THE SCIENTIFIC JOURNAL OF AGRICULTURE (SJA)
Year:2006 | Volume:29 | Issue:2|Papers Count:13

Application of iron (Fe) chelate is one of the most effective methods for correcting iron deficiency in calcareous soils. However, its efficiency may decrease due to the antagonistic effect of Fe on some nutrients including manganese (Mn).' An experiment was conducted in a loamy soil, low in available Fe (Fine-loamy, carbonatic, thermic, Typic Calcixerepts) in order to determine the effect of Fe on seed yield (SY) and chemical composition of 12 soybean [Glycine max (L.) Merril] genotypes under greenhouse conditions. Treatments consisted of a factorial arrangement of Fe rates (0, 2.5, and 5 mg kg-1 as Fe-EDDHA) and 12 soybean genotypes. Results of current study showed that Fe application only increased SY of Black hack but decreased that of Wells and had no significant effects on other genotypes; therefore, it seems that top dry weight response to Fe is not an adequate criteria for predicting SY of soybean genotypes. Addition of Fe increased mean seed Fe:Mn ratio and seed Fe concentration and uptake but had no significant effect on those of copper (Cu). Iron application had no significant effect on mean zinc (Zn) or phosphorous (P) concentrations. Iron application increased mean Zn uptake but reduced Mn concentration and uptake and P:Fe ratio. Also, our previous results indicated that application of Fe decreased Mn concentration in all soybean genotypes shoot. A significant regression equation between applied Fe rates and seed Mn concentration was obtained (R2=0.60). Iron did not increase soybean genotypes seed yield probably due to antagonistic effect of Fe on Mn absorption and or translocation. Growing Fe-efficient soybean genotypes is an appropriate approach for Fe deficient calcareous soils.

The objective of this project was to increase shelf life and partial clarification of date fruit extract. Major factors affecting the physiochemical characteristics of date fruit extract, pH, extraction and clarification method, were taken into consideration as variables and different treatments of date extract were made accordingly. The effect of each variable was monitored by measuring light transmission at 420 and 520 nm as color and clarity indices respectively as well as measuring soluble solids. The experimental trials were analyzed for pH and formic acid content. Total microbial, yeast and mold counts were also performed on the raw and clarified materials. The results indicated that the acids alone had no significant effect on color and clarity nor on had pectolytic enzymes. It was found that there were significant interaction effects between type of acid and enzyme in order to improve color and clarity. It was observed that employed process was effective in reducing total count of the product particularly due to application of acids.

In order to evaluate the shear strength parameters of compacted soils precisely it is necessary to determine these parameters in the laboratory by the compaction tests using remolded samples. The laboratory compaction test conditions should be comparable to the field compaction conditions. It is a common practice to conduct the compaction test in the laboratory using the dynamic compaction method (Proctor method) in which compaction is being performed by a hammer whereas sheep foot and smooth steel rollers are utilized in the field. In this study, evaluation of the effect of various compaction methods on shear strength parameters c and j and unconfined compression strength qu of soils has been done. The fine-grained soils selected in this study have been CL-ML, CL and CH classified according to Unified Soil Classification System. Static and dynamic compaction tests have been conducted on many remolded soil sample. The unconfined and triaxial compression tests have been done on these samples. The results of the unconfined and triaxial tests obtained from the samples compacted by the static method have shown greater strength compared to those obtained from the dynamic method.However, statistical studies indicate that the method of compaction has no significant effect on the shear strength of soils.

Some chemicals that have been proposed as attractants or feeding stimulants for termites were investigated to determine their effect on food consumption by the subterranean termite Microcerotermes diversus Silvestri in the laboratory. Paired choice feeding tests were conducted where consumption of chemically treated and solvent-treated filter paper disks were compared for each chemical over a range of concentrations. With the exception of hydroquinone, other chemicals acted as feeding stimulant at I or 2 concentrations in this study. Hydroquinone acted as a feeding deterrent at concentrations of 200 and 500 ppm. Adding lecithin to filter paper at concentrations of 1000 and 5000 ppm significantly increased consumption compared with control filter paper. Significantly more filter papers treated with L- aspartic acid or L- glutamic acid was consumed by M. diversus Silvestri at concentration of 1000 ppm than was control filter paper treated with water. Filter papers dipped in 0.8% urea solution were consumed significantly more than untreated filter papers. Collectively, these assays suggest that some food additives especially nitrogenous compounds may increase the efficacy of baits when used against termites in the field conditions.

