گندم

This research was carried out to determine the type and contribution of each of the human, technical and agricultural factors affecting the amount of grain loss in wheat harvesting with threshing combines; in this research the economic evaluation of replacing the conventional combine with a threshing combine was also evaluated. One hundred combine harvesters were visited, examined, measured, and sampled in farmers' fields by random sampling. In addition to the measurement of technical indicators including forward speed, farm capacity, and combine wheel index, information related to farm and product conditions, type, age and fuel consumption of combines, farm area, amount of straw harvested in farms and economic data including types, costs, and incomes were collected by face-to-face interviews with farmers and owners of combine harvesters and completing questionnaires. The farm capacity of the combine was estimated to be 0.38 hectares per hour on average, which is about one-third to half of the farm capacity of common types of combine harvesters in the country. The fuel consumption was 14.01 liters per hour or 37.1 liters per hectare. The average total combined and natural losses of wheat in the harvest stage was 5.05%, and the shares of natural and combined losses were 1.28% and 3.77%, respectively. To use thresher combines instead of conventional combines in the country, more number of combines (almost double) is needed due to less farm capacity. In general, the use of combine harvesters instead of conventional harvesters increased the net income of farmers and combine owners by 317,5220 and 244,8840 Rials per hectare, respectively.

One of the effective ways to reduce agricultural operations as well as production costs is to use cobined machines. In this study a seed-fertilizer drill has been combined with a heavy disk and evaluated in field condition and compared with other reduced and no till methods. Main plots were four tillage-planting methods included of: designed combine machine (T1), no tillage with direct drill (T2), two pass disk fallowing with grain drill (T3), chisel packer fallowing with grain drill (T4). Subplots were seed rated at three levels included of: 150, 175 and 200 kg/ha. The results show that treatments were significantly different from view point of technical indices however they were not significantly different from view point of agronomy indices except Percentage of Emergence Percentage of Emergence. The highest and lowest rates of fuel consumotion assigned to T4 and T1 with 38.4 and 14.5 l/ha, respectively. Also T1 tretment fallowed by T2 treatmet had the second grade in field capacity with 1.66 ha/h rate. The combined machine could save in operation time and fuel consumtion related to T4 with 17.6% and 62.2% rates, respectively. The results of evaluation of seed rates showed that seed rates upper than 150 kg/ha didn,t have significant difference from view point of agronomy indices exceot to spike numbers per m2. According to these results, this combined machine (fertilizer -seeder equiped with heavy disk harrow) is suitable for conservation tillage and seeding of wheat.

In conventional combine harvesters, wheat chaff is typically removed from the end of the machine and deposited on the field surface. Depending on the wheat cultivar, cultivation method, and growing conditions, the amount of chaff produced can range from 0.8 to 1.5 times the amount of grain harvested per hectare (Tavakoli, 2012). On average, this translates to an annual production of approximately 14 million tons of chaff, which is valued at around $240000000 based on regional prices in 2018-2019 ($1000 per kilogram). If collected, these chaff residues could be used as animal feed for livestock. Additionally, the long stems protruding from the back of conventional combine harvesters can interfere with subsequent cultivation efforts. Chaff combine harvesters have a similar structure to conventional machines, but feature a modified end that includes a tank and blower for collecting and depositing crushed chaff. Apart from the threshing unit, all other components of the harvester remain unchanged.

This study was conducted in 2019 in dryland wheat fields to determine the performance of Chaff combine harvesters in Kurdistan province. The study used 15 combine harvesters, including John Deere models equipped with chaff threshers from Shiraz, Bookan, and Hamedan, as well as the Hamedan Barzegar specific chaff collector combine. These combines were evaluated and compared based on natural losses, head and chaff storage losses, field capacity, purity percentage, and yield in field conditions in Kurdistan province. The total number of combines evaluated was 15, using a completely randomized design. Among these, 33% belonged to Shiraz company (5 samples), 33% to Bookan (5 samples), 20% to Hamedan (3 samples), and 14% to Hamedan Barzegar (2 samples). Sampling included measurement of natural losses, header losses, threshing tank losses (losses of the threshing unit, separating unit, and cleaning unit), and quality losses (broken grains and impurities) in the combine tank.

The results showed that the average yield, natural loss, and combine loss were 1,698.14 kg.ha-1, 2.39%, and 4.92%, respectively. In terms of the loss rates in different parts of the combine, 43.49% was related to the chaff storage of the combine, and 56.50% was related to the combine head.The natural loss rate in this province was 2.39%. The total combine loss was 5.18%, with 40.44% of that related to chaff storage and the rest related to the combine head. The results also showed a significant difference between the treatments in terms of field capacity, chaff storage loss, and purity percentage at a probability level of 5%.The total loss of the Hamedan Barzegar combine was 6.67%, which was higher than the other combines. The chaff storage loss of the Shiraz, Bookan, Hamedan, and Hamedan Barzegar combines were 0.87%, 2.64%, 0.78%, and 4.28%, respectively, showing a significant difference at a 5% level. There was also a significant difference between the treatments in terms of total grain loss.Based on these results, it is recommended to use the Hamedan, Bookan, Shiraz, and Hamedan Barzegar combines, with total losses of 4.33%, 4.33%, 4.52%, and 6.56%, respectively.

