فصلنامه تحقیقات غلات
سال دوازدهم شماره 4 (زمستان 1401)

 In the past decades, the increase in the use of high-yielding seeds, chemical fertilizers, pesticides and water, along with high production costs, has increased the yield of agricultural products significantly. This has led to an increase in dependence on the consumption of non-renewable inputs in the agricultural sector and environmental damage. Therefore, measuring sustainability and knowing the factors affecting it can play an important role in formulating sustainable agricultural policies and strategies. With this approach, the present study measures and evaluates the sustainability of the paddy farming system in Lahijan county.

 In this study, the required information was collected in the form of face-to-face interviews and by completing a questionnaire from paddy farmers in Lahijan county in the crop year of 2021. In addition, stratified sampling was used to determine the sample size. In the following, by using the combined index by the method of deviation from the optimal value, the optimal pattern for each farmer was determined; Finally, the hierarchical analysis process (AHP) was used to determine the weight of social, economic and ecological indicators.

The results of calculating the weight of indicators showed that ecological, economic and social indicators with weights of 0.558, 0.320 and 0.122, respectively, were the most important in evaluating the level of sustainability of the paddy production system. In addition, the results showed that the local and low-yielding cultivars had a more favorable situation in terms of sustainability indicators, and the farmers who benefited from agro-ecological management operations were at a higher levels in terms of ecological and economic sustainability as well as the overall sustainability. Besides, based on the results of the current study, farmers with single and concentrated lands had a more favorable situation in terms of economic stability and overall stability. Comparison of the management indicators also showed that the sub-index of agro-ecological management was the most important among the ecological sub-indices, and the rural participation was more important among the social sub-indices. Furthermore, the sub-index of gross profit margin had a higher relative weight among the economic sub-indices.

The results showed that participation in extension classes has a direct and significant effect on the sustainability of paddy cultivation, while the farmers who benefited from agro-ecological management operations were at a more favorable level of sustainability. Therefore, it is suggested to strengthen support services and sustainable operation skills among farmers and to encourage and promote more use of agro-ecological management operations at the farm level. Also, the results of the current study showed that farmers with single and concentrated lands had a more favorable situation in terms of economic stability as well as overall stability. Therefore, moving to larger farm sizes can have a positive effect on the sustainability of paddy cultivation.

There is a considerable gap between the grain yield of bread wheat and its production potential in Khuzestan province, but it seems that the yield of wheat can be increased with proper direction of environmental effects through suitable agronomical management. In this regard, planting date and nutrient application are very important. However, the application of little or much nitrogen reduces the grain yield under high temperature conditions, and in addition, using too much nitrogen can cause environmental pollution. Therefore, it is necessary to accurately determine the optimal level of nitrogen for different planting dates. The objective of the current experiment was to study the effect of planting date and application of nitrogen and zinc fertilizers on growth and yield of wheat.

To investigate the effect of planting dates and the application of nitrogen and zinc fertilizers on growth and yield of wheat (cv. Chamran), an experiment was conducted in experimental field of Khuzestan Agricultural University, Khuzestan province, Iran, during 2018-19 growing season. The experiment was carried out as split-split plots in randomized complete plot design with four replications. Planting date at three levels (Nov. 22, Dec. 11, and Dec. 31) were considered as main plots, nitrogen at four levels (0, 75, 150, and 225 kg.ha-1) as sub-plots, and zinc at three levels (0, 10, and 20 kg.ha-1) as sub-sub-plots. The evaluated traits were including grain weight, number of grains per unit area, number of days from planting to pollination, number of days from pollination to maturity, grain yield, grain protein percentage, grain zinc content, grain protein accumulation rate, grain filling rate and grain filling period.

