Electronic Journal of Biology, 2017, Vol.13(3): 280-287 The Forecast of Temperature on Cultivation of Rainfed Wheat in the Kohgiluyeh and Boyer Ahmad, Fars and Chaharmahal and Bakhtiari Provinces of Iran Hojatallah Abbasi1,*, Golam Ali Mozaffari2, Ahmad Mazidi2 1 PhD Student, Natural Geography, Yazd University, Yazd, Iran; 2 Associate Professor, Natural Geography, Yazd University, Yazd, Iran. *Corresponding author. Tel: 989906648776; E-mail: [email protected] Citation: Abbasi H, Mozaffari GA, Mazidi A. The Forecast of Temperature on Cultivation of Rainfed Wheat in the Kohgiluyeh and Boyer Ahmad, Fars and Chaharmahal and Bakhtiari Provinces of Iran. Electronic J Biol, 13:3 Received: June 05, 2017; Accepted: August 03, 2017; Published: August 10, 2017 Review Article particular importance. Wheat production for societies Abstract such as Iran, where wheat has a special role in the nutrition pattern, represents the creation of food Wheat is considered as a staple food of people security, while the poor and middle class welfare is and as a strategic product. Rainfed wheat is more extremely [1]. Wheat issue in Egypt was considered important than irrigated wheat and temperature as one of the major events of the twentieth century is among the most important climactic factors in this country [2]. Such a crisis occurred in South influencing its cultivation. The current study is aimed American countries such as Brazil during the 1960s to detect growing degree days for phenology period and 1970s [3]. Such crises led to deep structural of rainfed wheat cultivation for the next 20 years. The changes in policies associated with food security studied areas including Fars, Kohgiluyeh and Bouyer and wheat policies of these countries [3]. Wheat Ahmad, and Chahar Mahal and Bakhtiari provinces is an annual monocotyledonous plant belonging to were determined using digital elevation model of the grasses family (Geramineae) which more than 20 earth. Meteorological data required including daily wild and domesticated kinds of it are known. The crop temperature and rainfall during a common statistical is planted in more than 70 countries with different period of 20 years (1995-2015) were supplied from climatic conditions and soils [4]. Among other things, National Meteorology Organization. Properties of diversity of species and varieties, adaptability to temperature and rainfall discussed in terms of sub different climactic conditions, ease of planting and hypotheses were studied using statistical indices of production, easy transportation, fewer requirements central tendency, scatter and possible distributions. for water, storability, long storage, and higher Correlation methods, LARS WG and Mann Kendall calorie content can be mentioned as good features were used to study the future process and predict of wheat [5]. Nowadays, wheat is planted in a wide climactic elements and indices. Using findings of the range of weather conditions in rainfed and irrigated current study, database in geographical information form and producing it in dry conditions due to water system and to prepare maps required and finally shortage is of strategic importance. Irrigated wheat hypotheses testing were conducted. During a yield and rainfed wheat yield in Iran are 3672.46 statistical period of 2015 to 2035 predicted with kg and 1073.30 kg per hectare, respectively. The LARS WG model, southern parts of the studied area highest yield of irrigated wheat is assigned to Tehran and the northern part of Kouhrang station had the (5351.99 per hectare) and the lowest is assigned to least and highest amount of rainfall, respectively. Bushehr (2445.47 per hectare). Kerman and Bushehr Degree day index of the studied area increased from provinces with an average production of 2971.43 and the north to the south which the highest and lowest 43.73 kg per hectare have been ranked first and last amounts were assigned to southern station of the among rainfed wheat producers in Iran, respectively. area and northern stations of Borujen, respectively. Fars province with production of 10.36% of wheat Most of studied stations had an increasing trend in has been ranked first among wheat producers in degree days and only 3 stations including Eghlid, Iran (the Statistical Center of Iran, 2014). Acreage Zarghan and Borujen did not have any increasing under cereals cultivation has increased from 130000 and decreasing trend. ha in 1996 to 162770 ha in 2011. Acreage under wheat cultivation in Kohgiluyeh and Bouyer Ahmad Keywords: Rainfed Wheat; Climate; Fars; province has increased from 130000 ha in 1996 to Kohgiluyeh and Boyerahmad; Chaharmahal 162770 in 2011. Growth acceleration of acreage and Bakhtiari; Temperature. under cereals cultivation has been intensified in the 1. Introduction period 2001-2006. Generally, over the 15 years study period, 25.2% has been added to the acreage under Wheat as one of the basic agricultural products is of cereals cultivation, whereas the total cultivated area ISSN 1860-3122 - 280 - Electronic Journal of Biology, 