The average purity of harvested grains was 96.62%, and there was no significant difference between the combine harvesters in this regard.There was a significant difference between the combines in terms of field capacity at a probability level of 5%. The field capacity of the Bookan, Hamedan Barzegar, Hamedan, and Shiraz combine harvesters were 0.83, 0.87, 0.83, and 0.73 hectares per hour, respectively.In Kurdistan province, the average grain combine loss in dryland wheat harvesting with chaff combine harvesters was 4.92%, which is higher than in other provinces.The loss in the chaff tank of the Shiraz, Bookan, Hamedan, and Hamedan Barzegar combine harvesters was 0.87%, 2.64%, 0.78%, and 4.28%, respectively. Regardless of head losses, the loss in the Hamedan combine was less than other combine harvesters.The total losses of the Hamedan Barzegar, Bookan, Shiraz, and Hamedan combine harvesters were 6.56%, 4.32%, 4.52%, and 4.30%, respectively, with the Hamedan Barzegar and Hamedan combine harvesters having the highest and lowest losses, respectively.Based on the results obtained from this study, using the Hamedan combine is recommended in the dryland conditions of Kurdistan due to its low losses, high purity, and field capacity.

Remote sensing methods for mapping farms and crops have been widely used in the last three decades. This method is applied to identify irrigated areas around the world (Alipour et al., 2014), although most of these studies are in areas with semi-arid climates and low rainfall or lack of rainfall which has a significant effect on the spectral characteristics of plants. In this study, Landsat 8 and MODIS satellite images were used to identify and separate two irrigated and rain-fed wheat farms in Hamadan province. Two algorithms of support vector machine (SVM) and minimum distance (MD) were used simultaneously to classify irrigated and rain-fed farms. In the next step, the area under cultivation of rain-fed and irrigated wheat was predicted in the whole cultivated area of Hamadan province. Finally, the cultivation area of rain-fed and irrigated crops was calculated in the province using Sentinel 3 satellite images based on the random forest algorithm in 2016.

The study area is Hamedan province, which is located between 59◦ 33′ and 49◦ 35′ north latitude and also from 34◦ 47′ to 34◦ 49′ east longitude of the Greenwich meridian. A 50-hectare rain-fed wheat farm in Amzajerd was used as a sample to extract the properties of rain-fed wheat. Also, irrigated indices were extracted from a 100-hectare irrigated wheat farm located in Kaboudrahang. Satellite images were applied to separate irrigated and rain-fed wheat in Hamadan province. NDVI, EVI and NDWI indices were extracted from 16-day images of Landsat, MODIS, and Sentinel 3 sensors in the five-year period (2015-2019). Google Earth Engine (GEE) system was the environment for performing image processing calculations and extracting indices and maps.

The NDVI and EVI of irrigated and rain-fed wheat farms were calculated in 2015-2019. A small peak was observed in the rain-fed and irrigated NDVI trend in November due to the early germination of wheat leaves in winter, and the larger peak in May and June showed the maximum greenness of irrigated and rain-fed wheat, respectively. The ascending or descending trend of NDVI / EVI had no constant slope. This can be due to changes in meteorological parameters, which sometimes cause a sudden increase or decrease in the values of these indices. Despite the non-linearity of the NDVI / EVI trend over time, the maximum greenness was recorded just a month before the wheat harvest, which was seen in the third decade of May to the first decade of June. One of the cases is the sharp drop of NDVI / EVI after its final peak, which was definitely due to yellowing wheat and harvesting. Since the distinction between rain-fed and irrigated crops was difficult only based on NDVI, NDWI was also used to determine the water content of wheat so that irrigated wheat could be identified. However, the difference between rain-fed and irrigated wheat in terms of NDWI spectral density was insignificant; the maximum and minimum occurrence times of NDWI and NDVI of rain-fed and irrigated wheat were chosen for their separation. In order to map the cultivation area, in addition to the MODIS sensor, Sentinel 3 was used due to its ability to detect chlorophyll accurately. Due to the fact that the imaging of the Sentinel 3 satellite started since 2016, the map of rain-fed and irrigated cultivation as well as the cultivation area and their separation was done based on the random forest algorithm in 2016.

