Journal of Agricultural Sciences and Natural Resources
Year:2006 | Volume:13 | Issue:1|Papers Count:22

To evaluate, design or simulate border irrigation it is necessary to determine infiltration equation that represents natural field conditions for border irrigation. In this research, the parameters of the Kostiakov-Lewis infiltration equation for border irrigation in experimental farms of Isfahan University of Technology, Lavark and Khazaneh were determined using volume balance method. Field data collected including border length, border width, border slope, soil texture and measured data of advance time, recession time and border inflow and outflow. Using surface irrigation model input data including infiltration equation parameters, the surface irrigation model was studied for different field conditions and the sub-surface infiltrated water profiles were plotted. The results showed a good agreement between experimental data and model prediction.

Estimation of the water requirements of irrigated crops is one of the most important stages in designing irrigation and drainage projects. The accuracy of this estimation could secure the water requirements of field crops; it will also save water consumption. In general, water requirements of field crops is estimated by FAO-Penman-Montieth method based on the data collected from well irrigated stations (reference stations). However, most of the climatologically stations are not located in places where irrigation is practiced. These stations are referred as non-reference stations. Therefore using data of these stations might cause an overestimation of the evapotranspiration. In this study, the effect of site aridity on temperature and humidity data of Mashhad and Golmakan synoptic stations was surveyed compared with a reference station in Golmakan, during 136 days of the growing season.Evapotranspiration was estimated with Hargreaves-Samani and Samani methods in which only temperature data and geographic coordination of the station is needed. Based on that, the effect of aridity on evapotranspiration was also evaluated. The results show that the situation of Golmakan synoptic station is very similar to the reference situation because of the station position. Therefore, we can quite safely make use of the data of this station as reference data. But the effect of site aridity in Mashhad synoptic station is very clear.

Reference evapotranspiration (ETo) is a term used for a grass/alfalfa medium under no-stress conditions. ETo can be measured under lysimeters, or estimated by the empirical equations. Due to lack of lysimertric data in the Golestan province, and because of the acceptance of FAO-Penman- Monteith (F-P-M) as a standard method, we adopted two different groups of compound/temperature based ETO under three conditions of data. These conditions are not corrected, and corrected based on local and/or universal coefficients. In this way regression coefficients and statistical tests were conducted for the methods used. The results showed that Penman and Blaney-Criddle-FAO methods have highest and lowest R2, respectively. It was also showed that the stations of Gorgan and Gonbad did not need any aridity correction, while the Maraveh-Tappeh did need. Two methods of local and universal aridity corrections were almost similar. It was found that estimated daily ETo by Hargeaves- Samani method could be converted to corresponding ones of F-P-M via a suitable equation.

Erosion is defined as the separation and transference of the soil particles from the surface, which can take place by water or wind. Among the factors affecting soil erosion by water are; water or rain erosivity, soil erodibility, slope of the surface, coverage of the soil surface, and soil management. Rain erosivity index is the most well known index renderd in the universal soil loss equation (USLE) which is called as Wischmeier index (R). This index is defined as the sum of (E.I30) in which E is the kinetic energy of the rain and 130 is the maximum intensity of 30 minutes rain. in this research first a relationship between kinetic energy of the rain and its intensity was established. This work was conducted by a rainfall simulator. Then, Theran rainfall data extracted from the graphs of rain gauge record was collected. Rainfall data course was for a period of 20 years. Therefore, it was possible to calculate the total kinetic energy and then the R factor. The annual estimated average R in Tehran was 98 Mj.mm/ha/hr. Also it was possible to calculate the erosivity index for the whole year. Based upon the index of R for each rain or the annual R relationships between R and some rainfall parameters were investigated. These parameters were, amount of climate, daily rainfall, maximum daily precipitation, average 6-hour prectitation. Erosivity index for different return periods was also calculated. By this means, for which regions having the same type of the climate, the amount of erosivity index can be estimated.

