Responding to common questions on the conservation of agricultural heritage systems in China

Although the urgency of their conservation has been recognized, Globally Important Agricultural Heritage Systems (GIAHS) designated by the Food and Agriculture Organization (FAO) since 2002 and China Nationally Important Agricultural Heritage Systems (China- NIAHS) certified by the Ministry of Agriculture (MOA) of China since 2012 are faced with questions as to why to conserve them, what is to be conserved, who should conserve them, and how? This paper attempts to clarify and respond to such questions focusing on the conservation of agricultural heritage systems in China based on a review of both theoretical and practical progress. Agricultural heritage systems exhibit a multitude of values for sustainable and equitable development and therefore should be conserved for both present and future generations. Unlike most conventional heritages, the conservation of agricultural heritage systems is a complex, systematic “engineering” in which both physical and biological components and associated socio-cultural processes should be conserved in a dynamic way. Farmers and heritage sites must benefit from the continuance of traditional agricultural production under the premise of ecological functions being sustained and traditional culture being inherited. For a more effective conservation, a multi- stakeholder process should be established involving governments at different levels, multi-disciplinary scientists, communities and farmers, and business enterprises as well as social organizations. As has been demonstrated, the conservation of agricultural heritage systems aims to promote the regional sustainable development, to improve the livelihood, food security and well-being of farm people, and to provide references for the development of modern agriculture in China.     

Stream profile analysis,tectonic geomorphology and neotectonic activity of the Damxung‐Yangbajain rift in the south Tibetan Plateau

The Damxung‐Yangbajain rift is one of the most active north–south trending rifts in the south Tibetan Plateau, and it has been playing an important role in accommodating the east–west extension of the Tibetan Plateau. Both stream profiles on the Nyainqentanglha Range adjacent to the northwest part of the Damxung‐Yangbajain rift and tectonic geomorphology in the north of the rift are analyzed to assess the spatial pattern and intensity of rock uplift which is related to neotectonic activity. A total of 85 stream profiles across the Nyainqentanglha Range are analyzed, and 111 knickpoints are interpreted. Most of these stream profiles are characterized by prominent convexities with two or more knickpoints, many of which are formed due to the strong rock uplift evidenced by abnormal concavity and extremely high steepness indices during the Quaternary. Neotectonic activity in this region is well replicated in the stream profile indices and offset landforms. Tectono‐geomorphic analysis shows that the concavity and steepness indices correlate with the fault movements at many places. The Damxung‐Yangbajain rift is characterized by left‐lateral strike‐slip in the north of Damxung and by normal movement in middle and southern parts. The middle and southern parts have been undergoing higher uplift than has the northern area. It is most likely that the strong uplift is related to the heat flow under the crust. Earthquakes occurring in the Damxung‐Yangbajain rift, including a M8 in 1411 and M6.6 in 2008, are thought to be related to heat flow activity. All of the stream profile indices and tectonic geomorphology show that the Damxung‐Yangbajain rift is not in a stable state. Copyright © 2016 John Wiley & Sons, Ltd.     

巴丹吉林沙漠边缘地区植被特征

通过在巴丹吉林沙漠野外植被调查,描述了植被的生活型和群落的空间分布特征,分析了植被多样性、优势度及均匀度指数,并探讨了历年来气候变化对植被分布的影响。结果表明：（1）巴丹吉林沙漠植物种类较少,可分为小乔木、灌木、小灌木、半灌木、多年生草本和一年生草本6类生活型。其中灌木种类最为丰富,小乔木最少。（2）巴丹吉林沙漠东南一带物种丰富度和多样性高于西北一带,南缘地区植被群落分布及植被群落多样性亦均高于北缘地区。（3）近53 a巴丹吉林沙漠气温发生显著变化,蒸发量增加。南缘地区增温而降水减少。这种变化对于以水分为主导因子的沙漠地区植被发育来说极为不利,有加剧沙漠南缘荒漠化的威胁。     

Joint return probability analysis of wind speed and rainfall intensity in typhoon-affected sea area