The results of this study showed that the appropriate method for distinguishing between rain-fed and irrigated wheat is the simultaneous use of several indices. Also, the greatest difference is in the maximum greenness, which happened almost one month before harvest. MD and SVM classification algorithms could distinguish irrigated and rain-fed wheat from other crops with 90% and 80% accuracy, respectively. Distinguished maps of irrigated and rain-fed crops based on the random forest algorithm were obtained using Sentinel 3 satellite imagery which can show the fertility of agricultural lands in the province.

Soil protection against water and wind erosion is of great importance. Since most soils of arid and semi-arid regions of Iran are poor in organic matter and continuous use of conventional tillage (moldboard plow) has increased the severity of soil organic matter depletion and degradation of soil structure. Therefore replacing conventional tillage with conservation tillage (reduced tillage and no tillage) is needed to improve soil structure and increase soil organic matter. Due to the increasing population growth and the limitation of arable land, it is necessary to remove the fallow year in dryland. Legumes are crops that can be in rotation with wheat.

This study was conducted to evaluate the effect of crop rotation and different tillage systems on rain-fed wheat farming in Kaboudarahang Township during 2012-2014. The experiment was conducted as split-plot in a randomized complete block design with three replications. In this study, different crop rotations including fallow-wheat rotation, and chickpea-wheat rotation as main plots and different tillage systems including conventional tillage (moldboard plow + power harrow), conservation tillage (chisel plow equipped with roller), conservation tillage (sweep plow equipped with roller) and direct drilling were investigated as subplots.In the economic evaluation of this project, the economic impacts of the treatments were analyzed using the partial budgeting method and the cost-benefit ratio. For this purpose, the difference between treatments income and cost compared with control treatment has been calculated and compared. The differences in the benefits of the treatments are due to the different yields of wheat.

Results showed: 1- The highest wheat yield in the first and second years of the study was 605.3 and 2135.1 kg ha-1, respectively in rotation of fallow wheat. 2- In the first year, the highest wheat yield (690.7 kg ha-1) was related to direct planting (no tillage), but in the second year, the highest yield (2268.6 kg ha-1) was related to conservation tillage (sweep blades + roller). 3- In the first and second year, the highest value of treatment was related to direct planting and conservation tillage (sweep tiller + roller), respectively. 4- In the chickpea-wheat rotation, the highest net income in the first and second year was related to direct planting and conservation tillage (sweep + roller), respectively. Thebenefit-cost ratio in the conservation tillage (sweep + roller) (second year) and direct drilling (first year) methods shows that for each rial of expenses, 5.7 and 2.8 rials can be earned respectively. Therefore, economically, these tillage treatments are superior to the control treatment (conventional cultivation).5- In the wheat rotation, the highest net income in the first and second year was related to direct planting and conservation tillage (sweep + roller), respectively. The benefit-cost ratio in the conservation tillage (sweep + roller) (second year) and direct drilling (first year) methods shows that for   each rial of expenses, 4.2 and 1.3 rials can be earned respectively. Therefore, it is economically justified and these tillage treatments are superior to the control treatment (conventional tillage).

The results of this study showed that in the first and second years, economically the direct method and the conservation tillage treatment (sweep blades + roller) were superior to the conventional method, respectively. Therefore, conservation tillage methods can be replaced by the conventional method (plowing with moldboard plow) in dryland farming. Also, in dry years, direct cultivation (no tillage) is a good and economical method.

Organic matter based on their composition and the C/N ratio can have different effects on nutrient bioavailability, concentration and uptake in soil and plant. Beside that, organic fertilizer can increase the yield of different agricultural products and pave the wey for emergence of sustainable agricultural . Organic matter is relatively low in majority of soils in Iran, and continuous use of chemical fertilizer would create environmental hazards . Zinc deficiency is a worldwide nutritional constraint in crop production particularly in cereals growing on calcareous soils .

This research was conducted to investigate the effects of organic fertilizers such as bagasse, compost and biochar and chemical fertilizer ZnSo4 on yield of wheat and concentration and uptake of Zn in wheat ,a study based on randomized complete block design with 3 replications was conducted in Greenhouse Faculty of Agriculturar of Shahid Chamran University of Ahvaz during the years1395-96. Treatments included:1-control ,2- ZnSo4 , 3-Bagasse 4- Biochar 5- compost. Some Physical and chemical properties were determined using standard methods (table1).some basic properties of bagasse , compost and biochar were also determined (table 2). after the experiment ,soil and plant properties such as pH, organic matter content(OM), available Zn in soil. and yield , yield components and concentration and uptake of Zn in wheat were determined in samples.After seed ripening grain , yield and component yield were measured from the total pot of each treatment.Statisical analysis of the data was performed using SAS software and comporision using Toki method was also performed.

