Journal of Agricultural Sciences and Natural Resources
Year:2008 | Volume:14 | Issue:5|Papers Count:24

An experiment was conducted using a wheat cultivar (Zagros), three sowing depth (4,8, and 12 cm) and three soil salinity levels (0, 7.5 and 15 dsm-1) in 1384. The experimental design was a completely randomized with factorial arrangement and 3 replications. The results indicated that salt stress, sowing depth and the interaction effect of both studied factors were significant on seedling growth characteristics, including the time to emergence beginning,, the time to %90 emergence, rate and maximum percentage of emergence. Increasing of salt severity and sowing depth caused delayed the time emergence, while emergence rate and percentage emergency decreased. The highest value of emergence percentage (%85 for control treatment) decreased to less than 81 and %62 for salinity levels of 7.5 and 15 dsm-1 respectively. The highest value of emergence percentage (92% for 4 cm sowing depth) decreased to 83 and %54 for sowing depth of8 and 12 cm respectively. The interaction effect of salt stress and sowing depth showed a negative synergistic effect as the highest value of emergence percentage of 12 cm sowing depth (%80 in control) decreased to 65 and %42 for salinity levels of 7.5 and 15 dsm-1 respectively. In general, the effect of increasing salinity severity and sowing depth on emergence characteristics was negative. This effect was more when the effect of both studied factors was considered, simultaneous. There for, it seems that, the selecting proper sowing depth is a determinant factor to optimize the wheat cultivation in saline lands. Also, in same circumstances which we have to put the grains in deeper depth (for example in water deficiency situations in the soil surface), it is better to increase seed rate to prevent decreasing of plant density from advised density.

Priming is one of the seed enhancement methods that might be resulted in increased seed performance (germination and emergence) under stress conditions, such as salinity, temperature and drought stress. The objective of this research was to evaluate effect of priming on seed germination of cotton under drought stress in Gorgan University of Agricultural Sciences and Natural Resources.Treatments were combinations of 5 levels of drought stress (0, -2, -4, -6 and -8 bar) that was carried out by PEG 6000 in 2 levels of priming and control with 4 replications. Hydropriming method was used; seeds of siokra 324 were moistened in water for 16h at 25oC. Results indicated that with increase in drought stress, germination components such as germination percent, rate and seedling dry weight decreased, but priming seeds showed lower decrease. In all of the drought levels, priming seeds possessed more germination rate and seedling dry weight than control. Also germination percent in priming seeds was more than control which there was more increase in higher drought levels. Time to reach 10, 50 and 90% of maximum germination increased with drought enhancement, but the time was less for priming seeds. However it is concluded that priming results in improvement in germination components of cotton in drought stress conditions and increases the resistance of cotton to drought stress in germination phase.

In order to evaluate seed vigour tests and it's field efficiency of four forage sorghum cultivars (Speed Feed, Jambo, Super Dan and Sugar Graze) an experiment as complete randomized design with four replications was conducted during 2003-2004 in laboratory of Karaj Institute of seed and plant improvement, to study germination standard test, germination rate, first count test, cold tests and seedling growth rate. Also a field work as randomized complete block design with four replications was done at experimental station of agricultural College of Islamic Azad University, Mardabad, Karaj to study percentage of seedling and rate of seedling emergence and forage yield. Sugar graze and jambo cultivars had lower and higher percentage of seedling and rate of seedling emergence and forage yield, respectively. There was significant positive correlation between seed vigour tests, percentage and rate of seedling emergence and forage yield. Among the seed vigour tests, germination rate, first count and cool tests had the highest correlation with percentage and rate of seedling emergence and also the germination standard, first count and cool tests had the highest correlation with forage yield. So these tests are recognized as the best tests to evaluate seed vigour.

