فهرست مطالب m nasiri mahalati

Nitrogen (N) is one of the main limiting factors in agroecosystems all around the world. However, high application rates of N fertilizers would lead to negative environmental consequences. Reduction of N fertilizers consumption decreases production costs and environmental pollution. Therefore, N efficiency to be enhanced due to the high N fertilizer cost and required measures to prevent the waste of N. Cultivation of diverse crop cultivars with higher resources absorption and utilization efficiency is one of the major approaches in sustainable agriculture that would result in the effective use of natural and chemical inputs and reduce significantly the environmental risks. Quchan City is one of the potato production poles in Khorasan Razavi province. In this region, large amounts of N fertilizers annually are consumed in the potato agroecosystem. Therefore, the potato of the present study was evaluating N uptake and utilization efficiency, and finally, N uses efficiency in the potato agroecosystem of Quchan.

This experiment was performed in the cropping year of 2020-21 in Quchan located in Khorasan Razavi province. A split plots arrangement based on a randomized complete block design with three replications was conducted. Different nitrogen application rates (0, 50, 100, and 150 kg of pure nitrogen per hectare) were assigned to the main plot and the sub-plot factor consisted of two potato cultivars, Agria and Arinda. To calculate the efficiency of nitrogen application, the amount of nitrogen in the soil was also considered. Equations (1 to 3) were used to calculate nitrogen efficiencies:                                                                                                       Eq. 1
                                                                                                        Eq. 2
                                                                                                    Eq. 3

The results of the analysis of variance showed that the effect of nitrogen fertilizer and cultivar on yield was significant. At the same levels of nitrogen, the Arinda cultivar had a higher yield and with increasing nitrogen application, an increase in yield was observed in both Agria and Arinda cultivars. The effect of nitrogen application and cultivar on nitrogen uptake, utilization, and use efficiency was significant (p≤0.01). Comparing the interaction of nitrogen and cultivar on nitrogen utilization efficiency, showed that the Arinda cultivar had higher efficiency than the Agria cultivar.

By increasing the amount of nitrogen fertilizer application, improvement was achieved in most of the evaluated characteristics of potato cultivars, including yield. Arinda cultivar had better conditions in terms of tuber yield and nitrogen uptake, utilization, and use efficiency compared to Agria.

Climate change is rapidly degrading the conditions of crop production. For instance, increasing salinization and aridity is forecasted to increase in most parts of the world. As a consequence, new stress-tolerant species and genotypes must be identified and used for future agriculture. Stress-tolerant species exist but are actually underutilized and neglected. Quinoa, scientifically known as Chenopodium quinoa Willd. is a member of the Amaranthaceae family. Promoting the cultivation and nutrition of quinoa will diversify food products in the country, sustainable production, increase farmers' incomes and provide part of the community's food needs. Crop simulation models have been used for various studies such as selecting the appropriate cultivar, determining the best planting date, predicting the effect of diversity and climate change on growth. Field research requires a lot of time and money, while computer simulation models can save time and money by conducting extensive experimental simulations.

This research was conducted in two regions of Yazd province with 10 separate experiments in the form of a randomized complete block design with 3 replications. Experimental factors included 5 promising modified lines in Yazd Salinity Research Center with Titicaca cultivar. The lines consisted of four intermediate maturity lines, numbered 1 (NSRCQE), 2 (NSRCQC), 3 (NSRCQD), and 6 (NSRCQA), one late maturity line numbered 4 (NSRCQB), and the early maturity cultivar Titicaca numbered 5. Sampling and note-taking were performed regularly, once every three days, in proportion to the progress of the phenological stages of each line. A model based on degree-day-growth was prepared in FST language. In preparing the length table, due to the short day of Quinoa, for all lines in the model up to 12.5 hours, the development rate was one, and after 13.8 hours, the development rate was zero. The base temperature in the model was 2 °C. Then, the model was calibrated and evaluated with data taken from the field.

RMSE (CV) coefficient of variation between 7 to 12%, root mean square error (RMSE) between 4.4 to 6.4 days, Wilmot agreement index (d) between 0.99 to 1, model efficiency (ME) between 0.96  to 0.98, the mean deviation from the model (MB) was between 0.05 to 0.08 and the coefficient of determination (R2) was between 92 % to 98%. These values indicated a good estimate of the day to flowering of quinoa with the model written in FST language, and the values of day to flowering simulated gained the necessary validity. The coefficient of variation of nRMSE (CV) is between 6.8 to 8.6%, the root mean square error (RMSE) is between 6.2 and 8.7 days, the Wilmot agreement index (d) is between 0.75 and 0.92, The mean deviation from the model (MB) was between 0.05 to 0.08 and the coefficient of determination (R2) was between 92% and 98%. These values indicated a good estimate of the day to physiological maturity with the model written in the FST language, and the day values to the simulated physiological maturity gained the necessary validity. Calibration and evaluation of model efficiency using root mean square error (RMSE), coefficient of variation or nRMSE percentage (CV), Wilmot agreement index (d), model efficiency (ME), and mean model deviation (MB), coefficient of explanation (R2), line test 1: 1 day until germination, flowering and good physiological maturity was estimated.