2017, Vol.13(3): 280-287 in Kohgiluyeh and Bouyer has remained unchanged As noted in Figure 3, the minimum temperature is (Agriculture Organization of Kohgiluyeh and Bouyer related to Koohrang station in Chaharmahal and Ahmad). In 2011, 28500 ha of Chaharmahal and Bakhtiari and the maximum temperature is associated Bakhtiari province were dedicated to irrigated wheat with Lar and Lamerd stations. cultivation and 37800 hectares were dedicated to the rainfed wheat cultivation and 110000 tons of 2.1 Thermal thresholds wheat was harvested out of the cultivated lands. In Plants need three thermal thresholds of minimum, 2014, 1500 ha of lands were dedicated to irrigated maximum and optimum temperatures called main wheat cultivation and 38000 ha were dedicated heating degrees or main points for their biological to the rainfed wheat cultivation with capacity activity [8]. production of 120000 tons per year (Agriculture Organization of Chaharmahal and Bakhtiari). Now The base temperature: Minimum temperature climate changes are a problem in the world [6]. below which no growth occurs. The base temperature Elements and climactic parameters have affected differs in terms of plant species and growth stages. the environmental conditions during past periods. For example, the base temperature for wheat and Agricultural production have always had risk of barley is 3-4.5°C [9]. climactic changes and fluctuations in international markets [7].This study is aimed to examine the trend Optimum temperature: As temperature of thermal of changes of climactic elements and predict them base increases, plant growth gradually increases and in the future and its effects on rainfed wheat in three maximum growth occurs at a certain temperature, provinces studied. varying in terms of plant species and growth stage which is called optimum temperature. Optimum 2. Materials and Methods temperatures for wheat and barley are 25°C and 20°C, respectively. Studied regions consisted of three provinces including Kohgiluyeh and Bouyer Ahmad, Fars and Maximum temperature: As temperature gradually Chaharmahal and Bakhtiari. Kohgiluyeh and Bouyer increases and passes the desired temperature, plant Ahmad province is located southwest of Iran between growth gradually decreases and growth completely (29° 52' to 31° 26' N, 49° 55' to 51° 53"E); Fars stops after a maximum temperature which is different province is located in south of Iran (27° 3' to 31° 40' in terms of plant species and growth stage. The N, 50° 36' to 55° 35"E); Chaharmahal and Bakhtiari mentioned threshold is called maximum plant species province is among mountainous areas of the central temperature. Maximum temperature for wheat is 30- plateau of Iran (31° 9' to 32° 38' N, 49° 30' to 51° 32°C and for barely is 38-40°C. At temperatures 26'E) (Figure 1). higher and lower than the optimum range, pre- germination metabolic activity is reduced [10]. Lower As shown in Figure 2, the minimum height is related temperature prevents germination and results in seed to Lar, Lamerd and Dogonbadan stations and the decay. Temperature above the optimum temperature maximum height is associated with Koohrang, may cause seed recession. Lordegan, Shahrekord, Yasuj stations. Thermal Units: It is stated for the first time in 1735 Figure 1. The geographical situation of the studied provinces (1: Kohgiluyeh and Boyer Ahmad, 2: Fars and 3: Chaharmahal and Bakhtiari) in Iran. ISSN 1860-3122 - 281 - Electronic Journal of Biology, 2017, Vol.13(3): 280-287 Figure 2. Topography of the studied regions (Kohgiluyeh and Bouyer Ahmad, Fars and Chaharmahal and Bakhtiari). Figure 3. The average temperature (°C) in the studied regions. that the total daily temperature of the air in the shade alter the thermal units are very complicated in non- between two stages of plant growth is constant for a irrigated conditions, so the use of a thermal unit which particular species of plant. The concept of thermal has been calculated for a certain area and season is units or degrees day represents the relationship hardly acceptable for different regions and seasons. between plant growth and the air temperature [11]. Thus, in the present circumstances there is no choice The concept indicates a direct linear relationship but to conduct experiments in each area and every between growth and air temperature. Degrees day season. The use of soil temperature rather than air is the mean deviation of daily temperature from temperature makes thermal units more accurate a minimum thermal threshold. It is the minimum when the plant is out of the soil, because at this stage threshold temperature below which no growth the plant is mostly influenced by soil temperature. happens. Degrees day is calculated by subtracting the base temperature from the average daily Total of annual thermal units: Thermal units include temperature [12]. As the factors and interactions that from the beginning of rainfall equal to or more than ISSN 1860-3122 - 282 - Electronic Journal of Biology, 2017, Vol.13(3): 280-287 5 mm in autumn to the end of June.