Showing 7 results for Crops
B. Najafi, M. Zibaei, M. H. Sheikhi, M. H. Tarazkar,
Volume 11, Issue 1 (4-2007)
Abstract
In this study wholesale prices of selected crops, namely, tomato, onion and potatoes in Fars province were predicted for various time horizons by using common methods of forecasting and artificial neural networks (ANN). Monthly data from September 1998 to June 2005 period were obtained from Ministry of Jihad-e Agriculture. For comparing different methods data selected from September 1998 to December 2004 were utilized, and latest six - month data were mainly used to monitor the power of prediction. The MAE, MSE and MAPE criteria were used for comparing the ability of different forecasting methods. Results of this study showed that ANN had the lowest error in prediction of prices for one - to three - month periods, but for six - month prediction, all forecasting methods were not statistically different.
N. Mirghaffari, H. Shariatmadari,
Volume 11, Issue 41 (10-2007)
Abstract
Concentration of soluble fluoride in groundwater, soil, and some crops in Isfahan region was determined by Ion Selective Electrode (ISE) method. The mean fluoride concentration of water samples in the study area was 0.3 and 0.05 mg L-1 in the spring and summer, respectively. These values are in an acceptable limit for irrigation, whereas for drinking water, they are in deficiency range. The average and maximum concentrations of soluble fluoride in soil samples were 1.0 and 3.2 mg kg-1, respectively. In general, the spatial distribution of fluoride in soils showed that fluoride content around major industrial centers such as Isfahan Steel Factory, Mobarakeh Steel Co., and Isfahan oil refinery was higher than other sites. The minimum and maximum fluoride contents of crops were observed in alfalfa as 0.2 and in corn as 4.2 mg kg-1, respectively. Tomato had the highest mean concentration of fluoride as 3.6 mg kg-1. The fluoride concentration in plants positively correlated with the fluoride concentration in irrigation water and soil (P < 0.01) and negatively correlated with cation exchange capacity of soil (P < 0.05).
M. H.nazarifar, R. Momeni,
Volume 15, Issue 56 (7-2011)
Abstract
Deficit irrigation is one of the strategies used to obtain products with maximum profits in recent years. In this context, research on determining appropriate levels of deficit irrigation is essential. Since determining the different levels of performance through field experiments is difficult, the use of simulation models is a strategy through which we can examine the water balance data, simulate the growth process, and to study different managerial scenarios. The purpose of this study was validation and evaluation of CropSyst, a plant growth model, to determine suitable cropping patterns in deficit irrigation conditions. Applying three deficit irrigation scenarios in model, with values of 10%, 20% and 30% on six crops, fava bean, bean, wheat, potato, sunflower and rice, we concluded that the applied deficit irrigation of 10% to bean, potato and beans, 20% to sunflower and 30% to wheat had been suitable, and it is better not to apply deficit irrigation in rice. Also, since in final selection, the rate of water productivity is one of the basic criteria in each crop mentioned above, determining net benefit based on drop index (NBPD) per cubic meter showed that the most NBPD is related to bean with 6853 Rials per cubic meters and the lowest amount is related to sunflower with a value equal to 2809 Rials per cubic meters.