This experiment was conducted to detennine the effects of temperature and photoperiod (day length) and various planting densities on branching and leaf appearance and senescence in chickpea (Cicer arientinum L.) var. Hashem. The experiment was carried out at Agricultural Research Station of Gonbad, Iran in 2002 in a Randomized Complete Block Design in a split plot arrangement with four replications. Main plots consisted of three planting dates (5 December, 20 January and 5 March). Four planting densities of 16, 32, 48 and 65 plants per square meters were designated as subplots. The results revealed that node (leaf) appearance on the main stem begins at 6.7 Biological Days (BD) after planting and continues at the rate of 1 node day-1 but no further leaves were produced after 35 BD when main stems had approximately 28.5 nodes. Leaf senescence on the main stem commenced after 16 to 20 BD and it continued at 0.65 leaf BD-1 until all leaves on the main stem died Appearance of leaves on the plant consisted of two phases and they were closely related to the node appearance. At the first phase, 2.9 leaves were added to the whole plant leaves with each increase in node on the main stem. The second phase started when there were fourteen nodes on the main stem. At this phase, 8 to 15 leaves were added to the leaves of the whole plant with each increase in node on the main stem. Leaf deaths on whole plant were closely related to leaf senescence on the main stem, and it had two phases. With each percent of leaves death on the main stem 0.5 and 2 percent of whole plant leaves died at first and second phases, respectively. Mean leaf life was about 23 BD. The results suggest that leaf and branch appearance and senescence in chickpea could be quantified using different equations.

To examine the effects of plant densities and sowing pattern on yield and agronomical characteristics of corn Hybrid T.W.C.647, a field experiment was conducted in 2001 and 2002 at Agricultural Research Center of Iranshahr. This experiment was laid out in a randomized complete block design arranged in a split plot with four replications for two years (2001-2002). Plant densities (D1=70000, D2=80000, D3=90000, D4=10000) were as main plot and sowing patterns (p1=single row, p2=double row with 15cm space and p3=double row with 20cm space) were as subplots. The results of combined analysis over two years showed that by increasing plant density, traits such as grain yield, forage yield, ear height, leaves, steam, ear and cob dry matter increased. But characters such as number of grain in ear, ear diameter, ear length, kernel weight, husk dry matter number of kernel in row and harvest index decreased. Most characters such as grain yield, forage yield, leaves, stem, ear, ear cob dry matter, total kernel per ear, ear diameter, ear length, kernel weight and number of kernel per row were increased by changing of planting pattern from single row to double row. Plant density and planting pattern interaction effect were significant at %1 level in grain yield and forage and 15 centimeter double row, 90,000 plant density traits with 14170 kg ha-1 produced the highest grain yield. The highest biomass (23330 kg ha-1) was produced on 15-centimeter double row, 100,000- plant density trait treatment. Also kernel weight, number of grain in row, harvest index, ear high, ear length, leaf, stem, ear, cob and husk dry weight also significant at %1 level level. The difference in number of grain in ear, husk dry weight, ear diameter, number of row grain in ear, was signification at %5 level. It was concluded that by using double planting pattern the inter plant competition was decreased and we could get high yield.

In order to investigate the change in morphological and Physiological aspects of different wheat cultivars and effect of them on increasing yield potential, an experiment was conducted in 1999 at the farm of agriculture faculty, Ferdowsi University of Mashhad. In this experiment, twelve wheat cultivars, which were released during the years of 1951-1995, were experimented in a Randomized Complete Block Design with three replications. The results indicated that Alamo cultivar with yield of 4259 kg/ha and the Omid cultivar with 2963 kg/ha had the highest and lowest yields, respectively and other cultivars had no statistical significant difference in this case. All cultivar differenced in total biomass and in this case Navid cultivar had the highest biomass (16630 kg/ha) and Ghods cultivar had the lowest (10300 kg/ha) while between the cultivars, the highest harvest index belong to Ghods and the lowest belong to Omid cultivar. Also in three cultivars, between H.I. and grain yield existed high positive correlation (R=0.65) but, grain yield did not show any correlation with total biomass. The amount of extinction coefficient (k) was higher in new cultivars compared to old cultivars. So that Azadi and Bezostaya cultivars had the highest (K=0.6) and lowest (K=0.26) respectively. The cultivars of third group had less tillering compared to other groups that indicate densitibility at new cultivars to old cultivars. Leaf Area index and Relative Growth Rate were higher at first group compared to other groups. Chlorophyll amount was difference until an thesis stage but did not exist any difference in an thesis stage. That was negative correlation between wheat heights and releasing year at all groups. Old cultivars had higher stem length and less number of grain in spike than new cultivars, but had no significant difference in grain thousand weights. Analysis between different traits indicated relatively positive correlation between flag leaf area and grain yield (R=0.99), high negative correlation between plant height and grain yield (R=-0.51) and, high negative correlation (R=-0.99) between number of floret in spike and grain yield.