Delay in sowing, and increasing plant density in order to compensate yield lose resulted from delayed sowings, induce some changes in morphological characteristics of cotton such as main stem height, main stem node number, and monopodial and sympodial branche number and length. Thus, in order to investigate the effects of planting dates and plant density on morphological characteristics of cotton, an experiment was conducted using Siokra cultivar in 2002 at Cotton Research Station of -Karkandeh, Kordkoy. The experiment was carried out as a split - split plot in a randomized complete block design with four replications. Three planting dates (May 15, May 31 and June 22) considered as main plots, and two row spacings (60 and 80 centimeters) and three plant distances (10, 20 and 30 centimeters) considered as sub- and sub- sub- plots, respectively. The results showed that delaying in sowing date decreased monopodial branche number and plant height, and increased length of the highest monopodial branche, the number of sympodial branche and main stem node. However, the influence of sowing date on the length of sympodial branches was not significant. In all three planting dates, an increase in plant density accompanied with decrease in monopodial and sympodial branche number per plant, length of the highest monopodial branche, sympodial branche length, and main stem node number, whereas main stem height increased to some extent. Among morphological characteristics of cotton, main stem node number (in normal planting date), and length of the highest monopodial branche (in other planting dates), showed the most sensivity to increasing in plant density.

In order to evaluate cell membrane stability and germination stress index in relation to drought tolerance in lentil (Lens culinaris Medik), twenty lentil genotypes were evaluated in three experiments. The experiments conducted in the form of completely randomized design with 3 replication in laborator and planthouse. A separate experiment was conducted in the field in the form of spilt plot design with three replications, irrigation regims (irrigation in three stages of plant growth and without irrigation) were taken as main factor and 20 genotypes as sub plot factor. The rolled blotter test revealed a positively significant correlation of stem length with both root length and plant weight. Germination test when carried out in polyethylene glycol (-0.06MPa) soulation showed that there was a significant difference among genotypes with respect to germination stress index (GSI).GSI was positively correlated with mean productivity index (MP), stress tolerance (TOL) geometric mean productivity (GMP) harmonic mean (HM), stress Susceptibility index (SSI), tolerance index (STI) and superority Measure (P). Cell memberane stability (CMS) showed significant differences among all genotypes. CMS was negatively correlated with GSI, MP, GMP, HM and STI index.Therefore GSI and CMS index might be used as a good criterion prior to conducting a field screening for drought tolerance at a large scale. According to the results, TN-1768 was identified as a drought tolerant genotype.

The effects of irrigation quantity and seed bed shaping on soil water and salinity variation, bulk density, root growth and dry matter was investigated with a split plot statistical design with a field trial in Zahak Agricultural Research Station in Sistan province in 2005. Irrigation intervals after 80 and 160 mm evaporation from class A evaporation pan were used as main plot. Flat surface, single, triple and six row beds with a 20 cm row space were used as subplots. There were 4 replications per treatment.Volumetric soil water content and bulk soil electrical conductivity were measured using TDR for 0-20, 20-40 and 40-60 cm depths in all replications at 9 occasions during growing season. Soil water contents were also measured at 0-10 and 10-20cmdepths using standard sampling rings at 4 occasions.Three and six row beds increased the electrical conductivity for saturated paste extract with the more frequent irrigation interval in this coarse textured soil. Soil water content, dry matter and root density were always greater with the more frequent irrigation interval. Root density was greatest in 0-20 cm depth with the single row bed treatment. Grain yield and root density were greatest with single row bed treatment due to bed shaping at the wheat root development stage (possibly due to a reduced mechanical resistance). A greater soil water content by the short irrigation interval method, increased grain yield and root density through reducing mechanical resistance. With loam sand, bulk density and mechanical resistance is increased rapidly after cultivation. Bed shaping at root development stage might enhance root growth and yield production. Apparently mechanical resistance was the most limiting factor with these loam sand soils rather than salinity.

