Iran Agricultural Research
Volume:36 Issue: 1, Winter and Spring 2017

Heat-moisture treatment is a physical method for starch modification to improve its functional properties depending on the application. The functional characteristics of the heat-moisture treated starch depend upon the source of starch and treatment conditions including time and temperature. The main objective of this study was to determine the functional properties of heat-moisture treated wheat starch under different conditions. Therefore, wheat starch was heat-moisture treated at 105 °C for 14 and 16 h and the physicochemical properties of the starch were studied. The results showed that the heat-moisture treatment caused the formation of some cracks and spots on the surface of the starch granules, while preserving the whole integrity of the granules. The water solubility of the samples increased after modification while increasing the treatment time had negative effects on it. The x-ray diffraction pattern of the samples remained unaffected but the degree of crystallinity increased significantly. The gelatinization temperature increased while the enthalpy of gelatinization decreased as a result of modification. Gel texture became harder, less adhesive and elastic after modification. Increasing the treatment time dramatically enhanced all these properties.

Paddy soils make up the largest anthropogenic wetlands on earth. Present study was performed to investigate and compare soil formation of paddy soils with long-term rice cultivation history with non-paddy soils and study the effect of waterlogging on soil pedogenesis. Soil samples were taken from paddy and non-paddy soils derived from the same calcareous parent materials. Some pedogenic properties such as organic carbon (OC), clay content, iron fractions, pH, electrical conductivity (EC), cation exchange capacity (CEC), and calcium carbonate equivalent (CCE) were measured. Results revealed that paddy management had profound impact on soil formations and led to faster soil forming processes in paddy soils under flooded condition. In the studied paddy soils OC and CEC content significantly increased in surface and subsurface soils; but soil pH significantly decreased. Chemical analysis revealed significant increase of clay portion in subsurface of paddy soils and non-significant increase of EC in surface and subsurface of paddy soils. The CCE content in surface and subsurface of paddy soils was non-significantly lower than non-paddy soils. Rice cropping system greatly affected on different Fe forms; so that paddy soils had more available Fe (Feex), total Fe (Fet), and poorly crystalline Fe oxides (Feo), but lower pedogenic Fe (Fed) and crystalline Fe oxides than non-paddy soils.

Water management is an essential concept for water intensive crop such as maize dealing with water shortage under drought conditions. Maize production is ranked after wheat and barely in Fars province, Iran. Therefore, the present study was conducted to investigate the effects of planting methods by conventional and modified planters on maize growth and yield at different irrigation regimes under semi-arid conditions. Irrigation treatments were full and deficit irrigation (100 and 80% of crop evapotranspiraton (ETc), respectively), and planting methods of on-bed and in-furrow bottom. Experiments were conducted and analysed in a split plots design (planting methods as a main plot and irrigation as a sub-plot) with three replications. Though planting methods did not significantly affect the yield; total dry matter yield increased by 3.7% for in-furrow bottom planting as compared with that obtained in on-bed planting. Water productivity (WP) was significantly affected by irrigation treatments. Maximum WP for total dry matter was obtained at 80% of ETc and in-bottom of furrow planting by 4.6 kg m-3. Considering the soil moisture content during the growing season, planting in-furrow bottom and deficit irrigation as 80% of ETc is recommendable for drought conditions.

Soil salinity has been recognized as the most serious problems for agriculture in arid and semi-arid areas of the world. To evaluate the changes in some growth parameters and chemical composition of two forage sorghum (Sorghum bicolor var. sudanense lines (KFS1, KFS2) under salinity stress [0 (control), 3, 6, 9, 12 dS/m of sodium chloride], a pot experiment was carried out at College of Agriculture, Shiraz University, Shiraz, Iran in 2012 . The experiment was conducted as factorial arranged in a completely randomized design with three replications. Results showed that increasing salinity levels decreased accumulation of K, emergence percentage and other growth parameters, and increased Na, proline and total proteins contents in shoot and leaves. Stepwise regression and correlation analysis showed that root density is the most important factor for plant productivity. KFS1 line generally had higher power of survival, growth and emergence rate and can be a favorite one for selecting and crossing programs with KFS2 to obtain higher salinity tolerance.

Optimizing the source size and its utilization by the sink is one of the main factors enhancing the yield potential and decreasing water demand in crops when exposed to drought. To investigate the effect of defoliation on leaf water relations, chlorophyll content and yield components of five triticale genotypes including Sanabad, Juanillo, ET-83-3, ET-84-5 and ET-84-8 under well-watered (100% FC) and water stress (50% FC) conditions, a controlled experiment was carried out at Shiraz University in 2013. The results showed that ET-84-8 and Sanabad genotypes had higher chlorophyll content (ranged from 49.1 to 54.6 SPAD unit) under water stress. Among the triticale cultivars, water stress caused 21 to 42% decline in rate of water loss (RWL) In all genotypes except ET-83-3 and Juanillo, the excised leaf water retention (ELWR) was slowly decreased under water stress conditions. In all triticale genotypes except ET-84-8, water stress declined main shoot yield 21-22%, while in ET-84-8 was only 9%. Interestingly, in ET-84-8, grain number per spike was not affected by moisture regimes. Sanabad cultivar, with 2.57 g/g had the highest initial water content (IWC) at defoliation of all leaves except the flag leaf and penultimate leaf treatment under water stress. Under defoliation and water stress, ET-84-8 and Sanabad genotypes showed a greater 100-grain weight ranged from 3.60 to 3.74 g. It was concluded that triticale cultivars were more sink-limited especially under water stress, and source restriction by defoliation which had less effects on main shoot yield could be used as a useful tool for lowering water consumption during grain filling.

