جستجوی مقالات مرتبط با کلیدواژه "برنج" در نشریات گروه "محیط زیست"

The study was conducted to determine population fluctuation of two Haplothrips species in rice fields with two different climates. Samples were collected from different growth stages of rice in four fields located at Chardavol (cold climate) and Darreh-Shahr (Tropical climate) cities, in Ilam province (western Iran), during 2017-2018. Totally, eight thrips species belonging to six genera and three families were collected and identified. Amongst them, Haplothripsganglbaueri Schmutz and H. aculeatus (Fabricius) were the dominant species accounting for 73.16% and 17.83 (in Darreh-Shahr) and 61.19% and 27.25% (in Chardavol) in abundance. According to the results, both Haplothrips species in both cold and tropical regions were observed from the stem stage of rice. The highest density of adult for both Haplothrips species in Darreh-Shahr was related to dough stage of rice (0.8 and 0.33 thrips), but for both adult and larval stages was related to flowering stage of rice (0.9 and 1.40 for H. ganglbaueri, 0.33 and 0.6 for H. aculeatus). In addition, the highest density of adult for H. ganglbaueri in Chardavol was related to flowering stage of rice (0.73 thrips) and for larval stage and (adult+larva) was related to heading stage of rice (0.93 and 1.40 thrips). The above information for H. aculeatus for adult and (adult+larva) was related to dough stage (0.26 and 0.43 thrips) and for larval stages related to flowering stage of rice (0.23 thrips). The results of the T-test for two Haplothrips species between Darreh-shahr and Chardavol showed that there was no significant difference between the two regions. In general, population fluctuation for the immature stages of thrips in both regions showed the low density in beginning of rice growth and there was a decreasing in the flowering stage of rice. Adult thrips were also observed in the early stages of rice growth, so that the density of adults was low at the beginning of the season and then, after a gradual increase, the density of thrips decreased during the dough stage.

Given the importance of soil and water resources in the development of sustainable agriculture, increasing world population and the growing need for crop production, predicting crop yields using plant simulation models and remote sensing technology is very crucial. The aim of this study was to estimate the yield of rice components including straw, paddy and biomass of Hashemi cultivar during different growth stages with SWAP model and to provide regression equations by extracting NDVI and SAVI plant indices from Sentinel-2 and Landsat-7 and 8 satellite images. It was done in the National Rice Research Institute. Comparison of statistical variables indicated that the mean values of coefficient of determination (R2) and model efficiency factor (EF) in estimating the yield of rice components in different stages of growth with SWAP model were more than 0.70 and 0.90, respectively, and with an error of 1.93 to 6.54% was equivalent to 134.21 to 470.43 kg/ha. The slight difference between the measured and simulated values showed that the SWAP model estimates the rice yield in the study area with appropriate accuracy. The results also showed that the extracted NDVI and SAVI indices with very good accuracy estimate the yield of rice components at different stages of growth. However, the highest amount of correlation was related to the reproductive development stage. Finally, R2 for NDVI at different growth stages as well as  the entire growth period for straw, paddy, and biomass were higher than the SAVI index, revealing more accuracy of NDVI than SAVI.

Considering the significance of the issue, this research was performed to study the elements of Zn, Pb and Cd in the rice products available in the markets of Hamedan in 1394.

Accordingly, ten types of that rice were sampled through a standard method. After passing the preparation stages of the samples by acidic digestion method, the concentration of elements was read in Atomic Emission Device. Spss was applied to process the statistical data.

The results indicated that the minimum and maximum average of element concentration in rice samples (according to mlg/kg) were as the following: for Zink with 0.0862±0.0002 and 1.02±0.00781 in B rice and C respectively, for Lead with 0.226±0.00529 and 4.894±0.00529 in A and H rice, and for Cadmium with 0.006±0.001 and 0.043±0.00436 in H and A. The results also showed meaningful, statistical deviation of accumulated concentration average of heavy metals in rice samples available in the markets of Hamedan through WHO. Concentration averages of Zinc and Cadmium are less while concentration average of Lead is more than permissible level.

Finally, it can be stated that the rice product which is being consumed in Hamedan is exposed to Lead pollution which is more than permissible level and it can cause psychological and behavioral problems and health consequences which cannot be compensated.

