• Energy Research

Les stress abiotiques sont l'une des principales contraintes à la production agricole et à la sécurité alimentaire dans le monde. La situation s'est aggravée en raison des changements drastiques et rapides du climat mondial. La chaleur et la sécheresse sont sans aucun doute les deux stress les plus importants ayant un impact énorme sur la croissance et la productivité des cultures. Il est très important de comprendre les interventions physiologiques, biochimiques et écologiques liées à ces stress pour une meilleure gestion. Un large éventail de réponses des plantes à ces stress pourrait être généralisé en réponses morphologiques, physiologiques et biochimiques. Il est intéressant de noter que cette revue fournit un compte rendu détaillé des réponses des plantes aux stress liés à la chaleur et à la sécheresse, en mettant particulièrement l'accent sur les points communs et les différences. La croissance et les rendements des cultures sont affectés négativement par un approvisionnement en eau sous-optimal et des températures anormales en raison de dommages physiques, de perturbations physiologiques et de changements biochimiques. Ces deux contraintes ont des impacts multilatéraux et, par conséquent, une action mécanique complexe. Une meilleure compréhension des réponses des plantes à ces stress a des implications pragmatiques pour les remèdes et la gestion. Un compte rendu complet des approches conventionnelles et modernes pour faire face aux stress liés à la chaleur et à la sécheresse a également été présenté ici. Une discussion critique côte à côte sur les réponses saillantes et les stratégies de gestion de ces deux stress abiotiques importants fournit un aperçu unique des phénomènes. Une approche holistique prenant en compte les différentes options de gestion pour faire face simultanément au stress dû à la chaleur et à la sécheresse pourrait être une approche gagnant-gagnant à l'avenir. El estrés abiótico es una de las principales limitaciones para la producción de cultivos y la seguridad alimentaria en todo el mundo. La situación se ha agravado debido a los cambios drásticos y rápidos en el clima global. El calor y la sequía son, sin duda, los dos estreses más importantes que tienen un gran impacto en el crecimiento y la productividad de los cultivos. Es muy importante comprender las intervenciones fisiológicas, bioquímicas y ecológicas relacionadas con estos estreses para un mejor manejo. Una amplia gama de respuestas de las plantas a estas tensiones podría generalizarse en respuestas morfológicas, fisiológicas y bioquímicas. Curiosamente, esta revisión proporciona una descripción detallada de las respuestas de las plantas al estrés por calor y sequía, con especial énfasis en resaltar los puntos en común y las diferencias. El crecimiento y los rendimientos de los cultivos se ven afectados negativamente por el suministro de agua subóptimo y las temperaturas anormales debido a daños físicos, interrupciones fisiológicas y cambios bioquímicos. Ambas tensiones tienen impactos multilaterales y, por lo tanto, son complejas en la acción mecanicista. Una mejor comprensión de las respuestas de las plantas a estas tensiones tiene implicaciones pragmáticas para los remedios y la gestión. También se ha presentado aquí una descripción completa de los enfoques convencionales y modernos para hacer frente al estrés por calor y sequía. Una discusión crítica lado a lado sobre las respuestas sobresalientes y las estrategias de gestión para estas dos importantes tensiones abióticas proporciona una visión única de los fenómenos. Un enfoque holístico que tenga en cuenta las diferentes opciones de gestión para hacer frente al estrés por calor y la sequía simultáneamente podría ser un enfoque beneficioso para todos en el futuro. Abiotic stresses are one of the major constraints to crop production and food security worldwide. The situation has aggravated due to the drastic and rapid changes in global climate. Heat and drought are undoubtedly the two most important stresses having huge impact on growth and productivity of the crops. It is very important to understand the physiological, biochemical, and ecological interventions related to these stresses for better management. A wide range of plant responses to these stresses could be generalized into morphological, physiological, and biochemical responses. Interestingly, this review provides a detailed account of plant responses to heat and drought stresses with special focus on highlighting the commonalities and differences. Crop growth and yields are negatively affected by sub-optimal water supply and abnormal temperatures due to physical damages, physiological disruptions, and biochemical changes. Both these stresses have multi-lateral impacts and therefore, complex in mechanistic action. A better understanding of plant responses to these stresses has pragmatic implication for remedies and management. A comprehensive account of conventional as well as modern approaches to deal with heat and drought stresses have also been presented here. A side-by-side critical discussion on salient responses and management strategies for these two important abiotic stresses provides a unique insight into the phenomena. A holistic approach taking into account the different management options to deal with heat and drought stress simultaneously could be a win-win approach in future. الضغوط اللاأحيائية هي واحدة من القيود الرئيسية على إنتاج المحاصيل والأمن الغذائي في جميع أنحاء العالم. وقد تفاقم الوضع بسبب التغيرات الجذرية والسريعة في المناخ العالمي. لا شك أن الحرارة والجفاف هما أهم ضغوط لها تأثير كبير على نمو وإنتاجية المحاصيل. من المهم جدًا فهم التدخلات الفسيولوجية والكيميائية الحيوية والبيئية المتعلقة بهذه الضغوط من أجل إدارة أفضل. يمكن تعميم مجموعة واسعة من استجابات النبات لهذه الضغوط في الاستجابات المورفولوجية والفسيولوجية والكيميائية الحيوية. ومن المثير للاهتمام أن هذه المراجعة تقدم سردًا مفصلاً لاستجابات النبات للحرارة والجفاف مع التركيز بشكل خاص على تسليط الضوء على القواسم المشتركة والاختلافات. يتأثر نمو المحاصيل والمحاصيل سلبًا بإمدادات المياه دون المستوى الأمثل ودرجات الحرارة غير الطبيعية بسبب الأضرار المادية والاضطرابات الفسيولوجية والتغيرات الكيميائية الحيوية. كل من هذه الضغوط لها تأثيرات متعددة الأطراف، وبالتالي فهي معقدة في العمل الميكانيكي. إن الفهم الأفضل لاستجابات النبات لهذه الضغوط له آثار عملية على العلاجات والإدارة. كما تم تقديم سرد شامل للنهج التقليدية والحديثة للتعامل مع ضغوط الحرارة والجفاف. توفر المناقشة النقدية جنبًا إلى جنب حول الاستجابات البارزة واستراتيجيات الإدارة لهذين الإجهادين اللاأحيائيين المهمين نظرة ثاقبة فريدة للظواهر. يمكن أن يكون النهج الشامل الذي يأخذ في الاعتبار خيارات الإدارة المختلفة للتعامل مع الحرارة والجفاف في وقت واحد نهجًا مربحًا للجانبين في المستقبل.

