جستجوی مقالات مرتبط با کلیدواژه « پنبه » در نشریات گروه « مکانیزاسیون کشاورزی »

In this project, 931, 932 and 933 hybrid cottonseeds were used. ‎This project was carried out on an area of 30 hectares. NDVI index is always helpful in assessing ‎plant health on farm. The most important reason for this capability is that the changes in this index ‎are consistent with the physiology of the plant and in simple terms with the changes in pigments and ‎staygreen of the plant cover. According to the trend of changes in NDVI index, hybrid cotton 933 ‎had the best greenness during the growing period. The variety 933 is the oldest figure in this study. ‎On the other hand, 931, which has the lowest NDVI, is the earliest figure. As the results show, the ‎yield of cotton transplanting was significantly differences by cotton seed planting method. ‎Transplanting yield is more than twice that of cottonseeds in November, especially for cultivar 931. ‎As expected, the highest yield was observed in transplanting 931 and the lowest yield was taken in ‎‎933 seed treatment. With help of NDVI index in September, it is possible to comment on the early ‎maturity of cotton cultivars.‎

In this study, the effect of conservation tillage and irrigation methods on the soil properties, cotton yield, and water productivity was evaluated in a wheat-cotton cropping system in the form of a split-plot experimental design. The main plots were irrigation using the three methods including surface irrigation, drip tape irrigation, and sprinkler irrigation. Tillage methods including zero tillage, reduced tillage, and conventional tillage were considered as subplots in this research. Results showed that tillage methods had no significant effect on cotton yield; whereas, the cotton yield was significantly affected by irrigation methods (p˂0.05). Tape and sprinkler irrigation methods saved water compared to surface irrigation for 51% and 28%, respectively. The maximum water productivity (0.324 kg m-3) was obtained from the tape irrigation and the minimum water productivity (0.146 kg m-3) was related to surface irrigation. Results also indicated that irrigation and tillage methods had a significant effect on the soil bulk density and infiltration rate so that drip tape irrigation and conventional tillage had the highest infiltration rates, and tape irrigation and reduced tillage had the highest soil bulk density.

Analysis of important energy indices in cotton cultivation is includes all stages in seed production of cotton seed from the stage of seed bed preparation until after harvest (cotton seed cracking). In Iran, up to harvesting studies have been done in conventional tillage method, and no research has been done from seed preparation till post harvest stage in different tillage methods. In this study was investigated the amount of energy consumed from seed bed stage to post harvest stage (seed cracking) in different tillage methods. Tillage treatments that were divided by reduction in energy consumption included conventional tillage (CT), low tillage(RT), minimum tillage (MT) and no tillage (direct planting) that were evaluated in a completely randomized block design. The results showed that conventional tillage with average yield of 3636.4 kg/ha had the highest yield and tillage treatment with average yield of 1753.3 kg/ha had the least amount of cotton yield. The results of this study showed that conventional tillage had the highest energy consumption (38942.44 MJ/ha) and no tillage treatment had the lowest energy consumption (32063.02 MJ/ha). The highest direct energy consumption were in conventional tillage method (19302.99 MJ/ha) and the no tillage method had the lowest direct energy consumption (12423.57 MJ/ha). The highest direct energy consumption was related to irrigation input and then fuel consumption respectively with 5850 and 4704.4 MJ/ha. The total amount of indirect energy consumed, including pesticides and fertilizers, was calculated to be 19639.45 MJ/ha. The highest Energy Ratio and energy Productivity were obtained in conventional tillage respectively values of 1.99 MJ/MJ and 0.09 kg/MJ and the lowest values were obtained in no tillage respectively with 1.17 MJ/MJ and 0.05 kg/MJ. According to the results of researches and the higher Energy Ratio and energy Productivity in conventional tillage method, this method can be recommended as a tillage method in this area.

