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Consideration of crop yield variability caused by long-term climate change offers a way to quantify the interplay between climate change, crop growth, and yield. This study employed the APSIM model to simulate the potential winter wheat yield under varying climate scenarios in 1961–2100 in the Loess Plateau. It also evaluated the long-term response and adaptation differences of winter wheat yield to climate change. The results show that there is a slight downward trend in inter-annual precipitation during the winter wheat growth period, with a reduction of −2.38 mm·decade−1 under the S245 scenario (abbreviated SSP2-4.5) and −2.74 mm·decade−1 under the S585 scenario (abbreviated SSP5-8.5). Interestingly, the actual yield of winter wheat was positively correlated with precipitation during the growth period but not with temperature. By contrast, climatic yield exhibits a significant correlation with both factors, suggesting that future crop yield will largely depend on its sensitivity to climate change. In addition, climate change may marginally improve yield stability, although regional variations are evident. Notably, potential yields in water-restricted areas, such as Qinghai and Gansu, are significantly influenced by precipitation. This study provides an important reference for formulating long-term adaptation strategies to enhance the resilience of agricultural production against climate change. [ABSTRACT FROM AUTHOR]

Accurately predicting the wheat potential yield (PY) is crucial for enhancing agricultural management and improving resilience to climate change. However, most existing crop models for wheat PY rely on type-specific parameters that describe wheat traits, which often require calibration and, in turn, reduce prediction confidence when applied across different spatial or temporal scales. In this study, we integrated eco-evolutionary optimality (EEO) principles with a universal productivity model, the Pmodel, to propose a comprehensive full-chain method for predicting wheat PY. Using this approach, we forecasted wheat PY across China under typical shared socioeconomic pathways (SSPs). Our findings highlight the following: (1) Incorporating EEO theory improves PY prediction performance compared to current parameter-based crop models. (2) In the absence of phenological responses, rising atmospheric CO2 concentrations universally benefit wheat growth and PY, while increasing temperatures have predominantly negative effects across most regions. (3) Warmer temperatures expand the window for selecting sowing dates, leading to a national trend toward earlier sowing. (4) By simultaneously considering climate impacts on wheat growth and sowing dates, we predict that PY in China's main producing regions will significantly increase from 2020 to 2060 and remain stable under SSP126. However, under SSP370, while there is no significant trend in PY during 2020–2060, increases are expected thereafter. These results provide valuable insights for policymakers navigating the complexities of climate change and optimizing wheat production to ensure food security. [ABSTRACT FROM AUTHOR]

Fisheries in India are a burgeoning industry with immense potential and opportunities. Ironically, because of its enormous but untapped potential, reservoir fisheries are called as "a sleeping giant". The average productivity from these reservoirs in India is about 30 kg/ha compared to the production potential of 250 kg/ha. Inadequate management leads to low rate of fish production in Indian reservoirs. A major impediment to science -based fish productivity in reservoirs is the lack of authentic data on target stocks. Inland fisheries, like those in reservoirs, are particularly affected. Investigators generally rely on simple catch statistics and hypothesis statements to assess fish production and potential yields due to inadequate resources, population data, and experts in the area. The present paper emphasizes the quintessential 44sq km huge Tehri hydro-power dam reservoir, located in the Bhagirathi and Bhilangana valleys of the lesser Himalayas in the Garhwal hills. On average the fish productivity from Tehri reservoir in the year 2021-2022 is reported as 13.75 kg/ha but, this is significantly lower than its actual productivity. Thus, the current technical paper addresses this issue by condensing and synthesizing the current status of fisheries in the Tehri Dam reservoir with past status in terms of fish species diversity. It provides baseline information on fish production and various data shortfalls in fisheries activity management. The paper also describes the ecological and economic aspects that affect fish catch to utilize the reservoir resources and mired the cold-water fishery management in the Tehri reservoir. [ABSTRACT FROM AUTHOR]

The first step to achieving ecological sustainability and intensification in agricultural systems is to have a comprehensive agroecological analysis of agricultural systems. This research analyzed the agroecological ecosystem of potato cultivation in the Torbat-e Heydariyeh Region of Iran over fifteen years (2001-2016). Based on the results, potato yield increased by 0.28 t ha-1 yr-1. The average potential yield of potato was calculated by the FAO method to be 64 t.ha-1. Also, the potential yield did not increase significantly during the study period. The average yield gap of potato was calculated to be 32.44 t ha-1. Also, with increasing yield, the yield gap showed a decreasing trend. The ecosystems experienced a steady rise in intensification, and the stability decreased. It was observed that although nitrogen fertilizer application was increased, its efficiency dropped from 110 kg tuber per kg of nitrogen fertilizer to 70 kg. Due to the decreasing trend of NUpE (Nitrogen uptake efficiency) and NUE (Nitrogen use efficiency) during the studied years, the NUE gap was the main factor in increasing nitrogen consumption, increasing intensification, and reducing stability in the studied systems. Therefore, changing the management method to increase the efficiency of nitrogen consumption can be suggested as the first step for moving towards ecological intensification and improving the sustainability of potato production systems. [ABSTRACT FROM AUTHOR]

Sorghum is the fifth most required cereal crop globally. Sorghum bicolor has the advantage of being adaptive to both lowland and dryland, with drought-tolerant and wide adaptability. The low nutrient availability in dryland requires additional effective fertilizers to increase sorghum productivity. The research aimed to assess the application of organic, inorganic, and biofertilizers for sorghum productivity on dryland. Research in Central Java, Indonesia as dryland sorghum areas, from November 2022 to February 2023. The experiment cooperates with the farmers in a split-plot design, the main plot was two varieties and subplots of four fertilizers. The enhanced sorghum yield (21.38%–36.06%) with combined fertilizer was greater than the existing fertilization. Nutrient control does not rely on inorganic fertilizers but also on applying biofertilizers. The sorghum farming economic value farming indicated that combinations of fertilizer treatments and varieties provide benefits of USD 929.81–1955.81 with a revenue-cost ratio (R/C) value >1. Sorghum is an essential food commodity that faces the threat of the global crisis and an unfavorable environment. This study indicated balanced fertilizers could provide sufficient nutrients to the soil and increase nutrient absorption availability for sorghum growth and productivity. Balanced fertilization increases the uptake of N, P, and K nutrients correlates with an increase in yield of 21.38%–36.06%. [ABSTRACT FROM AUTHOR]