The results of analysis of variance showed that three-way interaction of planting date × nitrogen × zinc was significant on all studied traits at 1% probability level, except for number of grains per unit area which was only affected by nitrogen levels. The highest wheat grain yield (7486 kg.ha-1) was belonged to the first planting date (Nov 22) along with the second level of nitrogen (75 kg.ha-1) and zinc (10 kg.ha-1). The delay in planting led to a decrease in grain yield, so that planting on Dec. 11 and Dec. 31 caused a decrease of about 23 and 40 percent in wheat grain yield, respectively. The application of chemical fertilizers at delayed planting date led to a certain extent to compensate for the decrease in grain yield, so that the application of 75, 150 and 225 kg.ha-1 of nitrogen on the planting date of Dec. 11 increased grain yield of wheat by 44%, 52% and 55%, respectively. With the delay of planting from Nov. 22 to Dec. 31, grain filling rate and grain protein percentage increased by 19% and 25%, respectively, but the grain filling period (28%), grain weight (20%), protein accumulation rate (27%), protein yield (50%) and grain zinc content (3%) decreased. The highest grain filling rate (1.37 mg.day-1) and the highest grain protein content (12.7%) of wheat were obtained on the planting date of Dec. 31 along with 150 kg.ha-1 N and 10 kg.ha-1 Zn. Also, the highest grain filling period (46.1 days) was observed on the first planting date (Nov. 22), but there was no significant difference among different levels of nitrogen and zinc in this regard.

In total, the results of the current experiments showed that to avoid exposure of wheat to high temperatures during the grain filling period in the studied region, it is better to do planting on earlier date (Nov. 22). In delayed planting dates, using 150 kg.ha-1 N and 10 kg.ha-1 Zn can relatively compensate for the negative effects of high temperature after anthesis. The delay in planting, increased the grain protein content due to the acceleration of the grain filling period, however, it decreased total protein yield, which shows that the protein yield (kg.ha-1) is more dependent on the grain yield.

Food security has become one of the most important global issues due to rapid population growth and changing weather conditions, drought and heat stress. Cereals and especially wheat are among the strategic and important agricultural products and they have a special role in the food security of many countries of the world including Iran. Increasing mechanization, improving production methods and the widespread use of fertilizers during the 20th century have greatly helped to increase production and the production of agricultural products is the result of a complex interaction between various environmental factors such as soil properties and management operations. Different tillage systems have different effects on crop production in rainfed agriculture. Nitrogen is one of the most important nutrients in the production of crops, which affects the growth and performance of the plant. The purpose of this experiment was to determine the most appropriate method of seedded prepartion and the amount of nitrogen fertilizer on wheat grain yield and soil properties.

To investigate the effect of raised bed and flat planting methods and the amount of nitrogen fertilizer on soil characteristics, radiation efficiency, energy balance and grain yield of Kohdasht wheat cultivar, a factorial experiment was conducted in randomized complete block design layout with three replications in the cropping years of 2019-2020 and 2020-2021 were implemented in an experimental farm in the suburbs of Rostam Abad, Rudbar, Guilan, Iran. The experimental factors included the methods of raised bed and flat planting and nitrogen fertilizer at four levels of zero, 75, 150 and 225 kg.ha-1. Measured plant traits and other indices included plant height, 1000 grain weight, fruiting efficiency, radiation efficiency, grain protein content,  biological yield, grain yield, soil bulk density, soil porosity and energy balance.

Results showed that in the treatment of 225 kg.ha-1 of nitrogen in the method of raised bed and flat planting, the highest plant height (66.3 cm), grain yield (4908 kg.ha-1), 1000 grain weight (40 g), grain protein content (11%), fruiting efficiency (88 grain.g spike-1DW), radiation use efficiency (2.05 g.MJ-1) and biological yield (11349 kg.ha-1) were obtained. Raised bed planting methods increased the soil bulk density (1. 16 g.cm-3) and decreased soil porosity. The results showed that in terms of the total energy consumption for wheat production, the lowest and highest amounts were related to raised bed and flat methods, respectively (11681.1 and 13606.8 MJ.ha-1). The highest amount of energy consumed in the flat method was allocated to nitrogen fertilizer (51%) and fuel (19%), respectively.

Increasing nitrogen fertilizer application through the faster canopy closure and sooner maximum leaf area index caused an increase in the number of grain.spike-1, 1000 grain weight and the absorption of radiation, which ultimately increased the efficiency of radiation, biomass and grain yield. Due to the minimization of the traffic of machines on the soil by reducing the soil preparation operations, the tillage system of the raised bed planting method led to a decrease in the hours and energy required for the work of the machines per hectare compared to the flat planting method. Also, raised bed planting system along with nitrogen fertilizer increased the soil bulk density and decrease the porosity. According to the results of this experiment, it seems that the method of raised bed planting along with the consumption of 225 kg of nitrogen fertilizer.ha-1 is due to having favorable weather conditions in terms of grain yield and other studied traits for the production of Kohdasht wheat cultivar in the region, the subject of study seems to be more suitable.

