广东江门水稻品质与地质地球化学关系研究   总被引：2，自引：0，他引：2  

朱鑫 《江苏地质》2014,38(2):302-308

重点开展了江门水稻种植区的生态地球化学调查。系统采集了全区表层土壤、稻谷及配套根系土样品,实测了营养、有益元素以及大米营养品质含量。通过开展生态地球化学评价,查明了影响水稻品质的主要地质地球化学因素,建立了特色农产品地质地球化学模型,开展了农产品适宜性评价和区划。  相似文献   

晋西北地区马铃薯生态需水量对气候变化的响应   总被引：3，自引：0，他引：3  

郭伟  ;阳伏林  ;张荣  ;赵丽平  ;郝振荣 《干旱气象》2014,(4):516-520

基于晋西北地区8个地面气象站1960~2010年的气象资料及马铃薯生育期平均资料,运用P-M公式,计算了马铃薯生态需水量,分析了生态需水量的时间演变特征及其对气候变化的响应。结果表明:晋西北地区马铃薯生态需水量整体上呈显著下降趋势,但不同时段下降幅度差异较大;风速和日照时数的变化对马铃薯生态需水量的影响最为突出。气候变暖对该地区马铃薯生态需水量的影响表明,气温的升高会增加马铃薯的需水量,且不同地区需水量的增幅不尽相同,气候变暖对寒冷地区马铃薯需水量的影响更加显著。  相似文献   

DIETARY PHOSPHORUS REQUIREMENT OF YOUNG ABALONE, HALIOTIS DISCUS HANNAI INO.     

谭北平  麦康森  刘付志国 《中国海洋湖沼学报》2002,20(1)

ＩＮＴＲＯＤＵＣＴＩＯＮＰｈｏｓｐｈｏｒｕｓｉｓａｎｅｓｓｅｎｔｉａｌｄｉｅｔａｒｙｎｕｔｒｉｅｎｔｆｏｒｌｉｖｉｎｇｏｒｇａｎｉｓｍｓａｎｄｈａｓａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｃｅｌ ｌｕｌａｒｆｕｎｃｔｉｏｎ ,ａｓｉｔｉｓａｎｉｍｐｏｒｔａｎｔｃｏｍｐｏｎｅｎｔｏｆｎｕｃｌｅｉｃａｃｉｄｓ,ｐｈｏｓｐｈｏｌｉｐｉｄ ,ｐｈｏｓｐｈｏｐｒｏｔｅｉｎｓ,ＡＴＰａｎｄｓｅｖｅｒａｌｉｍｐｏｒｔａｎｔｅｎｚｙｍｅｓ,ａｎｄｃｏｅｎｚｙｍｅｓ.Ｉｎａｄｄｉｔｉｏｎ ,ｐｈｏｓｐｈａｔｅｓｅｒｖｅｓａｓａｂ…  相似文献   

Estimation of groundwater use by crop production simulated by DSSAT‐wheat and DSSAT‐maize models in the piedmont region of the North China Plain     

Yonghui Yang  Masataka Watanabe  Xiying Zhang  Xiaohua Hao  Jiqun Zhang 《水文研究》2006,20(13):2787-2802

Sustainable water use is in serious crisis in the piedmont region of the Taihang Mountains in the North China Plain, owing to rapid groundwater drawdown. Estimating the water requirement for agriculture, the biggest user of groundwater, will be helpful in understanding groundwater decline. Through the use of DSSAT‐3·5 wheat and maize models, we assessed water use in winter wheat and maize, two staple crops in the region, in 1987–2001. Trends between groundwater change and simulated agricultural water use were compared. The results showed that groundwater decline was sensitive to simulated crop water requirement and irrigation requirement. According to regression analysis, 100 mm of water requirement by cultivated land (mainly wheat and maize) resulted in about 0·64 m of groundwater decline. This relationship might be useful in understanding the regional water balance and to help decision‐makers control groundwater decline through controlling crop water use or through long‐distance water transfer. The study demonstrated the usefulness of using the DSSAT model for estimating crop water use and the effectiveness of clarifying the reason for groundwater decline using the simulation results of water use. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Advances in the Study on Nutrient Requirements of Grouper（Epinephelus sp. ）：a Review   总被引：1，自引：0，他引：1  

LUOZhi LIUYongjian MAIKangsen TIANLixia 《中国海洋大学学报(英文版)》2005,4(2):93-98

The paper reviews the recent advances in studying grouper nutrition requirement for the development of cost-effective and environmentally friendly artificial diets. It consists of seven parts: protein and amino acid, lipid and essential fatty acid, carbohydrate, vitamin, mineral, alternative protein source, broodstock and larval nutrition. The review provides some basic information for further investigation of nutrient requirements of groupers.  相似文献   