Golestan province is one of Northern provinces in Iran. The area under cultivation of agricultural products in this province is 724.697 hectares, of which about 694.618 hectares are used for farm products (AJMDC, 2011). Cotton as one of oilseed is a potential feedstock for biodiesel production (Ahmad et al., 2011). In the study of energy consumption and greenhouse gas emissions for cotton production in Alborz province, results showed that the total energy input was 31.237 MJ ha-1. Energy efficiency and energy productivity were 1.85 and 0.11, respectively, and greenhouse gas emissions of cotton production in Alborz province were 1195.25 kg CO2eq ha-1 (Pishgar-Komleh et al., 2012). Another study on energy analysis, greenhouse gas emissions and economic analysis of agricultural production was performed in Northern Iran (AghaAlikhani et al., 2013; Royan et al., 2012; Pishgar-Komleh et al., 2011; Mohammadi et al., 2010; Taheri-Garavand et al., 2010). The aims of this study were to determine the energy flow, greenhouse gas emissions and economic analysis of cotton production in the Golestan province and also to determine the effect of energy inputs on cotton yield. This research was conducted during 2011-2012 in three areas including Gorgan, Aq’qala and Gonbad in the Golestan province. The primary data were collected from the rice producers through a field survey with the help of a structured questionnaire. The number of subjects were studied by the Cochran formula (Snedecor and Cochran, 1980). Accordingly, 43 cotton producers were determined. In this study, eight energy inputs including seed, labor, machinery, diesel fuel, chemical fertilizers, chemicals, water for irrigation and farmyard manure for cotton production system were considered as independent variables. The outputs of the system including lint and seed were considered as dependent variable. Energy indices including energy efficiency, energy productivity, specific energy and net energy were calculated. In this study, the effect of energy inputs on yield was estimated using the Cobb-Douglas function. In order to determine the sensitivity of energy inputs in the production of cotton in the Golestan province, the marginal physical productivity method was applied. Greenhouse gas emissions, inputs of agricultural machinery, fuel, chemical fertilizers, chemicals and farmyard manure in cotton production in the Golestan province were calculated by the coefficients of each of these inputs. For economic evaluation of cotton production in the Golestan province, the variable costs, fixed and total production per unit area were considered. Economic indices of total production value, gross income, net income, economic productivity and benefit to cost ratio were estimated. Data analysis was performed using JMP8 software. Cotton yield in the Golestan province was about 2650 kg ha-1. Average cotton yield in the Alborz province was reported to be 3430 kg ha-1 (Pishgar-Komleh et al., 2012). In this study, diesel fuel had the highest energy consumer among other inputs like the other studies that have been done on energy crop production in Iran. Labor energy input with energy consumption of 2413 MJ ha-1, is known to be the fourth high-energy input in cotton production in the Golestan province. However, in many studies in Iran, this input was accounted to be less than one percent of the energy consumption in the production of agricultural products (Saeedi et al., 2013; Khoshnevisan et al., 2013; Mobtaker et al., 2012; Mobtaker et al., 2010). Chemical energy input with 1036 MJ ha-1, was allocated as 3.6% of energy consumption in the cotton production in the region. Seed energy input was the lowest energy among the other inputs in cotton production in the Golestan province. The results revealed that the total energy inputs for cotton production in the Golestan province was 28.898 MJ ha-1. The average energy efficiency for cotton production in the Golestan province was obtained to be 1.58. Energy productivity for cotton production in the Golestan province was calculated to be 0.092. From the results of Cobb-Douglas function to determine the relationship between energy input and yield of cotton in Golestan province, the effects of human labor, diesel fuel, water for irrigation, chemical fertilizers and farmyard manure inputs on the yield were positive, and the effects of agriculture machinery and chemicals inputs on cotton yield were negative. Greenhouse gas emission from diesel fuel input hadthe highest value of 646.23 kg CO2eq ha-1 with a 45.2 percent share. Farmyard manure with 23.5 percent of greenhouse emissions was identified as the second largest input in greenhouse gas emissions in cotton production. Variable costs, fixed and total cotton production in the Golestan province were calculated to be 3042429, 851880 and 3894309 Toman ha-1, respectively. Benefit to cost ratio for the cotton production in the Golestan province was calculated as 1.16. The results of this study showed that the energy efficiency for cotton production in the Golestan province was less than the energy efficiency for cotton production in the Alborz province, Hatay province of Turkey, and canola, soybean and sunflower production in the Golestan province. Also, the energy efficiency of cotton production was less than that of cotton production in Antalya Turkey and canola in the Mazandaran province. The highest share of energy consumption and greenhouse gas emissions belonged to diesel fuel with the share of 45.6 and 45.2 percent, respectively. However, this input accounted for 2.7 percent of variable costs.