  Environmental assessment of the life cycle of crops in production systems is an accepted method for achieving agricultural sustainability. Moreover, the agricultural sector has a significant contribution to greenhouse gas emissions and global warming. Hence, improving agricultural operations is an appropriate way to mitigate the effects of climate change. Therefore, the aim of this research was the environmental assessment of different scenarios of the production of improved rice cultivars. Material and After preliminary evaluation and consultation with rice specialists, 100 paddy fields were selected for semi-mechanized planting method and 100 paddy fields for traditional planting method in Sari region from 2015 to 2016. After recording the data, each planting method was converted into four planting systems based on agronomic management and input consumption, which formed a total of eight scenarios. Four scenarios of the semi-mechanized method were systems of low-input (SL), conservation (SCI), conventional (SCII) and high-input (SH). Four scenarios of the traditional method were systems of low-input (TL), conservation (TCI), conventional (TCII) and high-input (TH). The results indicated that the average paddy yield in eight scenarios was 6418 kg.ha-1. The average input energy in eight scenarios was 28138.93 MJ.ha-1, which contained 45.44% renewable (biologic) energy and 54.56% non-renewable (industrial) energy. The highest input energy was observed in scenarios IV and VIII, which was related to the SH in both planting methods. The average output energy in eight scenarios was equal to 197076 MJ.ha-1. The highest output energy was obtained in scenarios III, IV, VII and VIII. The average energy productivity in the eight scenarios was equal to 0.23 kg.MJ-1 that the least amount was obtained in both planting methods and the other scenarios were on the same level. The average CO2 emissions in all eight scenarios were 1120.37 kg CO2.eq ha-1, which had the highest share related to seed, fuel, and machinery. In terms of global warming potential per unit area, scenario VIII was ranked first and scenario IV ranked second. The highest global warming potential per grain weight and GWP per input energy were achieved in scenarios I and V. The highest heavy metal emission into water and soil was observed in the SH and SCII, respectively. The highest net primary productivity (NPP) in production scenarios was related to SCII and SH, which was higher in the semi-mechanized method than the traditional method. In both planting methods, the most relative carbon inputs (Ri) were obtained in scenarios of the SH (I and V). With regard to input-output carbon and net carbon in eight scenarios, the average sustainability index was 4.66. The highest sustainability index was observed in scenario II (5.05), which was related to the conservation system. The scenarios V, I, III and VI were next ranked in terms of the sustainability index. In fact, the correct management of the paddy field in the SCI has led to a reduction in emissions of environmental pollutants. According to the findings, SL and SCI were closer to sustainable development indicators in both methods. Furthermore, the economic efficiency of rice production was more important to farmers than environmental sustainability and energy efficiency. Hence, using the findings of this research can be very effective in increasing environmental sustainability and reducing the environmental impacts of chemical inputs and achieving agricultural sustainability.

Population growth and rising water demand make our country, which is part of the world's arid regions, on the brink of a crisis of water. Water scarcity is one of the challenges that the world faces today. Water resources constraints have attracted the attention of researchers and authorities to the fundamental use of unconventional waters such as saline water and urban and industrial wastewater. Among the low quality water sources, municipal wastewater is less expensive and considered attractive for irrigation in water-scarce regions. This wastewater is composed of 99.9% water together with small concentrations of suspended and dissolved organic and inorganic solids. It generally contains carbohydrates, lignin, fats, soaps, synthetic detergents, proteins and their decomposition products. It may also include a broad spectrum of contaminants such as macro- and micronutrients for plants, salts and specific ions, and inorganic substances, including a number of toxic elements such as heavy metals. The composition of wastewater, however, differs widely from place to place, even within a country. High energy costs, technology requirements and frequent problems with maintaining treatment plants render wastewater treatment ineffective for use in most developing countries. The results of water comparison showed nitrogen and acidity of wastewater were significantly higher than well water. The results of analysis of soil parameters showed that soil carbon in rice lands with an average value of 1.14 was higher than cauliflower with an average value of 1.01 and Soil acidity in cauliflower lands with a mean value of 51.5 was higher than rice land with an average of 6.9. On the other hand, all soil parameters of the fields that are irrigated with well water and wastewater have a significant difference. As a result, the water used to irrigate it has a direct impact on soil factors, so that soil factors in irrigated fields have higher values relative to irrigated wells. The presence of solids in sewage and municipal wastewater, by increasing organic carbon, salinity and reducing soil acidity, have caused changes in physical indices such as porosity reduction, permeability, water diffusion and water conductivity, or density increase, penetration resistance and soil density. The effect of changing the amount of these parameters on the soil is to destroy the soil structure, reduce the rate of penetration and movement of water, create runoff and soil erosion, which has an adverse effect on the plant due to reduced water holding capacity, reduced water and nutrient uptake, decreased growth And performance.