the intial soil was clay loam with organic matter content( om=0.79).Results showed that the treatments had significant effect (p≤ 0.01) on percentage of organic carbon, organic matter, the availability of Zn and pH of soil . Also content of soil micro element affected by treatments and amount of these parameters were increased by using of organic fertilizers .Increase the organic matter in soil by compost improved a must of chemical peroperties and Increase concentration nutrient element in soil. Results showed that pH in the control decreased significantly from 7.74 of soil to 7.53 of soil in the compost. Results showed that the available Zn in the control increased significantly from 0.5 mg kg-1 of soil to 0.71 mg kg-1 of soil in the compost.The results of the experiment showed that all treatments except bagsse increased factors wheat yield . Compost showed greatest yield and bagasse the lowest yield in the the wheat root, grain and shoots (compared to the control). The highest grain yield was obtained from the application of compost. The maximum amount of chlorophylls (a, b, total and SPAD), with application compost. The highest Plant height was obtained from the application of biochar. The results showed that the highest and the lowest of va lue concentration and uptake of Zn in wheat to compos and bagasse respectivity.
The maximum amount of chlorophylls (a, b, total and SPAD), with application compost. The highest Plant height was obtained from the application of biochar. The results showed that the highest and the lowest of va lue concentration and uptake of Zn in wheat to compos and bagasse respectivity.

The obtained result highlight the increased effects of compost on yield and yield components and Zn uptake change in wheat, also in comparison to other treatments, it emphasizes ore on the soil though they were useful too. Therefore, it can be concluded that applying organic fertilizers especially composted form would have, useful effects on plant growth and increasing the concentration of Zn of wheat .The obtained result highlight the increased effects of compost on yield and yield components and Zn uptake change in wheat, also in comparison to other treatments, it emphasizes ore on the soil though they were useful too. Therefore, it can be concluded that applying organic fertilizers especially composted form would have, useful effects on plant growth and increasing the concentration of Zn of wheat .The obtained result highlight the increased effects of compost on yield and yield components and Zn uptake change in wheat, also in comparison to other treatments, it emphasizes ore on the soil though they were useful too. Therefore, it can be concluded that applying organic fertilizers especially composted form would have, useful effects on plant growth and increasing the concentration of Zn of wheat .

Wheat is the most important crop and nutrient in the human consumption pattern. So that more than 50% of the required nutritional energy in Iran is provided by bread wheat. Harvesting is one of the most important stages of crop production. During 2017-2018 crop year, the present research was carried out to determine the cost and income of combine owners and to evaluate the profitability of using combine harvesters in line with profitability indices. In this regard, 49 combine harvesters including conventional combine JD 955, JD 1055, CLASS S 68 and NEW Holland TC 5080 combine were investigated in agricultural farms in 5 city of Ardabil provinces, Iran. To find out if the assumption is proved, we used partial budgeting technique including net present value, economic and non-economic test for substitution of harvesters under minimum, mean and maximum harvesting condition and marginal rate of return (MRR). The highest effective field and capacity was for NEW Holland TC 5080 which were 1.16 ha hr-1 and 5.14 ton hr-1 respectively. Economic analysis revealed that JD-955 combine, compared to the other combines, had the lowest cost and highest profits. MRR for replacement of JD 955 combine, instead of other combines was estimated more than 60.63%. In highest harvesting capacity, New-Holland (TC 5080) combine was more profitable. MRR for replacement of New-Holland (TC 5080) combine was at the high rate of 64.70%. Finally, it was revealed that in an average sustainable yield John-Deer (JD 955) combine and in maximum sustainable yield New-Holland (TC-5080) combine recommended for Ardebil province farmer.

Salinity is one of the most important environmental stresses limiting agricultural production in arid and semi-arid regions, which occupies a relatively large area of arable land. Nutrient availability is decreased in saline conditions in soil solution and plant nutrient balance is changed. Nitrogen fertilizer management as an essential nutrient for plant growth is very important under salinity stress. Also, salicylic acid is a plant growth regulator involved in defense mechanisms of plants against biotic and abiotic stresses. Therefore, the aim of this study was to investigate the effect of salinity on the concentration of nutrients in wheat in response to salicylic acid consumption at different levels of nitrogen.

In order to investigate the effects of salicylic acid and nitrogen fertilizer application rates at different salinity levels on nutrient concentration of wheat cv. Morvarid, an experiment was conducted as a split plot factorial based on a randomized complete block design with four replications in the fields of Mazraeh-E-Nemooneh located in Anbarolum, Aq Qala city, Golestan province. The main factor included three soil salinity levels (3-4 below wheat tolerance threshold (control), 9-11 and 13-15 dS.m-1) and sub factors included two levels of salicylic acid (0 and 1.5 mM) and three levels of N fertilizer (from urea source, 46% N) were 1) N based on soil test recommendation, 2) 30% N more than soil test recommendation and 3) 30% N less than soil test recommendation, respectively. Salicylic acid was foliar applied twice for about 2 weeks in the tillering stage and 10 days after the second stage spraying, content in them was determined. Nitrogen treatments were applied in three stages - one third before planting with ammonium sulfate (21% N) and remains top-dressed with urea (46% N) at tillering and stem elongation stages. At the emergence stage of the cluster or the beginning of flowering of wheat, the amount of nitrogen in the flag leaf was measured. The concentrations of nitrogen, potassium and sodium in grain and straw were also measured by standard methods.

