جستجوی مقالات مرتبط با کلیدواژه « cereals » در نشریات گروه « اکولوژی »

Wheat and maize are important and strategic crops in Iran. These crops are widely grown in the Dez catchment area. Therefore, due to climate change, recent droughts, water bankruptcy in the country, low water consumption efficiency in agriculture, and the excessive consumption of input which pose a serious threat to agriculture and food security, it is necessary to achieve a correct understanding of the sustainable production of crops in the region. Improper use of chemical fertilizers, pesticides, fossil fuels, machinery causes irreversible damage to the environment. To reduce these adverse environmental effects of methods the idea of sustainable agriculture and the transformation of agriculture from high-input to low-input consumption is very important. The footprint index determines the amount of pressure on nature caused by man or other man-made systems. The carbon uptake criterion is used as a basis for assessing the ecological footprint. Ecological footprint estimates the amount of productive land needed to compensate for the environmental impacts of a particular activity by calculating resource consumption and carbon dioxide production. According to studies, each hectare of land can absorb 1.8 tons of carbon. The carbon uptake criterion is used as a basis for assessing the ecological footprint.

The method of the present study has a practical approach because it is in line with achieving sustainable agricultural development. This research was carried out in the cropping year of 2019-2020 at the Dez catchment. To determine the environmental sustainability of agriculture we used the modified ecological footprint method presented by Kissinger and Gottlieb (2012) and Guzman et al (2013). In this study, the ecological footprint was determined based on a place-oriented approach by obtaining energy consumption of the inputs, and the amount of crop and land energy. All the variables were collected in the form of a questionnaire and through interviews with 400 farmers of wheat and maize in the study area. Equivalent factors were also selected from similar studies. Independent samples t-test was performed between the two crops to determine whether there are differences in evaluation of EF.

The results of evaluating the ecological footprint method of wheat and maize cultivation in the study area at the level of one hectare were 3.50 and 4.66 global hectares, respectively. The results of the ecological footprint assessment for wheat and maize showed that both cropping systems are in an unsustainable state in terms of the environment. These systems produce 1.7 tons and 2.86 tons of excess carbon to produce wheat and maize, respectively which are more than the ecological capacity of one hectare to absorb environmental pollution. For both wheat and maize crops, nitrate fertilizer with 40.85% and 49.36%, diesel fuel with 18.57% and 17.60%, and water consumption with 14.57% and 16.31%, respectively, had the greatest impact on environmental instability in the study area. Mean comparison of the ecological footprint between the two crops showed that there was no significant difference between wheat and maize. The high ecological footprint of traditional agriculture was consistent with previous studies (Naderi Mahdei et al, 2015; Kissinger and Gottlieb, 2012; Bevec et al, 2011). Also, the important role of nitrate fertilizer and fossil fuels in increasing environmental hazards and ecological unsustainability was consistent with Fallahpour et al, (2012). It should be noted that No study was found to contradict the findings of the current study.

Both wheat and maize cropping systems were not environmentally sustainable and the total consumption inputs for both crops; chemical fertilizers, especially nitrate fertilizer and then diesel fuel have had the greatest impact on environmental instability in the study area. As a final result, the ecosystem of irrigated wheat production is more desirable than grain maize in terms of environmental sustainability, therefore, the production of both crops, especially maize, must be done with the highest accuracy and consider environmental considerations in the region.

 Occurrence of drought and reduction of rainfall in the future will limit the cultivation of irrigated crops. Thus, it is probable that a part of the present irrigated lands and orchards of Iran may be unavailable for the cultivation of irrigated crops, but it is possible to cultivate rainfed crops in these lands. However, the available potential for cultivation of rainfed crops with respect to the soil type, climate and other factors is not known. Limited water resources, on the one hand, and the growing population along with increasing the need to produce food, on the other, make it necessary to have a comprehensive, practical and accurate program. Therefore, research on this issue is essential. In this study, production potential of rainfed wheat (Triticum aestivum), barley  (Hordeum vulgare L.), chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik) and canola (Brassica napus)  in irrigated lands (fields and orchards) was modeled.