Conservation tillage, particularly no tillage (NT), has been recognized as an efficient farming practice, particularly in dryland agriculture, as it significantly enhances crop yields, improves soil health, and contributes to environmental sustainability. However, the influence of NT on winter wheat radiation interception and utilization, biomass, and yield under NT in irrigated fields, especially under drip fertigation, is unclear. A field experiment was carried out for two growing seasons in Shandong province, China, using a split-plot design with the tillage method as the main plot (no tillage, NT; rotary tillage, RT; and first plowing the soil and then conducting rotary tillage, PRT), and water–nitrogen management as the sub-plot (N fertilizer broadcasting and flood irrigation, BF and drip fertigation, DF). Our results showed that DF increased yield by 11.0–28.5%, but the yield response to DF depended on the tillage methods. NT had the highest response in yield of 26.3–28.5%, followed by RT of 14.6–15.1% and PRT of 11.0–11.9%. Both increased grains per ear and ear number, a result of the greater maximum stems number donating to the yield gain by DF under NT. This gain was also due to the substantially promoted post-anthesis biomass (36.7–47.3%), which resulted from the increased interception of solar radiation and radiation use efficiency after anthesis. In addition, the extended post-anthesis duration also benefited biomass and yield. To conclude, our findings underscore the critical need to optimize water and nitrogen management strategies to maximize yield under conservation tillage systems.

The rice production system is one of the most climate change sensitive agro-ecosystems. This paper reviews the effects of current and future climate change on rice production in China. In recent decades, thermal resources have increased during the rice growing season, while solar radiation resources have decreased, and precipitation heterogeneity has increased. The increasing frequency of high-temperature stress, heavy rainfall, drought, and flood disasters may reduce the utilization efficiency of hydrothermal resources. Climate change, thus far, has resulted in a significant northward shift in the potential planting boundaries of single- and double-cropping rice production systems, which negatively affects the growth duration of single-, early-, and late-cropping rice. Studies based on statistical and process-based crop models show that climate change has affected rice production in China. The effects of climate change on the yield of single rice (SR), early rice (ER), and late rice (LR) were significant; however, the results of different methods and different rice growing areas were different to some extent. The trend of a longer growth period and higher yield of rice reflects the ability of China’s rice production system to adapt to climate change by adjusting planting regionalization and improving varieties and cultivation techniques. The results of the impact assessment under different climate scenarios indicated that the rice growth period would shorten and yield would decrease in the future. This means that climate change will seriously affect China’s rice production and food security. Further research requires a deeper understanding of abiotic stress physiology and its integration into ecophysiological models to reduce the uncertainty of impact assessment and expand the systematicness of impact assessment.

Land use/land cover (LULC) change has serious implications for environment as LULC is directly related to land degradation over a period of time and results in many changes in the environment. Monitoring the locations and distributions of LULC changes is important for establishing links between regulatory actions, policy decisions, and subsequent LULC activities. The normalized difference vegetation index (NDVI) has the potential ability to identify the vegetation features of various eco-regions and provides valuable information as a remote sensing tool in studying vegetation phenology cycles. Similarly, the normalized difference built-up index (NDBI) may be used for quoting built-up land. This study aims to detect the pattern of LULC, NDBI, and NDVI change in Lodhran district, Pakistan, from the Landsat images taken over 40 years, considering four major LULC types as follows: water bodies, built-up area, bare soil, and vegetation. Supervised classification was applied to detect LULC changes observed over Lodhran district as it explains the maximum likelihood algorithm in software ERDAS imagine 15. Most farmers (46.6%) perceived that there have been extreme changes of onset of temperature, planting season, and less precipitation amount in Lodhran district in the last few years. In 2017, building areas increased (4.3%) as compared to 1977. NDVI values for Lodhran district were highest in 1977 (up to + 0.86) and lowest in 1997 (up to - 0.33). Overall accuracy for classification was 86% for 1977, 85% for 1987, 86% for 1997, 88% for 2007, and 95% for 2017. LULC change with soil types, temperature, and NDVI, NDBI, and slope classes was common in the study area, and the conversions of bare soil into vegetation area and built-up area were major changes in the past 40 years in Lodhran district. Lodhran district faces rising temperatures, less irrigation water, and low rainfall. Farmers are aware of these climatic changes and are adapting strategies to cope with the effects but require support from government.

