Spatial-Temporal Distribution Characteristics and Limiting Factors of Medium-low Yield Farmland in Tianjin

[Objective] This paper aimed to understand the area change and distribu- tion of medium-low yield farmland, and offered basis to the improvement of mediumlow farmland and its increase of grain production in Tianjin. [Method] Based on the statistical date of Tianjin and its relevant counties and districts, the yield standard was set up to classify high-yield, medium-yield and low-yield farmland in Tianjin. The author analyzed area change of medium-low yield farmland in six agricultural counties and districts （including Jixian County, Wuqing District, Baodi District, Ninghe County, Jinghai County and Dagang district of Binghai New Area） from 1980 to 2010. [Result] The results showed that the average yield of grain rose from 2 445 kg/hm^2 in 1980 to 5 130 kg/hm^2 in 2010, increasing 109.82%. The area of mediumlow yield farmland was reduced from 291 250.13 hm^2 in 1985 to 76 489.87 hm^2 in 2010, coming down 74%. In Tianjin, the area of medium-low yield farmland of 2010 accounted for 19% of the total farmland, of which the ratios of medium-low yield farmland of Jinghai County, Jixian County, Dagang district of Binghai New Area, Wuqing District, Baodi District and Ninghe County were 43.12%, 18.59%, 17.23%, 14.01%, 7.05% and 0, respectively. Low soil nutrient content, drought and water shortage, as well as soil salinization were the main yield limiting factors to mediumlow yield farmland in Tianjin in 2010. [Conclusion] The countermeasures to improve the medium-low yield farmland were proposed, involving enhancing the investment of the government, strengthening the construction of water conservancy infrastructure, further improving the soil fertility, as well as saline and alkaline land, optimizing the farming system and planting drought and salt tolerance crops, etc.

美国坯布市场动态

据美国棉布进口商最近宣称,自今年下半年以来,美国坯布市场上的进口坯布供应渐趋紧张,原因有二;1)主要棉坯布出口地区由于棉花和涤纶短纤维等原料价格大幅度上涨,而布价难以相应跟着上涨,布厂已陷入困境。

第十二届世界杯足球赛资料

(一)二十四国与世界杯足球赛今年参加西班牙第十二届世界杯足球赛最后阶段比赛的共有24个国家。它们参加前十一届世界杯比赛的情况怎样呢?最后统计以分数作表示,积分方法是:获得过世界杯足球赛冠军者得5分,获决赛权者得4分,获1/2决赛权者得3分,获1/4决赛权者得2分,参加决赛阶段比赛者得1分(见附表)。 (二)它们都是怎样出线的? 第12届世界杯足球比赛预选赛,自1980年3月26日起,于1981年1月10日全部结束,参加预选的共有107个队。

传承闽南文化 服务海西建设

漳州师范学院依据自身的地缘优势,多年来在科研与教学工作中,注重突出闽南文化特色。学校自1 994年起成立闽南文化研究所,2003年更名为闽台文化研究所。研究所成立后,经过多年的努力现已凝聚全院各系力量,大力开展闽南文化研究与两岸的文化交流工作,并取得了不斐的成绩。学校积极参与地方文化建设,服务"海西",并为海西建设培育各种人才。

Characteristics of Mulching Plastic Film Residue in Cotton Fields in the Yellow River Delta

In order to get a clear picture of distribution characteristics of mulching plastic film residue in cotton fields in the Yellow River Delta and make scientific pollution prevention and control strategies, an investigation was conducted in Dongying City. Five typical cotton fields were chosen, and then the number, distri- bution density and area of residual film were measured. The results showed that the residual film was 18. 84-53. 53 kg/hm^2 in cotton fields for more than 20 years, and the differences between fields were larger. The residual density was 225-340 thousand per hectare. There were great differences among residual pieces. The proportion of residual pieces over 25 cm^2 was 94. 1%, that between 100 cm^2 and 500 cm^2 was more than 50. 0%, and that bigger than 500 cm^2 was about 21. 0%. In the Yellow River Delta cotton region, large, thin and difficult to recovery were the main characteristics of mulching plastic film residue, and it had the possibility of mi- grating to deep soil. Thus, the ecological risk of mulching plastic film residue was higher. Key words The Yellow River Delta; Cotton field; Residue of mulching plastic film; Distribution characteristic

Effect of Land Reclamation on Nutrient Distribution in Reclaimed Farmlands Overlying Xuzhou Underground Coal Mines *1