  Weather stations (position and distribution), long-term weather data (15 to 30 years), HC27 soil map, crop management data plant parameters were used to determine the yield in this study using SSM-iCrop2 model. In each zone, the yield was determined and compared with the actual data. In other words, the model output were compared with the actual current rainfed yields of each province and then it was determined that whether the model precision was sufficient for this study. Other calculations (determining the average yield of provinces) and generation of maps were done using ArcGIS V.10.2. The yield obtained by farmers in these lands was considered as 50 and 70 percent of yield potential. Also, the yields were categorized into four classes of excellent, good, medium and non-suitable. This classification is based on economic- agronomic profit of crop harvest.

 The results of this study showed that the conditions of rainfed production in each province of the country is suitable/appropriate for some crops and unsuitable/inappropriate for some other. In case the yield of farmers reached 70 percent of yield potential by optimum management, all provinces will be classified into the upper average group (3, 18 and 10 provinces in excellent, good and medium groups) for wheat. For barley 30 (3, 10 and 17 provinces in excellent, good and medium groups), for chickpea 30 (3, 6 and 21 provinces in excellent, good and medium groups), for lentil 31 (13 and 18 and 10 provinces in good and medium groups) and for canola 30 (4, 5 and 21 provinces in excellent, good and medium groups) provinces will be placed in the upper average group. Based on 70 percent of yield potential of canola, barley and chickpea, only on province is placed in non-suitable group. On the other hand, in case the yield of farmers reaches 50 percent of yield potential due to improper management, for wheat 30 (2, 2 and 26 provinces in excellent, good and medium groups), for barley 28 (4 and 24 provinces in good and medium groups), for chickpea 18 (4 and 14 provinces in good and medium groups), for lentil 28 (3 and 10 provinces in good and medium groups) and for canola 25 (5 and 20 provinces in good and medium groups) will be classified into the upper average group. Based on 50 percent of yield potential of rainfed wheat, barley, canola, chickpea and lentil, 1, 3, 6, 13 and 3 provinces were placed in non-suitable group, respectively.

 According to the results of this study, a major part of the provinces will be placed in medium and non-suitable groups in case of improper management, and agricultural productions will not satisfy the needs of the country. Therefore, it is necessary to pay a special attention to agronomic management of rainfed crops, as the agricultural production of the country will not be acceptable unless 70 percent of yield potential is achieved.

In recent years, due to the excessive consumption of agricultural inputs, especially chemical fertilizers and common methods of crop production, problems have arisen that have led to more attention to sustainable agriculture.Zeolite is one of the natural minerals that also has nutritional value and can be considered a step towards achieving sustainable agriculture.

In order to investigate the effect of type and amount of zeolite on the yield of common millet, an experiment was conducted in the crop year of 2017-17 at the research farm of the Faculty of Agriculture of Birjand University. This factorial experiment was performed using randomized complete block design with 3 replications. Experimental treatments included two types of calcium and potash zeolites in two forms of powder and granules, which were considered at two levels (5 and 10 tons per hectare) with a control treatment without zeolite. In this study, common millet (Pursu) was used for cultivation.

