• Energy Research

AbstractVegetation growth is affected by past growth rates and climate variability. However, the impacts of vegetation growth carryover (VGC; biotic) and lagged climatic effects (LCE; abiotic) on tree stem radial growth may be decoupled from photosynthetic capacity, as higher photosynthesis does not always translate into greater growth. To assess the interaction of tree‐species level VGC and LCE with ecosystem‐scale photosynthetic processes, we utilized tree‐ring width (TRW) data for three tree species: Castanopsis eyrei (CE), Castanea henryi (CH, Chinese chinquapin), and Liquidambar formosana (LF, Chinese sweet gum), along with satellite‐based data on canopy greenness (EVI, enhanced vegetation index), leaf area index (LAI), and gross primary productivity (GPP). We used vector autoregressive models, impulse response functions, and forecast error variance decomposition to analyze the duration, intensity, and drivers of VGC and of LCE response to precipitation, temperature, and sunshine duration. The results showed that at the tree‐species level, VGC in TRW was strongest in the first year, with an average 77% reduction in response intensity by the fourth year. VGC and LCE exhibited species‐specific patterns; compared to CE and CH (diffuse‐porous species), LF (ring‐porous species) exhibited stronger VGC but weaker LCE. For photosynthetic capacity at the ecosystem scale (EVI, LAI, and GPP), VGC and LCE occurred within 96 days. Our study demonstrates that VGC effects play a dominant role in vegetation function and productivity, and that vegetation responses to previous growth states are decoupled from climatic variability. Additionally, we discovered the possibility for tree‐ring growth to be decoupled from canopy condition. Investigating VGC and LCE of multiple indicators of vegetation growth at multiple scales has the potential to improve the accuracy of terrestrial global change models.

Teak (Tectona grandis L.f.) plantations have increased recently in India; however, morphological descriptors for teak are still lacking. Thus, the goal of this work was to develop descriptors based on morphological characteristics. Among 30 seed sources collected from different states of India, 24 morphological descriptors, including leaf length, leaf width, presence of petiole, petiole length, leaf shape, shape of leaf apex, shape of leaf base, leaf texture, phyllotaxy, leaf attitude, leaf margin, leaf margin undulation, leaf brightness, leaf venation, leaf main vein, leaf veins, leaf vein color, leaf color, leaf pubescence, young leaf color, number of internodes, internodal length, trunk spots, and trunk color, were developed based on leaf and stem characteristics. These seed sources exhibited a difference in all traits except leaf shape, shape of leaf apex, leaf phyllotaxy, leaf margin, leaf venation, leaf main vein, and presence of trunk spots. The Jaccard similarity index was used to calculate the genetic similarity between the sources, and the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) method was used to perform a cluster analysis (four groups at a similarity of 0.5 were obtained). According to the observations made, most of the sources exhibited high similarity, which indicates that only a few characteristics can be used to distinguish the sources.

Los sistemas agrícolas mundiales se enfrentan a uno de los mayores desafíos de sostenibilidad: satisfacer la creciente demanda de alimentos sin dejar una huella ambiental negativa. Estados Unidos (EE. UU.) y China son las dos economías más grandes y representan el 39 % del total de las emisiones mundiales de gases de efecto invernadero (GEI) a la atmósfera. La labranza cero es una opción prometedora de gestión de la tierra que permite a la agricultura adaptarse mejor y mitigar los efectos del cambio climático en comparación con la labranza tradicional. Sin embargo, la eficacia de la labranza cero para mitigar los GEI sigue siendo discutible. En este metanálisis, evaluamos exhaustivamente el impacto de la labranza cero (en relación con la labranza tradicional) en el potencial de mitigación de GEI y la productividad de los cultivos en diferentes sistemas agroecológicos y regímenes de gestión en los EE. UU. y China. En general, la labranza cero en China no cambió el rendimiento de los cultivos, aunque las emisiones de CO2 (-8 %) y N2O (-12 %) del suelo disminuyeron significativamente, mientras que las emisiones de CH4 del suelo aumentaron en un 12 %. En contraste con la labranza cero china, se registró una mejora significativa en los rendimientos de los cultivos (hasta un 12 %) en las tierras de cultivo estadounidenses con labranza cero. Además, se observaron disminuciones significativas en las emisiones de N2O (-21 %) y CH4 (-12 %) del suelo. De los tres sistemas de cultivo, solo el trigo mostró una reducción significativa en las emisiones de CO2, N2O y CH4 en el sistema chino de labranza cero. En el caso de EE. UU., los sistemas de cultivo de arroz con soja y maíz sin labranza demostraron reducciones significativas de emisiones de N2O y CO2, respectivamente. Curiosamente, los rendimientos del maíz sin labranza en China y del arroz en Estados Unidos superaron a los de otros cereales sin labranza. En China, la labranza cero en suelos de textura media dio como resultado reducciones significativas en las emisiones de GEI y mayores rendimientos de los cultivos en comparación con otros tipos de suelos. En ambos países, es probable que los rendimientos de los cultivos relativamente más altos bajo la labranza cero regada frente a la no regada y las diferencias significativas de rendimiento en suelos de textura fina bajo la labranza cero estadounidense se deban a las reducciones sustanciales de N2O. En resumen, las disparidades de rendimiento de los cultivos de la labranza cero entre China y los EE. UU. se relacionaron con los efectos insignificantes en el control de las emisiones de CH4 y la mitigación exitosa del N2O, respectivamente. Este estudio demuestra exhaustivamente cómo el sistema de cultivo y las condiciones pedoclimáticas influyen en la efectividad relativa de la labranza cero en ambos países. Les systèmes agricoles mondiaux sont confrontés à l'un des plus grands défis de la durabilité : répondre à la demande croissante de nourriture sans laisser une empreinte environnementale négative. Les États-Unis et la Chine sont les deux plus grandes économies et représentent 39 % des émissions mondiales totales de gaz à effet de serre (GES) dans l'atmosphère. Le non labour est une option prometteuse de gestion des terres qui permet à l'agriculture de mieux s'adapter et d'atténuer les effets du changement climatique par rapport au travail du sol traditionnel. Cependant, l'efficacité du non-labour pour atténuer les GES est encore discutable. Dans cette méta-analyse, nous évaluons de manière exhaustive l'impact du non-labour (par rapport au travail du sol traditionnel) sur le potentiel d'atténuation des GES et la productivité des cultures dans différents systèmes agroécologiques et régimes de gestion aux États-Unis et en Chine. Dans l'ensemble, le non-labour en Chine n'a pas modifié les rendements des cultures, bien que les émissions de CO2 (−8 %) et de N2O (−12 %) du sol aient diminué de manière significative, tandis que les émissions de CH4 du sol ont augmenté de 12 %. Contrairement au no-till chinois, une amélioration significative des rendements des cultures (jusqu'à 12 %) a été enregistrée sur les terres cultivées américaines en no-till. De plus, des diminutions significatives des émissions de N2O (−21 %) et de CH4 (−12 %) du sol ont été observées. Sur les trois systèmes de culture, seul le blé a montré une réduction significative des émissions de CO2, N2O et CH4 dans le système chinois sans labour. Dans le cas des États-Unis, les systèmes de culture sans labour du riz de soja et du maïs ont démontré des réductions significatives des émissions de N2O et de CO2, respectivement. Fait intéressant, les rendements du maïs sans labour en Chine et du riz aux États-Unis ont dépassé ceux des autres céréales sans labour. En Chine, l'absence de labour sur les sols de texture moyenne a entraîné des réductions significatives des émissions de GES et des rendements agricoles plus élevés par rapport aux autres types de sol. Dans les deux pays, les rendements des cultures relativement plus élevés dans le no-till irrigué par rapport au no-till non irrigué et les différences de rendement significatives sur les sols à texture fine dans le no-till américain sont probablement dues aux réductions substantielles de N2O. En résumé, les disparités de rendement des cultures sans labour entre la Chine et les États-Unis étaient liées aux effets insignifiants sur le contrôle des émissions de CH4 et l'atténuation réussie du N2O, respectivement. Cette étude démontre de manière exhaustive comment le système de culture et les conditions pédoclimatiques influencent l'efficacité relative du