Iron and potassium are essential elements in plants. Optimal applications of these elements lead to improve the quantities and qualities yield of plants. Deficiency or toxicity effects of these elements inhibit plant growth and yield. The iron toxicity in plants may decrease by supplemental potassium levels. The main goal of this research was evaluation the effect of different potassium and iron levels and their interaction on growth, ions content and some biochemical parameters in rice. Experiments were performed in completely randomized design as factorial with three replications. Factor one was iron including four iron levels (2, 10, 50, 100mg/liter as Fe EDTA) and the factor two was potassium including three levels (0.5, 5, 10 mM K+ as KCI). Plants were cultivated in greenhouse condition in sand culture for 6 weeks. Nutrient solution was Yoshida that modified based on iron and potassium.The results indicated that supplemental potassium supply lead to greater K+ concentration in roots and shoots. However, increase of potassium in roots environment had no significant effect on plant growth. Iron deficiency in root (2 mg/l iron), induced significant decrease in growth, chlorosis, and carbohydrate content in all potassium levels. The highest growth was observed in 10 mg/liter iron treatment. Shoot growth did not changed markedly in 50 and 100 mg/liter iron treatments, but root growth decreased significantly. Increase of iron in root environment caused significant increment of iron concentration in both shoots and roots. However, iron accumulation in root was much higher.Supplemental potassium nutrition has no significant effect on alleviation of iron deficiency. The rice taram variety plants have certain ability to withstand under high iron concentration in roots environment, so that 100 mg/liter iron did not changed its shoot growth. However, toxicity inception could be indicated by root growth reduction. Further experiments with higher iron concentration in root medium are necessary to confirm these results.

In order to investigate effects of salinity on rice vegetative growth an experiment was conducted using ten rice cultivars (Tarom, Kados, Shafagh, Tabesh, Khazar, Fajer, Neda, Nemat, Sahel and Haraz) and four salinity levels (0.7, 4, 8, and 12dsm-2) in 2005. The experimental design was a completely randomized blocks with 3 replications in a factorial arrangement. The results showed that salinity, cultivar and their interaction had significant effects on all measured components including plant, survival percentage, and shoot number per plant, shoot height, leave duration and dry matter per plant at flowering stage. The salinity and cultivar interaction indicated while there were more than 93% survival plants in control, in the second salt level, there was more than 80%, except in Khazar, that showed more sensitivity even in lower salt stress in that cultivar. The difference among cultivars increased in 8 dsm-2 salt stress and also almost all the cultivars could not tolerate the salinity stress of 12dsm-2 and cultivation of these cultivars were not actually able in such salinity level. Generally, according to the data of plant survival and because that is the most important component of growth and yield in crops and the cultivars reaction in 8 dsm-2 salinity, the cultivars could classified to four groups, as tolerant with more than 66% plant survival (Haraz, Nemat and Shafagh), semi-tolerant that include only Neda cultivar with more than 53% plant survival, sensitive groups including Sahel, Tabesh, Fajer and Tarom with about 24 to 38% plant survival and fourth groups with two high sensitivity to salt stress as Khazar and Kados with lower than 18% plant survival.

In order to evaluate the effect of salinity on yield and yield components of Hull-lessbaley (Hordeum vulgar), an experiment was conducted in greenhouse condition during the years 2002 and 2003 growing season.Treatments were consisted of four salinity levels including 0.84, 5.48, 9.27 and 14.25ds/m prepared by solving NaCI-CaCl2 salts (1:1 weight ratio) and four genotype of Hull-less barley include: ICB_I 18305 (G1),4679 / 105 // VEA / 32th / ALGER(G2), ELDO /BERME_JO / 5 / CM67_B / CENTENO(G3), CERAJA/3/ATACO/ACHIRA/HIGO(G4). Results showed that all salinity levels imposed a significant effect on tillers yield and whole plant yield mean. While there was not any difference between salinity levels at 0.84 and 5.45 dS/m about number of fertile and non fertile tillers, ratio of fertile tillers to whole plant tillers, spike.Reduced main spike yield under salinity was mainly due to reduced seed number while reduced tillers and crucible yield was mainly due to reduced spike number. Among studied genotypes, G4 showed to be better than the others for cultivation under saline condition up to 4.5 ds/m, because of higher yield, yield thereshold and harvest index.