F.oxysporum f.sp. tuberosi is the causal agent of wilt, dry rot and stem end rot in potato (Solanum tuberosom). This investigation was carried out during 1999-2000 growing seasons to determine pathogenicity and vegetative compatibility groups in population of F.o. f.sp. tuberosi. Diseased poptato plants were collected from major potato producing areas in Fars (Daryon, Kooshkemola, & Maharloo) & Khuzestan (Aghili) Provinces. Totally, 57 isolates of F.oxysporum were isolated from root, crown and stem of potato using acidified PDA and Nash & Snyder media. Fifty of these were selected for the study. Results of the pathogenicity tests showed that 98% of isolates were pathogenic to potato plants, causing wilt disease symptoms on Draga cultivar plants, alld about 20% of these isolates camed dry rot symptoms on tubers of the same cultivar. Collectively 607 nit mutants were generated on PDC containing 3% KClO3. nit mutant phenotypes were identified based on their growth on Basal Medium (BM) containing one of the four different nitrogen sources (nitrate, nitrite, ammonium and hypoxantine). Results showed that 78.9%, 12.5% and 8.6% of nit mutants were nit1, nit3 and NitM respectively. The complementation test showed that there was 8 vegetative compatible groups among the isolates. There was a relationship between VCGs and disease type. Groups A, B, D, E and F caused wilting but members of C, G and H groups produced both dry rot and wilting. No relation was found between geographic origin of the isolates and their VCGs. Only isolates of F and H groups were found in the same location.

In order to determine the redistribution efficiency and redistribution of dry matter in different dryland wheat genotypes under supplimental irrigation, an experiment was conducted in 1998-99 at Ghamllo research station of Kurdestan province. A split plot based on RCBD with four replications, five main plots and six sub-plots were applaied. Main plot treatments consisted of five treatments including no irrigation (check), irrigation at sowing, flowering, milking and sowing + milking stages. Sub-plots consisted of six dryland wheat genotypes. Results showed that accumulation and redistribution of dry matter under irrigation were increased. There were significant differences at 5% probability level between irrigation and at 1% level between genotypes and irrigation * genotype for redistribution of dry matter. The highest redistribution belonged to irrigation at sowing stage with 97 g/m2 and the lowest belonged to milking stage with 53 g/m2. In this study, Sabalan cultivar with 93 g/m2 had the highest and Gelenson with 65 g/m2 had the lowest redistribution. It seems that the preference of Sabalan compared to other genotypes was related to capability of reserves of this genotype befor anthesis. Despite more dry matter redistribution in Sabalan genotype, redistribution efficiency of Sardari genotype was more under water stress conditions. Perhaps in terms of yield sustainability this is the reason why Sardari genotype could have better performance under water stress conditions during grain fillings.

Since drought and flood events have frequently hit various Iranian communities, prediction of precipitation plays and influential role for sustainable development. The canonical correlation analysis (CCA) is an elegant statistical model for investigating temporal and spatial variations of meteorological, hydrological and ocean graph variables. This model is extensively used for the seasonal prediction of rainfall and sea surface temperature (SST) over tropical regions. In this study, the monthly rainfall data in nine synoptic stations speared over different parts of southern Iran as well as the Persian Gulf (pG) sea surface temperature data for the period 1959-1993 were considered for developing CCA model for prediction of precipitation in the south west of Iran. The empirical orthogonal function (EOF) was carried out for the purpose of data reduction and extracting the principal components of SST such that two principal components of the precipitation data and four principal components of SST were considered. The retained EOFs of the rainfall and SST data are accounted for about 78% and 73% of total variance in the observed values, respectively. The first rotated EOF of rainfall data has a high loading over Fars, Bousher and Khuzestan provinces. The 2nd rotated EOF was dominant over Hormozgan province. The rotation is generally employed for the detection of the dependence of each PC with the raw data set. The amplitude score of predict and (precipitation) and predictors (SST) are used as the CCA input files. The results hav indicated that the fluctuations of SST in central part of the Persian Gulf, off the coast of Bousher, are accounted for a large portion of the total variance in SST data. These fluctuations during winter time play an essential role for explaining the variance of considered rainfall data. The four retained EOFs of the PG SSTs are accounted for about 27% of total variance of winter rainfall. The influential role of the PG SST was more evident over Fars and Bousher rather than Khuzestan province. The SST process during spring and summer was found to be a considerable element influencing winter rainfall in Khuzestan.