The results of this study indicated that, the quinoa model prepared for quinoa in terms of degree-day-growth well predicts the developmental stages (emergence, flowering and maturation) of this plant in terms of maturity (early, medium and late) and can be its help determined the appropriate planting date in different areas. This calibrated sub-model can now be used to evaluate different temperature and photoperiod effects for decision making in a wide range of growth environments in quinoa cultivation systems in current and future climatic conditions. Therefore, this sub-model can be used in educational-research and applied work in the field.

During the 1950s and 1960s, the green revolution led to a dramatic increase in global food and fodder production to eliminate hunger and boost food security. This production enhancement was accompanied by an intensified agricultural and chemical input consumption and increased cultivated area and mechanization. Although yield per unit area has improved in most crops, concerns about food security for the world's rising population are still significant. Guaranteeing food security in the future will necessitate a shift in management approaches to boost output, agroecosystem sustainability, and stability and reduce the environmental harm caused by agriculture. The first step to achieving sustainability and ecological intensification in agricultural systems is to have a comprehensive agroecological analysis of agricultural systems in each region. Hence, the complete evaluation and analysis of agroecological features according to their type in each region is necessary for establishing an optimal management technique. After analyzing the present state of each region's shared ecosystems, the optimal strategy for boosting production stability must be devised and implemented.

The goal of this study was to undertake a detailed investigation of the agroecological state of the sugar beet ecosystems on a local scale. For this purpose, data were collected on the area under cultivation, yield, and input consumption (including nitrogen and phosphorus fertilizers and chemical pesticides) from 2001 to 2016. Data was acquired from the Ministry of Agriculture and other related organizations and direct interviews with the farmers. In addition, data on climatic parameters (including daily minimum and maximum temperatures, precipitation, and sunny hours) were collected from the Torbat-e Heydariyeh meteorological station. This study researched the most important agroecological indicators of sugar beet farming systems in the Torbat-e Heydarieh region. Study indicators include variations in sugar beet cultivation area and yield, Potential yield via the methods FAO and FAO modified, beet yield gap, Regional Yield Factor trend, Changes in the intensification, yield stability, nitrogen uptake, and nitrogen utilization, and nitrogen use efficiency.

According to this study results, sugar beet production increased by 59 percent between 2001 and 2016. During the research years, sugar beet ecosystems saw a drop in the cultivation area. Potential yield calculations using both FAO and modified FAO methodologies revealed that potential yield was nearly consistent over the research period in the region.The sugar beet yield gap averaged 35 ton.ha-1 over the research period. According to the findings, the percentage of sugar beet yield gap ranged from 53 to 69 %, with an average of 63 %. The extent of the yield gap decreased over the research period. The study of the regional yield factor (RYF) revealed that improving the management system resulted in higher actual yield and thus a smaller yield gap in sugar beet ecosystems. In sugar beet cultivation systems, the results revealed that by increasing intensification, the stability decreased. In sugar beet cultivation systems, there was a reduction in yield stability. Given that nitrogen consumption efficiency is one of the most important factors influencing the degree of stability in agricultural systems, the findings revealed that the rate of nitrogen uptake efficiency (NUpE), nitrogen utilization efficiency (NUtE), and nitrogen use efficiency (NUE) all decreased during the studied years in the region.

According to the findings, the major cause of the increase in nitrogen consumption, growing intensification, and decreasing stability in the analyzed systems appears to be a deficiency of nitrogen use efficiency and its downward trend. As a result, planning and altering management methods focusing on enhancing Nitrogen use efficiency may be proposed as the first step toward boosting sustainability in the Torbat-e Heydarieh sugar beet agroecosystems.

Sugar beet (Beta vulgaris L.) is the second most important sugar crop after sugarcane, which annually produces about 40% of total sugar production worldwide and is adapted to different climatic conditions (El-Hag et al., 2015). Due to global warming, autumn cultivation of sugar beet is predicted to become more priority in the future, but autumn cultivation is in danger of bolting and flowering in many areas. Excessive bolting reduces sugar content, root yield, and purity of raw syrup. In general, both early sowing and delayed sowing reduce root yield, sugar, and leaf area index and increase the percentage of impurities. Therefore, this experiment was designed and implemented with the aim of feasibility study of autumn cultivation of sugar beet and determination of the best planting date in North, Razavi, and South Khorasan provinces for three new varieties resistant to sugar beet.

