JOURNAL OF AGRICULTURAL SCIENCE AND SUSTAINABLE PRODUCTION
Year:2002 | Volume:12 | Issue:3|Papers Count:13

rder to evaluate and introduce suitable plants for creating landscapes, an experiment was carried out in the agricultural field of Ezmir city, Turkey, in 1992-93 on the species of Agrostis stolonifera, Agropyrun cristatum, Festuca rubra, Festuca ovina, Poa pratensis and Dactylis glomerata. This experiment was done in a randomized complete block design with four replications. At first, seeds were germinated in containers and then some of their seedlings were selected and planted in the field plots. The characteristics being studied were as follows: Tillering and stem elongation time, growing form, leaf dimensions, plant height, number of nodes on the stem, fresh and dry weight, and seed yield. The results showed that there were three suitable species, Agrostis stolonifera, Festuca ovina, Festuca rubra, for creating the green cover in the region. Other species under study were suitable for pastures development.

Lack of attention to appropriate operation of water resources and hydraulic structures causes the loss of initial costs and failure to realize predicted profit. This complicates planning, design and operation of water resources and needs a logical process for decision making. Mathematical models are tools that simplify decision making for water resources design and operation pattern. In recent years, application of simulation and optimization techniques for water reservoir management were developed. For appropriate water distribution and management, simulation and optimization models were used in a deficits from optimization model were compared with those from simulation models and linear decision rule. Deficits resulted from simulation model were compatible with optimization model 9-reservoir system in Kalamarz basin. For simulating the system, results from linear optimization model with probability constraints and the 25-year data were used. For reservoir yield evaluation, percent of results. High amounts of deficit indicate no sufficient attention to constructing optimum reservoirs volume and vast development of farmlands for each reservoir, without considering water potential of Kalamarz river. Simulation results show deficit in majority of years under study.

Beet army worm, Spodoptera exigua, is a severe polyphagous pest and has developed relative resistance to Bacillus thuringiensis. Therefore, to increase the efficacy of B.thuringiensis we used henna powder which is a cheap and available plant material. In this research three different concentrations of henna powder, 3000, 4000 and 5000 pp m, were added to the lowest lethal concentration of B.thuringiensis (1000 ppm) against the 3rd larval instars. The B.thuringiensis concentration was estimated carrying out suplementary bioassays. The experiment was conducted in a randomized block design with 6 treaments and 4 replicates. Results revealed that, although the larval mortality was delayed in mixtures of B.thuringiensis and henna powder in comparison with B.thuringiensis alone, but it enhanced the B.thuringiensis efficacy.

Soil water characteristics curve (SWC), is one of the most important traits of every soil and is employed in many aspects of soil management such as irrigation, drainage, land reclamation, infiltration and erosion. Laboratory method to determine this curve is time consuming, costly, difficult and involves some errors. For this reason researchers have tried to estimate it with the help of mathematical and statistical models. One of these models has been suggested by Arya and Paris. The primary concept of this model has been developed on the basis of shape similarity between SWC and cumulative soil particle size distribution (PSD) curves. An experimental coefficient (a) have been employed in this model. Arya and Paris obtained the mean of 1.38 for a. Evaluating the generality of this value for soils of various physical properties, particulary texture, was the main objective of this study. For this purpose, five soil series (Balestan, Arzanagh, Sharabian, Sarab and Gonbadan) were selected from the Sarab region in northwest of Iran. Within each series seven sites were specified and core (undisturbed) samples were taken from each site in triplicate. Composite disturbed samples also were taken. Percentage of soil particles, saturated water contents, soil bulk and densities and PSD curves were determined for all samples, and finally SWC curves were simulated by employing Arya and Paris model. The experimental SWC were also prepared using suction and pressure plate apparatus. Comparison of experimental soil water content at specified soil water potential with those predicted from the model indicated that a values ranged from 1.3 to 1.43. Within this range 1.3 seems justifiable for the most series and implies that the model with a=1.3 simulates SWC curves accurately enough. The generalization, however, may need more investigation.

The aim of this study was to investigate different concentrations of zeatin (05, 1, 2 and 4 mg/l) and Benzyl amino purine (0.5, 1, 2 and 2 mg/l) using OMI (Olive Medium Initial) medium on shoot proliferation of one node microcuttings of Olea europaea L. cv. Dezfouly. Highest number of leaves and buds were obtained in the presence of 2 mg/l of zeatin. In all above mentioned concentrations of zeatin a compact and greenish callus was developed in the basal parts of micro cuttings, while tpicrocuttings cultured on OMI medium supplemented with different concentrations of BAP did not show any shoot initiations in this cultivar. Transferred callus to the OMI medium supplemented with 2 mg/l zeatin show shoot proliferation initiation.

To study effects of different levels of water stress on growth, yield, leaf chlorophylls and essential oil content of basil (Ocimum basilicum), a pot experiment in randomized complete block design with four treatments and four replications was conducted. Water stress treatments were: 100% of field capacity (non - stress), 85% of field capacity (mild water stress), 70% of field capacity (moderate water stress) and 55% of field capacity (severe water stress). According to the results of statistical analysis, water stress had significant effect on growth, yield, amounts of chlorophyll and essential oil. As the soil water content decreased, the plant height, leaf number and area, the number and length of axillary shoots, leaves, stems and roots fresh and dry weight, yield. leaf area index (LAI), specific leaf area (SLA), leaf area ratio (LAR), leaf chlorophylls (a, b and total) content and essential oil yield decreased but the root to shoot ratio and essential oil content increased. The highest amounts of essential oil yield and content were in non-stress and moderate water stress conditions, respectively.

