حسنا فیاضی

Global climate change is among the most important agricultural and food security challenges. This study tries to investigate the effect of climate change on potential yield and water productivity of forage maize (Zea mays L.) in Iran. Two scenarios of RCP4.5 and RCP8.5 are used to predict the future climate (2050s) and climate data of 2001-2015 have been used as the base period. Potential yield is estimated using SSM-iCrop2 model according to the GYGA protocol and the climate changes for both scenarios are applied in the model. The results show that the climate change will not have a considerable effect on forage maize yield compared to the current conditions (85.6 ton ha-1) and will only lead to an increase of 0.9% and 1.6% in on both scenarios, respectively. This may be attributed to maize being a C4 plant and thus non-effectiveness of CO2 increase on its growth. Also, the temperature will remain in optimum range for maize in most of the main regions for forage maize cultivation areas in Iran. Water productivity in both scenarios will increase by 0.4% and 1.6%, compared to current conditions (10.4 kg m-3), respectively, which may be due to increased CO2 concentration and more closure of stomata. Also, improved water productivity in forage maize may be attributed to increase yield potential due to the fact that no considerable changes are observed in terms of the required water, evapotranspiration and irrigation times.

Maize (Zea mays L.) is the most important silage plants in the world because of its high yield, high energy and quality forage and low fibr. Due to the severe water shortage in Iran and the high water demand of corn crop, the only way to increase corn production is to increase the yield per unit area and reduce the yield gap by optimizing production management. Therefore, this study was aimed to estimate the potential yield and yield gap in the main forage maize production areas in Iran. For this purpose GYGA protocol method was used. Yield potential based on the data from a 15-year period (2001-2015) was calculated using the SSM-iCrop simulation model. Before use, parameterization and evaluation of the simulation model for the studied plant were performed using data from all over the country. In the major maize production regions of Iran, 27 reference weather stations (RWS) and 11 main climatic zones (CZ) were selected. The average Ya and Yp of maize in Iran was estimated at 49.3 and 85.6 ton ha-1, respectively. Furthermore, in the major climatic zones was 9.9 ton ha-1 yield gap in the country. In fact, forage yield and production in Iran can be increased from current 49 ton ha-1 and 11.2 million ton to 68 ton ha-1 and 15.6 million ton through optimized management and elimination of exploitable yield gap.

In recent decades, agricultural production has become increasingly dependent on the consumption of chemical inputs to obtain higher yields, which in turn has led to major problems such as environmental pollution and consequently, arresting sustainable production. In order to reduce these hazards, application of resources and inputs must lead to long term-sustainable agriculture system as well as supplying the current needs of plant. Proper plant nutrition and soil fertility management can enhance environment protection and moreover, improve input use efficiency and the quality of water, reduce erosion and maintain biodiversity. The valuable medicinal plant “purple coneflower”, is widely used in pharmaceutical, food, cosmetics and health industries. Although not native to Iran, the plant has been recently categorized as an indigenous plant. This plant has been used in the past for the treatment of snakebite, gums and mouth disorders, colds, cough, and sore throat. In the last 50 years, due to its anti-viral, anti-fungal and anti-bacterial properties, purple coneflower is globally well-known and its derivatives are categorized as immune system tonics. Nowadays, products of purple coneflower are presented as blood purifier, antiseptic and sedatives. Therefore, according to background of the use of medicinal plants and change in point of view regarding to this kind of crops as well as increasing global demand for the use of these plants in the treatment of diseases, and considering the harms caused by the consumption of chemical drugs, it is necessary to conduct a comprehensive research on medicinal plants.
The experiment was carried out as split factorial based on randomized complete block design with four replications in experimental fields of Khuzestan Agricultural Sciences and Natural Resources University between 2013-2014. Foliar application of vermicompost tea was performed at two levels (with and without tea use) and was assigned to the first factor in main plot; the second factor was organic fertilizer which was applied at three levels (zero application, vermicompost and cow manure); and finally biofertilizer was the third factor and had two level (without biofertilizer application and azospirillum biofertilizer). The latter two factors were assigned to the subplots. In this experiment, some qualitative characteristics such as mineral elements, photosynthetic pigments and the amount of substance active ingredients were evaluated.
According to the results, the highest root and total fenol were obtained from vermicompost treatment, whereas the highest leaf nitrogen, stem nitrogen, leaf phosphorus, stem phosphorus, chlorophyll type a, chlorophyll type b, carotenoid, leaf fenol and stem fenol was observed for the combination of vermicompost and tea vermicompost treatments. The highest flower fenol and chicoric acid content was recorded in vermicompost treatment together with azospirillum biofertilizer. On the other hand, the lowest stem and leaf potassium belonged to the combined treatment of tea vermicompost foliar and azospirillum biofertilizer. Generally, organic and bio-fertilizers, directly and indirectly, increased nutrients absorption in coneflower via improving plant access to macro-micro nutrients as a result of altering physico-chemical circumstances, stimulating the activity of beneficial soil microbes, increasing water absorption, availability of macro and micro elements and presence of hormones such as auxin, humic acid and GA3. Foliar spraying of vermicompost as a complementary to soil fertilizers provides quick and direct absorption of nutrients through shoots. Consequently, the treatments applied in this study simultaneously improved the characteristics of purple coneflower and the amount of its active ingredient.
The research showed that the combined treatment of vermicompost and foliar application of vermicompost tea was more feasible in the cultivation of purple coneflower rather than other treatments applied, so it was identified as the ideal treatment.

The present study was conducted to investigate the yield and some morphological characteristics of Echinacea Purpurea. The experiment was conducted in Research Farm of the Ramin Agriculture and Natural Resources University of Khuzestan during 2013- 2014. The experiment was performed as a split plot factorial based on a randomized complete block design (RCBD) with four replications. The foliar application of vermicompost tea (control and vermicompost tea) was applied in the main plot and other factors include organic fertilizer (control, vermicompost and cow manure) and biofertilizer (control and of Azospir biofertilizer) were used in the sub-plots. Results showed that maximum diameter of the flower was obtained by vermicompost application. The maximum root dry weight, stem dry weight, leaf dry weight, number of flowers per plant and lateral shoot number were obtained by mixed application of vermicompost and Azospir biofertilizer. It was also found that vermicompost with Azospir biofertilizer treatment caused the highest flower, dry weight, biological yield and root diameter. Most collar diameter was created by the integrated treatment of manure and bio-fertilizer. The highest LAI value was obtained by combined Azospir biofertilizer and vermicompost tea. The foliar application of vermicompost tea and Azospir biofertilizer caused the highest plant height. However, the highest harvest index was observed in control treatment. As a result, it was found that integrated treatment of vermicompost and vermicompost tea was remarkably recognized better than other treatments which could improve the yield of Echinacea Purpurea.