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991.
利用1980-2012年间的统计数据,对辽宁省主要作物播种面积变化规律进行分析。结果表明:农作物播种总面积呈现小幅度增加的趋势,主要是随粮食作物播种面积的增加而增加的。粮食播种面积基本稳定,近年略有增加,主要是由水稻和玉米面积增加导致的;经济作物表现为波动趋势,其中油料作物呈现出较为强烈的波动,主要是由花生和向日葵面积变化导致的。 相似文献
992.
随着社会经济快速发展,环境问题日趋严重,经济发展与环境保护之间的矛盾凸显。环境伦理教育在实现环境与经济"双赢"过程中发挥着重要作用。本研究论述了环境伦理的理论基础,提出了环境伦理教育实施的主要途径和模式,展望了环境伦理教育的发展趋势。 相似文献
993.
Phosphorus change point indicating the threshold related to P leaching, largely depends on soil properties. Increasing data have shown that biochar addition can improve soil retention capacity of ions. However, we have known little about weather biochar amendment influence the change point of P leaching. In this study, two soils added with 0, 5, 10, 20, and 50 g biochar kg-1 were incubated at 25℃ for 14 d following adjusting the soil moisture to 50% water-holding capacity (WHC). The soils with different available P values were then obtained by adding a series of KH2PO4 solution (ranging from 0 to 600 mg P kg-1 soil), and subjecting to three cycles of drying and rewetting. The results showed that biochar addition significantly lifted the P change points in the tested soils, together with changes in soil pH, organic C, Olen-P and CaC12-P but little on exchangeable Ca and Mg, oxalate-extractable Fe and Al. The Olsen-P at the change points ranged from 48.65 to 185.07 mg kg-1 in the alluvial soil and 71.25 to 98.65 mg kg^-1 in the red soil, corresponding to CaCl2-P of 0.31-6.49 and 0.18-0.45 mg L~, respectively. The change points of the alluvial soil were readily changed by adding biochar compared with that of the red soil. The enhancement of change points was likely to be explained as the improvement of phosphate retention ability in the biochar-added soils. 相似文献
994.
YE Qing ;YANG Xiao-guang ;LIU Zhi-juan ;DAI Shu-wei ;LI Yong ;XIE Wen-juan ;CHEN Fu 《中国农业科学(英文版)》2014,(7):1546-1554
Based on climate data from 254 meteorological stations, this study estimated the effects of climate change on rice planting boundaries and potential yields in the southern China during 1951-2010. The results indicated a signiifcant northward shift and westward expansion of northern boundaries for rice planting in the southern China. Compared with the period of 1951-1980, the average temperature during rice growing season in the period of 1981-2010 increased by 0.4°C, and the northern planting boundaries for single rice cropping system (SRCS), early triple cropping rice system (ETCRS), medium triple cropping rice system (MTCRS), and late triple cropping rice system (LTCRS) moved northward by 10, 30, 52 and 66 km, respectively. In addition, compared with the period of 1951-1980, the suitable planting area for SRCS was reduced by 11%during the period of 1981-2010. However, the suitable planting areas for other rice cropping systems increased, with the increasing amplitude of 3, 8, and 10%for ETCRS, MTCRS and LTCRS, respectively. In general, the light and temperature potential productivity of rice decreased by 2.5%. Without considering the change of rice cultivars, the northern planting boundaries for different rice cropping systems showed a northward shift tendency. Climate change resulted in decrease of per unit area yield for SRCS and the annual average yields of ETCRS and LTCRS. Nevertheless, the overall rice production in the entire research area showed a decreasing trend even with the increasing trend of annual average yield for MTCRS. 相似文献
995.
Spatio-Temporal Changes in the Rice Planting Area and Their Relationship to Climate Change in Northeast China:A Model-Based Analysis 总被引:3,自引:0,他引:3
XIA Tian ;WU Wen-bin ;ZHOU Qing-bo ;YU Qiang-yi ;Peter H Verburg ;YANG Peng ;LU Zhong-jun ;TANG Hua-jun 《中国农业科学(英文版)》2014,(7):1575-1585
Rice is one of the most important grain crops in Northeast China (NEC) and its cultivation is sensitive to climate change. This study aimed to explore the spatio-temporal changes in the NEC rice planting area over the period of 1980-2010 and to analyze their relationship to climate change. To do so, the CLUE-S (conversion of land use and its effects at small region extent) model was ifrst updated and used to simulate dynamic changes in the rice planting area in NEC to understand spatio-temporal change trends during three periods: 1980-1990, 1990-2000 and 2000-2010. The changing results in individual periods were then linked to climatic variables to investigate the climatic drivers of these changes. Results showed that the NEC rice planting area expanded quickly and increased by nearly 4.5 times during 1980-2010. The concentration of newly planted rice areas in NEC constantly moved northward and the changes were strongly dependent on latitude. This conifrmed that climate change, increases in temperature in particular, greatly inlfuenced the shift in the rice planting area. The shift in the north limit of the NEC rice planting area generally followed a 1°C isoline migration pattern, but with an obvious time-lag effect. These ifndings can help policy makers and crop producers take proper adaptation measures even when exposed to the global warming situation in NEC. 相似文献
996.
997.
辽宁省大洼县50年气候变化特征分析 总被引:1,自引:0,他引:1
利用大洼县1961~2010年的气温、降水、日照等资料,统计分析该县50年气候变化特征。结果表明,近50年大洼县全年及春、夏、秋、冬季四季平均气温总体呈上升趋势,以冬季增温最为明显;降水全年及春、夏、冬季有增多的趋势,秋季有减少的趋势,夏季降水量增幅最大;全年及四季的日照变化明显呈减少趋势,其中夏季日照时数减少幅度最大。 相似文献
998.
对农村居民点整理的现实潜力进行合理的评估,是指导农村居民点整理及落实增减挂钩政策的重要步骤。该研究以东乡县为例,建立农村居民点整理潜力模型,从自然因素、整理需求和整理能力3个方面选取地形、交通条件、地方财政收入等8个指标,构建综合评价指标体系,计算综合修正系数,求取全县农村居民点整理的现实潜力。结果表明:东乡县各乡镇综合修正系数介于0.220~0.881;2020年农村居民点整理现实潜力为1 066.78 hm2。研究认为,农村居民点整理顺序,应按照现实潜力的大小在时空上进行合理安排。 相似文献
999.
利用SPSS软件对太原市气温、降水量和日照进行分析,制作趋势图和5阶多项式拟合曲线图,指出太原市气候变化的主要特点,研究气候变化对太原市农业产生的影响,针对其不利影响提出应对策略,为适应和降低气候变化对农业的影响提供科学依据. 相似文献
1000.
以二氧化硫(SO2)、二氧化氮(NO2)和可吸入颗粒物(PM10)作为评价因子,利用模糊综合评价法对安徽省大气环境质量进行了评价与分析.结果表明,可吸入颗粒物是安徽省的首要污染物,但铜陵市有所不同,首要污染物为二氧化硫.模糊综合评价显示,安徽省大气环境受到一定程度的污染,16个市中黄山市的大气环境综合质量最好.近年来,安徽省大气环境质量有所改善,但改善幅度较小. 相似文献