This investigation was conducted to evaluate the qualitative land suitability for wheat, soybean, cotton and to test accuracy of the applied land suitability evaluation methods. The area is locatd in southwest of Gonbad-e-Kavous, Golestan province, northeastern-Iran. For classification, soil profiles from each of the separated land units were discribed and classified (according to Soil Taxonomy, USDA, 2006). The studied soil profiles were all classified as Mollisols with mollic diagnostic surface horizon and subsurface cambic, calcic, argilic and natric horizons. The land suitability class was determined in the next step by matching land characteristics with the crop vegetative requirements using simple limitation method, number and intensity of limitation method, Storie method and Square method. The results of physical evaluation revealed that the most important limitations for crop production in the area are the climatic limitations, salinity, alkalinity, acidity, high calcium carbonate and drainage. For determing the accuracy of the applied land suitability evaluation methods, yield potential of irrigated wheat, climatic conditions and topographic situation of the region were first evaluated. In the next step land production potential (predicted performance of wheat) was calculated by using irrigated yield potential and soil limitating factors. Finally the evaluated performance was compared with Farmers performance. Cofficient of determination test and Chi-square tests showed a good correlation between FAO model and the land suitability evaluating methods, specially the Storie method in wheat in cultivated areas.

one of the important parameters measured continuously in meteorological stations is air temperature under the shelter. As the temperature at soil surface and underground surface are not measured continuously, the lack of soil temperature data is encountered. Since the soil temperature regime has direct effect on plant growth, plant diversity and soil nutrients and biological activities, data reconstruction is important in bioclimatic and agricultural studies. The aim of this study is estimating soil shallow depths temperatures by construction regression correlation between air temperature at 1.8 m height (meteorological shelter) and soil temperatures at 7 and 20 cm soil depths. For this purpose, temperature data of Sari Meteorological Station (Faculty of Agriculture, Mazandaran University) were employed. The soil texture is sandy clay (SC). This investigation was carried out in both annual and daily basis, separately, using Pearson product-moment correlation coefficients. The accepted level of significance was P<0.05. Then relationships of the maximum, minimum and mean temperatures of shelter air with corresponding soil temperatures of 7 and 20 cm depths for annual regime were found highly significant (r=0.9 to 0.97). Daily analysis was also conducted for the above points. For each season, daily analysis was done on the average hourly temperature data. For these analyses, the correlation coefficients were also highly significant (from r=0.84 to 0.99). To improve the predicted results obtained from regression relationships, lag time and curve analysis were performed. These two approaches improved the estimated values by 5-10 percent and 8-12 percent, respectively. In conclusion, curve analysis showed to be more reliable for predicting soil depth temperatures.

In order to evaluate the effect of irrigation regimes on seed yield and yield components of determinate and indeterminate soybean cultivars an experiment was conducted in Isfahan University of Technology Research farm. The experiment was arranged in a randomized complete block design as split-plot with three replications. Irrigation regimes (5 different combinations of irrigation after 60, 90 and 120 mm cumulative evaporation from a class A evaporation pan during vegetative and reproductive phases) were the main plots and the subplots were two soybean cultivars (Williams (indeterminate) and Hobbit (determinate). Hand-seeding was carried out on May 16 and 17. The analysis of variance showed that the effect of irrigation regime on grain yield was significant (a= 0.01). The maximum seed yield obtained from irrigation after 60 mm cumulative evaporation.Increasing irrigation intervals during vegetative phase from 60 to 90 mm didn't result in a significant decrease in grain yield whereas further increase in irrigation intervals (from 90 to 120 mm) during this phase reduced grain yield significantly. Also, a significant reduction in grain yield occurred when irrigation based on 90 or 120mm cumulative evaporation continued up to the beginning pod formation (R3). Forward step by step regression revealed that changing pod number per plant was the major cause of grain yield changes in different treatments, and other yield components (seed per pod and seed weight) were very stable in different treatments. Findings this experiment suggest that irrigation intervals can be increase in vegetative phase up to cited level in order to reduce water consumption for soybean production.