This research was carried out to evaluate the effect of the reclamation procedure with respect to soil fertility and nutrient distribution pattern in the reprecipitated reclaimed soil. Although there was an obvious indication of low levels of essential nutrients in the reclaimed farmlands (organic matter=0.32 g kg -1 ,total N=380.8 mg kg -1 , available P=4.7 mg kg -1 ), compared to the undisturbed farmlands (organic matter=2.5 g kg -1 , total N=1 220 g kg -1 , available P=20.8 mg kg -1 ), the uneven pattern of nutrient distribution was also shown to have been the major limitation to successful reclamation. Further improvement can be achieved through the integration of intensive eco farming systems using proper fertilizer field correction (PFFC) and organic manure for successful reestablishment and management of newly reclaimed farmlands overlying the Xuzhou coal mine subsidence.

Technology and Practice of Stabiliing Oil Production and Controlling Water Cut in Kalamkas Oilfield in Central Asia

In this paper, by in-depth geological research of Kalamkas Oilfield in Central Asia, the geological body has been re-ascertained; combined with fine study of reservoir engineering, based on the understanding of the distribution of remaining oil horizontal wells have been given full play to stabilizing oil production and controlling water cut, reducing the producing pressure drop, improving well productivity and other advantages, and the development and deployment has been optimized; horizontal wells have been applied to solve problems such as old well casing damages, shutting down wells, low-productivity and low- efficiency wells, and high water cut wells to improve the utilization rate of old wells; through separate layer system improved injection production pattern, adjustment wells have been optimized and deployed, and part measures wells have been preferably selected to tap the residual oil improve the degree of reserves control realize the stabilization of oil production and control of water cut in an old oilfield, and further improve the development effects.

大雪要了将军命

唐穆宗长庆二年(822年)正月十一日,魏州(今河北大名东北)的魏博节度使府衙内,哭声一片。跪在大堂中央的戎装将领,一抬手,将手中的尖刀,刺入自己胸膛。自杀者即魏博节度使田布。他为何要自杀?田布的父亲是前魏博节度使田弘正。安史之乱结束后,投降的叛军将领被授予魏博、成德和幽州三镇的节度使,即“河北三镇”。

齐兵：脖上饰物见证变迁

想想这三十年,值得回忆和思考的事情多得数不过来,但是从我脖子上的"饰品",或许就能看出岁月的轨迹……红领巾:时隔多年,我依然清晰地记得——1984年的9月1日,我上一年级了!更为自豪的是,我戴上了红领巾,成为了一名少先队员,老师说,那是红旗的一角,蓝蓝的天空下国旗在飘扬,弯过头顶的胳膊还略带吃力,大大的太阳,现在想来还是那样,明晃晃的有些刺眼。我是个喜欢接受新事物的人,随着年级的增长,

声音

杨保军中国城市规划设计研究院副院长假如潜在危险化工产品放在居民区,就如同是个定时炸弹,爆炸的可能性也许很小,但你抱着炸弹睡觉踏实不踏实?田布雷华榕新能源国际投资董事局主席氢能技术改变了人类使用能源动力的方式,是新一轮产业升级和一场深刻而广泛的能源革命。未来能源结构中,氢能将扮演重要角色。

Profile Distributions of Dissolved and Colloidal Phosphorus as Affected by Degree of Phosphorus Saturation in Paddy Soil

Soil dissolved phosphorus (P) and colloidal P mobilization could be closely related to the degree of phosphorus saturation (DPS). Effects of a wide range of DPS on the distributions of dissolved P and colloidal P in a paddy soil profile were investigated in this study. Dissolved P and colloidal P in water-dispersible soil colloid suspension increased obviously with increasing DPS. The change point of DPS was at 0.12 by using a split-line model. Above the value, dissolved P (3.1 mg P kg-1 ) in soil profile would increase sharply and then transfer downward. Compared with dissolved P, colloidal P was the dominant fraction (78%-91%) of P in soil colloid suspension, and positively related to DPS without a significant change point. The high release of colloids in subsoils with low DPS was attributed to the low ionic strength and high pH value in subsoils. The DPS also had a significant and positive correlation with electrical conductivity (EC), but it showed a negative correlation with pH value. However, the concentration of colloidal P was not greatly correlated to the pH value, EC and optical density of the soil colloid suspension. The results indicated that DPS was an important factor that may affect the accumulation and mobilization of water-extractable colloidal P and dissolved P.