Field monitoring is the basis of many information, actions and researches in agriculture. As long as there is no real information and data from fields and orchards, many of the initial steps in research and implementation will be incomplete and inconclusive. Today, continuous monitoring, as the foundation of sustainable production of healthy food, is on the agenda of international organizations and institutions, and global threats are being monitored through remote sensing systems and ground monitoring in high-risk areas. Of the three main components of monitoring (i.e. environment, plant and damaging factors), climate and host plant variables can be monitored using remote sensing systems, but accurate and reliable monitoring of variables related to damaging factors (especially pests, diseases and weeds), even in developed countries, is done based on field monitoring (or in some cases a combination of both methods). The purpose of this research was to present a real picture of the state of wheat fields in Golestan province in terms of plant protection characteristics.

To determine the status of infection of wheat fields in Golestan province with important diseases, a team consisting of plant protection experts of the province was formed and wheat fields in 14 counties of the province were surveyed in the crop year 2017-2018. At each survey, a monitoring form was completed containing field information, crop specifications, and the amount of pests and disease of the field. After the finalization of the data obtained from monitoring and the elimination of their problems, the statistical and geostatistical analyses of the data were done and the geographic information system (GIS)-based maps were prepared.

After five months of project implementation, 238 wheat monitoring forms were received by the center. The total area of monitored wheat fields was 773 (with an average of 4.3) hectares and 31015 kg of seeds (with an average of 190.3 kg per hectare) were planted in these fields. Of the 18 cultivars of wheat planted, 20% of the fields were allocated to Marwarid and Ehsan varieties. In terms of planting date, eight two-week groups were defined, where 39% of fields were planted in the first half of December. Eight types of autumn crops and 8 types of spring crops were grown in rotation with wheat in the fields, and wheat (77%) and fallow (39%) were ranked first. The average final severity of powdery mildew, Septoria leaf blotch and tan spot was 5.3, 3.5 and 15%, respectively. The average percentage of occurrence and severity of Fusarium head blight was 1.1 and 1.2 out of 3, respectively, and the average severity of stripe rust disease was 0.6 out of 2. The percentage of field infection with powdery mildew, Septoria leaf blotch, tan spot and stripe rust was 60, 38, 77 and 50, respectively.

The highest disease intensity for three diseases of powdery mildew, Septoria leaf blotch and tan spot was recorded in Ramian and Turkmen counties, and the highest intensity of stripe rust was observed in Kordkuy county. The maps drawn in this research were different from the maps drawn before by the researchers of the Agricultural Research Center and plant conservation experts for Golestan province, and the changes made after six years were evident in the case of some diseases. The findings of this research showed that disease monitoring should be done as a continuous program to determine the gradual changes in the distribution of diseases and high-risk areas in the the studied region, and the effect of climate change and other factors on these maps can be tracked and analyzed.

Covered smut disease caused by the biotrophic fungus, Ustilago hordei (Pers.) Lagerh., is one of the significant limiting factors in barley cultivation. This disease is present in all barley cultivation regions, and if seeds of sensitive cultivars are planted without the use of fungicides, it can become a serious problem. Moreover, this disease adversely affects grain quality by contamination of healthy seeds with teliospores. The contamination level in the farms of Karaj and Zabol in 1990-1992 ranged from zero to 90%. Considering the importance of organic agriculture and the public demand for production systems with reduced chemicals inputs, planting improved seeds with genetic resistance is the most effective and economical approach to control this disease. This research was conducted to assess the sensitivity of barley cultivars to the covered smut disease and to evaluate the effect of this disease on the phenological, physiological, and agronomic characteristics of barley cultivars.

 In this study, 148 spring barley varieties from common commercial varieties from European countries along with Oxin and Zehak cultivars from Iran were investigated. This experiment was conducted in field conditions using an alpha lattice design with two replications under two environmental conditions, disinfection of seeds with fungicide and disease stress by inoculation of the covered smut pathogen, in the Zehak Agricultural Research Station, Sistan and Blouchestan province, Iran, in 2021-22 growing season. To induce the stress of covered smut disease, the seeds of the studied cultivars were artificially contaminated. The measured traits in this experiment included phenological, morphological, physiological, and agronomic traits, as well as spike infection percentage after maturity. To perform statistical analyses, the normal distribution of the collected data was firstly tested using the Shapiro-Wilk test, and then combined analysis of variance was conducted. Comparison of means, simple correlation coefficients between traits, principal component analysis, and heritability of the studied traits were conducted.