Introduction: Crops yield can be considered in different situations, which is called different production levels. Potential yield level is that determined by radiation, temperature and cultivar traits without limitations of biotic or abiotic factors; while attainable yield level is that limited by water or nutrient supply, and actual yield level is that determined in the present of the limiting (water or nutrient) and reducing factors (such as weed, harmful insects and plant diseases). The yield gap is the difference between the potential yield level and actual yield level. Identifying the yields at different production levels and quantifying the yield gaps through field experiments may involve many years of data collection on which to make meaningful inferences. Crop simulation models are an alternative tool for analyzing interactions between water and nitrogen availabilities on yield generation. The objectives of the present study was to estimate potential yields and yield gaps for irrigated wheat using the CERES-Wheat model, and other limiting and reducing factors in the main wheat growing regions of Kermanshah province. Materials and Methods: The study was conducted at 3 locations in Kermanshah province, which is located in west of Iran. Historical weather data for 1999 to 2016 were obtained from the Iran Meteorological Organization for the 3 locations. The weather data included daily solar radiation (MJ m-2 d-1), daily maximum and minimum temperatures (°C), and daily rainfall (mm). The CERES-Wheat model was calibrated for Pishgam cultivar of wheat and validated for a main wheat growing regain to estimate yield gaps in some locations of Kermanshah province in west Iran. In order to calibrate and validation of the model, in another study, leaf area index, phenological growth stages, total dry weight yield and grain yield were used. The validated model was used to simulate long-term yield under three management conditions (potential, water-limited, nitrogen-limited). The experiments were conducted in the Campus of Agriculture and Natural Resources Field at Razi University, Kermanshah, Iran (34◦19'N, 47◦50'E, altitude 1320 m) on soil classified as Inceptisol typic during 2014-2015 and 2015-2016. The treatments were included 4 levels of nitrogen fertilizer application (90, 180, 300 and 360 kg ha-1 urea). Results and Discussion: The simulation results indicated that averaged simulated potential yield was 8.9 t ha-1, while water and nitrogen limitation yields were 8.0 and 7.1 t ha-1, indicating 10.3% and 20.2% reduction in wheat yield, respectively. The potential yields changed spatially due to changes in temperature and solar radiation. The average actual yield was 5.5 t ha-1 which was 3.4, 2.7 and 1.8 t ha-1 less than potential, water limitation and nitrogen limitation yields, respectively. There was fairly large gap between the actual and the potential yields (about 3.4 t ha-1). When averaged over years, total yield gap obtained for Kermanshah was 2.7 t ha-1, for Kangavar was 3.7 t ha-1, and for Ravansar was 3.8 t ha-1. Across locations, contribution of yield gap from water limitation was 26%, for nitrogen limitation was 51.3% and for other limiting and reducing factors was 22.7%. Conclusion: It can be concluded that the management timing of nitrogen application might reduce yield gap across locations. On the other hand, improved irrigation methods might lead to improved actual yield through preventing of the water and nitrogen leaching which it can reduce the total yield gap. In this study, only the role of water and nitrogen limitation was evaluated. The data collected from questionnaires showed that the yield gap of wheat was affected by the unsuitable of crop management practices, including optimum planting date, and pest and weed management that were not studied in the simulations. [ABSTRACT FROM AUTHOR]

Objective: The present study was conducted in order to estimate the yield gap of faba bean in the main production areas of this plant in Golestan province, including Gorgan, Ali Abadkatol and Aq Qola cities, and to identify the factors that cause it and to determine the contribution of each of them. Methods: Based on this, the information related to the production management of 445 faba bean farms in Gorgan, Aliabadkatol and Aqqola regions in 1398-1399 and 1399-1400 was collected and the yield gap was estimated using the comparative performance analysis (CPA) method. Results: The average, maximum, and gap yield of faba bean seeds were 2742, 4000, and 1258 kg per hectare, respectively. Additionally, based on the results obtained, the most important reasons for the yield gap and the contribution of each of them in creating the yield gap were: planting date 21%, pests 15 percent, the amount of pure nitrogen (N) 14 percent, the number of disc times 14 percent, the amount of seed used 12 percent, diseases 12 percent, waterlogging 5 percent, weeds 3 percent, non-use of working row 2 percent and improper planting depth 1 percent. Conclusion: In general, by optimizing the management of faba bean production and eliminating the mentioned factors of yield gap, it is possible to increase the yield of faba bean in the regions of Gorgan, Ali Abadkatol and Aq Qala of Golestan province by 46 percent (equal to 1258 kg per hectare) compared to the current amount increased. [ABSTRACT FROM AUTHOR]

Fisheries in India are a burgeoning industry with immense potential and opportunities. Ironically, because of its enormous but untapped potential, reservoir fisheries are called as "a sleeping giant". The average productivity from these reservoirs in India is about 30 kg/ha compared to the production potential of 250 kg/ha. Inadequate management leads to low rate of fish production in Indian reservoirs. A major impediment to science-based fish productivity in reservoirs is the lack of authentic data on target stocks. Inland fisheries, like those in reservoirs, are particularly affected. Investigators generally rely on simple catch statistics and hypothesis statements to assess fish production and potential yields due to inadequate resources, population data, and experts in the area. The present paper emphasizes the quintessential 44sq km huge Tehri hydro-power dam reservoir, located in the Bhagirathi and Bhilangana valleys of the lesser Himalayas in the Garhwal hills. On average the fish productivity from Tehri reservoir in the year 2021-2022 is reported as 13.75 kg/ha but, this is significantly lower than its actual productivity. Thus, the current technical paper addresses this issue by condensing and synthesizing the current status of fisheries in the Tehri Dam reservoir with past status in terms of fish species diversity. It provides baseline information on fish production and various data shortfalls in fisheries activity management. The paper also describes the ecological and economic aspects that affect fish catch to utilize the reservoir resources and mired the cold-water fishery management in the Tehri reservoir.

Accurately predicting the wheat potential yield (PY) is crucial for enhancing agricultural management and improving resilience to climate change. However, most existing crop models for wheat PY rely on type-specific parameters that describe wheat traits, which often require calibration and, in turn, reduce prediction confidence when applied across different spatial or temporal scales. In this study, we integrated eco-evolutionary optimality (EEO) principles with a universal productivity model, the Pmodel, to propose a comprehensive full-chain method for predicting wheat PY. Using this approach, we forecasted wheat PY across China under typical shared socioeconomic pathways (SSPs). Our findings highlight the following: (1) Incorporating EEO theory improves PY prediction performance compared to current parameter-based crop models. (2) In the absence of phenological responses, rising atmospheric CO2 concentrations universally benefit wheat growth and PY, while increasing temperatures have predominantly negative effects across most regions. (3) Warmer temperatures expand the window for selecting sowing dates, leading to a national trend toward earlier sowing. (4) By simultaneously considering climate impacts on wheat growth and sowing dates, we predict that PY in China’s main producing regions will significantly increase from 2020 to 2060 and remain stable under SSP126. However, under SSP370, while there is no significant trend in PY during 2020–2060, increases are expected thereafter. These results provide valuable insights for policymakers navigating the complexities of climate change and optimizing wheat production to ensure food security.

China's severe particle pollution could affect the regional climate and weather conditions that consequently threaten local to global food security. Yet, the underlying mechanisms and quantitative assessment of aerosols on crop yields remain unknown. Here, by integrating a meteorology–chemistry model and a crop model, we show the impacts of atmospheric aerosols on China's meteorology and soybean yields. We find that the potential yields of soybean would decrease in most parts of China due to direct aerosol radiation effects, while showing diverse responses in parts of the Northeast and North China Plain. Moreover, because of the high sensitivity of soybean growth to water, potential yield fluctuations are closely related to aerosol‐induced precipitation changes in most soybean‐growing regions of China. In particular, aerosols play the most important role during soybean's pod‐filling stage, in which the influence of both precipitation perturbations and negative solar radiative forcing is about 5–10 times that of air temperature on crop yield. Our study thereby identifies aerosol mitigation can bring a notable increase in crop yields, highlighting the potential for important co‐benefits in food security across polluting developing countries. [ABSTRACT FROM AUTHOR]