The results showed that by increasing salinity, the flag leaf N concentration, N and K concentration of wheat staw and seed decreased. However, Na concentration of straw and seeds increased. With increasing N and salicylic acid consumption, the concentration of N flag leaf, the seed and straw N and K concentrations increased, but the concentration of Na in seed and straw decreased. The interaction of salinity, salicylic acid and nitrogen on seed N and K concentrations and also on flag leaf N concentration was significant but there was no significant effect on other measured elements. Comparison of the mean of simple effects of salinity on the evaluated elements indicates a significant reduction of all studied elements due to salinity treatment. Also, comparison of the mean of simple effects of nitrogen fertilizer showed that all elements were affected by the treatment. The results of mean comparison showed a positive and significant effect of salicylic acid on the leaf N concentration of the flag leaf, so that the N concentration in the flag leaf in a 1.5 mM salicylic acid treatment was significantly increased compared to the non-use treatment.

according to the results, more nitrogen consumption at moderate salinity can have a positive effect on plant nutrition, and vice versa, at high salinity levels, it is better to reduce nitrogen consumption. The interactions of salicylic acid and nitrogen showed that in general nitrogen treatments with salicylic acid increased the N concentration of seed and straw. Nitrogen fertilization at higher and medium salinity levels increased the concentration of N and K in straw and seeds; However, at high salinity, less nitrogen fertilization improved the concentration of N and K. Also, nitrogen application with salicylic acid improved these traits under saline conditions. Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity.Therefore, the application of salicylic acid and nitrogen fertilizer management to some extent reduced the adverse effects of salinity up to moderate salinity levels and improved plant nutrition by increasing plant tolerance to salinity. Key words: Salicylic acid, salinity stress, wheat, Nitrogen fertilizer management

Introduction:

Due to the use of fossil fuels, land use changes, and deforestation, it increases atmospheric carbon dioxide, which affects greenhouse gas emissions, results in global warming, effectively. Since crop production directly depends on climate, agriculture is one of the first sectors affected by climate change. Increasing greenhouse gas emissions leads to warming up and warming has devastating effects on organisms life, damaging natural ecosystems, causing floods, droughts, and disrupting the climate and ecological balance. Total soil organic carbon is the ability of trees and other plants to absorb carbon dioxide from theatmosphere and store it as carbon in wood, roots, leaves, and soil.Total soil organic carbon of plant biomass and Total soil organic carbon under this biomass is the simplest and most economically feasible solution to reduce atmospheric CO2. In this regard, an experiment was carried to investigate the effect of three amendment materials (alfalfa residues, straw and wheat straw, and poultry manure) on some soil characteristics, soil and wheat organ Total soil organic carbon potential.

Materials and Methods:

To investigate the possibility ofimproving soil carbon sequestration, carbon content of plant and soil and some soil characteristics, an experiment was design in a randomized complete block design (RCBD) in the crop year 2018-2019, in a farm in Dasht-e Aramou, Dare Shahr-Ilam province, in three replications on the wheat plant. Trial factors include two factors, the types and amount of amendment materials (alfalfa residues at 5, 10 and 15 t/ha, straw and wheat straw at 5, 10 and 15 t/ha, poultry manure at three levels of 2, 4 and 6 t/ha and chemical fertilizer is 100 percent fertilizer requirement). The studied traits included root carbon, shoot carbon, root total organic carbon, and shoot total organic carbon, total organic carbon, soil organic carbon percentage, total soil organic carbon, soil nitrogen, soil phosphorus, soil potassium, soil pH and soil Electrical Conductivity (EC).

Results and Discussion:

The use of amendment materials had a positive effect on most of the studied traits compared with the lack of application of amendment materials. The results showed that the amount of Total soil organic carbon and the percentage of carbon in shoots were higher than roots. The highest total organic carbon, percentage of carbon in plant and soil phosphorus were observed in 6 t/ha poultry manure (M6) while the highestTotal soil organic carbon and soil carbon content was obtained in 15 t/ha straw and wheat straw (G15). Also, the highest amount of soil nitrogen and potassium was obtained in 15 t/ha (Y15) alfalfa residues and the lowest amount in control treatment which were 47and 64 percent higher than the control, respectively. Contrary to all measured traits, pH and EC values were decreased by adding soil amendment materials. The highest was obtained in control treatment and lowest was observed in 15 t/ha (G15) straw and wheat straw which was 4.4 percent and 50.8 percent lower than the control, respectively.

