Agricultural Meteorology
M. Abdollahi Fuzi; B. Bakhtiari; K. Qaderi
Abstract
IntroductionSpring frost is considered an important threat to agricultural products in high and middle latitudes. The damage caused by Late Spring Frosts (LSFs) significantly impacts vulnerable plant organs. This event has caused more economic losses to agriculture than any other climatic hazard in Asia, ...
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IntroductionSpring frost is considered an important threat to agricultural products in high and middle latitudes. The damage caused by Late Spring Frosts (LSFs) significantly impacts vulnerable plant organs. This event has caused more economic losses to agriculture than any other climatic hazard in Asia, North America, and Europe. Also, these phenomena have contributed to low crop yields in Iran. The latest statistics released by the Food and Agriculture Organization of the United Nations (FAO) show that Iran is one of the largest producers of agricultural products and the world’s second-biggest producer of pistachios. Kerman province is one of the significant areas of pistachio production. This province has a large share of the pistachio word area plantation. Spring frost damage to pistachio crops has led to low yields in recent years. A key aspect of studying frost is the ability to accurately estimate its occurrence. In this study, artificial neural network methods have been used to estimate late spring frost in the pistachio crop of Kerman city. Materials and MethodsIn this study, the efficiency of this method was investigated in the estimation of minimum temperature. For this purpose, the daily data of the synoptic station of Kerman city were obtained from Iran Meteorological Organization from 2000 to 2020. Meteorological data including mean, maximum, and minimum temperatures, relative humidity, wind speed, saturated vapor pressure, and sunshine hours were used. Five different combinations of these variables was considered as input variables in artificial neural network method for minimum temperatures modeling. After entering data into network and modeling with each combination, RMSE and R2 values were calculated. Finally, the combination of 8 variables including average and maximum temperature, the minimum temperature the previous day and two days prior, relative humidity, wind speed, saturated vapor pressure, and sunny hours were selected as the most suitable combination of variables. Subsequently, a simulation of minimum temperature values was conducted using 10% of the data. The performance of the methods was evaluated using statistical indices of coefficient of determination (R2), mean square of error (RMSE), Mean Bias Error (MBE), and Coefficient of Nash–Sutcliffe (NSE). Results and DiscussionThe accuracy of an analytical method is the degree of agreement between the test results generated by the method and the true value. Upon examining the models, the M1 model was identified as the best due to its lowest RMSE and higher R². ANN model results were evaluated using various performance measure indicators. The simulated outcome of the model indicated a strong association with actual data, where the correlation coefficient was above 0.95, and the MBE index was zero. Also, the RMSE value was positive and close to zero, and the NSE value was above 0.75. Therefore artificial neural network method had high accuracy. In this study, mean annual minimum temperature was estimated using artificial neural network models (from March 10 to May 20). Comparison between the observed and calculated data showed that these data were in good agreement. Also, the results showed that temperature fluctuations were high between March 10 and March 31. From 2011 to 2017, an almost uniform temperature trend has been observed between March 10 and March 31. However, the years 2000, 2006, and 2020 showed a noticeable decrease in temperature. From 2018 to 2020, this trend of temperature reduction continued. In April, the temperature values were between 7 and 10 degrees Celsius. The years 2001, 2005, 2006, 2009, 2016, and 2019 had a noticeable decrease in temperature. In May, the mean minimum temperature was between 10 and 14 degrees Celsius. Therefore, the probability of frost occurrence in early-flowering cultivars was higher in late March than in April and May. The years 2000, 2004, 2005, 2012, 2015, 2019 and 2020 had the highest number of frost days in the last two decades. ConclusionThe results showed that the artificial neural network method had a high performance in estimating the minimum temperature. The values of the statistical indicators were R2=0.963, RMSE=0.027oC, MBE= 0 and NSE=0.966 respectively. In addition, the ANN method performed well in estimating the number of critical frost days for pistachio crops. The results showed that, although reducing the amount of input data in models decreases their output precision, data-driven methods can still be useful tools for minimum temperature estimation.
Soil science
A. Farajnia; K. Moravej; P. Alamdari; M. Eslahi
Abstract
Introduction: FAO agro-ecological model determines the production capacity, creating a logical relationship between the natural potential of the environment, the needs of communities, human activities, and sustainable adaptation. With the development of plant growth simulation models, researchers have ...