In order to investigate the effects of nitrogen fertilizer amount and its spliting on rice (Hashemi variety) yield and nutrients uptake from urea source, was conducted in the National Rice Research Instituteduring during a two- year experiment. The study has been done based on a Randomized Complete Block Design (RCBD) with three replications. Increasing amount of nitrogen fertilizers based on urea source in four categories was as the first factor, i.e. 30, 60, 90, and 120 kg nitrogen ha-1 and the time of its application was as the second factor i.e. basal application at transplanting, two splits i.e. at transplanting and at the beginning of tillering, and three splits i.e. at transplanting, at the beginning of tillering and just before flowering. Results showed that yield and nitrogen uptake by grain and straw increased significantly by applying of increased amount of urea fertilizer and when the fertilizer was used in two or three splits application (P

Nanoparticles with a wide range of unique features have been allocated many applications in the field of nanotechnology. Their special properties and their interaction with biological molecules have grabbed the attention of many researchers. These particles, because of their small size and unique characteristics, can be used in various fields, especially the life sciences. Because the lack of any logical model of nanoparticle and biomolecule interaction, their properties and influences on the environment have been evaluated using various separate and non-comparable studies. Nanoparticles interact with plants, animals, and humans and have various and essential impacts on them and these should be considered. The aim of this article is to conduct a morphological and proteomic study of the interaction of biomolecular, bacterial and plant models with silver nanoparticles. The findings are associated with trypsin and human blood serum albumin (as a molecular model), Staphylococcus aureus and Bacillus Thurigiensis (as bacterial models) and Oryza sativa L. (rice) as a plant model.

Optimal management approaches can be adopted in order to increase crop productivity and lower the carbon footprint of grain products. The objective of this study was to estimate the carbon (C) footprint and global warming potential of rice production systems. In this experiment, rice production systems (including SRI, improved and conventional) were studied. All activities, field operations and data in production methods and at different input rates were monitored and recorded during 2012. Results showed that average GWP across production systems was equal to 2803.25 kg CO2-eq ha- 1. The highest and least GWP were observed in the SRI and conventional systems, respectively. GWP per unit energy input was the least and most in SRI and conventional systems, respectively. Also, the SRI and conventional systems had the maximum and minimum GWP per unit energy output, respectively. SRI and conventional system had the greatest and least GWP per unit energy output, respectively. Therefore, the optimal management approach found in SRI resulted in a reduction in GHGs, GWP and the carbon footprint.

Chemical wastes in particular wastes obtained from pesticides production are very dangerous, so control and recovery of them has attracted attention of many researchers and environmental organizations in recent years. Wastes in butachlor industries are formed under undesirable conditions in the process and also during filtration step and cause serious problems. In this study, recovery of butachlor from waste and its effects on rice plant was investigated.
Material and

Waste and off-spec samples containing 55.8% and 63.3% butachlor, respectively, were subjected to solvent extraction. GC/MS and FT-IR were used to identify components of the extracts. The determination of butachlor recovered from waste and off-spec samples was carried out by HPLC and its amount was found to be 88.4% and 89.7%, respectively. Field tests were done on the rice plants to investigate using recovered samples in rice fields. The treatments were exposed at 1.5 Kg active ingredient / hectare of recovered butachlor, waste, off-spec and commercial samples.

The phytotoxicity degrees of both waste and off-spec samples were 100% and the plants died after 28 days. The phytotoxicity degrees of commercial and recovered butachlor from waste and off-spec samples were 6.5, 8.5 and 8% under the same conditions, respectively, which indicates that the recovered butachlor can be used as effectively as the commercial sample in rice fields.

This study conducted by the purpose of investigating agricultural wastes (usable in wood and paper industry) remained in farm lands which due to factors such as burning caused environmental contamination in Golestan province. In this way, from applicable findings, remained farm products in Golestan field such as wheat, rice and barely have been used. Study Result showed that about 1/3 of the agricultural plants stem in agricultural field remained and burnt without harvesting, including wheat, rice and barely. In this study, estimating amount of the wastes in one square meter area of the Golestan field randomly and finally in hectare level and total cities have been generalized. Results showed that the highest amount of burnt waste related to wheat straw and the lowest on related to rice straw.