The main pollutant factors affecting Isfahan groundwater were studied and the intensity of each factor as well as effected area were evaluated. Zayandeh Roud River has been made a special case on the aquifer. So 21 of existing wells and municipal drinking water were selected as water samples. The microbial and chemical analyses were done in two time steps on the water samples. The chemical result shows that there are four following types in the aquifer, calcium bicarbonate, calcium sulfate, sodium chloride and sodium sulfate. A major part of aquifer from the river axis to Darvazeh-Tehran and Razmandegan Square are affected by river water. The north part of the aquifer is the effect of Ghohab aquifer. The southern east part of the aquifer water type is sodium sulfate and calcium sulfate because of shale bedrock. In this area, the water quality decreases from south of aquifer to the river in the north. Nitrate pollution was seen as a source point pollution near the Takhte-Folad and Faize Square with a maximum concentration 120-mg/l. we concluded that the dead burning and spreading of its contamination toward the water table may be the main factor of rising nitrate in groundwater. The Coliform numbers in a 100 ml of sample was 3.6 to 460 that presents a high microbial risk. It was concluded that the river water is polluted because of recharge of wastewater, and the Groundwater is polluted because of the seepage from the sewage pipes. Heavy metal contamination in groundwater is also evaluated. There are some noticeable signs of heavy metal contamination, but more experiment is needed.

Date bunch fading disorder has been one of the important problems of date growers in Iran. It usually takes place during fruit development from 'khalal' to 'rutab' stage. In this study, the effects of two factors, including different thinning methods and bunch covers, were studied as factorial experiment in form of Randomized complete block design with 16 treatments and 4 replications on date palm cv. "Kabkab" in Boushehr province, during 2002-2003. Sampling for determining the treatment effects on disorder damage and fruits quantity and quality characters in experimental plots was done at harvesting time. The results showed that the above mentioned factors have significant effects on disorder damage at 1% level probability. The mean damage percent in aluminum Foil, mate-like basket, wax and control were 7.9, 8.6, 19.5 and 29.8 respectively. The mean damage percent in thinning treatments, one third of inflorescence tip at pollination time, thinning one third of bunch tip plus 10% of central strands at Kimiri stage, thinning one third of central strands of bunch at kimiri stage and control were 10, 11.5 , 14 and 21.8 respectively. The effects of thinning on weight, length and diameter of fruits and the effects of bunch covers on weight and diameter of fruits and pulp to seed ratio have been significant at 1% level 'probability. Finally, thinning of inflorescence tip at pollination time along with using mate-like basket cover are recommended as the best treatments for decreasing damage of the date bunch fading disorder and improving the quality characters of fruits.

