PLANT AND ECOSYSTEM
Year:2009 | Volume:5 | Issue:17|Papers Count:8

Tilia is a very valuable species of north woods of Iran. To regarding the importance of Tilia, the evaluation of quantitative and qualitative characteristics, multiplication and selecting the best site are main purposes of this study. Thus, the wood sites, Garmabdasht and Gharnabad, in Gorgan, were chosen. In each site four ha square sampling area were selected. The factors measured in each sampling area are: quantitative characteristics (number per ha, total height, dichotomous ramification height, the first branch height, the crown initiation height, crown diameter and diameter against chest), qualitative properties (canopy, crown symmetry, bending and convolution percentage) and Tilia multiplication. Tilia spreads in a wide range of environmental conditions was observed. The data, analyzed by T. Test and Spss statistical software showed no significant difference between number per ha, total height, dichotomous ramification height, crown initiation height and crown diameter but significant difference between diameter against chest and the first branch height in both sites. No significant difference was shown between qualitative properties (canopy, crown symmetry, bending and convolution percentage). Multiplication data in both sites indicated that Tilia multiplication was insignificant between plants lower than 1.3m but it was significant between ones higher than 1.3m. Continental studies of evaluated regions indicated that there are humid climate with moderate winter in Garmabdasht's wood and humid climate with cool winter in Gharnabad's wood. Eventually it seems that regarding quantitative characteristics, Gharnabad is a more suitable site than Garmabdasht for Tilia growing, but Garmabdasht is better for multiplication than Gharnabad.

Beginning the industrial revolution and even-increasing mankind change, demand and usage of fossil fuels led to the increase of green house gases such as carbon dioxide in the atmosphere. Development of wood vegetation, brush and tree short is a method to reduce the amount of carbon dioxide in the atmosphere. Atriplex lentiformis is one of the foreign species was used for dedesertification. This plant because of its wood texture, has high potential carbon sequestration by photosynteses.The purpose of this research is to measure carbon in soil, root and aerial biomass For this purpose. The effect of row spacing in 3 levels (2500, 625 and 278 stem/ha) with 45 repeatation, totally 135 sample soil, aerial biomass and 18 sample soil was examined. After planting common method, with 500 to 1000 stem/ha was studied. The result indicated that row spacing had no significant difference on soil carbon. But on carbon aerial biomass and root had significant difference. The most amount of carbon related to 2×2 m row spacing.

This research was conducted to determine the more salinity tolerant species of Agropyron desertorom, Bromus tomentellus, Secale montanum. Two genotype were selected for each species. The experiment was conducted based on a factorial design including five salinity levels of 0, 100, 200, 300 and 400 mM Nacl and Cacl2 treatments.Data were recorded and analyzed for Chlorophyll (a) concentration (chl.a), Chlorophyll (b) concentration (chl.b) and total Chlorophyll (t) concentration (chl.t).The result of chlorophyllmetri revealed that there was a significant difference (P<0/01) between species, chl.a and chl.t had significant difference. In addition the study of intraction between species and salinity, Agropyron in highest different levels had the highest concentration of chlorophyll a.

This study implemented to determine the levels of heavy metals pollution in roadside soils of Tehran-Damavand. The lead and Cadmium levels of roadside soil are directly related to traffic density and long-range transport in roads. Tehran-Damavand is one of the most traffic roads in Iran. Heavy metals are found in gasoline, petrol, oil, lead additives and supplement fuels. Cadmium and Lead cause to pose the risk of plants, animals, groundwater resources and finally risk of human. They cause to increase environmental risks for ecosystem. For this purpose soil samples were collected from three areas Sorkhehesar, Jajrood, Pardis at distances of 0, 10, 50 m and 5, 15 cm depth in spring, summer and autumn. Some physico-chemical characteristics were determined. Samples were digested with HNO3 4N. The concentrations of lead and Cadmium were measured by Atomic Absorption Spectroscopy. Lead concentration in soil samples varied from 3 to 45 mg/kg. It shows some samples are polluted. Statistical results showed that lead has negative correlation with distance and precipitation. Cadmium has negative correlation with depth and precipitation at the 0.05 level.