The experiment was conducted as a split-plot design based on a randomized complete block design with three replications in the provinces of North Khorasan (Shirvan), Khorasan Razavi (Mashhad), and South Khorasan  (Khezri Dasht-e Bayaz) in 2019-2020. The main plots included three planting dates (2, 7, and 12 October) and the subplots included three bolt-resistant sugar beet cultivars (Giada, Merak, and Sharif). Each plot consisted of 6 rows with a length of 5 m, at a distance of 50 cm and a distance between two plants of 20 cm, and planting was done manually. To determine root yield from the middle rows of each plot by eliminating the margin, harvest was done at an area of 4 m2. A sample of root paste of each treatment was sent to the Beta Lizer laboratory of Mashhad Agricultural Research and Agricultural Services Company to determine the percentage of sugar. Other quality parameters were measured by Beta Lizer (Braunschweig method). Using the polarimetry method (Sucromat), the percentage of sugar content and white sugar yield, and other quality parameters were calculated for all experimental plots. Combined analysis of variance for different locations and mean comparison based on least significant difference (LSD) at the level of 5% probability using SAS 9.4 software was performed. Also, the graph plots were performed using Excel software.

The results of the analysis of variance showed that the interaction effects of the location and cultivar were significant on bolting percentage, root yield, sugar content, Na content, yield coefficient, and white sugar yield. The first planting date (October 2) in Mashhad region for all three cultivars led to the highest percentage of bolting (78-90%). Delay in planting date from 2 October to 12 October, the bolting percentage of cultivars was reduced, significantly. The bolting percentage in Shirvan region was less than 8%. On the third planting date (October 12) in all regions, cultivars showed also a bolting percentage of less than 10%. Giada cultivar in Mashhad region with 47.3 ton.ha-1 had the highest and Sharif cultivar in Shirvan region with 22.6 ton.ha-1 had the lowest root yield. Shirvan region had less root yield than the other two regions. The highest sugar content (18.78%) belonged to Giada cultivar in Shirvan region and the lowest sugar content (13.01%) was observed in Sharif cultivar in Mashhad region. The planting date of 12 October was significantly lower in impurities, alkalinity coefficient, and molasses compared to earlier planting dates. The first planting date had the lowest (62.3%) and the third planting date had the highest (74.2%) extraction coefficient. Giada cultivar in Shirvan region had the highest extraction coefficient (78.1%) and the lowest extraction coefficient (60.8%) belonged to Sharif cultivar in Mashhad region.

In Shirvan and Khezri regions, Giada cultivar but in Mashhad region, Merak cultivars had the highest white sugar yield. In general, the results showed that in Shirvan region, planting on 2 October and in Mashhad and Khezri regions planting on 7 October could lead to reaching maximum white sugar yield.

Cantaloupe (Cucumis melo L.) is one of the most important melons in Iran especially in Khorasan province. The cantaloupe seed is a good functional and nutritional source for human, having large amounts of essential amino acids and unsaturated fatty acids. In spite of nutritional and functional aspects, it does not have considerable applications in food industry yet. Cantaloupe seed milk's pH is about 6.8, so cannot be stored for a long time. In this work, pH of cantaloupe seed milk decreases to 4.15 in 3 treatments (citric acid, orange concentrate, and orange sacs) and a constant amount of lemon juice. At first, nutritive value of seed milk was measured. According to results, this milk is a good source of protein (1.52%), phosphorus (41/3 ppm) and potassium (17 ppm). After that, storage stability of cantaloupe seed beverage at refrigerator temperature (4 °C) for 42 days was evaluated by analyzing changes in the chemical, microbial and sensory properties. The results showed that the orange concentrate-cantaloupe seed beverage reached the highest score of total acceptance (3.67 on a 5-point hedonic scale). In these conditions, we couldn’t find any molds and yeasts in the samples, thus the shelf life of the mentioned beverage could be 6 weeks at 4 °C.

The present experiment was aimed to evaluate the freezing tolerance of two cold tolerant (MCC426 and MCC252) and a cold susceptible (MCC505) chickpea genotypes. The study was carried out in a split-plot factorial design with three replications. Factorial arrangement of genotype and acclimation (acclimation and non acclimation) were imposed as main plot and temperatures (0, -4, -8, -12, 16, -20ºC) as subplot. The effect of freezing temperature (FT) on plant survival was significantly different among genotypes (p<0.05). According to the average effects of acclimation and FT, the plant survival in MCC426 and MCC252 was 40% and 31% respectively more than in MCC505. Lethal temperature for 50% response (LT50) and temperature resulting in 50% lower dry matter (DMT50) in MCC426 were –10.8ºC and –8.4ºC, respectively and were lower than the other genotypes. Acclimation increased the freezing tolerance such that MCC426 tolerated up to –12ºC without any mortality, however, at this temperature, plant mortality rates in MCC252 and MCC505 were 25.7% and 67.7%, respectively. Plant regrowth was affected by the intensity of FT, such that plant dry weight (PDW) and stem height (SH) in –12ºC decreased about 63% and 50%, respectively, compared with non - frozen control plants. The most freezing damage was observed in MCC505, -12ºC treatment caused 90% decreases in PDW and SH, but at this temperature, PDW and SH in MCC425 decreased 55% and 49% and in MCC252, the reduction was about 60%and 54%, respectively. It seems that the use of controlled experiments would contribute to the evaluation of freezing tolerance and screening programs in chickpea germplasm for the estimation of LT50 and DMT50 .