To evaluate the effects of Glycine Betaine (GB) on yield and seed quality of some cotton (Gossypium hirsutum L.) cultivars in response to drought stress, a field experiment was conducted in northern part of Iran, Gorgan. The experiment was a factorial on the basis of a randomized complete block design with four replications. Field research survey consisted of two factors; GB concentration and cotton cultivars. Glycine Betaine was applied to filed-grown cotton at three rates: 0 kg/ha foliar application of GB at the first flowering + application at one and two weeks later, 3 kg/ha foliar application of GB at the first flowering + application at one and two weeks later (two times GB application) and 6 kg/ha foliar application of GB at the first flowering + application at one, two, three and four weeks later (four times GB application). Four cotton cultivars were selected based on their proportional susceptibility to drought stress including Tabladilla and Nazili, considered as drought tolerant, and Varamin and Sahel, considered as drought sensitive cultivars. The results showed that spraying with GB at different levels (3 and 6 Kg/ha) enhanced cotton yield, boll numbers, sympodia branch numbers, early maturity, plant height, final node on main stem, boll retention at 2nd position and boll abortion, seed bulk density, but had no significant effect on monopodia branch numbers. This research could ultimately result in higher yield production and improved tolerance to water deficit condition with applying following treatments: Tabladilla and Nazili with 3 kg/ha foliar application of GB at the first flowering + application at one and two weeks later for tolerant cultivars and Varamin and Sahel with 6 kg/ha foliar application of GB at the first flowering + application at one, two, three and four weeks after first flower.

One of the reasons for planting cotton crop in a high density in developing countries is reducing the cost of cotton (Gossypium hirsutum L.) production. There are some mehods to change the dencity in the field, including hill planting, reducing the space between rows or plants on the row. To investigate the effects of plant density on yield of cotton and to compare hill and row planting methods, a split plot experiment in randomized complete block design was conducted in three locations, (gorgan, kashmar and varamin) and in two years (2005, 2006). The factors were density (31250, 62500, 93750,125000, 156250 plant/ha) and plating methods (hill and row planting) as main and subplots respectively. Plant density in subplots were in consistance with each main plot. The varieties used in current study were sahel in Gorgan and varamin in kashmar and varamin regions. Results showed that yield were not effected by density in Gorgan and Kashmar regions. In Varamin, the effect of density was significant and 93750 plant/ha showed the best yield (P>0.05). There were no significant differences between two planting methods for yield in all locations.

Multiple shoot induction has been suggested to be a suitable method for regeneration of hybrid plants in wide crosses as well as for regeneration of transgenic plants. Shoot and root induction response were studied in four species of cotton consisting of G.herbaceum G.arboreum, G.hirsutum, and G.barbadense. Two media were employed and explants were prepared from plantlets originated from mature and immature cotton embryo cultures. According to obtained results, seeds planted on MS1 and MS2 medium germinated after 48 hours and produced roots and cotyledons after 3-4 days. G.hirsutum and G.arboretum showed the highest and the lowest germination percent among four species. In complete embryo cultures of tetraploid species, emergence and development of shoots occurred in the second week whereas, in the case of diploid species it occurred in the third week. In general, the results showed that MS2 and SH were the best media for shoot and root induction, respectively. Tetraploid species showed to be superior to diploid cotton species for shoot number and G.barbadense and G.arboreum were superior for root production. Based on present study, multiple shoot induction would be appropriate for micro-propagation and regeneration of recalcitrant species and new genetically modified cottons (GM cottons) derived from biotechnological methods, as well as, preparation of sterile tissues, organ and seedling by in vitro culture.