Number of clusters per plant: Analysis of variance of data showed that the effect of treatment on this trait was not statistically significant at the level of 5% probability. However, the control treatment had fewer clusters than the potassium powder and granular treatments of 10 tons per hectare and the calcic powder and granule treatments of 10 tons per hectare. Also, the control treatment had more clusters than the calcium granular and powder treatments of 5 tons per hectare and the potassium granular and powder treatments of 5 tons per hectare. Comparison of the average effect of zeolite content on the number of clusters per plant showed that increasing the application of zeolite from 5 tons per hectare to 10 tons per hectare caused a significant increase in the number of clusters per millet plant at a probability level of 5%.
Thousand-grain weight: Analysis of variance of 1000-grain weight data as a treatment, to compare with the zeolite control treatment showed that the effect of zeolite treatment on millet 1000-grain weight was significant at 5% probability level. The results of factorial analysis of variance showed that the simple effect of zeolite type on 1000-grain weight was significant at 5% probability level. But the simple effect of zeolite content as well as the interaction effect of type and amount of zeolite on this trait was not significant.
Grain yield: The results of analysis of variance of grain yield data to compare treatments containing zeolite with control treatment without zeolite showed that the effect of zeolite treatment on grain yield was significant at the level of 1% probability. The results of factorial analysis of variance showed that the simple effect of zeolite content at 1% probability level and the effect of type and amount of zeolite at 5% probability level on grain yield were significant. But the simple effect of zeolite type had no significant effect on this factor. The results of comparing the average amount of zeolite on grain yield showed that increasing the amount of zeolite increased millet grain yield at a probability level of 5%.
Water use efficiency: The results showed a significant effect of zeolite treatment on water use efficiency at a probability level of 1%. The results of variance for water use efficiency showed that this trait was significantly affected by the simple effect of zeolite content and the interaction between type and amount of zeolite at 5% level but the effect of zeolite type on it was not significant. The results of comparing the average amount of zeolite on water use efficiency showed a statistically significant difference between the application of 5 and 10 tons per hectare of zeolite at the level of one percent.

The results showed that the application of different types of zeolite caused a significant increase in 1000-grain weight and number of grains per panicle at a probability level of 5% and grain yield, water use efficiency at a probability level of one percent compared to control treatment (no application of zeolite). Increasing the application of zeolite from 5 to 10 tons per hectare significantly increased the number of spikes per plant, number of seeds per spike, 1000-seed weight, biological yield, grain yield and water use efficiency. Therefore, with the optimal using of this fertilizer, the effects of drought stress on plants are somewhat reduced and it is recommended for using in dry areas.

Cereal production systems in Iran are often associated with high costs and low productivity, improper use of inputs causes irreversible damage to the environment. Efficient farm management is one of the most important issues in achieving sustainable performance. This study aimed to determine and compare the ecological sustainability of two production ecosystems of irrigated wheat and grain maize using emergy analysis.

This research was carried out in the cropping year of 2019-2020 in Dez catchment. Interviews were conducted with 400 farmers of wheat and maize based on a questionnaire to collect data on production processes in farms. In this study, the emergy analysis method was selected to measure the sustainability of the desired agricultural products. Finally, the sustainability of the systems was evaluated using the value of emergy indicators.

The total emergy inputs for the irrigated wheat and maize production ecosystems were 1.60347E+16 and 2.54883E+16 sej ha-1 per year, respectively. The results indicated the production of both crops is in an environmentally unsustainable condition, and of all consumption inputs; chemical fertilizers, especially nitrate and phosphate, and then diesel have the most impact on environmental unsustainability in the study area.

As a final result, the ecosystem of irrigated wheat production is more desirable than grain maize in terms of yield, renewability, and environmental sustainability, and wheat production in the region is the superior system for achieving sustainability compared to maize production.

Weeds in wheat (Triticum aestivum L.) fields have always been a big problem in Iran and worldwide and must be managed by non-chemical especially cultural methods. A field experiment as factorial based on a randomized complete block design with four replications in a 1000 m2 field in Research Farm of Shirvan College of Agriculture was conducted during 2007-2008. Treatments included wheat densities of 400، 600 and 800 plants. m-2and planting dates of 1st of Nov.، 20th of Nov.، and 1st of Dec 2007. The results represented that the presence of Rapistrum rogusum، Phalaris spp.، Descurainia sophia، Alopecurus myosurides and Hordeum murinum dominance. Delay in planting of wheat increased relative density of weeds. The lowest relative frequency of weeds was observed in planting date of 1st of November. Increase in crop density significantly decreased weed biomass، while it showed little effect on weed density trend. Effect of planting date was also significant on weed biomass. The highest weed biomass occurred in the planting date of Dec. the 1st. In conclusion، delay in planting of wheat create more chance and space for weed establishment، and therefore planting dense (600 plants. m-2) and early in season of wheat is recommended for lower weed damage.