Conclusion :

Gradual degradation of organic matter increases the efficiency of nutrients, the effect of these compounds on the plant's yield and soil properties for several years. The use of high quality plant residues, if combined with optimized management, will have a good result, especially if the timing of the release of nutrients from decomposing plant debris coincides with the need for the crop. Under such conditions, the time gap between the release of elements from plant residues and absorption of elements by the plant will be reduced and by reducing nutrition elements, it will increase absorption efficiency. In general, the effect of fertilizer type and plant residue on the amount of carbon of the plant and soil as well as the amount of nutrients in the soil was significant at 1% level. Among the different treatments, 6 ton/ha of poultry manure had the most effect on total soil organic carbon and carbon storage in plant organs, and treatment of 15 ton/ha wheat straw had the most effect on total soil organic carbon and carbon storage in soil. Alfalfa residue treatment had the most effect on soil phosphorus and potassium content and poultry manure had the most effect on soil nitrogen. Regarding to the lower price of plant residue, it is more appropriate than poultry. Due to availability of poultrymanure in the most parts of the country, it recommends more than other fertilizers.

Introduction :

Herbicides are chemicals that are used to inhibit the growth or to eliminate weeds in agricultural fields to increase the yield of crops in crop production. By the end of the 19th century, with the increasing labor supply problems, the need for chemical methods to control weeds became apparent. It was first reported in France in the 1980s, that sulfuric acid was used in the fight against weeds in sugar beet fields. Nowadays, most of the herbicides used are organic herbicides, which share organic carbon in their chemical structure.The use of herbicides since about a century ago has been suggested as an effective way of eliminating crop competitors, though herbicides that remain in the soil for longer periods of time prolong weed control and thus increase weed management efficiency. On the other hand, their increased stability in soil may be of a magnitude that can damage crops in the following crop rotations. Soil properties can have a significant impact on the stability of herbicides in soil.

Materials and Methods :

For this purpose, soil samples were taken from 0-30 cm depth from field of experiment No. 2 in College of Agriculture Shahid Chamran University of Ahvaz. After sampling and passing through 2 mm sieve, the physical and chemical properties were measured using standard methods. The pot experiment was conducted in a factorial completely randomized design with 32 treatments including soil salinity (at 2.5 and 6 dS / m), Ultimo herbicide rate (at 4 concentration levels of 0, 25, 50 and 100% Recommended dose) and planting time (60 and 120 days after herbicide application) with 3 replication. Wheat was selected as the experimental crop and variety was "Mehregan" which has been cultivated in most of Khozestan province. Herbicide was applied and soil was rested for 60 and 120 days then wheat was sown. For germination percentage, wheat seeds were sown directly in soil after germination test. After germination the percentages were recorded and kept in an equal number of plants in the pot. It should be noted that in order to eliminate the effect of nutrient deficiency on plant growth at appropriate intervals, nutrient solution was applied and irrigated according to the need of the plant.After 9 weeks (before flowering stage) the plant was harvested and the growth components including root length, root dry weight, shoot length, shoot weight and nutrient concentration including nitrogen (in plant dry matter), phosphorus, potassium, calcium, magnesium, iron, zinc, copper and manganese were measured in the extract obtained from dry digestion of plant tissue (aerial parts of plant). Statistical analysis was performed using SAS software and mean comparisons were performed by Duncan's multiple range test. Charts were drawn using Excel software.

Results and Discussion:

 According to the results, increasing the level of herbicide decreased the growth parameters of the plant, which is intensive under salinity stress. The results showed that considering 60 days sowing after herbicide application, shoot dry weight in 100% RD herbicide application in salinity of 2.5 dS/m was 1.6 g which was not showed significant difference with 50% herbicide application under salinity of 6 dS/m. Therefore, in higher salinity levels lower herbicide dose can damage the plant as much as higher levels of herbicides in lower salinity, and lower levels of herbicides in more soil salinity produce more negative effects. By increasing planting time from 60 to 120 days the residual effects of herbicides on soil decreased and plant showed better yield. By increasing salinity level from 2.5 to 6 dS / m, all growth components of wheat decreased, except for shoot length and shoot dry weight, this significant decrease was not reported for other components.

Conclusion :

Therefore, it can be concluded that selection of sowing time after herbicide application in crop rotations is very important and by selecting the correct time can greatly reduce the deleterious effects of consuming more herbicides.Planting wheat at 60 days after application of herbicide compared to 120 days after application of herbicide, decreased the growth components of the plant. Therefore, selection of wheat sowing time in crop rotation 60 days after application of herbicide (especially at 100% recommended dose) is not recommended in maize – wheat cropping system. Also considering soil chemical properties such as salinity as an influencing factor on herbicide behavior in soil can be effective in controlling residual effects of herbicides in soil and plant.