Introduction: Feeding the Iran's over than 90 million people has been recognized as one of the most important challenges of country in 2050; so we need to increase yields of crops in cultivated areas. Mostly the actual yields obtained by farmers are less than the potential yields of the region, due to management, climatic, nutrients, soil properties, weeds and/or other living and non-living stress factors. The differences between these potential yield levels and actual farmers' yields define the yield gaps, and precise spatially explicit knowledge about these yield gaps is essential to guide sustainable intensification of agriculture. The goal of this experiment is finding of limiting factors that affected the wheat yield and then reduce the yield gap between potential and actual yields of farmers in the fields of Abarkooh city located in Yazd province. Materials and Methods: Eleven wheat farms were selected with the coordination and consultation of agricultural service centers in different regions of Abarkooh counties. Soil samples were prepared from all farms before planting. All agricultural operations performed by farmers such as tillage methods, planting date, cultivars used, seed rate, cultivation area, crop rotation, fertilizers used and fertilization time, irrigation operations, pest and disease control, weeding and/or spraying herbicide and harvest methods were noted or measured. At the end of tillering phase and harvest time, soil was sampled and its nutrients, organic matter and salinity were determined. At harvest time, samples were taken from different parts of the field by one square meter plots and 10 plants were randomly selected to measure yield components. The farmer's performance with the combine was also recorded based on the farmers' claims and the approval of the local expert. Nitrogen, phosphorus and potassium levels were measured in grain, straw and soil after harvesting operation. Meteorological data were collected daily from the Abarkoh weather station. The potential yield of region was calculated using regression model and the difference between obtained yield and potential yield was considered as yield gap. Eighty percent of potential yield is also considered as exploitable yield. Using step-by-step regression, the most effective factors in yield reduction were identified and a suitable regression model was fitted for these variables against grain yield. Then, the degree of influence of each variable was determined using Comparative Performance Analysis. Results and Discussion: The results showed that the average yield obtained from these farms was 5040 kg/ha and the yield gap was 4659 kg/ha, of which 2721 kg can be attainable. The order of the importance of agricultural operations in reducing yield in the form of insufficient number of irrigations (24 percent), lack of crop rotation with pulses (18 percent), low consumption of nitrogen fertilizer (16 percent), the method of preparing the cultivation bed and plowing times (12 percent), lack of manure fertilizer consumption (12%), improper weed control (11%), improper planting date (4%) and insufficient nitrogen split (3%). The analyze of grain yield components also showed that the share of the number of spikes per square meter, number of seeds per spike, 1000 kernel weight and harvest index in yield reduction are 39, 24, 12 and 25% respectively. Conclusion: Based on the results obtained, we can to define an optimal crop management: enough irrigation (10 times), rotation with legumes, use enough nitrogen fertilizer, use animal manure to increase soil organic matter, plowing in summer and autumn, weed control, proper planting date and Nitrogen split 3 times. Considering that management factors mentioned above have mutual effects on each other and cannot cause a significant yield increase alone, therefore, in order to have a successful agriculture, it is necessary to act on the basis of a suitable management package. [ABSTRACT FROM AUTHOR]

With continuous increase of population and demand for nutritional food, analyzing potential yield of world maize affected by global warming is of great significance to direct the crop production in the future. Thus, in this paper both average and top (national) yields of world maize between 2021 and 2030 are projected creatively using ARIMA-TR (Auto-regressive Integrated Moving Average and Trend Regression) model based on historic yields since 1961. The impact of global warming on the yields of world maize from 1961 to 2020 was analyzed using unary regression model. Our study concludes that between 2021 and 2030, average yield of world maize is projected to be from 5989 kg ha-1 to 6703 kg ha-1 while the top yield from 36530 kg ha-1 to 44271 kg ha-1, or the average ranging from 16.39% decreasingly to 15.14% of the top; from 1961 to 2020 global warming exerts positive effect on average yield of world maize less than on the top, which partly drives the gap between these two yields widened gradually; for world maize by 2030, the opportunities for improving global production should be mainly dependent on the advantage of high-yield countries. [ABSTRACT FROM AUTHOR]

This study focuses on the possibility of using fruit tree species, from an urban area in central Italy, to evaluate their possible productive, ecosystem, and economic contribution. The realization of the food forest was conducted through the use of a web app that can evaluate the climatic and ecosystem performance of trees in the city. This simulation can provide the city's government with useful information on the ecosystem and the socioeconomic benefits of planting fruit trees in an urban park. Among the four chosen species, both Ficus carica and Morus nigra showed good potential fruit production of 1300 kg and 865 kg and a CO2 storage of 2.5 and 1.5 tons. The production and economic potentials from selling the fruits of the selected species were evaluated, and the Morus nigra species showed the highest economic value over a 50-year period of about 6000 USD, with an average price of 7 USD/kg. Another positive aspect of edible food forest landscapes is their ability to give rise to an ecosystem and habitat that can attract animals, birds, and wildlife, consequently improving urban ecosystem biodiversity. [ABSTRACT FROM AUTHOR]

The rice yield gap (YG) is a global concern, requiring more detailed studies spatially and temporally. As a staple food in Indonesia, rice was produced from 7.4 Mha paddy fields in 2019. Better insight into the YG helps assess measures to boost rice production. However, the information on YG variation among regions scale is limited. This study aimed to identify the rice YG based on 295 historical trial datasets from 23 provinces in Indonesia. We surveyed published trial results from 2012 to 2022 and analyzed YGs, expressed as the percentage of farmer yield (FY). The potential yield (PY) was estimated from field trial results using introduced rice cultivation technology package, whereas FY from results using existing farmer practices. Our study showed that the average YG was 62% in rainfed, 54% in tidal, and 32% in irrigated paddy fields. The YG was significantly high in the paddy fields of Kalimantan (74%) and Maluku-Papua (49%), while the lowest was in Sulawesi (27%) and Java (31%). The YG varied significantly with geo-regions, rice varieties, and cultivation technology packages. Closing the YG and ensuring sustainable rice production requires the implementation of sustainable intensification through applying site-specific technology packages, reallocation of agricultural interventions to a higher YG region, and rice variety improvement to increase PY.

Potato is one of the staple food crops in North China. However, potato production in this region is threatened by the low amount and high spatial-temporal variation of precipitation. Increasing yield and water use efficiency (WUE) of potato by various water management practices under water resource limitation is of great importance for ensuring food security in China. However, the contributions of different water management practices to yield and WUE of potato have been rarely investigated across North China's potato planting region. Based on meta-analysis of field experiments from the literature and model simulation, this study quantified the potential yields of potatoes without water and fertilizer limitation, and yield under irrigated and rainfed conditions, and the corresponding WUEs across four potato planting regions including the Da Hinggan Mountains (DH), the Foothills of Yanshan hilly (YH), the North foot of the Yinshan Mountains (YM), and the Loess Plateau (LP) in North China. Simulated average potential potato tuber dry weight yield by the APSIM-Potato Model was 12.4 t ha−1 for the YH region, 11.4 t ha−1 for the YM region, 11.2 t ha−1 for the DH region, and 10.7 t ha−1 for the LP region, respectively. Observed rainfed potato tuber dry weight yield accounted for 61, 30, 28 and 24% of the potential yield in the DH, YH, YM, and LP regions. The maximum WUE of 2.2 kg m−3 in the YH region, 2.1 kg m−3 in the DH region, 1.9 kg m−3 in the YM region and 1.9 kg m−3 in the LP region was achieved under the potential yield level. Ridge-furrow planting could boost yield by 8–49% and WUE by 2–36% while ridge-furrow planting with film mulching could boost yield by 35–89% and WUE by 7–57% across North China. Our study demonstrates that there is a large potential to increase yield and WUE simultaneously by combining ridge-furrow planting with film mulching and supplemental irrigation in different potato planting regions with limited water resources.

With continuous increase of population and demand for nutritional food, analyzing potential yield of world maize affected by global warming is of great significance to direct the crop production in the future. Thus, in this paper both average and top (national) yields of world maize between 2021 and 2030 are projected creatively using ARIMA-TR (Auto-regressive Integrated Moving Average and Trend Regression) model based on historic yields since 1961. The impact of global warming on the yields of world maize from 1961 to 2020 was analyzed using unary regression model. Our study concludes that between 2021 and 2030, average yield of world maize is projected to be from 5989 kg ha-1 to 6703 kg ha-1 while the top yield from 36530 kg ha-1 to 44271 kg ha-1, or the average ranging from 16.39% decreasingly to 15.14% of the top; from 1961 to 2020 global warming exerts positive effect on average yield of world maize less than on the top, which partly drives the gap between these two yields widened gradually; for world maize by 2030, the opportunities for improving global production should be mainly dependent on the advantage of high-yield countries.