Takrib is defined as cutting of the date palm frond stubs. Akfa is the most conventional device used for takrib. In some cases handsaw is also used. Utilization of motorized saw in some regions is recently reported. Unfortunately, there is no information about performance of these devices. Therefore, this research was conducted to evaluate the performance of these devices in a randomised complete block design with three treatments namely; akfa (A), handsaw (H), and motorized saw (M) with 8 replications on date palm C. V. "Barhee". Results showed that the differences in operation rate, quality, and workload means in short palms (shorter than 1.5 m) were significant, and M was faster than other devices in performing takrib operation. Operation rate in this treatment was 2.64 palm/hour (Pph) and is 1.4 and 2.1 times faster than H and A, respectively. Operation quality in H was better than operation quality achieved in A and.M. Heart rate, which was selected as a workload criteria in H & M, was in moderate level and was in high level in A. Heart rate for three treatments was 103, 122.3, and 130.1 for M, H, and A, respectively. In tall palms (taller than 1.5m) operation with M in combination with traditional climbing method was impossible. The difference of operation rate means for tall palms in H and A was significant and H was 1.66 times faster than A. Operation rate in H was 1.18pph. Difference of means for heart rate and operation quality in tall palms was not significant. Economic appraisal showed that takrib operation with handsaw is more economic in date groves smaller than 10 hectare. Consequently, with respect to the current mean size of date groves in the country, which was estimated to be lower than 1 hectare, handsaw is a more suitable device. The results also showed that there is a need for new and high performance method of performing takrib operation.

The relationships between L-asparaginase and urease activities with some soil characteristics were addressed. Simple linear and stepwise regressions, principle component analysis and path analysis have been used to demonstrate the associations. Twenty different soil series from Isfahan province were selected; the soils represent the soil variability of the region. Results indicated that L-asparaginase and urease activities are significantly correlated with soil organic carbon (OC) and total nitrogen (TN). No significant relationships were observed between the activity of the enzymes and particle size distribution, PH, cation exchange capacity (CEC) and calcium carbonate equivalent (CCE). Stepwise regression revealed that only OC could enter the model. Principle component analysis supported the results obtained by regression analysis. The significant relationship between the activities of the enzymes and TN was debatable because the role of soil nitrogen in adsorption and immobilization of the enzyme molecules were not previously demonstrated. Path analysis indicated that OC is directly related to the activities of the enzymes whereas the direct effect of TN on L-asparaginase and urease activities is low. Therefore the associations of TN with the soil enzyme activities are mainly indirect due to strong correlation of OC and TN.

A survey was carried out to determine aphids fauna and their natural enemies in wheat and barley fields in Khuzestan during 2003-2004. Four species of aphids and seventeen species belong to twelve genera, as well as three genera and one subfamily of their natural enemies were collected and identified. Those with one and two asteriks are considered to be new records for the province and Iran, respectively. A) Aphids: APHIDIDAE: 1) Sitobion avenae (Fabricius), 2) Rhopalosiphum padi (L.), 3) R. maidis (Fitch), 4) Schizaphis graminum (Rondani). B) Natural enemies: COCCINELLIDAE: 1) Coccinella septempunctata (L.), 2) C. undecimpunctata (L.), 3) C. novemnotata (Herbst), 4) Adalia bipunctata (L.), 5) Hippodamia variegata (Goeze), 6) Scymnus levaillanti (Mulsant). SYRPHIDAE: 1) Episyrphus balteatus (De Geer), 2) Eupeodes nuba (Wiedmann), 3) Eu. Corolla (Fabricius) 4) Melanostoma melinum (L.),5) Sphaerophoria scripta (L.), 6) S. bengalensis (Macquart). CHRYSOPIDAE: 1) Chrysoperla carnea (Stephens).APHIDllDAE: 1) Praon gallicum (StaIy)**,2) Diaeretiellarapae (M'Intosh),3) Aphidiusrhopalosiphi (Destephani)*, 4)A. matricaria(Haliday)*. APHELINIDAE: Aphelinus jlaviventris.(Dalm.).ENCYRTIDAE:1)Aphidencyrtusaphidivorus(Mayer)**2) A.arundicola (Hoifer) ** MEGASPILIDAE: 1) Dendrocerus comwentziae (Gahan)**. EURYTOMIDAE: 1) Harmolita comatae (Phillips) ** 2) Eurytoma sp. (Illiger) ** . CYNIPIDAE: Alloxystinae*. In addition, the population aboundance of aphids and their natural enemies were determined in Ahwaz, Mollasani and Safi-abad. The parasitoids activity period was also determined.