Spatiotemporal distribution and historical evolution of polders in the Dongting Lake area, China

Dongting Lake is the largest lake in the middle reaches of the Yangtze River in China. For centuries, people inhabiting the Dongting Lake area have been reclaiming land and constructing dams for flood resistance, agricultural production, and rural settlement, forming geographical entities known as polders. In this study, the regional spatial distributions of polders in the Dongting Lake area in 1949, 1998, and 2013 were obtained using historical maps and modern remotely sensed data, revealing changes since the establishment of the People's Republic of China. Nanxian County was then selected to demonstrate polder changes at the county level, because it has undergone the most dramatic changes in the area. Different polder change models for the Datonghu, Yule, and Renhe polders were analyzed for eight periods: 1644(the early Qing Dynasty), 1911(the late Qing Dynasty), 1930(the Republic of China), 1949(the People's Republic of China), 1963, 1970, 1998, and 2013. Three resulting polder evolution models are: 1) reclaiming polders from lakes, 2) integrating polders by stream merging, and 3) abandoning polders for flood release. The polder evolution models demonstrate the wisdom of local people in using land resources according to the specific regional conditions. Throughout their long-term historical evolution, the spatial distribution of polders in the Dongting Lake area tended to be homogeneous, and the degree of human disturbance tended to be stable. However, a shift occurred, from pure polder area growth or removal to more comprehensive management and protection of the regional environment.

Use of brGDGTs in surface geochemical exploration for petroleum —A case study of oil and gas fields in the Jiyang depression

Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker compounds.In this study,brGDGTs were used to explore the relationship between the absolute abundance of brGDGTs and the distribution of oil and gas fields in the Duoshiqiao area of the Jiyang depression.The results showed that the concentrations at the Xiakou fault and in the oil and gas fields were obviously higher than those in the contrast areas.The clear relationship among the concentration of brGDGTs,the distribution of oil and gas fields,and the acidolysis hydrocarbon(ethane)indicates that the concentration effectively responds to hydrocarbon seeps from the oil and gas field below.brGDGTs may become some of the most important indicators in surface geochemical prospecting for oil and gas.

Mapping paddy rice with multi-date moderate-resolution imaging spectroradiometer (MODIS) data in China

The objective of this study was to obtain spatial distribution maps of paddy rice fields using multi-date moderate-resolution imaging spectroradiometer(MODIS) data in China.Paddy rice fields were extracted by identifying the unique char-acteristic of high soil moisture in the flooding and transplanting period with improved algorithms based on rice growth calendar regionalization.The characteristic could be reflected by the enhanced vegetation index(EVI) and the land surface water index(LSWI) derived from MODIS sensor data.Algorithms for single,early,and late rice identification were obtained from selected typical test sites.The algorithms could not only separate early rice and late rice planted in the same fields,but also reduce the uncertainties.The areal accuracy of the MODIS-derived results was validated by comparison with agricultural statistics,and the spatial matching was examined by ETM+(enhanced thematic mapper plus) images in a test region.Major factors that might cause errors,such as the coarse spatial resolution and noises in the MODIS data,were discussed.Although not suitable for monitoring the inter-annual variations due to some inevitable factors,the MODIS-derived results were useful for obtaining spatial distribution maps of paddy rice on a large scale,and they might provide reference for further studies.

Heavy Metal Contamination of Agricultural Soils in Taiyuan, China

To evaluate the current state of the environmental quality of agricultural soils in Taiyuan City, a hotspot for China's industrial development, the concentrations of 8 heavy metals in soils were investigated by means of extensive sampling in farmlands, forestlands,and grasslands in the city. Statistical analyses and spatial distribution maps were used to identify the most significant heavy metal pollutants. The mean concentrations of As, Cd, Cu, Hg, Pb, Zn, Ni, and Cr were slightly higher than their background values in Taiyuan's topsoil, but were lower than the maximum permissible concentrations in the Chinese Environmental Quality Standard for agricultural soils. Farmland soils in Taiyuan had the highest average Cd, Cu, Hg, Pb, Zn, and Cr concentrations, but the As and Ni concentrations did not differ significantly among the farmland, forestland, and grasslands. Soil contamination by Cd, Cu, Hg, Pb,Zn, and Cr was mainly derived from farming practices, especially the use of sewage water for irrigation. In contrast, As and Ni might derive mainly from the soil parent material. The identification of heavy metal sources in agricultural soils may provide a basis for taking appropriate action to protect soil quality.