JOURNAL OF RESEARCH IN AGRICULTURAL SCIENCE
Year:2007 | Volume:2 | Issue:2|Papers Count:9

This experiment was conducted to compare, two methods of early feed restriction on the growth, performance and carcass characteristics of broilers. Two hundreds and sixty one-day-old broilers (Lohman) were assigned to five treatments with four replicates in a completely randomized design. Chicks were full-fed from 7 to 13 d or given 25% and 50% of ad libitum intake on a daily basis, or 100% of ad libitum intake on a daily basis, when the diets were diluted 25% and 50% with rice hulls. The body weight, feed intake and feed conversion ratio were determined weekly and carcass characteristics were measured at 49 d of age. Feed restriction depressed significantly (P<0.05) the body weight gain and feed conversion in restriction period. The chicks were able to fully recover body weight depression by 49 d. The method and severity of restriction had no effects on body weight, feed intake, daily gain and feed conversion at 13 to 49 d. The 50% qualitative feed restricted birds showed significantly (P<0.05) lower abdominal fat pad in comparison with the full-fed birds. The mortality rate was not affected by treatments. The results of this experiment showed with early feed restriction especially quantitative feed restriction at level of 25% we can get similar body weight between restricted and full-fed broilers at 49 days of age.

Effect of drought stress at three different stages of growth compared with normal irrigation and plant density at three levels on the yield and some agronomic traits of hybrid maize (Sc301) were studied on a research farm of seed and plant research institute (Karaj, iran) in the summer of 1998 by using a split-block design (strip plots) with three replications. The treatment included drought stress at three stages: before flowering, during flowering and during seed filling period compare with normal irrigation as check. The basis for drought stress was to stop irrigation until the moisture content of the soil reaches a tension of -15 Atmosphere at the above described stages and then starting the irrigation three days after that. Plant densities in three levels including 60000, 75000 and 90000 plants per hectare. The traits were: grain yield, kernel number per ear, 100 kernel weight, days to 50% anthesis, anthesis- silking interval and days to physiological maturity. The results showed that drought stress reduced the yield of corn. Drought stress at the flowering stage reduced grain yield about 42%. The drought stress at the grain filling period and before flowering reduced the corn yield about 15.8 and 12.5 percent.

In comparison to other horticultural crops, Citrus species are among the saline sensitive plants. One way to increas saline tolerance is by grafting sensitive cultivars on to tolerant rootstocks. Sweet orange (Citrus sinensis) is one of the most sensitive species to salinity of soil and water, and under such conditions, drastic reduction of both vegetative and yield occurs. The present study was conducted to evaluate salinity tolerance of Valencia orange grafted on different rootstocks, namely: Sour orange (C. aurantium), Mexican lime (C. aurantifolia), Volkameriana (C. volkameriana) and Bakraei (C. reticulata× C. limetta). These species are used chiefly in the southern part of Iran both as rootstock and seedling. The four levels of salinity imposed were: 0, 20, 40 and 60 mole L1- NaCl in a completely randomized design in factorial arrangement with four replications. One year old seedling of rootstocks were potted containing calcareous soil and grafted with Valencia orange scion. After six months, salinity treatments were exposed for ten weeks. At the end of the experiment, concentration and distribution of sodium, potassium and chloride ions in shoots and roots were measured. Rootstocks had a great effect on concentration of ions in scion. Concentrations and distribution of ions were significantly varied in control and other treatments. Salinity increased Na and Cl ions in shoots and roots, but the rate of increasing varied among rootstocks and treatments. The lowest concentration of Na and Cl ions were in the shoots of scion on Volkameriana and Bakraei. Under salinity stress K concentration increased in shoots of scion on all rootstocks. Salinity increased K concentration in root of all rootstocks. The general conclusion was that under the conditions of this experiment, Volkamer lemon and Bakraei, could induce salinity tolerance in Valencia orange scion.

