关键词： climate change   agricultural reservoir   design flood   uncertainty   interval estimation   non-parametric resampling   bootstrap technique  

摘要： Agricultural reservoirs play such a central role in supplying water to rural areas that it is essential to properly estimate the design flood for agricultural reservoirs under climate change. The objective of this study was to estimate the inflow design flood interval using a non-parametric resampling technique for agricultural reservoirs under climate change. This study suggested an alternative method to point estimation using insufficient past data by providing the interval of the inflow design flood under the representative concentration pathway. To estimate the interval of the inflow design flood, we employed the bootstrap technique, which estimated the confidence interval corresponding to the 95% confidence level. This study covered a spatial range of 30 agricultural reservoirs in South Korea and a temporal range of past and three future representative periods: the base period (2015s: 1986-2015) and future periods (2040s: 2011-2040, 2070s: 2041-2070, 2100s: 2071-2100). We analyzed the results of a 200-year return period and 24-hour duration as a representative case. For the 97.5th bias-corrected and accelerated percentile value, the overall inflow design floods were larger than the base period value (2015s) with the safety factor applied. The northern and midwestern regions of South Korea showed relatively greater changes than the southeastern region. Some agricultural reservoirs showed a decrease in the design flood during the 2040s but generally increased after the 2070s. Through the non-parametric resampling technique, the interval estimation was provided considering the uncertainty of the inflow design flood. By presenting the results for three periods, we can provide policymakers with information to select according to the target period. The findings may provide an essential step in replacing a safety factor used for determining the design flood of agricultural reservoirs with the confidence interval calculated in accordance with statistical characteristic

关键词： Agricultural practices   Climate change   Land use and land use change   Soil organic carbon  

摘要： Purpose Soil organic carbon (SOC) plays a key role in soil functioning and in greenhouse gas exchange with the atmosphere. Land use and land use changes can critically affect SOC. However, despite various methodological developments, there is still no scientific consensus on the best method to assess the holistic impact of land use and land use change within LCA. The SOCLE project aimed to review how SOC contribution to climate change is accounted for in LCA and to test the feasibility and sensitivity of best methodological options. Methods In total, five crop products (annual/perennial, temperate/tropical) and two livestock products were investigated through 22 scenarios of land use changes (LUC) and agricultural land management changes (LMC). Three methods were applied: IPCC Tier 1-2 (2006), Muller-Wenk and Brandao (2010) and Levasseur et al. (2012). We also carried out a sensitivity analysis on key variables, notably carbon stocks, reference states, and regeneration times. Results and discussion The accounting for LUC and LMC influenced greatly the results on the climate change impact. Compared to the impact of other GHG emissions, (i) LUC impacts ranged from - 23 to + 1702% with the IPCC method and from - 5 to + 336% with the Muller-Wenk and Brandao method, and (ii) LMC impacts from - 130 to + 54% and from - 31 to + 11%, respectively. The sensitivity analyses stressed the critical influence of all methodological and data choices on final results. Conclusions Based on the project results, we recommend accounting systematically for the impact of LULUC on climate change by applying,a minima, the comprehensive IPCC Tier 1 approach (2006), which provides default factors for SOC accounting. Where available, case-specific data should be used (e.g., Tier 2) for SOC stocks but also C:N ratio in order to model the degressive impact over 90% of the time period needed to reach equilibrium.

关键词： Pollen-spore   Cultural transformation   Agricultural adaptation   Nile flow   ITCZ   Holocene climate  

摘要： To investigate how Holocene climate patterns influenced the development of early Egyptian agriculture at the archaeological site of Sais on the Nile Delta, we conducted a palynological study. Seven palynological zones were defined to reveal Holocene climate fluctuations. Zone I (ca. 9000-7000 cal yr BP) was a period of warming climate, succeeded by a progressive drying climate phase in Zones II-VII (ca. 7000-2000 cal yr BP). Pollen records indicate Nile flooding prevailed before 7000 years ago, making the study area uninhabitable, before it later developed into a wetland setting. The earliest farming started at ca. 6700 cal yr BP, as indicated by the abrupt appearance of cereal (Poaceae > 35 mu m), during a time of climate warming (Zone III), This material can be differentiated from wild Poaceae (< 35 mu m), which occurs throughout the profile, indicating the cereal was introduced to this area for agriculture. Results further reveal the transformation of human activities, from passive adaptation to climate, to actively remolding the environment against the background of long-term drying. During the early farming stage (ca. 6700-5500 cal yr BP), climate-human indicators were synchronous in distribution, suggesting lower pressure from climate change on population growth;however, this reversed from ca. 5500 cal yr BP, as intensive agriculture was required to meet shortages of natural resources during climate drying. Perhaps, the best evidence for adaptation is the increased abundance of Azolla from ca. 4000 years ago, a fern that favours growing in still-water bodies, hinting that much more irrigation was required at the time to sustain societal development.