During 1998-1999, a survey was conducted on the Thripid family fauna of Shiraz region. Several collections were made from various plants by beating the leaves or flowers over a white plastic tray and the thrips specimens were removed by a fine brush into collecting vials. After microscopic slides being prepared, the species were examined and determined. The samples belonged to two subfamiles, four tribes, twelve genera and twenty one species. In this research, three species including Chirothrips kurdistanus zur Strassen, Chirothrips pallidicomis Priesner and Odontothrips meliloti Priesner are reported for the first time from Iran, also the genera Agrostothrips Hood and Tenothrips Bhatti denoted for the first time from Iran.

The main impediment in using conventional L-shape subsoiler is the high-energy requirment due to chisel point and landside. Also not every farmer has access to high power tractor. The main advantage in using bentleg plow is the low draft requirement. There is a hope for improving draft efficiency of conventional L-shape subsolier with removing chisel point and substituting a short cutting leg like bentleg plow. In order to achieve this goal a single leg subsoiler as the same as bentleg plow with rake angle of 15° and tilt angle of 30° but with shorter leg was constructed. This new subsoiler was called oblique blade subsoiler. Field experiments on performance of oblique blade and L-shape subsoiler were conducted in the Fars Agricultural Research Center. A randomized complete block design experiment with split split plot arrangement was conducted with three replications. The texture of soil was clay loam and three levels of moisture content (dry, medium and wet) and three different depths (250, 350 and 450 mm) were considered. The tractor forward speed was maintained at 3-3.5 km/h through out the experiments. Analyses of the results indicated that soil moisture content and working depth have significant effects at 1% level and subsoiling tool have no significant effect on draft force, specific draft and power consumption. All factors had significant effect on specific draft force. The average draft per unit width of conventional L-shape subsoiler was less than olique blade subsoiler because the width of soil failure in the surface was longer but soil disturbance in the oblique blade was greater than chisel point area. The study also revealed that subsoiling tools has no significant effect on the cumulative infiltration, cone indices and the cross-sectional area. Larger unit draft demand of the oblique blade subsoiler, no good penetration in the dry soil, no good pulverizing and twisting in the shank are important disadvantages compared to L-shape subsoiler.

This study was conducted to determine digestibility and nutritive value of vetch and bitter vetch seed by proximate analysis of feed. In addition, digestibility coefficients of dry matter and nutrients of vetch and bitter vetch seed were measured. The chemical analysis indicated that percentage of dry matter (DM), organic matter (OM), crude protein (CP), crude fiber, (CP) ether extract (EE), nitrogen free extract (NFE) and Ash for vetch seed were 92.23, 87.42, 24.65, 7.76, 2.29, 52.72 and 12.58%, respectively. The similar analysis for bitter vetch seed were: 93.34, 88.99, 22.97, 9.50, 1.34, 55.18 and 11.01 %, respectively. In vivo digestibility coefficient of both vetch and bitter vetch seed were determined by using four Mehraban ram. The diets were formulated by using 40% straw plus 60% vetch or bitter vetch seed, based on maintenance requirement of sheep. The digestibility coefficients of DM, OM, CP, CF, EE and NFE of vetch seed were 90.02, 94.67, 85.83, 84.47, 79.84 and 97.90%, respectively. Similar measurements for bitter vetch seed, were 80.22, 82.81, 74.66, 52.60, 75.31 and 89.59%, respectively. These findings demonstrated that digestibility of vetch seed is significantly higher (P<0.05). Than bitter vetch seed. Total nutrient digestibility (TDN), Lara metabolic energy (ME), Net energy (NE) and Barerm unit of feed (UP) were 83%, 3032.93 Kcal/kg DM, 2032.93 Kcal/kg DM and 1.14 U.F./kg DM, respectively for vetch seed and were 74%, 2695.60, 1695.6 and 0.94 for bitter vetch seed. These results show that vetch seed is more valuable than bitter vetch as far as nutritive value is concerned.

During the last two decades, research on flood frequency analysis has been found of great importance due to its tremendous impression on economic and environment. In presented research the co-behavior flood regions, have been delineated using peak flood data with statistical period of 20 years (1973-1993) at the 100 selected hydrometric sites over the catchments of Aras river and Orumiyeh lake, and the complete linkage method as a cluster analysis procedure has been used for this purpose. The proper clusters have been selected from resulted dendrogram and transference of them to the map produced 7 homogenous flood regions. According to water erosion study as well as present study on the floods, the floods of homogenous regions are controlled by main factors as follows: Region no. 1 by vegetation cover and drainage density; regions no.2 and no.3 by vegetation cover; region no.4 by rainfall, vegetation cover, drainage density and slope; region no.5 by soil erodibility, rainfall and slope; region no. 6 by rainfall, vegetation cover and main strema length; and region no.7 by rainfall and drainage density. According to the results the performance of soil conservation plants especially increasel in the regions no. 5, 6 and 7.

An experiment was carried out in the experimental field of Faculty of Agriculture, University of Tabriz in 1997 in order to study competition and yield of corn and soybean intercropping. The experiment was factorial based on randomized complete block design with three replications. Different combinations of corn and soybean densities constituted the treatments in the experiment. Assessing all intercropped treatments with LER index showed that the combination of 5.3 per m-2 corn x 42 per m-2 soybean, acquired the highest biological efficiency. We used ELER and SLER indices to choose the most efficient system. On the basis of other competition indices corn was a good competitor. However, in all intercropped treatments, competition of corn and soybean was complementary, because, land equivalent ratio in all intercropping treatments were greater than unity. This indicates the superiority of intercropping of these two species over their pure stands.