Zahra Saadati, Nader Pirmoradian, Mojtaba Rezaei,
Volume 17, Issue 64 (9-2013)
Abstract
The modeling of yield response to water is expected to play an increasingly important role in the optimization of crop water productivity (WP) in agriculture. In this study, the CropSyst model was used to simulate two local rice varieties yield response under five irrigation treatments consisting of continuous flooding irrigation and irrigation at 0, 3, 6 and 9 days after the disappearance of water from the soil surface. The experiment was conducted at Rasht region during two growing seasons of 2003 and 2004. The model was calibrated using the first year data and validation of that was done using the second year data set. The result of F test shows that there was not a significant difference between the measured and simulated yield at confidence level of 99%. The relative errors of yield estimation were obtained between -0.81 to 12.58% and -2.4 to 19.42% for Binam and Hasani cultivars in 2003, respectively. These values were 0.83 to 16.4% and -2.82 to 21.27% in 2004, respectively. The results showed that due to the CropSyst model ability in simulating yield of rice under different irrigation regimes, this model can be used to explore management optimum options to improve rice water productivity
H. Kheirabadi, M. Afyuni, S. Ayoubi, A. Soffianian,
Volume 19, Issue 74 (1-2016)
Abstract
Heavy metals are known to have deleterious effects on human health. The main route of human exposure to heavy metals is the daily intake of food. This study was designed to investigate the heavy metal concentrations (Cu, Zn, Mn, Fe, Cr, Ni and Cd) in soil and major food crops (wheat, potato and corn) and estimate the health risks of metals to humans via soil and the crops consumed in Hamedan Province, using the total non-cancer hazard quotient. Daily metal intakes were estimated for three receptor groups and then compared with health guideline values. The non-cancer risk estimations showed that chromium, manganese, cadmium, zinc, Iron, Nickel and copper have oral Hazard Quotient values less than a value of one. The Hazard Index values were greater than 1 for all age groups, suggesting that adults and children in the study area may experience a potential non-cancer risk due to diet of heavy metal via wheat, corn and potato consumption and soil ingestion. Consumption of plant foods particularly wheat was found to be the major route of human exposure to heavy metal. The soil ingestion route is also important.
M. Shamsalddin Saied, A. Ghanbari, M. Ramroudi, A. Khezri,
Volume 21, Issue 1 (6-2017)
Abstract
Cover crops, conservation tillage systems and organic fertilizers have played an important role in maintaining or enhancing soil quality. In order to assess the combined effects of these techniques on soil quality an experiment was conducted as split Plot experiment based on randomized complete block design with three replications at Shahid Bahonar University of Kerman in 2011-2012.
The method of return of cover crops to soil included reduced tillage (disc) and no-till (herbicide glyphosate + cutting) as the main factor and manure application management included cover crops (wheat, canola and peas) without the use of urea, cover crops with a consumption of 25 t/ha of manure, Cover crop with 75 kg of urea and fallow treatments (without cover crop) as subplots. The results showed that the highest concentration of nutrients (except N and P concentrations in the plant), the nutrient yield and biomass of cover crops belonged to wheat treated with urea fertilizer. Soil properties such as bulk density, pH, organic matter and soil nutrient concentrations (nitrogen, phosphorus and potassium) were significantly affected by fertilizer management and the method of return of cover crops to soil (except pH) and soil organic matter content and nutrient concentration were affected by their interactions. In wheat cover crop treatments with urea with %27.53 reduction in bulk density, %20.88 increase in the porosity, organic matter 2.4 times and nitrogen 1.5 times compared to the fallow treatment was the best treatment that wasn’t significantly different from the wheat treated with manure in low- tillage system. Wheat treated by manure had the highest phosphorus that was 3.5 times of the phosphorus concentration in the fallow treatment. So, in order to develop sustainable agriculture, reducing the use of synthetic fertilizers and environmental protection, the wheat cover crop treatments with manure and low- tillage cropping systems would be appropriate in Kerman.
B. Raheli Namain, S. Mortazavi, A. Salman Mahini,
Volume 23, Issue 2 (9-2019)
Abstract
Agriculture production with high quality and adequate income for farmers and the least harmful effects in environment are the main objectives of agriculture optimization. The main objective of this study was ranking, optimization and land allocation of Gonbadkavoos’s Drylands for strategic products such as wheat, barley, oilseed rape and soybean under environment and socio-economic scenarios. Because the available information on fertilizer and pesticide consumption was not sufficient and reliable, this data was collected through face-to-face interviews with farmers. The results showed that some slightly and moderately hazardous pesticides were consumed in study area. In this study, the optimized combination of agriculture products was applied by using the modeling approach and considering environmental and socio-economic aspects in Gonbadkavoos County. This approach uses MCAT software, which is based on multi-criteria techniques and metaheuristic algorithms. The results of the environmental scenario show ed that barley, oilseed rape and soybean, with little difference, had the highest benefit-to-cost ratio and profitability, respectively. The slight difference could be related to the use of fertilizers and pesticides. In the socio-economic scenario, oilseed rape, wheat and barley had the highest benefit-to-cost ratio and land allocation, respectively. The represented approach using the decision support system (MCAT) can help planners to design optimal cropping systems and aid good management of fertilizers and water consumption.