This study was undertaken to better understand the probable mechanisms of salt stress tolerance induced by seed priming of salicylic acid (SA) in barley. The barley seeds were pre-soaked by SA or water and then sown under different saline watering regimes including 0.62 (tapwater), 5, 10 and 15 dS m-1 in petri dishes and trend of water absorbing, seedling growth, germination rate and percentage were measured. After 11 days, seedlings were transplanted to pots and K and Na accumulation and storage factor were determined. The results showed that salt stress reduced absorbed water (50%), germination rate (39%), seedling growth (74%) and K accumulation (38%) and increased Na accumulation (fivefold). In all hours after sowing, SA-primed seeds had greater absorbed water with higher growth rate and this trend was true for all days after sowing. SA-primed seedlings had higher germination rate (30%), as well as, shoot (17%) and root length (38%). Enhanced K and reduced Na accumulation was also found in SA-primed seedlings. Reduction in Na absorption due to SA application was found to be greater at lower salinity stress levels and this was consistent with its effect on seedling growth. Storage factor, devised for quantifying partitioning of absorbed ions, were found to be increased for K and decreased for Na at higher salt stress levels; this means that at higher salinity levels, greater Na and lower K were transported to the shoot and this was associated with greater loss in seedling growth. Indeed, SA-primed seedlings showed a greater Na storage factor i.e. they kept more Na in their roots, in non- and light salt stress treatments. Accelerated water imbibition, greater germination rate, less Na, higher K accumulation, and greater Na storage in roots might be some mechanisms for salt stress tolerance in SA-primed barley seedlings.

In this research, the performance measures of water equity and productivity have been optimizedin the entire DoroodzanIrrigation Network by using genetic algorithms. Results indicated thatirrigation water management improvement at field scale[increasing irrigation application efficiency (Ea) and water reduction fraction (WRF)] has much more impressive impact on raising the performance measures than improvement of conveyance efficiency of channels (Ec).Increment of Ea (40% to 90%) andEc (70% to 90%)resulted inmaximumand minimumincremental effect onwater equity (on average 48.2% and 17.7%, respectively) and productivity (on average 92.0% and 10%, respectively).The incremental effect of WRF (0.0 to 0.8)on water equity and productivitywas on average31.4% and 10%, respectively.Furthermore, the values of performance measures decreased from wet water year to drought water year.Tape irrigation system was considered as the best choice at low quantities of WRF (=0.6), sprinkler irrigation system was considered as the best choice for achieving higher values of water equity and productivity.Meanwhile, when equity and productivity were considered together for a specific method of deficit irrigation scheduling, under specified quantity of irrigation water, with increasing equity the water productivity reduction was negligible.

The aim of this research is to present a simulation model for reducing economic damages of mechanized wheat harvesting in the weather conditions of Khuzestan province and similar areas. The simulated model is composed of three sub-models, for determining of the appropriate working hours, grain losses, and economic sub-model. In order to determine the appropriate working hours, a mathematical model was devised. For determining the grain losses, 52 fields in Hamidieh, a small town in southwest of Iran were selected. Several mathematical models were developed for predicting the natural cutting platform and combine end losses plus the percentage of broken seed. The average appropriate working hours was obtained by a computer simulation model based on meteorological information of an 8 year period. The maximum acceptable speed for two the combines, 955 John Deere and TC56, was 2.5 and 4 km per hours, respectively. A minimum grain loss happened in 4 days after physiological maturity and the best time range for wheat harvesting in Khuzestan was 2 to 15 days after physiological maturity. At the beginning of the harvest season the combine loss in the early hours of day, due to high moisture of crop, was more than the mid-day time or afternoon. However, after 10 days of physiological maturity, the reverse happened. Results showed that despite the growing cost of delay in harvesting, no matter how vast the fields are it will not justify combine ownership; thus employing rental combines is more cost-effective in fields of any size in Khuzestan.

The aim of this study was to determine the quinolone residues in beef and chicken meat samples collected from Urmia region local markets.A total of 395 beef and chicken meat samples varied in three various brands were analyzed in Urmia, Iran by using a sensitive and reliable analytic method based on ELISA detection, for quantification of quinolone antibiotics residues. Samples preparation was performed according to the instructions of the Ridascreen kit (RBiopharm AG, Darmstadt, Germany).Two hundred seventeen of 395 (54.9%) examined chicken meat and beef samples were found to be positive for quinolone antibiotic residue. Seventy-nine number (48.7%) of beef samples and 138 number (59.2%) of chicken meat samples were contaminated to quinolone residues. The mean levels of quinolone antibiotic residue were found to be 37.86± 0.57 μg/kg in positive chicken samples and the mean levels of quinolone residues were as low as 5.51± 1.17 μg/kg in positive beef samples. Present study indicated that 395 samples of beef and chicken meat sold in Urmia contained residues of quinolone antibiotics. In terms of preventing antibiotic resistance in humans, the low level of quinolone residue levels observed in this study represents a positive result for local food control.