Strong wind and rainfall induced by extreme meteorological processes such as typhoons have a serious impact on the safety of bridges and offshore engineering structures. A new bivariate compound extreme value distribution is proposed to describe the probability dependency structure of annual extreme wind speed and concomitant process maximum rainfall intensity in typhoon-affected area. This probability model takes full account of the case that there may be no rainfall in a typhoon process. A case study based on the observation data of typhoon maximum wind speed and maximum rainfall intensity in Shanghai is conducted to testify the efficiency of the model. Weibull distributions with two parameters are applied to fit respective probability margins, and the joint probability distribution is constructed by Gumbel–Hougaard copula. The fitting results and K–S tests show that these models describe the original data well. The joint return periods are calculated by Poisson bivariate compound extreme value distribution we have proposed. They indicate that typhoons with no rain have smaller joint return periods, and wind speed is the main factor which impacts the change of the joint return periods.     

Effects of landscape patterns on soil erosion processes in a mountain–basin system in the North China

This study was taken up to investigate the effects of landscape patterns on the soil erosion processes in a mountain–basin watershed. The revised universal soil loss equation and sediment delivery distribution models were used to estimate the soil erosion processes. The landscape patterns include the landscape metrics at the landscape level, landscape composition and configuration indicators on the basis of source–sink landscape theory. In the study area, the grassland, bare land, farmland and construction land were the sediment-source landscape; the forest and shrub were the sediment-sink landscape. The correlation analysis results showed that the soil erosion processes were significantly associated with the landscape patterns of the study area. At the landscape level, fragmentation metric was positively correlated with soil erosion; diversity metric was negatively related to soil erosion and sediment yield at the sub-basin scale. Among the source–sink landscape composition and configuration indicators, the composition indicator was positively correlated with soil erosion rate and sediment yield. In the configuration landscape indices, the shape index was negatively correlated with soil erosion rate and sediment yield; the fragmentation index was positively correlated with soil erosion rate and negatively correlated with sediment delivery rate. These results indicated that the optimization measures, such as increase in the area, connectivity and regularity of sediment-sink landscape, or decrease in the proportion, connectivity and regularity of sediment-source landscape, were favorable for soil conservation. Furthermore, the landscape indicators based on the source–sink theory could provide more information for landscape pattern optimization to reduce soil erosion.     

强非线性和色散性Boussinesq方程数值模型检验

采用同位网格有限差分法,建立了强非线性和色散性Boussinesq方程数值计算模型。以稳恒波Fourier近似解给定入射波边界条件,对均匀水深深水和浅水域不同非线性的行进波、缓坡地形上深水至浅水域的浅水变形波、以及缓坡和陡坡地形上的波浪水槽实验进行了数值计算,并将计算结果与解析解、解析数值解以及实验值进行了较为详细的比较,从而检验了模型的色散性、非线性以及不同底坡下非线性波的浅水变形性能。     

施肥对盐沼沉积物微生物生物量和细菌群落组成的影响

The effects of nitrogen(N) addition on microbial biomass, bacterial abundance, and community composition in sediment colonized by Suaeda heteroptera were examined by chloroform fumigation extraction method, real-time quantitative polymerase chain reaction, and denaturing gradient gel electrophoresis(DGGE) in a salt marsh located in Shuangtai Estuary, China. The sediment samples were collected from plots treated with different amounts of a single N fertilizer(urea supplied at 0.1, 0.2, 0.4 and 0.8 g/kg(nitrogen content in sediment) and different forms of N fertilizers(urea,(NH_4)_2SO_4, and NH_4NO_3, each supplied at 0.2 g/kg(calculated by nitrogen).The fertilizers were applied 1–4 times during the plant-growing season in May, July, August, and September of 2013. Untreated plots were included as a control. The results showed that both the amount and form of N positively influenced microbial biomass carbon, microbial biomass nitrogen, and bacterial abundance. The DGGE profiles revealed that the bacterial community composition was also affected by the amount and form of N.Thus, our findings indicate that short-term N amendment increases microbial biomass and bacterial abundance,and alters the structure of bacterial community.     