In an attempt to provide ecosystem management plans, the ecological status and potential capabilities of the nomadic ecosystems of Yekkeh chenar have been studied in an area of 19240 hectares south of Maraveh Tappeh in Golestan Province of Iran. After calculating minimal area for each plot, the plot techniques were used to collect field samples and determined major plant types together with dominant species in each type. The range condition was assessed by using the six-factor method, its trend through the scaling method and grazing capacity employing cutting and weighing in each of the six identified range types. By offering improvement and development, plans and nomadic allotment map for each group of nomads and the range types based on the assessed conditions were developed.

In order to determine the most suitable cultivar and N level on yield, yield components and protein content in grain of grain sorghum, an experiment was conducted at Isfahan University of Technology Research Farm located at Lavark, Najaf-Abad during summer of 2000. The experiment was arranged in a split-plot design with four replications. Four levels of nitrogen (0, 50, 100 and 150 kgN/ha) were the main plot and the subplots were four sorghum cultivars, including Payam, Sepideh, Local and Kymia. Seeds were hand sown on June 5 the with a inter row space of 60 cm and intra row space of 10 cm. The result showed that with increasing level of N, number of ear on plant, number of grain in ear, weight of 100 grain, biological yield and percent of protein in grain increased. There was significant difference among cultivars for all characteristics. Local cultivar produced the highest number of grain in ear, weight of 100 grain, yield of grain, biological yield and percent of protein in grain. This cultivar produced 9.42 ton/ha grain with 13.65 percent of protein. Local cultivar produced the highest yield of grain followed by Sepideh, Payam and Kymia, respectively and also Local cultivar produced the highest protein content in grain followed by Payam, Kymia and Sepideh, respectively. Based on the results obtained Horn this study, 100 kg N/ha was the most suitable N level for yield of grain, thought 150 kgN/ha level produced. The most grain yield but it was not significantly different from 100 kgN/ha level. For percentage of protein in grain, 150 kgN/ha was the most suitable level. Local cultivar was the best and produced the highest grain yield and protein content in grain.

Salinity is one of the most important problems of Iran. The effects of salinity and potassium on growth and proline accumulation of two barley cultivars (Reyhan and Afzal) were investigated in a randomized complete blocks design in sand and half-strength Hoagland solution culture. The results have shown that, photosynthesis, stomata conductance, transpiration rate, tissues potassium content and dry weight of shoots and roots decrease by increasing of salt concentration. This dry weight reduction was higher in Reyhan cultivar. Under sand culture medium, proline content of shoot of both cultivars, treated with NaCl, were higher than those of control plants. However, application of potassium accompanied by salinity resulted in more roots and shoots tissues with higher shoot tissues potassium content. This may be due to more uptake of potassium instead of sodium. Since most of the higher plants have high selectivity in the uptake of K+ as compared to Na+. According to the above results, it seems that cultivar Afzal exhibits a higher salt tolerance than Reyhan cultivar.

The purpose of this study was to examine the relationships between plants communities and certain physiographical variables including elevation, slope and aspect as well as rainfall in Babolrood Basin, Mazandaran province. Vegetation and topographic maps of the study area with the scale of 1:50000 were digitized. Digital Elevation Model (DEM) was constructed and slope and aspect images were derived from DEM. Rainfall map of the area was also prepared. Vegetation map was coregistered to other images. At least 90 points were randomly located and sampled in each vegetation types and their values were extracted from the slope, aspect, elevation and rainfall maps. Vegetation and different layers were overlaid and cross-classifed to examine the impact of the variables on discrimination of different plant communities. The result of ANOVA showed that there is a significant difference between vegetation types and the variables. Discriminant Function Analysis was performed to understand the discriminatory power of the variables. The results confirmed that the attitude and rainfall are the most important variables to distinguish spatial distribution of plant communities in the study area.