Climate change is projected to impact wheat production stability around the world. Understanding the spatiotemporal distribution of climate suitability of rainfed wheat under current and future climates helps to minimize crop production risks and ensure food security. This study determines climate suitability of rainfed wheat worldwide with a water-limited yield (Yw) of at least 10 t ha− 1 under current and future climatic conditions. Climate information from 469 stations worldwide was used in this study. The relationship between climate factors and the Yw at the reference weather stations was investigated using boundary line analysis. A three-segmented function was then used to classify regions based on the optimum range of each factor into unlimited and limited classes. The climate suitability layer was then created by overlaying the classified layers. The results indicated that about 30% (~ 66 Mha) of the world's wheat cultivation areas are in suitable climate zones (unlimited class), and about 70% (~ 155 Mha) are in unsuitable climate zones (limited class). The majority of the suitable climate areas are found in the Europe, eastern China, and the eastern United States. Under future climate scenarios, the climate suitability for rainfed wheat is likely to decrease markedly at low and mid latitudes. The findings of the study highlight that temperature is a slightly more limiting factor than precipitation while climate change conditions will intensify the negative effects of both. The method proposed in this study is simple for large-scale assessment and replicable for other crops. [ABSTRACT FROM AUTHOR]

China is the largest soybean-consuming country in the world, but its self-sufficiency rate (SSR) of 16% is very low and it therefore has to heavily rely on imports. To solve the soybean dilemma in China, it is necessary to examine the maximum amount of soybean that could be grown on the land currently used, how much land could reasonably be used to expand soybean acreage, and whether China could sustainably increase soybean self-sufficiency to reduce the risks of import reliance. To answer these questions, our paper presents a high-resolution spatial analysis of potential soybean production in China using primary data of weather and crop production practices that govern this potential. We employed a "bottom-up" scaling protocol to estimate gaps between potential yield with optimal management and current yields in three major soybean-planting regions, namely, Northeast China, Central China, and South China. We found that current soybean yield gap (Yg) in China is 49% and 45% of potential yield under irrigated and rainfed cropping systems, respectively. By closing the yield gap, Northeast China could provide additional soybean production equivalent to 32% of the current national total. Our results show that SSR could only be increased to 21–23% in 2030 by Yg closure alone but could be increased to a maximum of 52% by combining Yg closure and a reasonable area expansion. Even so, at least 61.08 million tons of soybean accounting for 38% of global soybean trade would still need to be imported to meet future domestic demand. We discuss strategies for soybean production increase based on Yg closure in the most valuable areas and cropland expansion in a sustainable manner in order to increase SSR as well as lessen the import pressure on the global market. [ABSTRACT FROM AUTHOR]

To address challenges associated with climate change, population growth and decline in international trade linked to the COVID-19 pandemic, determining whether national crop production can meet populations' requirements and contribute to socio-economic resilience is crucial. Three crop models and three global climate models were used in conjunction with predicted population changes. Compared with wheat production in 2000–2010, total production and per capita wheat production were significantly (P < 0.05) increase in 2020–2030, 2030–2040 and 2040–2050, respectively, under RCP4.5 and RCP8.5 due to climate change in China. However, when considering population and climate changes, the predicted per capita production values were 125.3 ± 0.3, 127.1 ± 2.3 and 128.8 ± 2.7 kg during the 2020–2030, 2030–2040, 2040–2050 periods under RCP4.5, or 126.2 ± 0.7, 128.7 ± 2.5, and 131.0 ± 4.1 kg, respectively, under RCP8.5. These values do not significantly differ (P > 0.05) from the baseline level (127.9 ± 1.3 kg). The average per capita production in Loess Plateau and Gansu-Xinjiang subregions declined. In contrast, per capita production in the Huanghuai, Southwestern China, and Middle-Lower Yangtze Valleys subregions increased. The results suggest that climate change will increase total wheat production in China, but population change will partly offset the benefits to the grain market. In addition, domestic grain trade will be influenced by both climate and population changes. Wheat supply capacity will decline in the main supply areas. Further research is required to address effects of the changes on more crops and in more countries to obtain deeper understanding of the implications of climate change and population growth for global food production and assist formulation of robust policies to enhance food security. [ABSTRACT FROM AUTHOR]

The cultivation of dry-season sorghum on residual moisture in West and Central Africa is highly affected by sowing dates and ecotypes used. Fifty-five dry-season sorghum ecotypes collected from three zones in southern Chadian were sown on two dates, early and late, in 2013 and 2014, in an α-Lattice, and replicated five times to evaluate the effect of sowing date on potential yield, flowering time, and other agro-morphological traits and to determine their photoperiod sensitivity. Trials were conducted in the research fields at the Agricultural Research Extension Farm in Youé, Chad. Year, sowing date, and their interaction significantly affected most of the assessed traits. Delaying sowing significantly decreased potential yield, duration of vegetative phase, and other agro-morphological traits, except staygreen. All cultivars were photoperiodic with late sowing requiring a lower cumulative growing degree unit to flower. The flowering window was not affected by sowing dates across cultivars; however, the flowering time was affected by a decrease in daylength, but not low night temperatures. Generally, late sowing decreased potential yield across cultivars. However, this decrease varied with the region of origin, with seven cultivars having average potential yields at or above the regional potential yield of 1 t/ha, irrespective of year or sowing dates. [ABSTRACT FROM AUTHOR]

Increasing feed grain supply, particularly domestic supply, is intended to guarantee feed grain security and, as a result, food security. Based on the Global Agro-Ecological Zones (GAEZ) model, the potential yield and actual yield of feed and food grain in China were estimated. According to the theory of factor endowment, the yield potential development coefficient and the yield efficiency advantage index were then constructed to determine whether the current spatial layout of feed grain is reasonable and how it could be adjusted. The results showed that: (1) There was an imbalance in feed crops production: yield loss in high-potential regions and excessive development in low-potential regions. The imbalances lead to a mismatch between feed production and resource endowment which causes productivity losses and ecological risks. (2) There was considerable potential for increasing the feed grain yield on the Northeast China Plain, the Loess Plateau and in the northern arid and semiarid region. The soybean yield can be increased by about 25%, and the maize yield can be increased by even more. (3) The feed grain should be planted in regions with sufficient potential yield but insufficient actual yield; 26.42% of China's soybeans and 34.74% of its maize were planted in these regions. (4) Some 16.69% and 15.65% of wheat and rice planting areas could be adjusted to soybeans, respectively; 20.76% and 21.04% of wheat and rice planting areas could be adjusted to maize, respectively. Through agricultural technology research and development, infrastructure support, comprehensive planning design and policy design, the yield potentials of feed grain can be realized. This will redress the imbalance wherein a food grain surplus and a feed grain shortage coexist. [ABSTRACT FROM AUTHOR]

Rising temperatures and more frequent droughts caused by global climate change reduce yields and increase climate risk, especially in rain-fed agriculture. Together with scarce land and water resources, this poses a serious threat to food security. Field experiments have shown that relay intercropping systems under irrigated conditions can improve productivity. However, little is known whether these improvements could also be obtained with simultaneous intercropping in rain-fed agriculture under water-limited conditions. To investigate this question, we analyzed a maize/soybean simultaneous intercropping system, using a modeling approach. A light interception model for strip intercrops was implemented into the APSIM classic model for simulating crop growth and yield in strip-intercropped maize and soybean and then calibrated and validated using field experiments conducted from 2017 to 2019 at 4 sites in Northeast China. We then ran a simulation using climatic data (1961–2020) from these sites. Model validation showed good agreements between observations and simulations. The results obtained from our simulation over the period from 1961 to 2020 showed that intercropping was predicted to increase total yields by 41.3% and subsequently enhanced total economic revenue by 23.8% compared to sole systems. It also reduced yield gap of maize by 33%, soybean by 56%, and the system by 45%. Attainable land equivalent ratio (LER) under rain-fed conditions was 1.27 over 60 years across the 4 sites, with a relative yield gain of maize of 0.35 and a relative yield loss of soybean of 0.08. Attainable LER was higher than potential LER. Yields and LER were significantly higher between 1991 and 2020, indicating a potential increase in land productivity with intercropping under a warming climate. Our results thus suggest that simultaneous intercropping offers great opportunities for yield enhancement in rain-fed agriculture under global climate change. [ABSTRACT FROM AUTHOR]

