AGRICULTURAL RESEARCH
Year:2005 | Volume:5 | Issue:2|Papers Count:6

To Compare twenty olive cultivars growth rhythm and evaluate some of vegetative characters, two years old olive plants were cultivated during 2002-2003, at the agricultural research field of Chamran University, Ahwaz. The statistical design based on a randomized complete block with four replications was employed. To evaluate the vegetative growth rhythm, every two weeks, main stem length, lateral branch length and main stem diameter were recorded. Main stem length, lateral branch length, stem diameter and canopy volume of olive trees were recorded after fifteen months. Results showed that Rougheni had significantly (p<0.05) the most main stem length with 142.4 cm. Abosatl cultivar had significantly (p<0.05) the least main stem length with 92.60 cm after fifteen months. Rougheni cultivar had significantly (p<0.05) the most lateral branch length with 78.11 cm. T2 and Konservalia cultivars had maximum and minimum stem diameter with 24 mm and 15.43 mm respectively. After fifteen months the results showed that Manzanila and Abosatl cultivars had the most canopy volume with 0.451 m3 and the least canopy volume with 0.129 m3, respectively. The results of growth rhythm comparison of cultivars showed that growth of main stem and lateral branch were periodic in some of cultivars. Diameter growth rhythms of main stem in all of cultivars were constantly and had nearly a linear curve in the end of experiment.

In order to evaluate resistance of potato cultivars to black leg, five tubers of each certificated cultivar were inoculated by 200 microlitres of 1*107 cfu suspensions of pectobacterium (Erwinia) carotovorum sub sp. carotovorum (P.c.c.) and covered with plastic to maintain the moisture. Seven days after inoculation, the length of black leg lesions (soft rot, discoloration, black rot) are measured on tuber by a 0-5 scale (O=non symptoms, 5= maximum rot, discoloration, black rot of tubers). In laboratory experiments, 19 out of 50 tested cultivares were found tolerant potato cultivars were screened for resistance to black leg. Potato cultivars including Condor, Diamant, Aranka, Moren, Sante and Cosima were more tolerant to disease. Granulla, Barraka, Bollesta, Casmus, Exira, Sinda, MN101, Romina, Empalla, Mirpam, Samanta, Herta, Asonia, Concord, Gigant, Desiree, Stete and Aziza cultivars were fairly susceptible. In green house tests in completely Randomized design 19 cultivars were planted. Seedlings were inoculated using stem puncture with bacterial suspension when their growth reached to 10-15 centimeter. Inoculation were made with pure cultures of P.c.c. by (200 microlitres per plant) bacterial 107 cfu suspension placed in the axil of the first expanded leaf below the stem apex.After inoculation, plants were kept in a mist system to create high relative humidity. Seven to ten days after inoculation, plants were assessed with a scale 0-8 (0= non symptoms, 8= maximum symptoms). Analysis of susceptibility of potato cultivars to P.c.c. under green house conditions showed that cultivares Moren, Rimarka, Marfona, and Sante were relatively tolerante to black leg. But Sinja, Serenad, Idol, condor, Romano, Aranka and Diamant were susceptible. Moren was the most tolerant cultivar and Condor was the most susceptible cultivar to the pathogen.

To investigate the effect of irrigation amount and method (tape and furrow) on yield, yield components and quality characteristics of potato, an experiment was performed at Hamadan Agricultural Research Center (Ekbatan Station) in 2004. The experiment was split plot in randomized complete blocks design with 3 levels of irrigation water amount as main factor (75, 100 and 125% of cumulative evaporation from class A pan) and subfactors of irrigation method (including tapes in the middle of furrow ridge on soil surface, tapes in the middle of furrow ridge at the depth of 5 cm, tapes on the sides of furrow ridge on soil surface, and furrow irrigation) with 3 replications. The results indicated that the least yield (21.35 ton/ha) was obtained in furrow irrigation and maximum yield (28.92 ton/ha) was obtained in tape irrigation (tapes in the middle of furrow ridge at the depth of 5 cm). The effect of irrigation method, irrigation water amount and their interactions on number of main stems per plant and per square meter was not significant. The least percent of tubers smaller than 35 mm diameter (13.80%) was obtained in tape irrigation method, tapes at the depth of 5 cm from soil surface, and the highest loss (21.46%) was obtained in tape irrigation method, tapes on the soil surface and on sides of the ridge. The highest amount of tubers smaller than 35 mm (21.11%) was in irrigation water treatment of 75%. The highest amount of tuber production (60.41%) in marketable size (tubers larger than 55 mm) was obtained in tape irrigation method, tapes at the depth of 5 cm from soil surface. The effect of irrigation method on reducing sugars, dry matter and specific gravity of tubers and also the effect of irrigation water amount on dry matter was not significant but in irrigation water treatments of 75 and 100%, the amount of reducing sugars was 138.042 and 112.167 mg per 10 g potato flour, respectively. The amount of reducing sugars in irrigation water treatment of 125% was equal to 107.375 mg per 10 g potato flour which is 4.27% less than irrigation water treatment of 100%.