The most important agricultural products in our country is wheat that plays an important and distinct role in preparing food for people.Like other products of agriculture, we see many losses in this product from producing to consuming. According to the results in harvesting irregular or old combines can affect the products by breaking grains or not separating the wheat from chaff. Doing this study, some parts of Varamin which have most wheat farming land have been chosen such as Javad Abad, Ghaleh Sin and Khaveh. The average of losses in Varimin has been estimated 7 percent for one hectare. Amount of losses was like this damage losses 4.2 percent, quantitative losses.1.6 percent, cylinder losses 0.6 and sieve losses 0.6 percent. It can be said that the main reasons for these losses were: age of combine, speed of machine, cuter bar height, planting method, lack of adaptation between reel speed and combine speed, the farmer’s lack of fumiliarity with the combine, incongruity speed of fans, weed pollution, unsuitable of grain wheat during harvesting and irregularity of sieve. Accordingly, there are some suggestions: Land leveling, determination of useful age of combines and the best time for replacing, farmer’s and operators training, arrangement of combine device parts and using suitable ways for planting and irrigation.

In order to determine the best herbicide composition of narrow leaf weed control, an experiment was carried out based on randomized complete block design included 4 replications.Treatments were: prosolphocarb with 2, 3, 4, 5 liter/ha, metribozin750gr/ha, pendimetalin 3, 5 l/ha, Rihm solphoren40 and 60 gr /ha paraquat3 L/hand control. Measurements were done 3 times15, 30 and 45 days after treatment. According to the recorded results, the effect of herbicides on the Echinochloacrus galli (L.) P.Beauv, Sorghum halepense (L.) pers and Setaria viridis (L.) P.Beauv were significant and due to Duncan mean comparison, Paraquathad had the greatest effect on Echinochloacrus galli (L.) P.Beauv, Sorghum halepense (L.) pers and Setaria viridis (L.) P.Beauv in 30days after treatment and Sorghum halepense (L.) pers 30days after treatment.. paendymetalin5L/ha had the greatest effect on Echinochloacrus galli (L.) P.Beauv and Setaria viridis (L.) P.Beauv 30days and Sorghum halepense (L.) pers, Setaria viridis (L.) P.Beauv 45days after treatment. Also pendymetalin 3L/ha had the greatest effect on Echinochloacrus galli (L.) P.Beauv in the 45 days after treatment. It is concluded that Paraquat and Pendymetalin could be recommended as herbicide with the concentration of 5 L/Ha.

This study was conducted to determine the salt tolerance of olive (Olea europaea cv. Dezfol) and its effects as combined with application of kinetin and cycocel plant growth regulators on vegetative growth. The experiment was carried out in a completely randomized design with factorial arrangements with four replications. In this study, leaf number, leaf area, chlorophyll content, stem length and shoot and root dry weight were determined.The results indicated that increasing salinity level caused a decrease in shoot length, leaf area, shoot dry weight that was not significantly different at 5% level, DNMRT but at 200 mM salinity, leaf number differentiation and leaf chlorophyll decreased significantly. Application of 1000 mg/l cycocel increased leaf chlorophyll to 0.62 mg/kg at the 50 mM salinity and root dry weight to 0.532 at the 200 mM salinity, this increase was statistically significant at 5% level.

Salinity and nutrient deficiencies are the most important issues that reduce crop productivity in arid and semi arid regions. The purpose of this study was to model interactive response of sorghum (Sorghum bicolor L. Moench) to different urea fertilizer rates at different salinity levels. Consequently, a randomized complete block factorial experiment with two factors of irrigation salinity (7 treatments) and nitrogen fertilizer (5 treatments) with three replications was conducted. After harvesting, the obtained yield was measured and the relative yield was calculated. Two linear and non-linear models that are based on Liebig- Sprengel and Mitscherlich- Baule formulations were derived such that can be used for combined salinity and nutrients deficiency stresses. The derived models were then verified to predict relative dry matter, using the designated statistics. For the derived linear model, when the slopes of salinity response function and nitrogen were at optimal levels, a reasonable fit was obtained with the experimental data. However, by increasing salinity and nitrogen deficiency, more accurate predictions obtained with the nonlinear derived model. The­ both models have the same P-value that in level more than 0.01 are significant. It can be concluded that both models can reasonably well predict the relative yield when plant imposed to simultaneous salinity and nutrient stress. However, the statistics indicated that the non-linear model provides higher in accuracy and efficiency compares to linear model. The statistics for the MB nonlinear model (ME=0.16), (RMSE=0.08) are less than that of the LS linear model and the statistics (R2 =0.93), (CD=0.75) and (EF=0.89) in this model are larger than the MB model, indicating a better performance and accuracy for the LS model