In Ghana, maize (Zea mays) is a crop crucial to achieving food and nutrition security. Maize consumption has increased exponentially over the past decades and contributes to 25% of the caloric consumption in the country. In order to assist in decision-making and guide investment in sustainable intensification of maize production, this study set out to identify the determinants of yield and to arrive at potential interventions for closing the maize yield gap. These were quantified using analytical approaches that combine a light use efficiency crop model (LINTUL-1) with statistical and geospatial analyses. Legacy data, auxiliary covariables, and maize fertilizer trials on eight experimental stations in Ghana were used in this study. Overall, the maize yield gap across the stations and trial treatments ranged from 17% to 98%. The variation in yield gap within a single station indicates a significant scope for closing the yield gap through site-specific nutrient management. Multiple linear regression models that explained 81% of the variability in maize yield gap identified soil organic matter, soil water-holding capacity, root zone depth, rainfall, sulfur fertilizer, and nitrogen fertilizer, in that order of importance, as the major determinants for closing the yield gap in the major agroecological zones of Ghana. The yield gap decreased by 1.4 t ha-1 with a 1% increase in soil organic matter. A 1 mm increase of the soil waterholding capacity reduced the yield gap by 1.06 t ha-1, while an increase in pH and in the application of potassium fertilizer widened the gap. These results suggest that both soil physical and chemical properties, together with weather data, should be taken into consideration to arrive at site-specific fertilizer recommendation and other agronomic practices. [ABSTRACT FROM AUTHOR]

IntroductionPulses play an important role in supplying human food and are a major source of protein in developing countries, so they have a special role in producing food in these countries. Peas (Pisum sativum L.) belongs to legume family and is well adapted to the cold climate. This plant has a lot of crude protein and starch and is therefore high in energy. Evaluating the status of pulses production is essential because of their importance in feeding the people of the world and their role in the design of cultivation patterns. Eliminating the gap between the yield currently achieved on farms and the yield that can be achieved by using the best environmentally adapted varieties and the optimum water, soil and plant management techniques is a key strategy to overcome the nutritional challenge of a growing global population. In recent years, due to concerns about food safety issues, studies on the issue of yield gap have also been increasing worldwide and it is necessary to estimate the yield gap and its causes using appropriate methods. Therefore, the present study was conducted to determine the yield gap of peas and determine the limiting factors and their contribution to the yield gap in pea farms in Gonbad kavus. Materials and MethodsThis study was carried out in pea farms (40 farms) during 2017-18 in Gonbad Kavus, Golestan province. The required information about farms was completed through observation, questioning of farmers or measurement. Information on soil properties was obtained using digital maps available at the Agricultural Jihad Office of Gonbad Kavus. Comparative performance analysis (CPA) method was used to determine the yield gap rate and to identify its causes. In this method, the relationship between all measured variables (quantitative and qualitative) and yield was evaluated using multiple regression. In this section, first, we used stepwise method to determine which variables should be included in the final production model. The average yield was calculated by placing the observed variables (x) of the studied farms in the yield model. The maximum yield obtained was then calculated by placing the best observed value of the variables in the model. The discrepancy between these two functions was considered as the performance gap. The ratio of yield gap for each variable to total yield gap represents its contribution in the yield gap and was expressed as a percentage. Results and DiscussionThe actual and potential yield calculated by the model were estimated to be 7941 and 17708 kg/ha, respectively, and yield gap was 10078.7 kg/ha. The reasons for this yield gap were as follows: Seed rate (19.56%), Nitrogen rate (17.04%), Frequency of herbicide application (15.02%), amount of available potassium in soil (34 (13%), soil organic matter (12.81%), amount of available phosphorus in soil (11.87%), farmer experience (10.36%). Therefore, it seems that with proper management of farms and taking into account the yield gap factors mentioned above, the yield of peas in Gonbad kavus can be increased to about 10078.7 kg/ha in comparison with current yield. ConclusionBased on the results in 40 farms studied, out of 45 variables studied, the final model was selected with seven independent variables. In the yield model, the actual and potential yield of farms calculated by the model were 7941 and 17708 kg/ha, respectively, and the yield gap was 10078.7 kg/ha. The recommendations of this research are based on the findings of the mentioned years in the region. Obviously, these recommendations may change in the future with changing farming systems (such as extension of conservation agriculture), agricultural management and possibly climatic conditions. In addition, by modifying the first-order causing factors of the yield gap discussed in this study, the second-order factors will emerge. Therefore, monitoring and evaluation of crop management in farms should be carried out on a continuous basis and the yield gap and its causes identified and resolved. In this study, among all the common agricultural management of farms, the cases that have the most impact on the yield gap and need to be modified and improved in the first stage are identified.

IntroductionCassava production is essential for food security in sub-Saharan Africa and serves as a major calorie-intake source in Nigeria. Estimating the yield gap in Nigeria is essential to indicate the most important limiting factors for production, and identify the yield gap hotspot areas. Secondly, these assessments may help set agendas in policy development and research prioritization where current information is scarce.Materials and methodsHere, Wwe used a crop model, LINTUL5, calibrated for five different cassava varieties based on field experiments embedded into a modeling framework SIMPLACE to estimate potential, water- and nutrient (current) limited cassava yield gaps (YG) as affected by climate factors and contributing a better understanding of yield gaps and its potentials in 30 states of Nigeria.ResultsOur study shows that cumulative radiation and precipitation were the most significant factors associated with cassava yield variability (p < 0.01). The YG averaged across states was estimated as 18.2 Ton7ha-1, with a maximum of 31.2 Ton7ha-1 35 in Kano state. Across the states, nutrient limitation accounts for 55.3% of the total cassava yield gap, while the remaining 44.7% is attributed to water limitation. The highest untapped water-limited yields were estimated in the northern states, such as Bauchi, Gombe, and Sokoto, characterized by the short rainy season.ConclusionOur results showed that most northern states are better equipped to become leading cassava producers in Nigeria under adequate crop management practices involving irrigation and soil fertility enhancement. We reached this conclusion because the northern states usually receive the highest radiation from their characteristic reduced cloud cover, even Therefore, policy and management interventions can be prioritized in these areas. Conclusively, the current cassava yield levels can be increased by a factor of five by emphasizing nutrient and soil health management and irrigation, particularly in areas characterized by a shorter rainy season (Sudan Savanna) in Nigeria.