Transient nonlinear Richard’s and mass transport equations evaluated with Galerkin finite element and a computer model was developed based on the mathematical model. Initially, our numerical model was controlled using Panoch clay loam results of Antonopoulos and Papazafiriou. Then, using the experimental soil moisture characteristic data and RETC software the coefficients of empirical Van Genuchten equation were determined. Again, the model was run under equation Van Genuchten, and the results were compared to Antonopoulos and Papazafiriou results. Finally, the distributions of moisture content and concentration profiles were determined under initial condition and Drichlete boundary condition for the upper boundary of model. Results obtained by spatial resolution of 2.5cm and time interval of 1s are in a good agreement with each other. Therefore replacement of Van Genuchten equation in the Antonopoulos and Papazafiriou model not only does not reduce the accuracy but also makes it simpler. Also using the convergence of h-type for 1 second of time step and grid size of 0.5, 1, 1.25, 2.5, 5, 12.5 and 25cm was verified. For the spatial interval of 2.5 cm, the suggested CPU time is about 27.02 seconds. Therefore, both the results obtained by Antonopoulos and Papazafiriou can be applied.

In this study, a Tape irrigation system on Corn and Sunflower under fertigation was evaluated. The field experiments were located in Shahre-Kord Agricultyral Research Center.Irrigation water and fertilizers were applied through a solid set of Tape irrigation system.Two experiments were established with irrigation and fertigation during the growth season.The seasonal water Christiansen uniformity coefficients were varied from 95 to 98% for Tape with 20m and from 96 to 98% for 60m lengths. The fertilizer Christiansen uniformity coefficient was also ranged from 82 to 99% and from 94 to 96% for the Tapes with 20 and 60m lengths, respectively. Also, the Emission Uniformity that explains efficiency of the system was measured. The experimental results indicated that water emission uniformity was appeared to vary from 93 to 96% for Tape with 20m and from 95 to 96% for tape with 60m lengths, respectively. The obtained results were showed that the fertilizer emission uniformity varied from 88 to 99% for Tape with 20m and from 89 to 93m for Tape with 60m lengths, respectively. The results were also indicated that the uniformity of the applied fertilizer was increased with Tape irrigation water uniformity. The distributions of both the applied fertilizers and water through Tape irrigation system can be represented by a normal distribution function. The experimental results were also indicated that the Emitters coefficient of variation suits the established irrigation system. The evaluated Tape irrigation system did not show any problem such as fitting filter, emitters and fertilizer venture injection.

Agricultural development in Iran depends on the amount of water and evaluation of the irrigation projects and determination of the goal achievement of the stages of planning, designing and construction is necessary. In this study, for performance evaluation of the Gazvin Irrigation Network, some canal reaches were selected based on the quality of execution which is indicator of existing characteristics of the network. In each order of canal (1 to 4), three reaches were considered. Water loss in each teaches was measured with inflow and outflow method for four times starting March through August. Flow velocity was measured by current meter at two different depths of canal (0.2D and 0.8D). Then cross sections of canals were determined by measuring depth at different points of canal width.Average conveyance and distribution efficiency in canals from order 1 to 4 were 95.2, 90.5, 86.1, and 77.1%, respectively. Along the main canal conveyance efficiency was also determined by measuring the flow at the intake point of the network and discharge through outlets along the main canal then the ratio of sum of order 2 canal discharges to the total upstream discharge was obtained to be 94.8%. Due to lack of maintenance and repair of destroyed parts, particularly in distribution portion, irrigation network has lost its effectiveness after thirty five years of operation. In western part of the irrigation network which does not have long life, ineffectiveness was even more considerable.