Introduction :

Agriculture is an energy conversion process. In this process, solar energy, fossil fuel, and electricity are converted mainly into food and fiber. In the agricultural section, the trend of energy consumption increases rapidly every year. Constraints on agricultural land, population growth, changes in infrastructure, and a trend towards high living standards have contributed to increase energy use in the agricultural sector. Fuel, electricity, machinery, seeds, chemical fertilizers, and chemical pesticides have a significant share in supplying energy sources. Effective use of energy in agriculture reduces environmental problems and prevents the destruction of natural resources and develops sustainable agriculture as an economic production system. Wheat is the most strategic crop in Iran that more than 50.39% of arable land belongs to wheat.  

The current study has been done with the objects of evaluation of inputs and crop yield, input and output energy, and energy indices for irrigated wheat for seven provinces such as Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan. For this purpose, the required information gathered via study of publications, face to face interview with experts and leading farmers, and questionnaire completion by the irrigated wheat farmers in different cities of each understudy province. Then, with the help of equivalent energy equations, input and output energy and energy indices were calculated. In this research, simple random sampling method was used.

According to the results, total input energies of Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan provinces were calculated with 45458.84, 92714.8, 38755.34, 104701, 50971.2, 26198, and 49362. 64 MJ ha-1 respectively, while the output energy for those provinces were 162169.28, 131958.8, 77381.39, 122297, 141901.2, 134106, and 125511.69 MJ ha-1, respectively. The maximum share of energy input for Alborz, Ardebil, Khuzestan, Golestan, and Hamadan provinces were regarding to chemical fertilizers with amounts of 43.06, 43.16, 58.33, 38.05, and 47.57 percent, respectively, while irrigation energy requirement had maximum share in Isfahan and Khorasan-e Razavi with 62.36 and 57.17 percent, respectively. The minimum share of energy input for Alborz, Isfahan, Ardebil, Khorasan-e Razavi, and Golestan provinces was calculated for labor energy requirement with 0.39, 0.29, 0.79, 0.18, and 0.26 percent, respectively, while in Khuzestan and Hamadan, chemicals consumed the lowest energy with 0.55 and 0.89 percent, respectively. Share of direct energies for all understudy provinces were 44.61, 72.13, 41.22, 67.48, 30.75, 39.44, and 39.91 percent, share of indirect energies were 55.39, 27.87, 58.78, 32.52, 69.25, 60.56, and 60.09 percent, share of renewable energies were 27.99, 65.91, 32.35, 60.57, 19.26, 34.92, and 35.16 percent, and share of nonrenewable energies were 72.01, 34.09, 67.65, 39.43, 80.74, 65.08, and 64.84 percent, respectively. Energy ratio for Alborz, Isfahan, Ardebil, Khorasan-e Razavi, Khuzestan, Golestan, and Hamadan provinces were 3.57, 1.42, 3.48, 1.17, 2.78, 5.12, and 2.54, respectively, and energy productivities were 0.26, 0.11, 0.26, 0.08, 0.21, 0.38, and 0.18 kg MJ-1, respectively. Average input energy, output energy, energy ratio, energy productivity, and net energy gain for all provinces were 58308.83 MJ ha-1, 136092.15 MJ ha-1, 2.87, 0.212 kg MJ-1 and 77783. 31 MJ ha-1, respectively. Total input energy cost for irrigated wheat production was 57.966 ×106 Rial ha-1. The Energy intensiveness, Energy intensiveness value, Energy intensity cost, and Energy ratio cost were found as 1.299 MJ (103 Rial)-1, 0.641 MJ (103 Rial)-1, 10853.05 Rial kg-1, and 1.21, respectively.

In order to reduce the share of indirect energy and non-renewable energy, organic fertilizers should be replaced by chemical fertilizers and plant residues in the field. Minimum tillage should also be used in land preparation operations to reduce fuel consumption, maintain organic matter and soil moisture and reduce soil erosion. To compensate for some of the elements taken from the soil by the plant and the increase of organic matter and fertility of the soil, it is recommended to return part of the plant residues to the soil. The use of combined machines that can perform several simultaneous operations and minimizing and protecting soil tillage to reduce fossil fuel consumption through minimum use of machinery should be investigated as a national necessity.

