古地貌演化对洛阳盆地新石器中晚期至夏商时期水稻种植的影响

水稻是起源于中国南方长江流域的重要农作物,新石器中期以后传播到北方地区。由于北方较于南方相对干旱,因此对水分条件需求较高的水稻在北方地区的种植往往表现为更强烈的地域选择性。本文选取中原地区地形特征较为复杂的洛阳盆地开展了流域调查和浮选工作,结合前人在本区做的炭化植物遗存研究成果,分析了新石器中晚期至夏商时期洛阳盆地不同地貌部位水稻（Oryza sativa）遗存的分布特征,再根据本区平原区和黄土台塬沟谷区全新世地貌演化的不同特点,探讨了古地貌演化对洛阳盆地史前水稻种植的影响。研究表明,裴李岗文化时期暂未发现水稻遗迹,平原区湖沼遍布,不适宜人类居住,古人可能更倾向于居住在黄土台塬沟谷区的稳定阶地面上;仰韶文化晚期古稻主要分布在黄土台塬沟谷区,与当时沟谷区河流夹积形成的富含粘土的湿润冲积平原有关,而此时平原区距今7000~4000年为稳定干燥的T₁阶地面,更适合发展粟（Setaria italica）作农业;龙山时期没有在沟谷区发现水稻遗存,可能与距今4000年前后沟谷区河流下切侵蚀导致的泛滥平原减少有关,而龙山晚期在伊洛河平原区的遗址发现了古稻遗存,推测与龙山晚期降水增多和洪水频发,出现较多水洼低地有关;二里头时期,古稻在平原区和黄土台塬区都有分布且遗址数量较多,可能与距今4000~3800年龙山晚期古洪水事件后,洪水退去遗留的低洼地有关;二里头和二里岗时期,盆地内古稻遗址普遍增多,平原区古稻遗址可能占更大比重,推测可能与古地貌特征、人类文化自身发展,以及农田管理技术的进步等均有关系。

     

气候变化对我国南方双季稻发育和产量的影响

基于WOFOST作物模式,结合气候模式输出的气候情景资料,模拟研究了未来100a(2001-2100年)气候变化对我国南方双季稻发育和产量的影响。结果表明：未来气候情景下,我国南方大部分地区双季稻(早稻、晚稻)的生长期会有所缩短;产量可能会有所下降,但下降的幅度不是很大,其中早稻受气候变化的影响较大。     

GBW10010a大米标准物质复(研)制及数据特征

随着我国对生态文明建设的重视,自然资源综合调查势在必行,对生物标准物质亦提出了新的需求。当前相关调研工作已经大面积开展,自然资源综合调查、农产品与食品安全评价都需要对生物样品元素组成进行准确测试,需要以生物标准物质作为生物成分测试量值比对和溯源的基础,因此对生物基体标准物质的需求量大幅增加。大米作为主要粮食之一,其食品安全日益受到重视,对大米中的化学成分进行准确的分析测试具有重要的现实意义,因而对大米标准物质的需求量尤为突出,但目前大米成分分析标准物质已供不应求。本文严格按照《标准物质定值的通用原则及统计学原理》（JJF 1343—2012）和《地质分析标准物质的研制》（JJF 1646—2017）等相关规范要求,开展了GBW10010a大米成分分析标准物质的复（研）制工作,包括样品采集、加工制备、均匀性检验、稳定性检验、多家实验室协作定值测试及不确定度评定等关键环节。结果表明：本次复（研）制的大米标准物质定值成分多样、量值准确可靠,符合国家一级标准物质的要求。GBW10010a共定值54项主微量元素,包括Ag、Al、As、B、Ba、Be、Bi、Ca、Cd、Ce、Co、Cr、Cs、Cu、Dy、Er、Eu、Fe、Gd、Ge、Hg、Ho、K、La、Li、Ho、Mg、Mn、Mo、N、Na、Nb、Nd、Ni、P、Pb、Pr、Rb、S、Sb、Sc、Se、Si、Sm、Sr、Tb、Th、Tl、Tm、U、V、Y、Yb、Zn,其中的39项元素给出了标准值及不确定度,包括Ag、Al、As、B、Ba、Ca、Cd、Ce、Co、Cs、Cu、Dy、Er、Fe、Hg、K、Li、Mg、Mn、Mo、N、Na、Nd、Ni、P、Pb、Pr、Rb、S、Sb、Se、Si、Sm、Sr、Tb、Tl、Y、Yb、Zn;15项元素提供参考值,包括Be、Bi、Cr、Eu、Gd、Ge、Ho、Ho、La、Nb、Sc、Th、Tm、U、V。与原有GBW10010大米标准物质相比较,GBW10010a中As、Cd、Co、Cr、Cu、Hg、Mn、Mo、Ni、Zn等重金属元素含量显著下降,其中Cd、Cu、Zn降幅较大,分别下降约39%、43%、38.7%,一定程度上反映了农田生态环境的改善。本批标准物质定值元素总数量增加了6项,新增定值元素Ag、Nb（Nb给出参考值）,并且各项元素不确定度范围整体上有所缩小,如Al、Cd、Cu、Fe、K、Mg、Mo、Na、P、Pb、Se、Zn等对生物易有影响的重要元素,表明了地质分析测试方法技术的进步及定值水平的提高。本批标准物质定值元素涵盖了具有生物效应的大部分主微量元素,适用于农业生态环境地球化学调查与评价、生物样品测试、农产品质量与食品安全评价样品测试时的分析仪器校正、分析方法评价和分析质量监控等多个领域。     

