Sorayya Navid; Mohammadreza Jahansuz; Saied Soufizadeh
Abstract
Objective: This study aimed to characterize the production conditions and quantify the yield gap of spring wheat and barley in Alborz province using crop and climate models.Method: The potential regional yield over the past decade was estimated using the APSIM-7.1 sub-models (APSIM-Wheat and APSIM-Barley). ...
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Objective: This study aimed to characterize the production conditions and quantify the yield gap of spring wheat and barley in Alborz province using crop and climate models.Method: The potential regional yield over the past decade was estimated using the APSIM-7.1 sub-models (APSIM-Wheat and APSIM-Barley). These models were first parameterized for dominant local cultivars, and their performance evaluated using climatic data, regional management practices, and genetic coefficients. Data collection involved a four-year study in two phases: farm and field. Parameterization was based on a two-year experiment (2014–2015 at the Atomic Energy Organization farm and 2016–2017 at the University of Tehran), employing a randomized complete block design with 12 treatments (six wheat and six barley cultivars) and three replications. Model evaluation used data from 60 farms in Nazarabad during 2018–2019 and 2019–2020.Results: Model evaluation indices (nRMSE, CRM, D-index, R²) confirmed the effectiveness of APSIM in simulating wheat and barley yields. Simulations indicated potential yields of approximately 10,800 kg/ha for wheat and 10,350 kg/ha for barley over the past 10 years. The yield gaps at different levels were: Level 1 (difference between potential and leading farmers) –18.5% for wheat and 29.5% for barley; Level 2 (available vs. leading farmers) –14.9% and 3.1%; Level 3 (available vs. actual yields) –26.5% and 24.0%; and Level 4 (actual vs. regional average yields) –18.3% and 23.7%. Key management factors influencing yield gaps included irrigation schedule, water use, planting date, cultivar choice, nitrogen application, and plant density.Conclusions: Adopting optimal management practices—such as tailored irrigation, fertilizer application, planting timing, and cultivar selection—can help farmers reduce yield gaps and conserve resources. The APSIM model proves valuable for forecasting, scenario analysis, and decision-making aimed at improving productivity in Alborz province.
samaneh rahban; Benjamin Torabi; afshin soltani; Ebrahim Zeinali
Abstract
The present study tries to estimate the yield gap of irrigated canola in Iran as the first step for planning sustainable improvement of production. It has been performed in the modeling laboratory of Gorgan University of Agricultural Sciences and Natural Resources in 2017-2019. The protocol provided ...
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The present study tries to estimate the yield gap of irrigated canola in Iran as the first step for planning sustainable improvement of production. It has been performed in the modeling laboratory of Gorgan University of Agricultural Sciences and Natural Resources in 2017-2019. The protocol provided by the GYGA project is used for detection of climatic zones as well as major weather stations in canola production regions to estimate the yield gap. The actual yield of the irrigated canola in its major production regions is between 1184 to 2358 kg ha-1. The range of potential yield is estimated between and 3823 and 6520 kg ha-1. The highest potential yields belongs to Hamedan and Lorestan provinces and the lowest value to Khuzestan Plain. The range of the yield gap in its major production regions in the country is 2480 to 4365 kg ha-1, i.e. 53% to 77% of gap and with an average, 3276 kg ha-1 equal to 65% of the gap. With respect to the exploitable yield as the target yield, the exploitable yield is between 1544 and 3208 kg ha-1, with an average of 2261 kg ha-1. The magnitude of this gap indicates that the potentials of canola production in Iran are not exploited properly. Analyzing the reasons and methods of amendment the present yield gap and adoption of efficient management methods to achieve higher yields is crucial with regard to food security and economic.
Mohammad Sharif Nobatiany; ali Rahemi karizaki; Abbas Biabani; ali mansouri rad
Abstract
This study was conducted to evaluate the factors limiting wheat yield in Kalaleh County using the Comparative Performance Analysis (CPA) method in 2015-16. Collection of the required information was done by fieldwork, and personal interviews with farmers. To this aim, 60 wheat fields in dry land areas ...