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Introduction: FAO agro-ecological model determines the production capacity, creating a logical relationship between the natural potential of the environment, the needs of communities, human activities, and sustainable adaptation. With the development of plant growth simulation models, researchers have begun a large-scale effort to agroecological zoning of various crops on a regional scale. In this method, an area was divided into homogeneous units with maximum similarity in terms of climate and land characteristics. Then, the potential yield map predicted by a simulation model is used for zoning. Pistachio is a subtropical plant that has long been cultivated in the central areas of Iran. With the occurrence of drought in the last two decades, farmers cultivated Pistachio in East Azerbaijan province without considering this crop requirement. This study aimed to use the AHP model to evaluate the suitability of East Azerbaijan lands for cultivating pistachio.
Methods and Materials: East Azerbaijan province is located in the northwest of Iran, between the latitudes of 36˚ and 45' to 39˚ and 26' N and the longitudes of 45˚ and 5' to 48˚ and 22' E based on the geographic coordinate system. The area of the province is 45800 square kilometers. The climate is generally cold and semi-arid, but it has different climates due to its diverse and extensive topography. The area of agricultural lands is estimated to be 18,000 square kilometers, which is about 39% of the total area. In this research, climatic data were collected for 30 years from Tabriz, Jolfa, Mianeh, Sarab, Maraghe, and Malekan synoptic stations, and from four neighboring stations of Orumieh, Khoy, Miandoab, and Parsabad. Three criteria (i.e. climate, land, and soil) and 11 sub-criteria were studied. The sub-climatic criteria included the average temperature of the growing season, average temperature in the pollination stage, absolute minimum temperature in the coldest month of the year, and average percentage of relative humidity in the flowering stage. Land criteria were land use sub-criteria, land slope, and slope directions, and soil criteria were salinity (electrical conductivity of saturated extract), pH, soil texture, and soil lime content (CaCO3). The results of the analysis of about 9000 soil samples were prepared for zoning of soil factors from East Azerbaijan Agricultural and Natural Resources Research Center. Land characteristics of slope map and aspects were prepared from the digital elevation map of the study area and land use map was obtained base on the map provided by the Forests and Rangelands Research Institute of Iran. The parameters were then weighted upon AHP by the parameter importance for each region. Data were transferred to Expert Choice software and clustered, rated, integrated for producing the final layer.
Results and Discussion: According to the AHP model, there are no entirely suitable class areas for pistachio cultivation in East Azerbaijan province. Because one or more factors or sub-criteria created low restrictions for the cultivation of this crop. The results showed that 3887 square kilometers or 8.5% of the area was classified as a relatively suitable class. Although this area has low restrictions for pistachio planting, the profitability of this complex has increased the area of pistachio orchards rapidly. The suitable lands are mainly located by the agricultural lands and if water requirement could be met, they can be allocated for planting. The low water requirement and tolerance to salinity compared to other crops can be considered as the advantages of cultivating pistachio. Since 1998, droughts have occurred in different areas of the province. It caused a decrease in agricultural products by up to 35%. The declining water level of Lake Urmia is one of the consequences of the recent droughts, deteriorating the groundwater quantity and quality. The 6250 square kilometers (13.6%) of the province's lands was classified as the critically suitable class. Some of the sub-criteria studied in these lands such as the average temperature of pollination period, the average temperature of the growth period, amount and direction of slope, and soil texture were in the critical classes. The 35663 square kilometers (77.9%) of the studied lands were found to be unsuitable (N). The main reason for the unsuitability was the very high salinity of lands, as seen in the soil salinity map. Although it is a modifiable factor, the lack of quality for leaching, heavy soil texture, and the impossibility of draining drainage due to flatness, render the reclamation of these lands impossible. Under the current situation, East Azerbaijan province is much more capable of planting this crop. However, it is necessary to conduct more detailed studies to avoid pistachio cultivation in marginal suitable lands.
babak motesharezadeh; somayeh rezaezadeh; majid fekri
Abstract
Introduction: Boron is one of the seven essential microelements for the natural growth of plants. The toxicity of this element occurs in arid and semi-arid regions, which is because of its high level in soils and the irrigation water of mentioned regions. The aim of this study was to evaluate the effect ...