广东省晚稻干旱灾害评估及其特征分析

利用广东省1960—2016年5—6月逐日降水量资料、1983—2016年全省及各市早稻产量资料、1994—2016年灾情资料等,首先应用数理统计方法,建立早稻产量与“龙舟水”期间（5月21日—6月20日）总降水量、降水量距平百分率与暴雨日数的相关关系;然后,采用个例分析法,建立“龙舟水”灾害对早稻产量影响评估模型,再利用评估模型对受“龙舟水”影响严重的2008年早稻单产减产率进行评估检验,其正确率超过75%。最后,确定“龙舟水”期间暴雨日数大于等于1 d且降水量距平百分率大于等于20%为早稻“龙舟水”灾害保险阈值,在此基础上,设计了“龙舟水”灾害保险气象理赔指数。

     

中国稻田甲烷产生和排放研究 Ⅰ.产生和排放机理及其影响因子

综合论述了近 2 0年来中国稻田甲烷排放的研究状况 ,包括中国稻田甲烷排放通量的观测 ,稻田甲烷生成的生物学机理及产生、转化、传输的机理研究 ,稻田甲烷排放的影响因子 ,主要介绍了稻田甲烷产生和氧化过程、影响甲烷排放的因子     

Percolation losses in paddy fields with a dynamic soil structure: model development and applications

The hydraulic characteristics of the plough pan of paddy fields provide continuous ponding conditions during the growing season and control the water use efficiency in wet rice production. Its saturated hydraulic conductivity K_s, however, exhibits a large spatiotemporal variability as a consequence of a highly dynamic soil structure involving temporary shrinkage cracks. Water flow through the earthen bunds surrounding the fields further contributes to the uncertainty in water flux calculations. The objective of this study was to develop a simple deterministic model with stochastic elements (‘PADDY‐FLUX’) for depiction of deep percolation, and to assess the effect of different water management scenarios on percolation in two channel command areas. Darcy's law is used as the fundamental equation for water flow calculations with the ponding water depth h as a time‐dependent variable. Flux uncertainty is estimated by a Monte‐Carlo‐type implementation. K_s is treated as a random variable of a bimodal probability density function (PDF), which is the weighted sum of two Gaussian PDFs (accounting for a matrix and a preferential flow domain). The weighing factor α is a function of h, reflecting an increasing risk for preferential flow situations after desiccation and the development of shrinkage cracks. Under‐bund percolation is calculated using transfer functions. The results demonstrate that percolation losses increase in the following order: continuous soil saturation < continuous flooding (CF) < mid‐season drainage and intermittent irrigation (MD + II) < mid‐season drainage and continuous flooding. The bunds contribute up to 54 and 17% to total fluxes under CF and MD + II, respectively. Preferential water fluxes are responsible for the major part of water losses as soon as desiccation causes the formation of shrinkage cracks. As a conclusion, continuous soil saturation should be promoted as the least water‐intensive irrigation regime, while intermittent irrigation is recommended only in case that irreversible shrinkage cracks have already developed. Copyright © 2010 John Wiley & Sons, Ltd.     