The influence of intensive crop rotation on the distribution of potassium forms and clay mineralogy was assessed under a Mediterranean condition in the Piranshar region, northwest of Iran. For this purpose, surface soil samples in relation to six soil sub-groups from crop rotationfiled (sugar beet, wheat, pea, and barley) over five decades and the adjacent uncultivated lands were described and sampled. Soil analyses were concernedwiththe determination of physicochemical characteristics, clay mineralogy, the forms and adsorption properties of K. XRD-patterns revealed that soils were similar in clay mineral compositions, including illite, smectite, chlorite, and kaolinite for both cultivated and uncultivated soils, but some changes occurred in the peak intensity and position of the minerals mainly chlorite with cropping. Consistent with this, the sharp peak of chlorite (d001, 14.2 Ao) withthe intensity of 1700 to 1800 Cps in the uncultivated lands shifted toward peaks with intensity of about 1000 Cps in the adjacent cultivated soils along with the appearance of a disordered chlorite-vermiculite mineral.A pronounced decline in the solubleK from 0.001 to 0.53 mmol l-1 (a drop from 17 to 87%), exchangeable K from 6 to 115 mg kg-1 (a drop from 5 to 53%), and non-exchangeable K from 9 to 244 mg kg-1 (a drop from 1.5 to 29%) wereobserved for the majority of the studied soils as a result of crop rotation. Under cultivation, K adsorption effectively increased in the Chromic Calcixererts, TypicCalcixerolls, TypicCalcixererts, and TypicHaploxerepts where exchangeable and available K decreased.

Determining hydraulic conductivity of soil is difficult, expensive, and time-consuming. In this study, Algorithm Genetic and geostatistical analysis and Neural Networks method are used to estimate soil saturated hydraulic conductivity using the properties of particle size distribution. The data were gathered from 134soil profiles from soil and lander form studies of the Ardabil Agricultural Organization. Results showed that Or denary cokriging has the best fit for the geostatistical methods. The best-fitted vario gram was the exponential model with anugget effect of 0 cm day-1 and sill of 156 cm day-1 which is the strength of the spatial structure and full effect of the structural components on the vario gram model for the region; also, in the or denary cokriging method, an accurate estimate was obtained using R2 = 0.93 and RMSE = 3.21.Multilayer perceptron (MLP) network used the Levenberg- Marquardt (trainlm) algorithm with are gression coefficient (R2) of 0.997 and Root Mean Square Error (RMSE) of 1.22 to estimate the hydraulic conductivity of saturated soil. For GA model, parameters of root mean square error (RMSE) cm day-1 and the coefficient of determination (R2) were determined as 1.35 and 0.926, respectively. Performance evaluation of the models showed that the Neural Networks model compared with geostatistical analysis and genetic algorithm was able to predict soil hydraulic conductivity with high and more accuracy and results of this method was closer to the measurement results.

Nowadays farmers often use N-fertilizers to increase crop yield, but they lost quickly by leaching causes environmental contaminations that reported as most important source of pollutant. Although biofilters are useful for removing nitrate from drainage water, but many researches show that they need an external carbon source to sustain denitrification. Many researchers study on different method, but most of them need equipment or material that becoming use in laboratory experiment. So this study describes laboratory experiments that investigated nitrate removal with barley straw in different percentages layered or mixed with soil. Results showed that layering method was more effective for removing nitrate. The percentage of optimum volume mixture of barley straw in layering and mixing methods was 20% and 30% respectively, both removing approximately 80% of the influent nitrate. So barley straw can be used in a layered form as an effective, prompt, feasible and inexpensive method to remove nitrate.

One of the big problems today human societies are faced with is the problem of soil erosion. In this study, the "MPSIAC model" was used to estimate sediment yield and provide sediment yield map in Cachoyeh watershed. The MPSIAC method incorporates nine environmental factors that contribute to sediment yield of the watershed. These factors are: surface geology, soil, climate, runoff, topography, ground cover, land use, channel and surface erosion. ArcGIS 10.2 software was used to prepare the map of each factor and analyze them to create the sediment yield map and erosion map. According to the results based on MPSIAC model, 94.2 % (476.1km2) of study area was classified in the slight sedimentation and 29.2 % (147.5 km2) of it was classified in the moderate erosion classes. The total sediment yield of basin was calculated as 1236.5 (m3 km−2 year−1) and the total of erosion was calculated as 5091.6 (m3 km−2 year−1). The sensitivity analysis of parameters of MPSIAC model showed that the most sensitive parameters of the model based on their importance were: channel erosion, land cover and geology with Pearson correlation of 0.75 to 0.36. Land use factor was found to have a lower effect than the output model.