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Introduction: Boron is one of the seven essential microelements for the natural growth of plants. The toxicity of this element occurs in arid and semi-arid regions, which is because of its high level in soils and the irrigation water of mentioned regions. The aim of this study was to evaluate the effect of nitrogen application on boron toxicity tolerance in pistachio, Badami-Zarand variety. The effects of three nitrogen levels (0, 250, and 350 mg/kg of soil) on the reduction of toxicity due to the three levels of boron (0, 15, and 30 mg/kg of soil) were examined in Badami-Zarandi variety of pistachio under greenhouse conditions. After 7 months from sowing the seeds, pistachio seedlings were harvested and desired traits were measured. The results showed that by increasing boron application level, boron concentration in the shoot and root of seedlings increased whereas their dry weight decreased. Using of nitrogen reduced the negative effects of boron on the dry weight and led to increase dry weight and decrease boron concentration in the shoot and root of pistachio, Badami variety. Nitrogen application at the levels of 250 and 350 mg N per kg of soil reduced boron uptake in shoots by reinforcing plant vegetative system and increasing chlorophyll content by 13.5% and 30.2%, respectively and finally led to diluted boron concentration in the plant (dilution effect) and reduced the effects of boron toxicity. Hence, optimized nitrogen application is suggested as one of the management methods in controlling Boron toxicity under these conditions.
Materials and Methods: A factorial experiment based on randomized complete block design with four replications was carried out. Soil sampling was done in 0-30 cm depth in a zeekzack way from a pistachio garden that located in mahmoodiye area in Rafsanjan. The soil sample was air-dried and passed through a 2mm sieve. The soil chemical and physical properties were measured. In this study, badami-zarand cultivar seed was used because it is one of the most important pistachio cultivars. The seeds were soaked in water for 24 hours and disinfected by benomyl fungicide. When the seeds germinated, they were planted in the pots containing 4.5 kg soil and without drainage, so nutrients balance was kept during growing period. After 7 months, the seedlings were harvested and B was measured.
Results and Discussion: The results showed that increasing the boron levels from 0 to 30 mg kg-1 led to decrease shoot dry weight from 3.72 to 2.45 gram and root DM from 2.28 to 1.50 gram. Increasing 30 mg kg-1 boron led to 2.8 times increase of shoot boron concentration. The averages of shoot boron concentration in the levels of 15 and 30 mg kg-1 boron were 87.6 and 122 mg kg-1DM, respectively. The boron toxicity level in Badami-Zarand cultivar is 8.9 mg kg-1 DM (Sepaskhahet al, 1994), so these levels were the cause of boron toxicity and boron toxicity symptoms were seen as leaf burn, often at the margins and the tips of older leaves.
The results showed that increasing nitrogen levels led to decrease shoot boron concentration and increase their weight. The results also showed a significant negative correlation between the nitrogen levels and boron uptake. Boron uptake in the shoots of seedlings about 13.5 and 30.2 percent decreased when nitrogen levels increased. Shoot dry weight decreased when boron application increased, but it increased when nitrogen was used (Koohkan and Maftoun, 2009).
Conclusion: The reduction of dry weight and increasing boron concentration occurred when increased boron application. The Maximum of boron uptake was seen by leaves, and boron toxicity symptoms were appeared as leaf burn especially at the tips and margins of older leaves. Since, boron is immobile in pistachio; it is absorbed by mass flow, so the accumulation of boron at older leaves is persuaded. Nitrogen reduced the bad effects of boron on dry weight and the bad effects of increasing boron concentration by the synthesis of chlorophyll, so it was more useful in shoot than root. Boron uptake was also reduced by nitrogen application. This effect of nitrogen is probably concerned to the increase of dry weight more than boron concentration (Dilution effect). On the other hand, nitrogen caused to increase leaf index and increase the number of seedling leaves. The injured leaves due to boron toxicity were restored, because of high leaf chlorophyll. It is suggested that this study will be done under field conditions for fertilizer application recommendations and to be used for creation of tolerant cultivars of pistachio.