Development of industry and heavy traffic in developed and some developing countries resulted pollution of resources such as soils, air and waters. Because of the pollution of environment, monitoring of soil, water and air pollution is of major importance. Biomonitoring of pollutants has been attracting attention of many investigators since early decades of 20th century and even earlier. Some plants and animals have been used as biomonitors in many parts of the world. We used Acacia trees in order to monitor the intensity of soil and air pollution to some heavy metals (Fe, Zn, Pb, Cu, Mn and Cd) in the city of Isfahan. Soil samples and leaves of Acacia trees, in four sites Khorasgan (suburban), Hashtebehesht street (urban center), Industry area and Bagh Bahadoran (rural area) were collected at two stages (June and September 2005) for chemical analysis. Chemical analysis of soil samples at depth of 0-10 cm showed that the concentration of most of these elements were lower than the maximum recommended levels. Concentration of measured heavy metals in washed leaves were lower than those of unwashed leaves of Acacia and the difference was significant. The stages of leaf sampling did not show any significant effect on the concentration of the measured heavy metals in leaf samples. There was no significant correlation between the concentration of heavy metals in washed leaves and the concentration of these metals in soil. Results of this investigation showed that the industry and traffic were the main source of air heavy metal pollution in Isfahan, and Acacia tree is a dependable biomonitor for air and soil pollution investigations.

The aim of the present experiment was to study effects of Sodiumnitroproside (NO donor) on sperm quality (motility and viability) Post thawing in the Afshari rams. Fifty 3 to 4 years-old rams of Afshari breed were randomly selected from a flock of fertile rams and were introduced in to a training program of semen collection by artificial vagina. Semen was collected and analyzed, diluted and then was stored at –1960 C for 10 weeks. After 10 weeks, samples were thawing. All samples were divided in to 5 groups and incubated with (0, 25, 50, 100 and 200 nmol) sodiumnitroproside. The results of this study were shown, the low concentration of nitric-oxide increased motility and viability of spermatozoa. However, high concentration of nitric-oxide decreased motility and viability of spermatozoa. These results suggest that NO may play an important role in controlling of semen quality then thawing in rams.

This study was conducted to evaluate the effects of planting pattern on and cantaloupe production in two methods of mulch and traditional planting. The experiment of design was split plot factorial with three replications in two years. The main plot was planting method in two levels, without and with plastic mulch. The sub-plots were two between row space (1.5&2 meters) and three different plant spaces on rows (25, 50 & 75 cm) which together in the form of factorial were put in six sub-plots. The length of rows was 4.5 m and each plot consisted of two planting rows. The volumes of water irrigation in mulch cover and without mulch cover were 2000 and 3500 m3 with 7 and 13 times of irrigation respectively. The results of this study showed that the use of plastic mulch in furrow irrigations increased WUE (Water Use Efficiency) significantly and caused better control of weeds but did not have any significant effect on yield. The effect of plant space on rows was significant on yield and WUE was at level of 1%.Between row space did not have significant effect on the yield and WUE. Classification of mean yields among treatments showed that the highest WUE (7.05 kg/m3) resulted in mulched plots with 50 cm plant space between rows.

To study the effect of flag leaf and awn removal on grain yield and yield component using Randomized complete Block design, at Research farm of college of Agriculture Islamic Azad university of Khorasgan located at Khatoon-Abad. significant difference was observed between grain yield and yield component except number of grain per spike and number spikelet per spike. In this study the deletion of photosynthetical sources strongly affected the absorbing sinks so that the flag leaf removal without shading on spike, decrease grain yield (%18). In addition to all leaves removal in anthesis with shading on spikes decreased grain yield and 1000 seed weight %77 and %66 respectively. The difference between treatments for protein percent was not significant. The flag leaf is the most important source for photosynthetical matter because it is the last leaf which appearance in the other way owns which lemma and palea are important source to fill the grain. Remobilization of photosynthetical matter in shoots is important factor in filling grain after anthesis than pre anthesis.

This research has been done to determine the maximum and minimum volume of potential Evapotranspiration (ET0) in Chahrmahal va Bakhtiyari province base on wet and dry years for a 12 years periods (1988-2000). Four meteorological Synoptic stations and 4 climatological stations were selected in the province and the data was collected for the period. The rainfall analysis showed that the 1993 and 2000 were most wet and dry years in the period, respectively. The ET0 value was calculated with Balany-Cridle-FAO (BCF), Penman-Montith-FAO (PMF) and Hargreaves-Samani (HS) methods by using REF-ET software. A recent developed model called Standardized ASCE method was used in this study, too. The calculated value was compared with the statistical index. The result shows that total volume of ET0 in BCF is greater 42 percent in dry season in comparison to wet season. It also shows that BCF method overestimate ET0 more than 9 percent in comparison with HS, whereas HS method was successfully evaluated with the lysimeter data in the province. The result shows that the BCF and ASCE give maximum and minimum volume of ET0 respectively in compression with HS. As the ASCE method is spreading widely in the world rapidly, it strongly advice to calibrate the method for the province.