The Ghreso watershed basin with an area of about 1700 km2 is located in the southeastern part of Caspian Sea. The aquifers of this watershed with width of about 700 km2 consisted of the unconfined aquifers in the south and multiple unconfined to confined aquifers in the north and middle parts of the study area. Surface factors, which have threatened the contamination, especially high nitrate concentration, of the aquifers, are consisted of shallow depth of ground water, intensive agricultural activities in the plain, burial of Gorgan municipal effluents and coarse-grain texture of the southern aquifers. In order to assess effects of these parameters as well as determine the sources of nitrate pollution, sampling was carried out from 30 shallow and deep wells in two stages, pre-agricultural activity (may 2000) and post-agricultural activity (September 2000). According to the analytical results of collected samples from unconfined aquifers with depths of about 5 to 35 meter deep wells, which are drilled in confined aquifers, mean concentration of nitrate in the wet and dry seasons fluctuate between 7.26-12.56 mg/l and 10.79-33.70 mg/l in the deep and shallow aquifers, respectively. These results indicate that the unconfined shallow aquifers are more susceptible to pollution than deep confined aquifers. Moreover, nitrate concentration enrage between 10-67 mg/l in the Ziarat, Garmabdasht, and main branches of Ghreso rivers. So, this investigation manifests the agricultural activities and municipal wastewater along with surfacial runoff of the area play the most effective influences on the increasing of nitrate concentration in the aquifer.

Continues man's demands to soil resources and increasing of common knowledge from soil degradation and erosion have increased the need for confident evaluation and assessment of soil degradation rate and potential for food production. Moreover, information on sediment transport and nutrient from watershed and its erosive process are some necessities emergency for watershed management. The main objective of this study is to assess the Morgan and Morgan-Finney model using GIS in some part of Mehr watershed of Sabzevar. After collecting basic information, required maps with regard to fieldwork and typical tables of the model in water phase, average annual precipitation intensity was lumped and the other variables of this phase were taken as distributed variables. In the sediment phase, all model input variables in unit works were considered as distributed variables except soil erodibility factor for preparing map of soil detachment by splash. All input variables for generating the sediment transport by overland flow map (G) were used as distributed variables. Finally annual soil loss map was prepared from comparison of (G) and (F) maps and taking their minimum rate. In general, soil loss followed from (F) map and from 3 sub watersheds for model calibration, only in one case (actual was 4.8 times estimated) estimated results are close to actual. Average physical process of soil detachment and sediment transport were about 1.29 and 247.2 kg m-2, respectively in this sub watershed.

In many dry and mountainous regions of Iran, choosing land use and land, management is done without paying attention to land capability and land potentiality, which causes the loss of capital and also reduces the ecological capacity. The research zone, posht--e-kouh watershed, is located between Sari and Damgan spreading 41200 hectares with cold semi-arid climatic type. In this research, after preparing and collecting the main data layers from environmental resources, by using current systematic model in land use planning with bicompound and manual methods, the ecological potential of 387 environmental units are assessed. In continuation, by using the comparative qualitative method, the possible land uses priority has been determined and then the watershed land use planning map has been organized with 14 land use types and 76 nonrepeatedly equi-potential polygons at 1:50000 scale. Obtained results show that two range management and dry farming of class 1 (33 percent of the zone), and agro forestry (25 percent of the area) land uses contain the most area of the watershed. According to these matters, posht-e-kouh watershed is suitable for dry farming and range management utilization. Due to extremely geological unsuitable condition and lack of water and flood hazard controlling, the area requires to develop the multipurpose land use and production systems (Agro Sylvo Pastoral System). One of the most important results of this research is the requirement of the improvement of comparative qualitative method in the determination of land use priority due to incorrect effect of unequal number of classes between land use types.

An indoor rearing study was conducted for 12 days to evaluate the effects of photo tactic response, light and photoperiod on survival and growth in Rutilus frisii kutum larvae from 45 to 54 degree-day post hatching was investigated. Photo tactic response was measured as the number of larvae that responded by horizontal swimming toward, a light source (F) and median travel distance for the responding fraction of larvae (M) and was compared with control group (C) with 4.5 mg initial larvae weight. Larvae fed decapsulated Artemia cysts (first day), live Artemia nauplii (4 days) and live Artemia nauplii in combination with dry feed (7 days) under 24h continuous white light (24WL), 16h white light-8h dark (16WL:BD), 12h white light-12h dark (12WL:12D), 24h continuous red light (24RL), 16h red light-8h dark (16RL:BD), 12h red light-12h dark (12RL:12D), or complete darkness (0L or 24D).The specific growth rate (SGR) and final biomass was significantly greater (p<0.05) in a part of larvae responding photo tactically (F) and were reared under continuous red light (24RL) and lowest in the 0L treatment. Twenty four hours continuous red light promoted higher survival but there was no significant (p>0.05) different between treatments.