This research was conducted at Experimental Station of College of Agriculture on two species of genus Lycium (depressum and ruthenicum) which are native plants for dry part of the country. The effect of different irrigation levels on vegetative traits of these two species was investigated which could have usage for hedges in green space of urban areas. Irrigation levels were 8 days, 16 days, and no irrigation (control) as main plots and species as subplots. Irrigation levels had significant effects on vegetative traits such as plant height, leaf area, leaf density, fresh and dry weight of leave and stem.With increasing irrigation intervals from 8 days to 16 days, leaf area, crown diameter growth, fresh weight of branch and leaf and leaf to branch ratio of Lycium depressum were not changed significantly, while crown diameter growth, fresh and dry weight of branch, leaf density of Lycium ruthenicum was not changed significantly. In all irrigation treatments fresh and dry weight, leaf area and density were higher for Lycium depressum compare to Lycium ruthenicum. It seems that, the Lycium depressum is a good plant as hedges in green belt and space of urban areas of Mashhad. Besides this species remain alive without any irrigation.

Drought is one of the natural phenomena which occur in all regions. Despite its harmful effects on agriculture, natural resources, water resources, environment and..., its different aspects was not well known yet. A study was carried out to inspect the drought phenomenon and its trend in Uremia region.Monthly precipitation data of Uremia synoptic station for a 40 years period were obtained. 22 periods including monthly, seasonal and yearly periods have been considered for the occurrence of drought.The results showed that wet and dry condition, happened with different intensities and some normal conditions were taking place too. With the longer periods, lower occurrences of severe droughts were found. In contrast by using shorter study periods, higher ranges of coefficient of variations were obtained. The highest range of coefficient of variations was obtained in July and August. Moreover, the coefficient of variations of drought index was lower in annual period than that of others. There was also a sever drought or wet year observed in every 11years (between 10-12 years) in the regions.

By awareness of management concepts, educational managers performance style can efficient. This present survey research was done with purpose of the view point of educational managers in agricultural sciences and natural resources, and medical science universities, regarding to the effects on management concept in the performance style of manager on the 50 educational managers in 2006. the first, data were gathered by questionnaires including two parts, demographic variables and management concepts and then, data was analyzed by spss and statistical test manvitnney, to use liner regression model two variable. Results showed, 45.4% managers are known the awareness of planning concept were complete effect on the managers performance style. but 54.4% of them believed that awareness of total management in performance of managers was effect relatively. Also finding showed, the viewpoint of managers education in agriculture sciences and natural resources about effects on awareness of management concepts on the managers performance in compare with medical science university had been high degree. (19.43 vs. 17.20) and there was not significant correlation.also, data analyzed showed that between viewpoint management about effects of awareness on their management performance and variables such as age, sex did show significant correlation (P<0.05) the recognition of view point of educational managers showed the effect of awareness from knowledge and concept management on the perception and performance of managers was very important and it can cause increasing and correct promotion of management process in universities educational system.

The effects of different parameters of genetic improvement on distribution and accumulation of dry matter and nitrogen, drought resistance threshold and grain yield of chickpea (Cicer arietinum) was evaluated in a simulation experiment and optimum traits for using in future breeding programs was determined using Cyrus model. Decrease or increase of 8 effective parameters on chickpea (Hashem cultivar) was evaluated using 88 year weather data in rainfed conditions of Gonbad and Gorgan. In generally, the simulation study results showed that the decrease of vegetative growth and shoot dry matter in vegetative stage and therefore water maintain to grain filling period was the most effective character to increase grain yield in rainfed conditions of Gonbad and Gorgan. In Gorgan, the highest increase in grain yield (97 kg/ha) was obtained, via increasing 20% in RUE. The possibility of having a higher grain yield than Hashem cultivar in Gorgan was 84.4%. In Gonbad, with a more drought stress than Gorgan in terminal stages of growth, the highest increase in grain yield (90 kglha) was obtained by increasing 20% in HFPL, the portion of remobilizable dry mater to grain that accumulated during beginning of flowering until beginning of grain growth. The possibility of having a higher grain yield than Hashem cultivar in Gonbad was 96.59%.