关键词： 覆盆子   气候变化   产量   影响   德兴市  

摘要： 基于1959—2019年气象站观测资料和2011—2020年覆盆子产量资料,分析了江西省德兴市农业气候变化及其对覆盆子产量的影响。结果表明,与覆盆子产量显著相关的气象因子分别为无霜期日数、稳定通过10℃初终日期间隔日数、稳定通过10℃积温、年极端最低气温和3月极端最低气温。5个气象因子总体呈上升趋势,但阶段性特征不同。稳定通过10℃积温在1980—1989年呈减少趋势,其他时段均呈增加趋势;年极端最低气温在1960—1969年和2000—2009年呈略下降趋势,其他时段呈升高趋势;1990年以前,无霜期日数、稳定通过10℃初终日间隔日数和3月极端最低气温总体呈下降趋势,对覆盆子生长不利,而1990年以后呈显著上升趋势,有利于覆盆子生长。

关键词： 田东   气候变化   农业生产   气候倾向率  

摘要： 利用田东县1965-2019年气温、降水及日照等资料,通过气候倾向率、线性回归分析等方法,分析近55a田东气候变化特征,并探讨对农业生产的影响。结果表明,近55a田东平均气温、最高气温,最低气温均明显上升;年降水日数、年日照时数均有所减少;高温、暴雨发生频率增加。气候变化将影响农作物产量,加剧病虫害危害,应采取措施降低其不利影响。

关键词： 大别山区   气候变化   农业气象灾害  

摘要： 利用六安地区近55年(1961—2015年)的气象资料和农业生产数据,分别从气候变化对农业气候资源、农业气象灾害以及农业产量的影响3个方面进行了研究分析。结果表明:(1)1961—2015年,大别山区出现了以变暖为主要特征的气候变化;(2)1955—2001年,大别山地区旱灾的发生率呈显著上升趋势;(3)水稻、小麦和油菜籽的种植面积年际波动大,表明气候变化对粮油生产的负面影响已经显现。

摘要： The principles of conservation agriculture are frequently assumed to increase soil organic carbon and crop yield under all circumstances. A new analysis confirms that this is not the case, and that the likelihood of increasing either soil organic carbon or crop yield is environmentally dependent. This is a commentary on Sun et al. 26, 3325–3335.

摘要： How does environmental heterogeneity affect natural selection on tree swallow nestlings? Houle et al. (2020) show that more precipitation and higher temperatures result in stronger selection on body mass and wing length and that agricultural intensity can affect the direction of selection. These findings raise the question of how genetic diversity changes under strong selection pressures, which will be especially important under ongoing agriculture intensification and climate change.

关键词： Evapotranspiration   SWAT model   RCP scenarios   Appropriate agricultural scale   Water-saving irrigation   Heihe agricultural region  

摘要： Evapotranspiration (ET) is the component of the hydrological cycle that accounts for most water consumption across the agricultural region of the Heihe River basin in Northwest China. It is of great practical importance in the basin to allocate water resources for ensuring the security of food production, and to formulate effective science-based agro-ecological management policies to address climate change impacts due to the probable effects of future changing environment on regional ET. In this study, the Soil and Water Assessment Tool (SWAT) model were first driven by the downscaled climate data from three IPCC representative concentration pathways (RCPs) that have been projected by five General circulation models (GCMs) in the Coupled model inter-comparison project phase 5 (CMIP5) and the water-saving irrigation scenario to project ET per unit area, we then added to the model the upper and lower limits of the appropriate agricultural scale that considered the ecological health to simulate the behaviour of total ET for the period 2021-2050. Finally 12 case study scenarios were used to separate the effects of climate change and human activity on total ET. The results showed that total ET can be significantly decreased by > 1.22 x 10(8) m(3) when the RCP-water-saving irrigation scenarios were combined with the appropriate agricultural scale. The results suggest that the best set of strategies to reduce agricultural water consumption is to reduce the area of arable land through consideration of ecosystem health and aggressively utilize water-saving agricultural technology to counter the increased ET brought about by future climate change in the Heihe agricultural region.