non-labour dans les deux pays. Global agricultural systems face one of the greatest sustainability challenges: meeting the growing demand for food without leaving a negative environmental footprint. United States (US) and China are the two largest economies and account for 39 % of total global greenhouse gases (GHG) emissions into the atmosphere. No-till is a promising land management option that allows agriculture to better adapt and mitigate climate change effects compared to traditional tillage. However, the efficacy of no-till for mitigating GHG is still debatable. In this meta-analysis, we comprehensively assess the impact of no-till (relative to traditional tillage) on GHG mitigation potential and crop productivity in different agroecological systems and management regimes in the US and China. Overall, no-till in China did not change crop yields, although soil CO2 (−8 %) and N2O (−12 %) emissions decreased significantly, while soil CH4 emissions increased by 12 %. In contrast to Chinese no-till, a significant improvement in crop yields (up to 12 %) was recorded on US cropland under no-till. Moreover, significant decreases in soil N2O (−21 %) and CH4 (−12 %) emissions were observed. Of the three cropping systems, only wheat showed significant reduction in CO2, N2O and CH4 emissions in the Chinese no-till system. In the case of US, no-till soybean-rice and maize cropping systems demonstrated significant emission reductions for N2O and CO2, respectively. Interestingly, yields of no-till maize in China and rice in US exceeded those of other no-till cereals. In China, no-till on medium-texture soils resulted in significant reductions in GHG emissions and higher crop yields compared to other soil types. In both countries, the relatively higher crop yields under irrigated versus non-irrigated no-till and the significant yield differences on fine textured soils under US no-till are likely due to the substantial N2O reductions. In summary, crop yield disparities from no-till between China and the US were related to the insignificant effects on controlling CH4 emissions and successfully mitigating N2O, respectively. This study comprehensively demonstrates how cropping system and pedoclimatic conditions influence the relative effectiveness of no-till in both countries. تواجه النظم الزراعية العالمية أحد أكبر تحديات الاستدامة: تلبية الطلب المتزايد على الغذاء دون ترك بصمة بيئية سلبية. الولايات المتحدة والصين هما أكبر اقتصادين ويمثلان 39 ٪ من إجمالي انبعاثات غازات الدفيئة العالمية في الغلاف الجوي. عدم الحراثة هو خيار واعد لإدارة الأراضي يسمح للزراعة بالتكيف بشكل أفضل والتخفيف من آثار تغير المناخ مقارنة بالحراثة التقليدية. ومع ذلك، لا تزال فعالية عدم الحراثة للتخفيف من غازات الدفيئة قابلة للنقاش. في هذا التحليل التلوي، نقوم بتقييم شامل لتأثير عدم الحراثة (بالنسبة للحراثة التقليدية) على إمكانات التخفيف من غازات الدفيئة وإنتاجية المحاصيل في الأنظمة الإيكولوجية الزراعية المختلفة وأنظمة الإدارة في الولايات المتحدة والصين. بشكل عام، لم يغير عدم الحراثة في الصين غلة المحاصيل، على الرغم من انخفاض انبعاثات ثاني أكسيد الكربون (-8 ٪) وأكسيد النيتروز (-12 ٪) بشكل كبير، في حين زادت انبعاثات الميثان في التربة بنسبة 12 ٪. على النقيض من عدم الحراثة الصينية، تم تسجيل تحسن كبير في غلة المحاصيل (تصل إلى 12 ٪) في الأراضي الزراعية الأمريكية دون حراثة. علاوة على ذلك، لوحظ انخفاض كبير في انبعاثات أكسيد النيتروز (-21 ٪) والميثان (-12 ٪). من بين أنظمة الزراعة الثلاثة، أظهر القمح فقط انخفاضًا كبيرًا في انبعاثات ثاني أكسيد الكربون وأكسيد النيتروز والميثان في نظام عدم الحراثة الصيني. في حالة الولايات المتحدة، أظهرت أنظمة زراعة فول الصويا والأرز والذرة بدون حراثة انخفاضات كبيرة في انبعاثات أكسيد النيتروز وثاني أكسيد الكربون على التوالي. ومن المثير للاهتمام أن محاصيل الذرة الخالية من الحراثة في الصين والأرز في الولايات المتحدة تجاوزت محاصيل الحبوب الأخرى الخالية من الحراثة. في الصين، أدى عدم حراثة التربة متوسطة القوام إلى انخفاضات كبيرة في انبعاثات غازات الدفيئة وارتفاع غلة المحاصيل مقارنة بأنواع التربة الأخرى. في كلا البلدين، من المرجح أن تكون غلة المحاصيل الأعلى نسبيًا في ظل عدم الحرث المروية مقابل عدم الحرث المروية والاختلافات الكبيرة في الغلة على التربة ذات القوام الناعم في ظل عدم الحرث في الولايات المتحدة بسبب التخفيضات الكبيرة في أكسيد النيتروز. باختصار، كانت التفاوتات في غلة المحاصيل من عدم الحراثة بين الصين والولايات المتحدة مرتبطة بالتأثيرات الضئيلة على التحكم في انبعاثات الميثان والتخفيف بنجاح من أكسيد النيتروز، على التوالي. توضح هذه الدراسة بشكل شامل كيف يؤثر نظام المحاصيل والظروف المناخية للأطفال على الفعالية النسبية للحراثة في كلا البلدين.