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This study was conducted to evaluate the factors limiting wheat yield in Kalaleh County using the Comparative Performance Analysis (CPA) method in 2015-16. Collection of the required information was done by fieldwork, and personal interviews with farmers. To this aim, 60 wheat fields in dry land areas of Kalaleh were selected to have sufficient diversity in all crop management, planting, crop protection and harvesting. The amount of grain delivered to the wheat shopping centers was recorded after determining the amount of drop as the final yield of the farm. The CPA was used to determine the yield gap and identify the factors that caused it. The results of yield model showed that there was a difference of 4071.7 kg between achievable (7248 kg/ha) and actual yield (377.4 kg/ha). Among studied variable, the farmer experience, seeding rate, the amount of phosphorus in soil, frequency of use of fungicide, organic matter of soil, amount of potassium absorbed in soil and amount of applied nitrogen had the most influence on wheat yield gap in the study area, which were 19.4, 16.8, 14.9, 14.3, 12.7, 11.7 and 10.3 percent of the achievable yield. By amending these factors, it seems that it could reduce the difference between achievable yield and actual yield.
Shahram SekhavatiFar; ali Rahemi karizaki; Ali Nakhzari Moghaddam; Mehdi Mollashahi
Abstract
Understanding the performance potential and the gap between the actual yields of crops with the achievable function is necessary to diagnose the limiting factors of performance. The present study was conducted based on the method of CPA in 50 fields of Zavkooh villi (Kalaleh, Golestan, Iran) in 2016 ...
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Understanding the performance potential and the gap between the actual yields of crops with the achievable function is necessary to diagnose the limiting factors of performance. The present study was conducted based on the method of CPA in 50 fields of Zavkooh villi (Kalaleh, Golestan, Iran) in 2016 and 2017. In this study all information related to management practices, soil characteristics and farmer socio- economic status were measured and recorded. In the comparative performance analysis (CPA) method, using stepwise regression, the relationship between variables and yield was considered. And yield gap rate, its causes factors and it was also estimated the contribution of each of these factors to the creation of a yield gap. The results showed that between the average real yield (2308 kg ha-1) and the yieldable yield (4123 kg ha-1), there is 1818 kg per hectare of vacuum. Accordingly, the most important factors in yield gap for the region included: field size with 21.4 percent, Summer plowing with 15 percent, The time of land preparation and plowing with 14.7 percent, nitrogen fertilizer with 14.6 percent, potassium fertilizer with 14 percent, weeds density per unit area with 10.8 percent), seed treatment with 8.1 percent and Subsoiler with 1.4 percent.
Ali Mansouri rad; Ali Nakhzari Moghadam; Afshin Soltani; Ali Rahemi Karizaki; Benyamin Torabi
Abstract
One of the main problems of soybean production in the east region of Golestan, Iran is considerable difference between actual yield and attainable yield which is called yield gap. In recent years, this gap has been impressive, and therefore, identifying soybean yield-limiting factors is essentially needed. ...
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One of the main problems of soybean production in the east region of Golestan, Iran is considerable difference between actual yield and attainable yield which is called yield gap. In recent years, this gap has been impressive, and therefore, identifying soybean yield-limiting factors is essentially needed. The present study was conducted based on CPA method in 73 fields of Kalaleh )Golestan, Iran) in 2016. In this study all information related about management practices, soil characteristics and farmer socio-economic status were measured and recorded. Then, using stepwise regression, the relationship between variables and yield was considered. The results showed that there is a 2606.4 kg/ha difference (gap) between actual yield (average farmers' yield) and attainable yield (maximum farmers' yield). It was identified that farming experience, burying plant residues in the soil, planting date, Sprinkler irrigation, the amount of used water and plant density were contributed to yield gap, 30.1, 5.1, 14.7, 13.8, 13.8 and 22.5%, respectively. It could be concluded that improving these factors will increase the yield up to 1802.9 kg/ha.