In Ghana, maize (Zea mays) is a crop crucial to achieving food and nutrition security. Maize consumption has increased exponentially over the past decades and contributes to 25% of the caloric consumption in the country. In order to assist in decision-making and guide investment in sustainable intensification of maize production, this study set out to identify the determinants of yield and to arrive at potential interventions for closing the maize yield gap. These were quantified using analytical approaches that combine a light use efficiency crop model (LINTUL-1) with statistical and geospatial analyses. Legacy data, auxiliary covariables, and maize fertilizer trials on eight experimental stations in Ghana were used in this study. Overall, the maize yield gap across the stations and trial treatments ranged from 17% to 98%. The variation in yield gap within a single station indicates a significant scope for closing the yield gap through site-specific nutrient management. Multiple linear regression models that explained 81% of the variability in maize yield gap identified soil organic matter, soil water-holding capacity, root zone depth, rainfall, sulfur fertilizer, and nitrogen fertilizer, in that order of importance, as the major determinants for closing the yield gap in the major agroecological zones of Ghana. The yield gap decreased by 1.4 t ha-1 with a 1% increase in soil organic matter. A 1 mm increase of the soil water-holding capacity reduced the yield gap by 1.06 t ha-1, while an increase in pH and in the application of potassium fertilizer widened the gap. These results suggest that both soil physical and chemical properties, together with weather data, should be taken into consideration to arrive at site-specific fertilizer recommendation and other agronomic practices.

Today, food security is a major human concern. Therefore, research on crop yield and yield gap has been seriously increasing in recent years. For this purpose, the yield gap of rice fields in Guilan province was investigated using the ORYZA2000 model and integrated GIS-RS approaches. First, to estimate the coefficients of the ORYZA2000 model, an experimental survey was performed in the Rice Research Institute of Iran in the 2016 and 2017 years. At first, with the help of the model, the potential yield of rice in Guilan province was predicted. SDVIs (Satellite imagery-derived vegetation indices) were extracted from Sentinel-2 and Landsat 8 satellite images. SDVIs were evaluated to select the most proper one for generating the actual yield raster. Finally, the map of the yield gap was prepared from the differences between potential yield and actual yield rasters. The result showed that the NRMSE in the simulation of grain yield and aboveground biomass was less than 8%. The yield gap in rice cultivated farms of Guilan province during the two years of the experiment was estimated to be between 37 and 3090 kg ha−1. The results of this study can provide good basic information for optimizing rice yield. [ABSTRACT FROM AUTHOR]

As one of two most important cereals in the world, and with the continuous increase in population and demand for food consumption worldwide, rice has been attracting researchers' attention for improving its potential yield in the future, particularly as it relates to climate change. However, what will be the potential limit of world rice yield in the future, and how does global warming affect the yield of world rice? Therefore, analyzing the potential yield of world rice affected by global warming is of great significance to direct crop production worldwide in the future. However, by far, most modeled estimations of rice yield are based on the principle of production function from static biological dimension and at local or regional levels, whereas few are based on a time series model from a dynamic evolutionary angle and on global scale. Thus, in this paper, both average and top (national) yields of world rice by 2030 are projected creatively using the Auto-regressive Integrated Moving Average and Trend Regression (ARIMA-TR) model and based on historic yields since 1961; in addition, the impact of global warming on the yields of world rice is analyzed using a binary regression model in which global mean temperature is treated as the independent variable whereas the yield is expressed as the dependent variable. Our study concludes that between 2021 and 2030, the average yield of world rice is projected to be from 4835 kg/ha to 5195 kg/ha, the top yield from 10,127 kg/ha to 10,269 kg/ha, or the average yield ranging from 47.74% to 50.59% of the top yield. From 1961 to 2020, through to2030, global warming will exert a negative impact on the average yield of world rice less than that of the top yield, which partly drives the gap between these two yields and gradually narrowed; for world rice by 2030, the opportunities for improving global production should be dependent on both high and low yield countries as the average yield is approaching the turning point of an S-shaped curve in the long-term trend. These insights provide the academic circle with innovative comprehension of world rice yield and its biological evolution for global food security relating to global warming in the future. [ABSTRACT FROM AUTHOR]

IntroductionBarley (Hordeum vulgare L.) is considered as the second most important grain crop after wheat, due to 1.75 million hectares harvested areas and 3.2 million tons’ production in Iran. The irrigated fields are contributed up to 45% of total barley harvested areas (equivalent to 1.7 million ha) and 70% of total barley production (equivalent to 2.2 million tons). Based on the statistics reported in recent years, about 2.5 million tons of barley imported from other countries. According to the impossibility of extending the barley cultivated areas and even the necessity of reducing fields in some parts of the country, increasing productivity per unit area of cultivated lands is recognized as the only practical way to boost the production of barley in Iran. In this regard, this study was conducted to estimate barley yield gap (Yg) and the potential of increasing barley production in irrigated condition as the first step to promote the yield and production of barley over the country.Materials and MethodsFirstly, the main production zones of barley are determined; the zones which were contributed in more than 85% of barley production. The Designated climatic zones (DCZs) were identified using GYGA climatic zones (Global Yield Gap Atlas) and the distribution of barley harvested area raster layers. Subsequently, the Reference weather Stations (RWSs) within the DCZs were selected based on the values of the harvested area, and the types of soil in each of RWSs were determined by using of HC-27 soil map. SSM-iCrop2 as a crop simulation model has been employed to estimate the potential yield (Yp) in the RWSs of cultivated areas, which has previously been parameterized and evaluated, and the results have indicated the robustness of the model for simulating barley yield over the country. For estimating Yg, the data of actual yield (Ya) and the agronomic management data for estimating Yp during 15 growing seasons (2000-2014), were collected at RWSs scale. Using A bottom-up approach, the yield, and production gap values were calculated at RWSs and subsequently aggregated to DCZs and finally, extended from DCZ to country-level according to the spatial distribution of crop area and climate zones.Results and DiscussionBased on GYGA protocol, 48 RWSs within 12 DCZs of irrigated barley harvested areas were demonstrated. Aggregation from the RWSs results to DCZs illustrated that the average of potential yield in DCZs of irrigated barley was estimated 7090 kg.ha-1 and the range varied from 5283 to 8286 kg.ha-1. Nevertheless, the Ya range in these climate zones was calculated between 1406 and 3723 with an average of 3009 kg.ha-1. According to the results, the DCZs which confronted to higher temperatures during the growing season have lower yields and also a significant reverse correlation between the potential yield and the growth length period (R2 = 0.88 and p ≤0.01) were shown. The correlation between total received daily solar radiation during the growing and Yp in the DCZs was significant, positively season (R2 = 0.98 and p ≤0.01). At present, the range of difference between actual and potential yield varies between 3237 to 4697 kg.ha-1 with an average of 4081 kg.ha-1 (equivalent to 58% yield gap). In other words, just around 24 to 50 percent (on an average of 42 percent) of estimated Yp in irrigated barley fields can be attainable. According to the irrigated barley harvested areas, the actual and potential production gap are calculated about 2.21 and 2.99 million tons in the country, respectively, and under the best management condition can lead the production to be about 4.17 million tons.ConclusionAccording to the results, it was demonstrated about 58% relative yield gap between the averages of actual yield (3008 kg.ha-1) and potential yield (7090 kg.ha-1), which can be reduced by improving the production management in irrigated barley cultivated areas. For this reason, the current production of barley in irrigated lands can be increased from 2.12 to 4.17 million tons. This increase in production (1.96 million tons) could provide a significant part of the country's need to the barley and bring the country closer to achieve full self-sufficiency.