Agroforestry integrates woody perennials with arable crops, livestock, or fodder in the same piece of land, promoting the more efficient utilization of resources as compared to monocropping via the structural and functional diversification of components. This integration of trees provides various soil-related ecological services such as fertility enhancements and improvements in soil physical, biological, and chemical properties, along with food, wood, and fodder. By providing a particular habitat, refugia for epigenic organisms, microclimate heterogeneity, buffering action, soil moisture, and humidity, agroforestry can enhance biodiversity more than monocropping. Various studies confirmed the internal restoration potential of agroforestry. Agroforestry reduces runoff, intercepts rainfall, and binds soil particles together, helping in erosion control. This trade-off between various non-cash ecological services and crop production is not a serious constraint in the integration of trees on the farmland and also provides other important co-benefits for practitioners. Tree-based systems increase livelihoods, yields, and resilience in agriculture, thereby ensuring nutrition and food security. Agroforestry can be a cost-effective and climate-smart farming practice, which will help to cope with the climate-related extremities of dryland areas cultivated by smallholders through diversifying food, improving and protecting soil, and reducing wind erosion. This review highlighted the role of agroforestry in soil improvements, microclimate amelioration, and improvements in productivity through agroforestry, particularly in semi-arid and degraded areas under careful consideration of management practices.

Global climatic energy balance has been increasingly altered by massive emissions of greenhouse gases (GHGs), such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), leading to a variety of natural disturbances in terrestrial ecosystems. Further, the increasing use of fossil fuels and the looming climate crisis have created an unprecedented urgency for the development of a biobased circular economy. Therefore, production of biofuels from plant biomass is currently seen as a promising source of renewable energy, ensuring sustainable development with minimal carbon footprint. Soil acidification is considered one of the major obstacles to crop production and a significant source of GHGs emissions, especially N2O, because acidification changes the physicochemical and biochemical properties of the soil. Dolomite (DM) is the most widely used countermeasure to neutralize soil acidity to improve crop productivity and control net fluxes of GHGs. Nevertheless, the extent of GHG emissions following the application of DM under different environmental conditions is still unclear. Therefore, in this context, we conducted a meta-analysis using 32 peer-reviewed publications to determine the effects of DM, climate zones, and soil properties on GHGs emissions. The results of the current meta-analysis show that DM application significantly increased CO2 emissions (30.34 %) and CH4 emissions (4.91 %), but reduced N2O emissions by 54.88 %. A significant effect of DM (>10 t ha−1) on CO2, CH4, and N2O emissions was also observed. Increasing soil pH increased CO2 and N2O emissions by 188.34 % and 49.78 %, respectively, while reducing CH4 emissions by 81.94 %. Most importantly, WFPS, soil textural class, soil C:N ratio, and climate zones were identified as key edaphic factors affecting the GHG emissions following the application of DM. Overall, this meta-analysis fills in the gaps regarding the impact of the application of DM on GHGs emissions in different climates, soil properties, and experimental conditions. In ...