电子政务空间信息服务:需求、技术与应用   总被引：9，自引：2，他引：7  

刘纪平  王亮 《测绘科学》2006,31(2):54-56

本文总结了空间信息服务的现状,讨论了电子政务与空间信息服务的关系,提出了电子政务空间信息服务的要求,讨论了空间信息服务关键技术,介绍了电子政务空间信息服务的应用情况。  相似文献   

水资源约束下的阿克苏河流域适宜绿洲规模分析   总被引：2，自引：0，他引：2  

王志成  蒋军新  方功焕  陈忠升  蔡明  李卫红 《冰川冻土》2019,41(4):986-992

阿克苏绿洲是中纬度干旱区典型的绿洲灌溉系统,制定绿洲适宜发展规模、明确适宜耕地面积,可为实现绿洲的生态稳定与可持续管理提供科学依据。以中国西北干旱区的阿克苏河流域为研究对象,基于作物需水量和绿洲适宜面积模型的水热平衡法,借助典型绿洲结构模型,计算了阿克苏绿洲的适宜耕地面积。结果表明：2010-2015年阿克苏灌区的作物需水量高达740.3 mm,较20世纪60年代的539.6 mm增加了37.2%;考虑到山区来水和下泄塔里木河干流的水量要求,阿克苏绿洲的可用水量为42.6×10⁸ m³;阿克苏河流域绿洲已处于不稳定状态,耕地面积超过了水资源承载能力。计算得出绿洲适宜规模为12 430 km²,与现有水平相当。基于作物需水量和绿洲适宜面积模型的水热平衡算法计算的阿克苏绿洲的适宜耕地面积分别为4 674 km²和4 211 km²,需要在当前耕地水平上退耕18%至26%。  相似文献   

The Geography of Malnutrition     

Ty Beal  Daniel Ervin 《The Professional geographer》2018,70(1):47-59

The purpose of this article is to provide an overview of an emerging theme within the subfield of nutritional geography we call the geography of malnutrition. Work relating to malnutrition is a high-priority research topic, with growing relevance to geographical concepts, but there is no overview of geographical approaches to this theme. Using keyword searches in Google Scholar and Web of Science to obtain relevant publications, we identified the major foci of work within this theme: undernutrition, diseases that cause malnutrition, the nutrition transition, and critical and feminist approaches to malnutrition. We review these foci, provide examples of prominent work, and identify areas of research concerning malnutrition that are highly spatial but have yet to be effectively studied using geographic techniques.  相似文献   

2006-2015年内蒙古呼伦湖富营养化趋势及分析   总被引：4，自引：1，他引：3  

梁丽娥  李畅游  史小红  赵胜男  田野  张立杰 《湖泊科学》2016,28(6):1265-1273

以内蒙古呼伦湖为研究对象,20062015年水质数据为基础,分析呼伦湖的富营养化变化趋势及其影响因素.结果表明,20062015年呼伦湖各水质指标都有不同程度的变幅,其中盐度变化范围为0.75~1.71 ng/L,均值为1.32 ng/L,2010年达到峰值1.71 ng/L,随后呈现逐年递减趋势;pH的变化范围为8.78~9.40,水体偏碱性;透明度的变化范围为0.17~0.26 m,近三年来透明度持续下降;溶解氧浓度变化范围为4.05~10.62 mg/L,均值为7.12 mg/L.总氮浓度的变化范围为1.16~3.53 mg/L,总磷浓度的变化范围为0.13~0.25 mg/L,叶绿素a浓度的变化范围为3.31~10.36 mg/m³,N/P比变化范围为4.92~15.35,水质已经达到地表水环境质量Ⅳ~Ⅴ类水体标准,是磷限制性湖泊.利用综合营养状态指数法对呼伦湖水体富营养化进行评价,2006-2015年呼伦湖水体表现出中度—重度—中度—轻度的变化趋势.通过分析呼伦湖富营养化的影响因素,结果表明,影响呼伦湖富营养化的可能因素为外源输入和入湖径流量,同时水深和水温也是呼伦湖发生富营养化的驱动因素,pH、透明度和溶解氧是呼伦湖富营养化影响水质的最主要表现指标.  相似文献   

Simultaneous Bromate and Nitrate Reduction in Water Using Sulfur‐Utilizing Autotrophic and Mixotrophic Denitrification Processes in a Fixed Bed Column Reactor          下载免费PDF全文

Sevgi Demirel  İbrahim Uyanık  Adem Yurtsever  Hakan Çelikten  Deniz Uçar 《洁净——土壤、空气、水》2014,42(9):1185-1189

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