Is Larger Scale Better? Evidence from Rice Farming in Jianghan Plain

Small-scale household agricultural production has been in conflict with China’s agricultural modernization. In the context of vigorously promoting rural land circulation and moderate scale management nationwide, research on the relationship between farm size and scale efficiency has become increasingly important. In this paper, we use the “DEA-OLS” two stage method to analyze data from 368 surveys of rice farming households in the Jianghan Plain. The scale efficiency of rice farming was calculated, and the relationship between farm size and scale efficiency investigated. The results indicate that (1) the rice farm size is generally small in Jianghan Plain, with an average of 0.77 ha. The average scale efficiency is 0.88, and it is the main factor limiting an increase in comprehensive technical efficiency. Moreover, 88.32% of households are in the stage of increasing returns to scale. (2) There is a stable inverted “U” type relationship between rice farm size and scale efficiency. Considering characteristics of the householder, the household and land quality, the maximum scale efficiency corresponds to a household with 5 ha of rice farm. (3) Among householder characteristics, age has a significant negative influence on scale efficiency, and scale efficiency is lower for a household whose householder is engaged in non-farm work than for one whose householder is devoted to farming. As for land quality, there was a significant positive effect of irrigation on scale efficiency. Among family characteristics, the application of a machine during the seeding process increased scale efficiency by 3.07%. Therefore, we suggest that local government should actively promote rural land circulation, implement a staged-scale management subsidy, and other forms of support for the purchase of agricultural machinery and technical popularization. Increased investment in irrigation improvements and mechanical facilities and encouragement of farmers to enlarge their farm size could improve scale efficiency and farming profit and lead to the development of moderate scale management.     

Mangrove forest dynamics in Tanintharyi,Myanmar from 1989–2014, and the role of future economic and political developments

Mangrove forests in Southeast Asia provide many ecosystem services, though are experiencing extensive deforestation, especially in Myanmar. Recent political and economic reforms in Myanmar are projected to further increase development pressures on natural resources. Mangrove forests in the southern state of Tanintharyi have largely been spared clearance because of poor infrastructure and a volatile security situation, though this may change with plans for economic expansion. We quantified land cover dynamics and proximate drivers of mangrove deforestation in Tanintharyi between 1989 and 2014 using a remote sensing approach over five time intervals. Tanintharyi experienced low mangrove cover loss overall, as compared with other regions of Myanmar, with 3.2 per cent being deforested over 25 years. However, this statistic hides large site‐specific losses and gains, which varied significantly within the study area. Myeik district lost 210 km² of mangrove over 25 years, but also gained 132 km². Dawei and Kawthung had minimal net loss of mangroves because of extensive mangrove regeneration. This historical mangrove baseline is essential for supporting environmentally‐conscious development in Myanmar's southernmost state.     

近20年气候变暖对黑龙江省水稻增产的贡献

研究过去的气候变暖对作物产量的影响是认识变暖对农业影响的有效途径,但如何定量区分出气候变化和技术发展对粮食作物的影响程度是目前研究的难点。本文提出的算法在一定程度上可以克服传统算法缺陷,用此方法估算过去20年气候变暖对黑龙江省水稻单产增加的贡献率,结果表明：20世纪80年代相对于70年代水稻单产增加了30.6%,其中由气候变暖带来的增产量占实际增产量的12.8%~16.1%,相当于使70年代的单产增加3.9%~4.9%。20世纪90年代水稻单产较80年代增产42.7%,其中,气候变暖对单产增加的贡献率约为23.2%~28.8%,相当于在20世纪80年代的单产水平上增产9.9%~12.3%。     

中国南方调整水稻种植格局——一种水稻生产预先适应气候变化的选择(英文)

Rice planted in southern China accounts for 94% of the total in sown acreage and 88% of the total in production, which matters a lot to Chinese food security. However, due to the prolonged conflict between water availability and rice growth in spatial/temporal distribu-tion, rice production suffers from seasonal drought at acreage of 16%-22%, which compro-mises food production capacity and food security. Focusing on the spatial distribution of seasonal drought with rice and the practices to adapt to it, and based on an analysis of bal-anced water supply for and demand by rice at a growing season scale during 1981-2030, this paper assesses the changing seasonal drought in the process of rice production under the changing climate in the future, and identifies general rice re-cultivation options for climate change adaptation. Some conclusions can be drawn as follows. (1) Rice suggests a decline in seasonal drought, with early season rice (early rice hereafter) by 12,500 km2, middle season rice (middle rice) by 80,000 km2, and in particular late season rice (late rice) by 25,000 km2, which accounts for almost 20% of its cultivated acreage. It is indicated that due to climate change, seasonal drought in major rice producing areas tends to alleviate in general, late season rice in particular. (2) Future climate change brings about a significant impact on the spatial/temporal distribution of water resources in rice producing areas in China. Based on ’pre-designed’ adaptation actions for rice-re-cultivation, the rice cultivation pattern undergoes a significant alteration between 1981-2000 and 2001-2030. In eastern Guizhou and western Hunan, the pattern of single early plus single dry farming is changed into double cropping. In eastern Hunan, the pattern of dry cropping is changed into single early plus single dry farming. In northern Anhui, the pattern of dry farming cropping is changed into middle rice. All this is aimed at a potential adequate availability of water for rice production in the future. (3) Rice re-cultivation patterns developed in this paper help re-balance water demand and supply for rice growth using the spatial analysis tool to adapt rice growth to the changing water avail-ability from spatial perspective, and come up with rice producer-friendly re-cultivation options in response to climate change.