جستجوی مقالات مرتبط با کلیدواژه "عملکرد پتانسیل" در نشریات گروه "اکولوژی"

overcoming the growing human need for food, which is in line with population growth, is a global challenge. Therefore, this study has evaluated the potential performance and yield gap and identified the limiting factors of production using the border line analysis method.

In order to quantify the production and estimate the rice yield gap in Ghaemshahr region, the data collected from 164 paddy fields (local and high yielding cultivars) of this city were used. Information on important managerial, soil and plant factors were recorded during the growing season through continuous field visits and face-to-face interviews with farmers. In this study, using the boundary line analysis method, the yield gap, potential performance and optimal values of yield gap parameters were calculated and the best managements were determined simultaneously.

In the present study, the quadratic function was able to describe the trend of performance changes in relation to different traits. The required optimal minimum values of each factor were determined to achieve the highest performance. The average optimal yield (achievable) and the average actual yield were 9229 and 5160 kg.ha-1, respectively, and the yield gap was 4069 kg.ha-1, equivalent to 43.8% of the potential yield.

The border line analysis method was able to successfully estimate ways to increase production while reducing the yield gap in the region, significantly help. It is recommended that boundary line analysis be used as a functional analysis alongside other methods, for different crops and in other areas.

Potato (Solanum tuberosum L.) accounts for the largest share in production of food products after wheat, rice and corn, which plays an important role in the nutrition and food basket of the world. Currently, the issue of food security and supplying is very important in different parts of the world and thus prediction of its demand that is increasing. Also, growing population will intensify this issue too. A key strategy to overcome the nutritional challenge of the growing population of the world is eliminating the gap between the current achievement in farms and the yield which can be achieved by using the best cultivars compatible with the environment and the best water, soil and plant management methods.

In this study, potential yield of potato was estimated using the SSM-iCrop2. then the production and yield gap of potato were investigated with two methods of Global Yield Gap Atlas (GYGA) and Arc GIS software by interpolation method for Golestan province. For this aim, the information of potato cultivation management in the province level and the daily data of 23 synoptic weather station as well as their soil data were used. Meanwhile, potential yield gap analysis protocol (GYGA protocol) was used to identify the main weather stations named reference weather stations (RWSs) and climates where potato is planted in Golestan province. Potential yield of potato was estimated within the area covered by each RWS, and then scaled up to the province level. In order to implement the interpolation method in ArcGIS software, initially, potential yield of 23 stations in the Golestan province was estimated. Afterwards, the potential and actual yield in the whole province was estimated using Kriging and IDW methods, respectively.

According to the Agricultural Jihad Report, the actual yield of Golestan province (a ten-year average) was reported as 22 t.ha-1, while the actual yield calculated based on the interpolation method was estimated equal to 22 t.ha-1. However, the actual yield calculated using the global yield gap atlas (GYGA) method was estimated as 20 t.ha-1. Heigh yield of potato in the province was reported by farmers up to 55 tons, which was considered as potential in the province to be compared with GYGA and interpolation methods, so that in the GYGA method, 52 t.ha-1 and in the interpolation method, finding was 42 t.ha-1. yield gap and relative yield in the GYGA method (33 t.ha-1 and 38 percent), and interpolation (20 t.ha-1 and 52 percent) were obtained. Also, in GYGA method, the values ​​were estimated using only two stations, but in the interpolation method the province's yield was estimated using 23 stations and daily meteorological data. The GYGA protocol is a bottom-up approach used by Hochman et al. (2016) to assess the variation of national yield from climatic zoning to analyze similar agro-cluster groups. So far, several studies have been done using this protocol. Gobbett et al. (2017) showed that wheat lands in Australia are located in six key climatic regions. They selected 22 reference stations in this area and calculated the limited water potential yield using the APSIM model (for the years of 1996 to 2010).

The results showed that both Global yield gap Atlas (GYGA) and interpolation method had accurate estimation of actual and potential production and yield, but those values obtained using statistics and 23 weather stations in the interpolation method, and using just 2 weather station (Hashemabad and Gorgan stations) in the Global Atlas method. As previously mentioned, the GYGA method is designed to estimate the yield gap at the national level, which can calculate the potential yield, production, and yield gap in a wide range even with the least amount of information. One of the advantages of GYGA protocol is that the results obtained at any point in the world are comparable to other areas and cultivations of that particular product. Based on the comparison made in this study, it was concluded that the Global yield gap Atlas method should be used to estimate the yield of the country.