The results showed that the accurence rate of covered smut disease among the studied cultivars under disease inoculation conditions varied from 0% to 26.48% with the average of 3.51%. The genotype × environment interaction for all studied traits including days to tillering, tiller number per plant, plant height, flag leaf length and width, flag leaf sheath length, peduncle length, spike length, number of nodes, internode distance, 1000-grain weight, grain yield, biological yield, harvest index, water-soluble carbohydrate concentration, and disease infection percentage, was significant at 1% probability level, except for phenological traits including days to germination, days to tillering, days to heading, as well as canopy temperature. The heritability rate of resistance to covered smut disease was 97.89%. Also, a negative and significant correlation was observed between the percentage of disease infection with plant height, flag leaf sheath length, peduncle length, spike length at the 1% probability level, and with biological yield at the 5% probability level.

The results of this research showed that there was a significant genetic diversity among the evaluated cultivars and the studied cultivars exhibited diverse reactions to different environmental conditions. Due to the significant impact of covered smut disease or loose smut disease on spike-related traits during the maturity stage, therefore it is challenging to differentiate resistant cultivars from susceptible ones in other stages and traits, and the selection of resistant cultivars requires waiting until the end of the cropping season.

Drought stress is one of the most important factors affecting crop yield especially in irrigated agriculture in arid and semiarid regions. Application of some stress modulators (vermicompost, mycorrhiza, putrescine and zinc nanooxide) increases growth, yield and the resistance of plants against various environmental stresses such as drought. However, the effect of these compounds alone has been investigated on modulating the effects of stress, there are fewer reports about their interaction effects. In this experiment, the interaction effects of organic, biological and mineral fertilizers and stress modulators were investigated on the improvement of current photosynthesis, dry matter remobilization process, grain filling components and grain yield of barley under water deficit conditions.

To investigate the interaction effects of some stress modulators (vermicompost, mycorrhiza, zinc nanooxide and putrescine) on the contribution of dry matter remobilization and grain filling components of barley under water deficit stress conditions, a factorial experiment in randomized complete block design with three replications was conducted in research greenhouse of Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil, Iran, in 2022. The experimental factors were included irrigation in three levels (full irrigation as control, irrigation withholding at 50% of the heading and 50% of the booting stages, equal to codes 55 and 43 of BBCH scale, as moderate and severe water limitation, respectively), application of biofertilizer, and organic and inorganic fertilizers in four levels (no application of fertilizers as control, application of vermicompost, application of mycorrhiza, combined application of vermicompost and mycorrhiza), and foliar application of putrescine and zinc nanooxide in four levels (foliar application of water as control, foliar application of 0.4 g.L-1 Zn nanooxide, foliar application of 0.8 mM putrescine, combined foliar application of Zn nanooxide and putrescine). Mycorrhiza fungus (mosseae species) was purchased from Zist Fanavar Turan company and according to copany’s protocol, 10 g per kg soil was used. Vermicompost was purchased from Gilda company and according to copany’s protocol, 50 g per kg soil was used. Zinc nanooxide production of China, with an average particle size of less than 30 nm, a specific surface of more than 30 m2.g-1, a Zn content of about 65.21% and a purity of 99%, was purchased from Jahan Kimia company, Urmia, Iran. The barley variety used in the experiment was Nobahar variety, which was cultivated with a plant density of 400 seeds per m2.

The results showed that the combined application of stress modulators (vermicompost, mycorrhizal, Zn nanooxide and putrescine) under irrigation withholding at booting stage conditions decreased dry matter remobilization from shoot and stem (22.32% and 25.65%, respectively) and their contribution in grain yield (52.92% and 56.95%, respectively) compared to the no application of biofertilizers and no foliar application of putrescine and Zn. In contrast, application of stress modulators under irrigation withholding in booting stage conditions increased total chlorophyll (24.91%), current photosynthesis (62.57%), contribution of current photosynthesis in grain yield (30.54%), grain filling rate (6.62%), grain filling period (18.06%), effective grain filling period (27.67%) and grain yield (25.18%) compared to the no application of biofertilizers and no foliar application of putrescine and Zn.

The findings of the current experiment showed that the application of stress modulators (vermicompost, mycorrhizal, Zn nanooxide and putrescine) can increase grain yield of barley under water limitation conditions by improving the current photosynthesis and grain filling components.