Argentina grows the second‐largest area of lucerne in the world. Despite its importance, a yield gap exists between potential and measured yields, but factors contributing to it are still unclear. This study aimed to identify management factors and research needs to reduce the lucerne yield gap to improve the livestock systems in this region. We used meteorological data coupled with lucerne crop modelling and measured yields from the National Lucerne Cultivar Evaluation Network (NLCEN) to quantify the lucerne yield gap in nine sites located within the Argentinian Pampas (between parallels 30–45°S and meridians 58–65°W) and three sites outside the Pampas. Specifically, we used the model developed by McCall & Bishop‐Hurley (2003), adapted and calibrated for lucerne in Argentina by Berone et al. (2017) to estimate the potential yield (PY) for 12 locations (three irrigated and nine rainfed), and compared those results with measured yields from the NLCEN to calculate yield gaps. We found the average available photosynthetic active radiation (PAR) and temperatures were sufficient to achieve 21.5 ± 3.7 t dry matter (DM) ha−1 yr−1 under rainfed conditions (environments with mean annual rainfall from 400 to 1,200 mm). However, the average measured yield from the NLCEN was 16.8 ± 2.4 t DM ha−1 yr−1 (a 22% gap). Potential yields ranged between 10 and 25 t DM ha−1 yr−1 under rainfed conditions and between 25 and 39 t DM ha−1 yr−1 for irrigated crops. As latitude increased rainfed locations had lower yields, while irrigated locations had higher yields. Adding irrigation was predicted to increase yields to 35.4 ± 2.0 t DM ha−1 yr−1 (a 53% gap) in rainfed sites. For irrigated locations, the gap was smaller (27.3 ± 3.5 vs 32.4 ± 2.2 t DM ha−1 yr−1 for measured vs potential yield, respectively), and most likely linked to nutrient deficits. Also, current grazing management was estimated to achieve approximately 50% less grazing efficiency than optimal grazing management. Our results demonstrated that the livestock industry can potentially increase animal production under current environmental conditions. The four main adjustments to achieve this are increased use of irrigation, increased use of fertilisers, earlier commencement of grazing in spring and increased stocking rates. The costs of irrigation, fertilisers and grazing management are envisaged to be small compared with potential increases in incomes and thus profitability available to beef and dairy farmers using lucerne as a major feed source in Argentina. [ABSTRACT FROM AUTHOR]

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 laboratory2 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. [ABSTRACT FROM AUTHOR]

Spatial and temporal variations in the potential yields of highland barley is important for making policies on adaptation of agriculture to climate change in the Three Rivers Region (TRR), one of the main highland barley growing areas on the Tibetan Plateau. This research tries to explore a suitable strategy for simulating potential yields of highland barley by the WOFOST (WOrld FOod STudies) crop growth model, and further to identify variations in climate conditions and potential yields in TRR from 1961 to 2020 for making policies on adaptation of agricultural production to the climate change impacts on the Tibetan Plateau. Validation results indicated that WOFOST could accurately simulate the potential yields of highland barley with the global radiation estimated by the calibrated Angstrom model. The global radiation during the growth periods decreased at a rate of 0.047 MJ/m2a, while the temperature during the growth periods increased at rates ranging from 0.019 to 0.087 °C/a, which was greater than the average warming rate of the globe. The simulated potential yields ranged from 10,300 to 14,185 kg/ha in TRR, with an average decreasing rate of 28 kg/ha/a. The decrease in the potential yields was mainly attributed to the shortened critical period caused by warming effects, so cultivation of new varieties of highland barley with longer growth periods is suggested as an achievable strategy for the adaptation of highland barley to climate change in TRR. [ABSTRACT FROM AUTHOR]

Northeast China (NEC) is one of the major maize production areas in China. Agro-climatic resources have obviously changed, which will seriously affect crop growth and development in this region. It is important to investigate the contribution of climate change adaptation measures to the yield and resource use efficiency to improve our understanding of how we can effectively ensure high yield and high efficiency in the future. In this study, we divided the study area into five accumulated temperature zones (ATZs) based on growing degree days (GDD). Based on the meteorological data, maize data (from agro-meteorological stations) and the validated APSIM-Maize Model, we first investigated the spatial distributions and temporal trends of maize potential yield of actual planted cultivars, and revealed the radiation use efficiency (RUE) and heat resource use efficiency (HUE) from 1981 to 2017. Then according to the potential growing seasons and actual growing seasons, we identified the utilization percentages of radiation (PR) resource and heat resource (PH) for each ATZ under potential production from 1981 to 2017. Finally, we quantified the contributions of cultivar changings to yield, PR and PH of maize. The results showed that during the past 37 years, the estimated mean potential yield of actual planted cultivars was 13 649 kg ha–1, ranged from 11 205 to 15 257 kg ha–1, and increased by 140 kg ha–1 per decade. For potential production, the mean values of RUE and HUE for the actual planted maize cultivars were 1.22 g MJ–1 and 8.58 kg (°C d)–1 ha–1. RUE showed an increasing tendency, while HUE showed a decreasing tendency. The lengths of the potential growing season and actual growing season were 158 and 123 d, and increased by 2 and 1 d per decade. PR and PH under potential production were 82 and 86%, respectively and showed a decreasing tendency during the past 37 years. This indicates that actual planted cultivars failed to make full use of climate resources. However, results from the adaptation assessments indicate that, adoption of cultivars with growing season increased by 2–11 d among ATZs caused increase in yield, PR and PH of 0.6–1.7%, 1.1–7.6% and 1.5–8.9%, respectively. Therefore, introduction of cultivars with longer growing season can effectively increase the radiation and heat utilization percentages and potential yield.

This study is conducted to investigate the influential factors on rice yield gap in the Joibar Region, located in Mazandaran Province, by means of two methods of boundary line analysis and comparative performance analysis, in the cropping years of 2017-18 and 2018-19. It is carried out through fieldwork and face-to-face interviews with farmers, for which purpose, totally 120 rice fields located in the studied geographical area in each crop year have been selected in such a way that they had sufficient diversity in terms of location and time. In the comparative performance analysis method, the relation between yield and all measured quantitative and qualitative variables are examined, using multiple regression method. According to the suggested protocol in the boundary line analysis method, a boundary line is fitted to the data in the data distribution diagram. Results show that according to the yield comparative performance analysis model, the yield gap of Joibar rice fields has been 1842 kg/ha, and the harvest date has played the most important role in rice yield gap. Also, according to the findings of border line analysis, the yield gap of rice fields in this region has been 874 kg/ha with the biological control being the most important factor in rice yield gap. Therefore, continuous monitoring and evaluation of crop management on farmers' fields and its identification is essential to eliminate yield gaps along with the management factors causing them. [ABSTRACT FROM AUTHOR]

A yield gap analysis for rapeseed (Brassica napus L.) is critical to meeting the oil demand by identifying yield potential and yield constraints. In this study, potential yield (Yp), attainable yield (Yatt), and actual yield (Yact) for winter rapeseed were determined in five different zones of China. A boundary line approach was adopted to calculate Yp, based on a large-scale field experimental database. A meta-analysis was conducted on the data obtained from 118 published studies to evaluate the effects of agronomic factors on rapeseed yield. The main results indicated that farmers only achieved 37–56% of the yield potential across the zones. The low altitude areas (L-URY) and lower reaches (LRY) of the Yangtze River Basin (YRB), China had high yield levels. The total yield gap was 1893 kg ha–1, due to the agronomic management factors, environmental factors, and socioeconomic factors. The meta-analysis showed that weed control and drainage were the best management practices to improve yields (45.6 and 35.3%, respectively), and other practices improved yields by 17.1–21.6%. Consequently, to narrow the yield gap over the short term, the study could focus on techniques that are easily implemented to farmers.

Study Region: This research paper focuses on the application of slug test on South African fractured rock aquifers and the applicability of the test to provide potential aquifer hydraulics. The region of the study was Petrusburg which is situated in the Free State Province, South Africa. Study Focus: The aim of the study was to develop a methodology to relate slug tests to a potential yield estimation, therefore investigating and reviewing the applicability and accuracy of the slug test methodology in South Africa, applied on fractured rock aquifers as established in 1995 (Vivier et al., 1995). The aim was achieved by reviewing the methodology applied for slug tests that are related to potential yield estimations (Vivier et al., 1995); identifying the limitations of slug tests; investigating the possibility to update the potential yield estimation method of 1995; and, by investigating the possibility to relate slug tests, by implementing two-dimensional modelling, to potential yield and transmissivity estimations. New hydrological insight in the Region: It was determined that slug tests can no longer be used to relate the recovery time for 90% of the initial static water level (s) to the potential yield (L/s) as an exact value but can rather be seen as an estimation tool to determine what potential yield in terms of ranges. The investigation revealed that the use of simple, homogenous models can be used to determine the possible transmissivity for slug tests and relate that transmissivity to a potential yield (L/s). Note that this is not an absolute and is subject to limitations.