Soil microorganisms provide valuable ecosystem services, such as nutrient cycling, soil remediation, and biotic and abiotic stress resistance. There is increasing interest in exploring total belowground biodiversity across ecological scales to understand better how different ecological aspects, such as stand density, soil properties, soil depth, and plant growth parameters, influence belowground communities. In various environments, microbial components of belowground communities, such as soil fungi, respond differently to soil features; however, little is known about their response to standing density and vertical soil profiles in a Chinese fir monoculture plantation. This research examined the assemblage of soil fungal communities in different density stands (high, intermediate, and low) and soil depth profiles (0–20 cm and 20–40 cm). This research also looked into the relationship between soil fungi and tree canopy characteristics (mean tilt angle of the leaf (MTA), leaf area index (LAI), and canopy openness index (DIFN)), and general growth parameters, such as diameter, height, and biomass. The results showed that low-density stand soil had higher fungal alpha diversity than intermediate- and high-density stand soils. Ascomycota, Basidiomycota, Mucromycota, and Mortierellomycota were the most common phyla of the soil fungal communities, in that order. Saitozyma, Penicillium, Umbelopsis, and Talaromyces were the most abundant fungal genera. Stand density composition was the dominant factor in changing fungal community structure compared to soil properties and soil depth profiles. The most significant soil elements in soil fungal community alterations were macronutrients. In addition, the canopy openness index and fungal community structure have a positive association in the low-density stand. Soil biota is a nutrient cycling driver that can promote better plant growth in forest ecosystems by supporting nutrient cycling. Hence, this research will be critical in understanding soil fungal dynamics, improving stand growth and productivity, and improving soil quality in intensively managed Chinese fir plantations.

Forest ecosystem carbon (C) storage primarily includes vegetation layers C storage, litter C storage, and soil C storage. The precise assessment of forest ecosystem C storage is a major concern that has drawn widespread attention in global climate change worldwide. This study explored the C storage of different layers of the forest ecosystem and the nutrient enrichment capacity of the vegetation layer to the soil in the Castanopsis eyeri natural forest ecosystem (CEF) present in the northeastern Hunan province, central China. The direct field measurements were used for the estimations. Results illustrate that trunk biomass distribution was 48.42% and 62.32% in younger and over-mature trees, respectively. The combined biomass of the understory shrub, herb, and litter layers was 10.46 t·hm-2, accounting for only 2.72% of the total forest biomass. On average, C content increased with the tree age increment. The C content of tree, shrub, and herb layers was 45.68%, 43.08%, and 35.76%, respectively. Litter C content was higher in the undecomposed litter (44.07 %). Soil C content continually decreased as the soil depth increased, and almost half of soil C was stored in the upper soil layer. Total C stored in CEF was 329.70 t·hm-2 and it follows the order: tree layer > soil layer > litter layer > shrub layer > herb layer, with C storage distribution of 51.07%, 47.80%, 0.78%, 0.25%, and 0.10%, respectively. Macronutrient enrichment capacity from vegetation layers to soil was highest in the herb layer and lowest in the tree layer, whereas no consistent patterns were observed for trace elements. This study will help understand the production mechanism and ecological process of the C. eyeri natural forest ecosystem and provide the basics for future research on climate mitigation, nutrient cycling, and energy exchange in developing and utilizing sub-tropical vegetation.

To overcome the limitations of soil fertility and provide high crop output, soil fertility management, including the sensible use of mixes of organic and inorganic fertilizers, is a realistic approach. The strategy of integrated nutrient usage was used since there was a decrease in soil characteristics and crop productivity as a result of the overuse of chemical fertilizers. The present study was designed in 2019–2020 and 2020–2021 at the high-tech unit, Department of Horticulture, Udaipur to investigate the integrated use of FYM and inorganic fertilizers along with silicon on the development and output parameters of cauliflower (Brassica oleracea var. botrytis L.). The field experiment was carried out with fourteen treatments as a soil application under randomized block design. The results revealed that treatment T14 (50% recommended dose of nitrogen by FYM + 50% recommended dose of fertilizers + 100 kg Silicon/ha) showed maximum plant height at harvest (65.73 cm), number of leaves per plant (24.27), leaf area index (11.83), chlorophyll content at 50 days after transplanting (1.99 mg/g), stalk length (8.23 cm) and stem girth (7.41 cm), minimum number of days to curd initiation after transplanting (66.37), minimum number of days required for marketable curd maturity after transplanting (89.17), maximum plant weight (1154.74 g), diameter of curd (15.75 cm), curd yield (277.53 q/ha) and dry weight of curd (91.41 g) as compared to control. In the end, the results showed that the growth and yield of cauliflower were better when silicon, manure, and chemical fertilizers were used together.