Due to water shortages in Iran, it is not possible to increase areas of cultivation to supply the increasing demand for wheat (Nassiri Mahallati and Koocheki, 2009). There is a significant gap between the actual and potential yield (Koocheki et al., 2016). Specifying the potential and impact of each limiting factor in yield is important in determining alternative management strategies to reduce the gap (Varvani et al., 2016). This study was performed to evaluate the wheat yield potential and gap, and the relative contribution of climatic and management variables in Kerman Province.
For this study, meteorological and managerial information was extracted for all the regions of Kerman Province. Various wheat yield and growth parameters were simulated by CERES-Wheat model. The model was calibrated and validated using the extracted data from the designed experiments and previously conducted research from various regions of Kerman. Multiple regression was used to determine the relative contribution of each of the climatic and managerial factors on the yield potential and gap.
The results showed that CERES-Wheat model indicated an acceptable accuracy for simulating wheat growth and yield in Kerman. The 10-year average of wheat yield in Kerman ranged between 2 - 4.6 t/ha-1. The results of regression analysis showed that the relationship between water, N and P with actual yield was positive, and the highest R2 (0.97) was related to the amount of water consumed. Therefore the highest actual yield of wheat was assigned to the areas that consumed the greatest value of input. The potential yield was simulated at 6.6 - 8.2 t/ha-1 for different regions of the province. The analysis of regression confirmed that temperature is the most important factor affecting potential yield in the area and showed an inverse relationship with this parameter. The range of yield gap for different regions of the province varied from 2.33 t/ha-1 in Kahnuj to 4.84 t/ha-1 in Baft. In most parts of the province, water was the most important limiting factor for wheat yields, which included more than 50% of the yield gap in dry-climate regions. Replacing conventional cultivars with the high-yielding cultivars of Mihan for lower temperature regions and Chamran 2 for tropical regions had a significant role in improving actual yield and subsequently reducing the yield gap of these areas. The range of fertilizer contribution in yield gap was between 1.34 and 0.21 t/ha-1.
In general, the results illustrated that there is a remarkable gap between the actual and potential wheat yield in most regions of Kerman. Irrigation is the most important factor affecting the gap. It seems that the gap can be mitigated by identifying the limiting factors and appropriate management of water, fertilizer and cultivar.

Yield gap analysis provides an essential framework to prioritize research and policy efforts aimed at reducing yield constraints. To identify options for increasing chickpea yield، the SSM-chickpea model was parameterized and evaluated to analyze yield potentials، water limited yields and yield gaps for nine regions representing major chickpea-growing areas of Razavi Khorasan province. The average potential yield of chickpea for the locations was 2251 kg ha-1، while the water limited yield was 1026 kg ha-1 indicating a 54% reduction in yield due to adverse soil moisture conditions. Also، the average irrigated and rainfed actual yields were respectively 64% and 79% less than simulated potential and water limited yields. Maximum and minimum yield gap between potential yield and actual yield were observed in Quchan and Torbat-jam respectively. Generally، yield gap showed an increasing trend from the north (including Nishabur، Mashhad، Quchan and Daregaz regions) to the south of the province (Torbat- Jam and Gonabad). In addition، yield gap between simulated water limited potential yield and rainfed actual yield were very low because both simulated water limiting potential and average rainfed actual yields were low in these regions. Yield gap analysis provides an essential framework to prioritize research and policy efforts aimed at reducing yield constraints. To identify options for increasing chickpea yield، the SSM-chickpea model was parameterized and evaluated to analyze yield potentials، water limited yields and yield gaps for nine regions representing major chickpea-growing areas of Razavi Khorasan province. The average potential yield of chickpea for the locations was 2251 kg ha-1، while the water limited yield was 1026 kg ha-1 indicating a 54% reduction in yield due to adverse soil moisture conditions. Also، the average irrigated and rainfed actual yields were respectively 64% and 79% less than simulated potential and water limited yields. Maximum and minimum yield gap between potential yield and actual yield were observed in Quchan and Torbat-jam respectively. Generally، yield gap showed an increasing trend from the north (including Nishabur، Mashhad، Quchan and Daregaz regions) to the south of the province (Torbat- Jam and Gonabad). In addition، yield gap between simulated water limited potential yield and rainfed actual yield were very low because both simulated water limiting potential and average rainfed actual yields were low in these regions.