Black gram, a pulse, is one of the major export crops in Myanmar. Because of a decline in the maximum possible yield of this crop in farmers' fields, a yield gap exists between potential and farmers' actual yields. Reducing the gap between actual and potential yields is critical for increasing crop production. This study was carried out to generate yield gap mapping, and to investigate the reasons responsible for this yield gap in black gram production. An annual survey was carried out to determine farmers' actual yield at Kyee Inn Village, Pyinmana Township during October 2017 and 2018. Drone photos were consolidated and prepared for digitizing and analyzed with Pix4D software. ArcGIS 10.7 software was used to map the spatial distribution of the yield gap of black gram in the selected area. Yield gaps of black gram with a range of 0.02 t ha-1 to 2.70 t ha-1 in the two consecutive years were observed. The yield gap between potential and farmers' actual yields (Yield Gap I) was greater in 2018 compared to the 2017 season. The gap between the yield obtained through an organized farm trials and the yield harvested by the farmers (Yield Gap II) was also larger in 2018 than that for the 2017 crop season. A technology gap for the variety Yezin-6 (0.68 t ha-1) was observed in 2018 whereas there were no gaps for Yezin-2 and Yezin-5 in 2017 and non for these varieties in the 2018 post-monsoon season. The reasons these large yield gaps may exist, is probably due to differences in crop management practices used at the experimental stations and those by farmers. The results of this study should provide useful information for policymakers, researchers, extension agents, and other stakeholders to upgrade a location-specific package of practices and increase crop yield by supporting technological solutions and training for the farmers. [ABSTRACT FROM AUTHOR]

Increasing feed grain supply, particularly domestic supply, is intended to guarantee feed grain security and, as a result, food security. Based on the Global Agro-Ecological Zones (GAEZ) model, the potential yield and actual yield of feed and food grain in China were estimated. According to the theory of factor endowment, the yield potential development coefficient and the yield efficiency advantage index were then constructed to determine whether the current spatial layout of feed grain is reasonable and how it could be adjusted. The results showed that: (1) There was an imbalance in feed crops production: yield loss in high-potential regions and excessive development in low-potential regions. The imbalances lead to a mismatch between feed production and resource endowment which causes productivity losses and ecological risks. (2) There was considerable potential for increasing the feed grain yield on the Northeast China Plain, the Loess Plateau and in the northern arid and semiarid region. The soybean yield can be increased by about 25%, and the maize yield can be increased by even more. (3) The feed grain should be planted in regions with sufficient potential yield but insufficient actual yield; 26.42% of China’s soybeans and 34.74% of its maize were planted in these regions. (4) Some 16.69% and 15.65% of wheat and rice planting areas could be adjusted to soybeans, respectively; 20.76% and 21.04% of wheat and rice planting areas could be adjusted to maize, respectively. Through agricultural technology research and development, infrastructure support, comprehensive planning design and policy design, the yield potentials of feed grain can be realized. This will redress the imbalance wherein a food grain surplus and a feed grain shortage coexist.

The concept of yield gaps provides a basis for identifying the main sources of production losses, caused by water or management deficiencies, which may help foresters and forest companies to better plan and make decisions in their areas. Thus, the aim of this study was to identify the magnitude and the major causes of yield gaps of eucalypts, being this the most planted forest genus in Brazil, in different producing regions of the state of Minas Gerais that has the largest planted area. To these ends, potential (Yp) and attainable (Ya) yields were simulated using the agroecological zone model (AEZ-FAO) adapted and calibrated for Brazilian eucalypt clones. Actual yield (Yr) data were obtained from 22 sites located in the state of Minas Gerais from 2009 to 2016, considering an average forest rotation of 6.7 years and plantings occurring between 2002 and 2010. From this, the total yield gap (YGtot), yield gap by water deficit (YGwd), and yield gap by sub-optimal management (YGman) were determined. The YGwd ranged from 37 to 69 m3 ha−1 year−1 across the 22 sites assessed, with an average value of 55 m3 ha−1 year−1. On the other hand, the YGman ranged from zero (optimal management) to 31 m3 ha−1 year−1. The eucalypt yield gap in commercial areas of Minas Gerais state was mainly caused by water deficit, which represented 77% of the total yield gap. On the other hand, the deficiencies in forest management accounted for 23% of the total yield gap. [ABSTRACT FROM AUTHOR]

Objective: To determine potential and water-limited yields in oil palm producing areas in the State of Tabasco, México. Design/Methodology/Approach: The ERIC III v. 3.2 database (IMTA, 2009) was used to select climatological stations with daily precipitation and maximum and minimum temperature records, going back to more than 20 years. The methodology proposed by the FAO and improved by Fischer et al. (2012) was used to estimate the potential yield. The equation reported by Ruiz-Álvarez et al. (2012) was used to estimate the annual water deficit from the climatic water balance. Results: The average potential yield of oil palm with a high level of inputs varies from 35.8 to 40.6 t ha1 of fresh fruit bunches. The average water-limited yield can vary from 15.6 to 23.5 t ha1 in plantations of at least 8 years of age, under rainfed conditions. The reduction in the maximum average attainable yield was the result of 19.2-49.5% soil moisture deficits. Study limitations/Implications: In order to determine their impact on potential and water-limited yields, climate change horizons must be included in future studies; this would enable researchers to establish the future theoretical economic profitability of the crop. Findings/Conclusions: The analysis between the yields indicates that --if the gap between the current yields and water-limited yields is closed-- output and percentage would be 6.5-14.4 t ha1 and 72.8-129% higher than the potential yield. [ABSTRACT FROM AUTHOR]

Climate efficiency is an index that shows quantitative reduction related to production caused by the drought. Using climate efficiency in zoning agricolas sure is a vanguard in agrometeorology. Therefore, we aimed to simulate the climate efficiency for sugarcane production in Brazil and test its use in agricultural zoning. Mean annual air temperature, total annual precipitation, and climate efficiency were the climatic variables used to define suitable areas for sugarcane cultivation. Potential and actual yield was established using the agroecological zone method. Regions with mean annual temperatures between 28 and 38 °C, annual precipitations between 1000 and 1500 mm year−1, and climate efficiency higher than 0.65 were considered climatically suitable for cultivation. The interpolation and crossing of information allowed obtaining the climatic aptitude zoning of sugarcane production for Brazil. Kriging was used as an interpolation method, using the spherical model, one neighbor, and a 0.25° resolution (27.75 km). The Brazilian states were divided into three major groups, according to sugarcane climate efficiency. The most favorable states for sugarcane production had a mean climate efficiency of 0.92. On the other hand, the states with the lowest climate efficiencies presented values of 0.59. Climatic aptitude zoning shows that 24.45% of the Brazilian territory is climatically suitable for sugarcane cultivation. Mato Grosso do Sul State has favorable climatic aptitude in 98% of its territory. The aptitude of productive losses due to climate efficiency is the lowest from January to April in Brazil. The Midwest and Northeast regions have the lowest climate efficiencies from June to September, thus requiring other alternatives, such as irrigation systems for crop maintenance. The use of climate efficiency to elaborate agricultural zoning allows determining with a high accuracy suitable areas for sugarcane cultivation. [ABSTRACT FROM AUTHOR]