Quantitative information regarding biomass partitioning in chickpea (Cicer arietinum L.) is limited or inconclusive. The objective of this study was to obtain baseline values for biomass partitioning coefficients of chickpea (cv. Hashem) crops grown under well-watered conditions. A field experiment, with 3 sowing dates and 4 plant densities, was conducted in Gorgan during 2003-2004. Crop biomass and phenological stages were measured between emergence and maturity. During growing season dry matter partitioning among different organs were described by linear relation between dry matter organs versus total dry matter. A linear relation was found for biomass partitioning between leaves and stems before podding stage (R3). Mean partitioning coefficients until R3 stage were 0.36-0.55 for leaf and 0.50-0.64 for stem. During the period from podding (R3) to first-seed (R5), 60, 27 and 13 % of produced biomass had been transferred to stems, pods and leaves respectively. During the period from first-seed (R5) to maturity, 83% of biomass was partitioned to pods. It was concluded that using fixed partitioning coefficients after first-seed (R3) are not as effective as they are before this stage. Plant density did not affect partitioning of biomass. It was concluded that the obtained coefficients could be used for chickpea growth simulation models.

Allometric relation in plants describes development and growth variations and relative characteristics of a part of plant in comparison with total or other parts of plant. The objective of this study was to find allometric relations between plant height (cm) with node number in main stem, srem dry weight (g plant-1) and vegetative components dry weight (g plant-1). For this purpose, an experiment with 3 sowing dates (6 Dec. 2003, 20 Jan. 2004 and 21 Mar. 2004) and 4 plant densities (15, 30, 45 and 60 plants m-2)was conducted in the field at Agricultural Science Research Farm of the Gorgan University during 2003-4. Data of plant height stem dry matter weight and vegetative components dry weight was recorded. The power equation (y=axb) as linear changed form, {In(y)=ln (a)+bxln(x) was used to describe the relationship between plant height and the mentioned characteristics. Between plant height with nod number in main stem (y=0.92x1.26, R2=0.92), stem dry weight (y=26.57x0.42, R2=0.92) and vegetative components dry weight (y=18.54x0.46, R2=0.92) was significant relation. So, this relation can use to estimate plant height and or use them in crop simulations models for modeling competition.

On method for determination of optimal traits is the use of crop simulation models combined with long-term weather data. This research was conducted to evaluate different breeding strategies to increase crop yield under irrigated conditions of Gorgan and Gonbad with Cyrus chickpea model.Breeding strategies were increase or decrease in vegetative and reproductive stages, early vigor, radiation use efficiency (RUE), retranslation, nitrogen contents in green and yellow leaf and stem and grain nitrogen content. Results indicated that increase in RUE, increase in duration of grain filling alone or in combination with increase in duration of emergence- flowering lead to 7 to 9% increase in grain yield Increase in early vigor and nitrogen content of green leaves and stems and decrease in nitrogen content of senesced leaves and stems results in negligible yield increase. It was concluded that for achievement of higher yields at the region, the importance of combinations of traits should be evaluated.

The objective of this study was to obtain baseline values for extinction coefficient (Ks), radiation use efficiency (RUE, g MJ-1) of chickpea crops grown under well-watered conditions. The stability of these parameters during the crop life cycle and under different environmental and growth conditions created by season and sowing date and density, were evaluated. Field experiment, with three sowing dates (6 Dec.2003, 20 Jan.2004 and 21 Mar. 2004) and four plant densities (15, 30, 45 and 60 plants m-2), were conducted during 2003-2004. Crop leaf area index, light interception, and crop biomass were measured between emergence and maturity. Ks declined with an increase in solar elevation and plant density. Average Ks and RUE respectively 0.5 and 1 g MJ-1 were obtained. Plant density had no effect on RUE, but some effects of temperature were detected. There was no effect of solar radiation or vapor pressure deficit on RUE when RUE values were corrected for the effect of temperature. RUE was constant during the whole crop cycle.