Implementation methods and economic impacts of national node strategies

Pilot reforms gradually implemented through key nodes have become an important pattern of regional development in China since the policy of reform and opening up was introduced in 1978. On the basis of an analysis of the evolution processes and characteristics of regional development policies in post-reform China, this paper develops the concept and analytical framework of national node strategies (NNS), defined as regional development strategies centered on specific spatial nodes, by addressing their theoretical basis and research scope. The regional economic impacts of NNS were explored quantitatively through the examples of the Shenzhen Special Economic Zone, Pudong New Area and Tianjin Binhai New Area in different stages of the reform and opening up. The results indicate that the evolution of China’s regional development policies can be divided into three stages: the exploration stage led by Special Economic Zones (SEZs), the expansion stage dominated by Economic Development Zones and the optimization stage featuring State-level New Areas and National Comprehensive Reform Pilot Areas. During all the three stages, NNS have played an important demonstrative and leading role and promoted the rapid evolution of China’s regional development policies from localized to widespread implementation, and the role of the government has also changed accordingly. As an innovative application and development of the growth pole theory in transitional China, NNS have become engines of regional development as well as important conduits of institutional innovations. NNS and regional development have achieved a benign coupling and formed a gradated regional development model. Empirical research indicates that NNS are an important method used by the government to guide and regulate regional economic development, with complex and diverse economic effects that differ depending on the stage of regional development and the spatial scale of analysis.     

苏州第四纪深厚沉积层一维等效线性和非线性地震反应对比分析

合理描述土体动力本构关系对场地设计地震动参数取值的准确性有显著影响。以苏州城区200 m深的钻孔剖面为研究对象,对比分析了一维等效线性波传分析法（ELA法）和基于修正Matasovic本构模型的多自由度集中质量非线性分析法（NLA法）给出的深厚场地地震反应,研究了基岩输入地震动特性和地震基岩面的选取对深厚场地地震反应的影响。结果表明：（1）随基岩地震动强度（PGA）的增大,ELA法给出的地表PGA呈单调递增的特征,而NLA法给出的地表PGA呈先快速增大后缓慢减小或几乎不变的趋势;（2）ELA法和NLA法给出的地表加速度反应谱（Sa谱）在短周期范围内存在明显差异,ELA法对基岩高频地震动具有显著的滤波效应,而NLA法对基岩高频地震动的影响表现为随基岩PGA的增大先放大后减小的特征;（3）随地震基岩面深度的增大,地表Sa谱的谱值呈现出稍许增大的趋势,但对周期T<0.1 s部分,NLA法给出的地表Sa谱的谱值则呈现出稍许减小的现象;（4）中、大震作用下,地表地震动持时不仅与基岩地震动特性有关,还与地震反应分析方法和地震基岩面的选取密切相关,NLA法能更合理地反映基岩地震动强度和上覆土层厚度对地表地震动持时的影响。     

新疆北部地区二叠系幔源碳酸岩质喷积岩研究*

新疆北部地区的二叠纪芦草沟期发育陆内裂谷型欠补偿湖盆,形成了中二叠统芦草沟组的重要烃源岩系。该烃源岩系中夹有一套以深源碎屑为特征的新型沉积组合,即薄层、纹层状地幔岩浆—热液喷流型沉积岩——喷积岩。本文报道的碳酸岩质喷积岩包括喷爆岩和喷溢岩2种类型。碳酸岩质喷爆岩厚0.5~4 cm,岩石以微粒晶质方解石矿物为碎屑,方解石碎屑颗粒呈大小不一、形态各异的角砾状,星散分布于黑色基质中,并显示粒序特征;碳酸岩质喷溢岩多呈2~4 mm厚的纹层和2~3 cm厚的薄层被夹于黑色含油沉凝灰岩、含油凝灰质泥晶白云岩等纹层岩中。纹层中的方解石具有典型的镶嵌粒状结构、环带结构。喷爆岩中方解石的流体包裹体测温高达435 ℃以上;C-O、Sr-Nd同位素显示碳酸岩质喷积岩中的方解石源自地幔,但受到湖水的较大影响。研究表明,本区的碳酸岩质喷积岩是一种源自地幔的碳酸岩质岩浆—热物质流体喷发、溢流入湖底,与湖水混合沉积而成的一类新型沉积岩。