In order to identify the variability of characteristics of Colletotrichum gloeosporioides (Penz.) Penz. & Sacc.in Penz., the causal agent of citrus anthracnose, samples were collected from Golestan province during 2002-2004. Single spore isolates were derived from all of the cultures on potato dextrose agar (PDA). Then, all of the isolates were surveyed. The isolates were settled into two groups, differing morphologically and pathologically. The first group, were fast growing isolates with gray colonies and produced abundant mycelia. Conidia of this group were cylindrical with both apices rounded. The second group, were slow growing isolates with orange colonies and abundant production of conidial masses. This group had smaller fusiform conidia, most with one fusiform apex and the other apex was rounded. The growth rate of the first group was two time faster than the second group on PDA. Also, cultures of all isolates were grown under continuous light on PDA and examined for the presence of setae after 10 days. Most of the first group isolates produced four-septate setae. The second group isolates did not produce setae. In according to examine the pathogenicity, cultures of all isolates were inoculated to the leaves and blossoms of sweet orange (Citrus sinensis) trees. All isolates could not be compared pathogenically on detached blossoms. Also, inoculation with first group isolates produced no typical post bloom fruit drop symptoms; but the second group isolates were retrieved of diseased petals. The first group isolates were retrieved of the leaves. No typical symptoms were observed of inoculation the second group isolates to leaves.

The processes of rice production respect to other crops require to high mechanical power and human force and it is done by human force in Iran. At this research factors effect on requirement power and threshing losses, namely; drum speed, feed rate and effective length of threshing for two rice varieties (binam and 507) with different moisture conditions have studied after design, fabrication and evaluation of a new head-feed thresher. The threshing capacity of designed thresher was over two tones paddy per hour. The threshing losses were negligible. The maximum of measurement power of threshing and feed unites have been 2120 watt (variety) and 223 watt (variety 507) respectively. The effects of independent factors on requirement power and threshing losses are significant commonly. Only the effect of drum speed on requirement of feed unit was no significant.

In this study, welfare-effects of the guaranteed purchase policy on dates, cotton and raisin in Fars province was studied alongside with the similar effects of direct payment policy as an alternative. Two general views were considered to investigate the current situation of the guaranteed purchase policy. First, pessimistic view on the policy was reviewed by comparing the current situation with full covering of the policy where total produced dates, cotton and raisins can be sold at the guaranteed prices. Then, the effects were compared with and without the policy. Moreover, optimistic view on the policy by which the market price is believed to be higher at the existence of the policy was also studied. Finally, the guaranteed purchase policy was compared with direct payment policy. Although the results were not perfectly similar for all studied products, it seems that the latter policy has some advantages and therefore may be regarded as an alternative for the former.

Twenty-eight Dalagh male lambs (20±0.8 Kg average live weight, 6-7 months old) were used to study the replacing different levels of feeding barley grain by sugar beat pulp. Measurements were made of dry matter (DM) intake, growth, biochemical changes and carcass composition. The animals were allocated by randomized block design on the basis of live weight to one of four dietary treatments of T1 (0%), T2 (25%), T3 (50%) and (75%), respectively. At the end of the study from each treatment three lambs have been slaughtered for carcass compositions. Between average daily growth rate and final weight of the treatments had certain significant (p<0.05). T3 had the maximum final weight (35.22 kg) compare to T1 (31.14 kg) also T3 had the maximum daily growth rate of 176.82 gr against 125.5 gr of T1. Dry matter intake were significant effect among the treatments (P<0.05) but no different in feed conversion efficiency in all the treatments were observed. Diet composition had no significant influence on all the parameters of carcass characteristics except digestional tract (P<0.05). T1 had the maximum digestional tract weight than other treatments. It is concluded that as a results suggest that any limitations in growth performance by young male Dalagh lambs fed a diet containing high levels of MSBP may be effectively abolished by the replacement with barely at a substitution rate of 50%.

One t-test experiment was conducted with two rations including diammonium phosphate or dicalcium phosphate. Eighteen fattening young male cattle were used in each experimental group for 166 day experimental period. The animals were weighted every two weeks and serum calcium and phosphorous consentrations were measured before and during the 5th month of experiment. Average daily gain of the animals was 1.112 kg. There was not any significant differences of body weight gain between the diets in most of the periods except for the 5th period which, the diet contained diammonium phosphate had significantly higher weight gain (P<0.05). Average serum calcium and phosphorous consent rations of two experimental groups were similar with no significant differences between them (P>0.05). It is concluded that, by taking some considerations dicalcium phosphate can be completely replaced by diammonium phosphate in the diets of fattening young male cattle.