burier and Rototiller had significant efficiency for corn straw splitting and increased wheat seed yield than burning residual straw and reduced costs.

In order to assessment of drying temperature and seed bed situations in dryer effect on seed and seedling vigour and some related characters of Canola Option500 cultivar this study was conducted. Therefore, harvested seeds after conditioning, by a batch fluidized bed seed dryer at 30, 40, 50 and 60oC temperatures and three seed bed situations in dryer: constant seed drying bed situation, fluidizing thereshold and fluidized were dryed. Then, final germination percent (normal seedling number at 7th. day after planting), abnormal seedlings number, germination speed, seedling, primary root and shoot length, seedling dry mater seedling length and weight vigour indices were determined. Data analysis cleared that seedling dry mater and abnormal seedlings number unaffected by treatments and effect of drying temperature on normal seedling number, primary root length, germination speed and seedling vigour weight index weight, seed bed situations in dryer on seedling length and seedling length vigour index and drying temperature and seed bed situations in dryer interaction effect for primary root length were significant. Also, seedling field emergence, seedling leaf area and seedling dry weight in field determined. Results showed that drying temperature and drying bed interaction effect was significant for this characteristics. Results revealed that by using seed drying fluidizing method for drying high moisture seed can suitably dried and protect and seed germination and seedling field emergence of Canola Option500 as drying at 30 centigrade degree temperature in fix and fluidizing bed threshold and at 40 centigrade degree temperature in fluidized and fluidizing bed threshold.

In order to study the effects of different levels of drought stress and pyridoxine on yield and yield components in wheat plant  an experiment was conducted on split plot on the basis of complete block design in four replication in the year of 2009- 2010 in research field of Islamic Azad University, Saveh Branch . In this experiment main plot was three levels of drought stress including 1-normal condition (control), 2- drought stress in per anthesis (cod39 Zadoks) and 3- drought stress in post anthesis (cod 65 Zadoks) and sub plot was different levels of pyridoxine including, 1- without using pyridoxine (control), 2- treatment of seeds with 0.01 percent of pyridoxine and 3- treatment of seeds with 0.02 percent of pyridoxine. Seeds of wheat were kept in pyridoxine for 8 hours before planting for pyridoxine treatment. Pyridoxine significantly increased yield and yield components of wheat. Probably pyridoxine with positive effect on root growth and increasing the uptake of root improved the production of assimilate during vegetative growth of plant. The highest yield and yield components achieved in 0.02 percent of pyridoxine seed treatment. Results showed pyridoxine application of seeds significantly decreased the negative effect of drought stress specially in post anthesis condition.

The effects of water deficit stress and nitrogen were studied on the Growth and Quality Yield of Calendula (Calendula officinalis L.). An experiment was conducted at Research Field of Islamic Azad University of Takestan branch in 2006. Field experiment was carried out by a split plot design based on completely randomized block design with 4 replications. treatments were three levels of stress as irrigation after 40, 80 and 120 mm water evaporation from evaporation pan, and consumption of 0, 30, 60 and 90 kg/ha nitrogen. The results indicated that water deficit stress had significant effect on biological yield (50% flowering), biological yield100% flowering), biological yield100% flowering second) and biological yieldend flowering) (p£0.01). The highest biological yield100% flowering second) 9929 kg.ha-1 was observed with irrigation after 40 mm evaporation. Nitrogen had signification effect on biological yield (50% flowering), biological yield (100% flowering), biological yield (100% flowering second) and biological yield (end flowering) (p£0.01) .The highest biological yield (100% flowering second) 7350 kg.ha-1 were observed by applying of 90 kg.ha-1 nitrogen. Water deficit stress* nitrogen had significant effect on biological yield (50% flowering), biological yield (100% flowering) and biological yield (end flowering) (p£0.05). However, the highest TDM and CGR were obtained with 2319 and 1993 GDD and 40 mm water evaporation from evaporation pan and 90 kg.ha-1 nitrogen. The result growth indices show that an increase in water deficit stress modifies the effect of nitrogen on physiological indices and TDM and CGR graphs are compatible with each other.

Agricultural lands in some part of south of Tehran, are irrigated with treated wastewater. To investigate the uptake of heavy metals such as Pb, Cd, Ni and Cr in some crops under wastewater irrigation, an experiment carried out in split plot with a randomized compelete blocks design with three replication at Roodehen University. The main factor was irrigation (wastewater and pipe water) and sub factor was vegetables (Onion, Radish, Lettuce, Mint and Persicum). After doing treatments and collecting data, the analysis of variance was done. Results showed that the effect of irrigation was significant on all traits except fresh weight and there are significant differences between all crops for all traits .Also the interaction effect of irrigation in crops for Pb, Cd, Cr and dry matter was significant. The results indicated concentrations of Cd and Cr in all samples is more than permissible levels for plants and human. The most concentration of Cr and Cd was in order, lettuce 31.3, radish 2.2 and the least in onion 7 and mint 0.8 mg/kg. onion lowest, lettuce and radish showed highest uptake of heavy metals. According to results the uptake will be near zero when we used normal (pipe) water for irrigation .Therefore wastewater irrigation can increase environmental concerns and selection type of plants with low potential of metals uptake can be effective.

Due to study the effect of zeolit amounts and drought stress effects on extinction coefficient of rapeseed (Brassica napus L.) an experiment carried out in split plot design in the basis of randomized complete blocks with 4 replications in 2008 at research field of Islamic Azad University Shahr-e-Rey Branch. Irrigation intervals in 3 levels: Irrigation after 80, 130 and 180 mm evaporated water from class A evaporation pan as main factor and Zeolit amounts in 3 levels: 0, 6 and 12 ton/ha considered as sub-factor. Okapi was experimented cultivar.The Results showed that, simple and interaction effects of zeolit and Irrigation intervals on plant height, branch number, biological yield and extinction coefficient was significant at %1 level of probability. Mean comparison interaction effect of Irrigation intervals and zeolit showed that irrigation after 80 mm evaporated water from class A evaporation pan and and 12 ton/ha zeolit application gained to maximum amounts of plant height (145/50 cm), biological yield (13679.7 Kg/ha) and extinction coefficient (0.45). In highest drought stress condition or irrigation after 180 mm evaporated water from class A evaporation pan, increase in zeolit application to 12 ton/ha had possetive effect on all characters. In this case maximum amounts of plant height, branch number per plant, biological yield and extinction coefficient was 109.70 cm, 4.02, 9756.7 Kg/ha and 0.33 alternatively.