Nitrogen is a vital nutrient for agricultural, and a defieciency of it causes stagnate cotton growth and yield penalty. Farmers rely heavily on N over-application to boost cotton output, which can result in decreased lint yield, quality, and N use efficiency (NUE). Therefore, improving NUE in cotton is most crucial for reducing environmental nitrate pollution and increasing farm profitability. Well-defined management practices, such as the type of sources, N-rate, application time, application method, crop growth stages, and genotypes, have a notable impact on NUE. Different N formulations, such as slow and controlled released fertilizers, have been shown to improve N uptake and, NUE. Increasing N rates are said to boost cotton yield, although high rates may potentially impair the yield depending on the soil and environmental conditions. This study comprehensively reviews various factors including agronomic and environmental constraints that influence N uptake, transport, accumulation, and ultimately NUE in cotton. Furthermore, we explore several agronomic and molecular approaches to enhance efficiency for better N uptake and utilization in cotton. Finally, this objective of this review to highlight a comprehensive view on enhancement of NUE in cotton and could be useful for understanding the physiological, biochemical and molecular mechanism of N in cotton.

Solar radiation (SR) is essential for yield improvement in lentil, which is a crop of marginal environments. Herein, experiments were conducted over 2 years under a semi-arid environment to study the radiation interception (RI), efficiency, growth, and development of three lentil genotypes (Punjab Masoor-2009 (PM-2009), NIAB Masoor-2006 (NM-2006), and NIAB Masoor-2002 (NM-2002)) in relation to three nitrogen rates (13, 19, and 25 kg ha-1). Seasonal dynamics of intercepted photoactive radiation (IPAR) and cumulated photosynthetic photon flux density were highly associated with seasonal dynamics of leaf area index (LAI), with a high value of R2 (0.93 and 0.89) across all nitrogen rates and genotypes in both years. Nitrogen application promoted growth, and maximum LAI (3.97 and 3.57) and RI (324 and 301 MJ m-2) were attained for the first and second years of study, respectively. Biomass and yield were positively associated with IPAR. Variation in radiation absorption (RA) among genotypes was due to different patterns of LAI development. In both years, yield (23% and 25%) and radiation use efficiency (RUE) for grain yield (0.44 and 0.37 g MJ-1) were respectively higher for PM-2009 than for the other genotypes. Genotype PM-2009 had 15 days shorter crop cycle than others while 14% higher GDDs accumulated in the first year compared with the second due to the higher temperature. High nitrogen (25 kg ha-1) application resulted in higher dry matter (DM), and grain yield (GY), while RUE and PAR were not statistically different under 19 kg N ha-1 application across years. Genotypes PM-2009 and NM-2006 may perform reasonably well under arid to semi-arid regions at farmer field. These findings may assist researchers and crop modelers to optimize the lentil ideotype for efficient light utilization.

Currently, in most countries, the electricity sector is liberalized, and electricity is traded in deregulated electricity markets. In these markets, electricity demand is determined the day before the physical delivery through (semi-)hourly concurrent auctions. Hence, accurate forecasts are essential for efficient and effective management of power systems. The electricity demand and prices, however, exhibit specific features, including non-constant mean and variance, calendar effects, multiple periodicities, high volatility, jumps, and so on, which complicate the forecasting problem. In this work, we compare different modeling techniques able to capture the specific dynamics of the demand time series. To this end, the electricity demand time series is divided into two major components: deterministic and stochastic. Both components are estimated using different regression and time series methods with parametric and nonparametric estimation techniques. Specifically, we use linear regression-based models (local polynomial regression models based on different types of kernel functions; tri-cubic, Gaussian, and Epanechnikov), spline function-based models (smoothing splines, regression splines), and traditional time series models (autoregressive moving average, nonparametric autoregressive, and vector autoregressive). Within the deterministic part, special attention is paid to the estimation of the yearly cycle as it was previously ignored by many authors. This work considers electricity demand data from the Nordic electricity market for the period covering 1 January 2013–31 December 2016. To assess the one-day-ahead out-of-sample forecasting accuracy, Mean Absolute Percentage Error (MAPE), Mean Absolute Error (MAE), and Root Mean Squared Error (RMSE) are calculated. The results suggest that the proposed component-wise estimation method is extremely effective at forecasting electricity demand. Further, vector autoregressive modeling combined with spline function-based regression gives superior performance compared with the rest.