T. Poorbafrani; A. Tajabadi Pour; V. Mozafari; A.R. Akhgar
Abstract
Introduction: Pistachio is one of the most important crops in many regions of Iran with respect of production and export. There are more than 470000 ha of nonbearing and bearing pistachio trees mainly in Kerman province. Despite the economic importance of this crop, very little information is available ...
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Introduction: Pistachio is one of the most important crops in many regions of Iran with respect of production and export. There are more than 470000 ha of nonbearing and bearing pistachio trees mainly in Kerman province. Despite the economic importance of this crop, very little information is available on its nutritional requirements. Pistachio trees like other crops need to macro and micro nutrients. one of these elements is manganese (Mn). Manganese is an essential mineral nutrient, playing a key role in several physiological processes, particularly photosynthesis, respiration and nitrogen assimilation. This element is normally supplied to the plants by soil. Therefore, soil conditions affect its availability to plants. Soils with high pH, calcareous soils, especially those with poor drainage and high organic matter, are among the soils which produce Mn-deficient plants. Calcium carbonate is the major inactivation factor of Mn in calcareous soils. The soils of Iran are predominantly calcareous in which micronutrients deficiency, including Mn, is observed due to the high pH and nutrient fixation. The objective of this research was to examine the effect of manganese application on growth and chemical composition of pistachio seedlings in some calcareous soils with different chemical and physical properties.
Materials and Methods: For this purpose a greenhouse experiment was carried out as factorial (two factors including soil type and Mn levels) experiment in completely randomized design with three replications. Treatments were consisted of three levels of Mn (0, 10 and 20 mg Mn Kg-1 soil as Manganese sulfate) and 12 different soils from Rafsanjan region in Southern Iran. Soil samples were air dried and crushed to pass through a 2-mm sieve, and some physical and chemical properties of soils such as texture, electrical conductivity, pH, organic matter content, calcium carbonate equivalent, cation exchange capacity and iron, manganese, copper and zinc availability were determined. Then plastic pots were filled with 5 kg of these soils. Pistachio seeds (cv Badami Zarand) were placed in muslin sacks and pretreated for 24 h with Benomyl solution. The germinated seeds were planted in each pot, and each pot was irrigated with distilled water. Nitrogen and phosphorous were applied uniformly to all pots at the rate of 50 mg kg−1 soil as ammonium nitrate and potassium dihydrogen phosphate forms, respectively. Zinc, iron and copper also were added to treatments at level of 5 mg kg−1 soil as zinc sulfate, iron sequestrine138 and copper sulfate. After 24 weeks, the seedlings were cut at the soil surface, and the roots were washed free of soil. Leaves, stems and roots were dried at 70 oC for 48 h in an oven. The total leaf, stem, and root dry weights were recorded. The ground plant samples were dry- ashed at 550oC, dissolved in 2 N HCl, and made to volume with hot distilled water. Plant Mn, Cu, Zn and Fe concentrations determined by atomic absorption spectrophotometry. All data were statistically analyzed according to the technique of analysis variance (ANOVA) by MSTATC.
Results and Discussion: Results indicated that the application of manganese increased leaf, stem and root dry weight of pistachio seedlings so that the maximum amount of the dry weight of roots stems and leaves of pistachio seedlings were observed at 10 mg Mn kg-1soil. Application of 10 mg Mn kg-1 soil increased leaf, stem and root dry weight by 19.2%, 25.2% and 23.9% in comparison to control, respectively. Chemical composition (concentration and uptake) of shoot of pistachio seedlings was also affected by Mn application. Mn application decreased the concentration and uptake of iron, concentrations of copper and zinc in Pistachio seedling shoots so that the highest concentrations of these elements were observed in control treatment. Reductions in concentrations of zinc and copper elements in 10 mg Mn kg-1 treatment were not statistically significant but in 20 mg Mn kg-1 treatment they were significant.
Conclusions: The results of this research showed that the application of 10 mg Mn kg-1soilto highly calcareous soils significantly increased most of growth parameters of pistachio seedlings in comparison to control. Although higher amounts of manganese (20 mg Mn kg-1 soil) reduced the growth parameters than the previous level. In overall, the results of this study indicated that for optimum growth and chemical composition of pistachio seedlings in calcareous soils, application of 10 mg Mn kg-1 sol is necessary.