Presence of foreign materials with the product is one of the important problems of wheat production. The economic value of the produced wheat and the degree of purity of the produced seeds increases with the separation of wheat mass impurities. Hence, in this research, a gravity separator table was used to remove impurities from wheat bulk. The machine has adjusting five parameters of air velocity, frequency of oscillation, amplitude of oscillation, longitudinal slope and latitudinal slope of the table. The effect of these parameters was studied to achieve maximum impurity separation from wheat bulk. Statistical analysis was performed in two factorial experiments based on completely randomized design. In the first experiment, the effects of three parameters of longitudinal slope, latitudinal slope and frequency of oscillation of the table were investigated and in the second experiment the effect of two other parameters was investigated. Also, using dimensional analysis, a dimensionless number parameter was obtained which was effective in evaluating the effect and reducing the number of parameters. The results showed that the maximum separation of impurities from wheat bulk was 87.03% at longitudinal slope of 2.5 °, latitudinal slope of 1.5 °, frequency of oscillation of 395 cycles per minute, amplitude of oscillation of 5 mm and air velocity of 6.75 m/s,. Also, with increasing longitudinal slope from 2.5 ° to 4.5 °, latitudinal slope from 0.75 °  to 2.5 ° (in most cases) and the amplitude of oscillation of the table from 5 to 7 mm, the separation of impurities was reduced and with increasing the air velocity from 5.25 to 6.75 m/s the separation of impurities was increased.

Cereals as one of the most important sources of food plants could provide more than 70% of the food for the human population. Passing of water from the magnetic field is among approachable methods in order to reduce the total amount of water used for irrigation. Moreover, magnetized water is a new concept for increasing the water efficiency. Therefore, this study was aimed to investigate the effects of the magnetized water on some of features containing dry weight, germination velocity and percentage, length and weight vigor indices of five common wheat cultivars including Roshan, Sardari, Shiraz, Falat and Yavarus, to introduce the best cultivar considering the growth and germination indices as well as water and energy efficiency.

To perform this experiment, a device with a magnetic field of 500 millitesla was constructed to accommodate both the water path and the placement of seeds in the magnetic field. To perform the experiments, 10 seeds in 4-kg vases and 25 seeds in each Petri dish were cultivated in the greenhouse and laboratory, respectively. The experiments were carried out in the form of completely randomized factorial design. The factors are considered as the duration time of keeping the water in the magnetic field (three levels of 30, 60 and 120 minutes), the intensity of the magnetic field (three levels of 100, 150, and 200 millitesla), and five wheat cultivars (Roshan, Sardari, Shiraz, Falat and Yavarus) in three replications.
Experiments related to the both of rate and percent of germination and for dry weight were performed at room temperature in the laboratory and greenhouse under controlled conditions, respectively. The measured data were analyzed using SAS software. The F test was used to determine the significant level of treatments. The comparison of the means was evaluated using LSD test.

The obtained results, showed that the effect of magnetic water on all growth and germination indices compared to control samples was significant. Under the 150 millitesla and 120 minutes treatment, the Yavarus, Roshan and Sardari cultivar had maximum dry weight, respectively. The Roshan cultivar had the maximum germination velocity at 100 and 150 millitesla and duration time of 30 minutes. Moreover, the maximum germination percentage was found in the Roshan cultivar, which did not have a significant difference with Yavarus cultivar. The Roshan cultivar in 200 millitesla field and duration time of 60 minutes, had the maximum percentage of length vigor index, which showed a significant difference with other averages.In general, Roshan and Sardari cultivars had more length vigor index than other cultivars. Sardari cultivar had maximum percentage of weight vigor index under 200 millitesla and 120 minutes duration time, which had no significant difference with the percentage of weight vigor index at the same field level and with duration time of 60 minutes.

According to the obtained results to achieve the maximum value of dry weight, it is better to use the Yavarus cultivar. It is recommended to use the Roshan cultivar with the lower level of magnetic field and duration time to attain the maximum value of the germination velocity and percentage. To get the maximum value of the length vigor index and the weight vigor index the Roshan and Sardari cultivars, and the Sardari cultivar with field of 200 milli Tesla and lower duration time are preferred.

In Iran, salinity is a pervasive issue limiting production of agriculture, so that a large part of the arid and semi-arid regions of the country have saline sodic soils with different levels. Saline soils and waters are among the agricultural resources that can be used for cultivation by using full recognition of problem and proper management. This study was performed to evaluate a special grain drill performance which plants wheat seeds into furrows for semi-arid regions with saline soils conditions in margin of Uremia Lake. The experimental treatments of planting method by the grain drill included, (i) planting into the furrows with 60 cm width and furrow irrigation; (ii) planting into the furrows with 100 cm width and furrow irrigation; and (iii) planting on a flat soil and flood irrigation. Statistical analysis was conducted based on randomized complete block design with three replications. Seed emergence rate, crop performance indices, water consumption, water productivity, and soil salinity distribution after each irrigation practice were measured. According to the results, there was no significant difference between the methods of planting in any of the measured parameters at the 5% probability level. Results also showed that reducing the width of the furrow from 100 to 60 cm caused salinity reduction (about 37 percent) from inside the furrows. The water productivity of the planting into the furrows with 60 cm width was about 40 percent higher than those of other treatments. Therefore, wheat planting method by the grain drill into the furrows with 60 cm width can be recommended in semi-arid regions with saline soils.