提高耕地质量保障粮食安全———关于建设高标准基本农田的思考

1997年亚洲金融危机爆发后,我国经济发展逐渐由复苏走上繁荣,随着各项建设开工,全国耕地由1997年的19.49亿亩迅速减少到2007年的18.26亿亩,10年减少1.23亿亩.为此,时任国务院总理温家宝在2007年的全国两会期间提出,"一定要守住全国耕地不少于18亿亩这条红线",自此我国进入了"保发展,保红线"的"双保"时期,通过实行严格的耕地占补平衡制度,多年以来我国耕地数量一直稳定在18.26亿亩左右.不可否认,一部分占补平衡补充的耕地质量很难达到占用耕地的粮食生产能力,继续实施以数量平衡为侧重点的耕地保护已经无法确保我国粮食安全.     

中国耕地变化区的气候背景对比分析

研究我国耕地变化区的气候背景,对于了解耕地资源的生产能力,评价耕地占补平衡政策的实施效果,实现耕地资源保护和粮食安全等具有重要意义。本文在分析全国耕地空间变化的基础上,从年平均气温、年降水量和日照时数三个方面,研究耕地增加区和减少区的气候背景,并将其进行比较和分析,以期为国家保护耕地资源和发展农业生产等提供建议。研究结果表明,20世纪80年代末至2008年4个时段,耕地减少区比耕地增加区的年平均气温高0.45~1.05℃,年降水量高56.77~79.59mm,年日照时数少45.80~98.83h。耕地显著减少区比耕地显著增加区的年平均气温高0.81~1.85℃,年降水量高85.69~305.26mm,年日照时数少86.96~207.85h。在四个时段中,我国耕地重心逐渐北移且海拔升高。若海拔高度不变,耕地增加区比耕地减少区北移0.5-1个纬度,耕地显著增加区比耕地显著减少区北移1-2个纬度;若纬度不变,耕地增加区比耕地减少区,海拔升高100~200m,耕地显著增加区比耕地显著减少区,海拔升高150~350m。随年份增加,耕地增加区和显著增加区与耕地减少区和显著减少区在水分条件上的差别越来越大。这些结论对于研究我国粮食生产能力、评价耕地占补平衡、调整产业布局等具有重要意义。     

2005-2008年中国耕地变化对区域生产潜力的影响

我国人多地少,粮食安全问题一直是国家关注的头等大事。而耕地资源与粮食生产能力是保障粮食安全的基础,因此,研究中国耕地变化对区域生产潜力产量的影响具有重大的现实意义,可以为国家相关决策提供科学依据。本研究基于2005-2008年最新的气象观测数据和卫星反演数据,并结合2005、2008年耕地数据及其变化数据,从耕地资源的数量变化与质量特征两方面,研究2005-2008年耕地变化对我国全境内光温生产潜力的影响。研究结果显示:在耕地的变化过程中,光温生产潜力增加区与减少区产量变化不对等:增加区增加785.14万t,减少区减少2543.61万t,净减少1758.47万t;增加区与减少区光温生产潜力单产不对等:增加区平均光温生产潜力单产为11.89t/hm²,减少区平均光温生产潜力单产为20.99t/hm²,后者约为前者的2倍;增加区与减少区空间分布不同:增加区主要分布在新疆、黑龙江、内蒙古、宁夏、青海等西北、东北地区,生态用地开垦是其增加的主要原因,占77.25%,减少区主要分布在江苏、安徽、山东、广东等黄淮海平原、长江三角洲、珠江三角洲地区,建设用地占用耕地是其减少的主要原因,占69.20%。     

浅议士地整理与土地生态保护

土地是我们人类赖以生存的最基本的生产和生活资料,随着经济的发展和城市化进程的加快,耕地这一重要的生产资料正在迅速地减少,保护耕地已经成为一个全球性的问题。我国耕地总面积19-51亿亩,人均耕地1.59亩,为世界人均耕地的43％,其中,有7个省级地区人均耕地不足1亩,有400多个县级地域人均耕地不足0.5亩;我国的耕地总体质量水平低,大量耕地属于中低产田,而优质高产田只占少数,有灌溉设施和水源保证的耕地只占耕地总面积的39.8％;     

滨州市耕地保护现状及措施研究

1 滨州市耕地资源利用现状及特点 1．1 耕地总量大,人均多 滨州市地处黄河三角洲腹地,土地资源丰富。2006年,全市农用地625357hm^2,占土地总面积的66％,其中耕地437952hm^2,占农用地的70％,在耕地中,水浇地面积369862hm^2,占耕地面积的84．4％,是最主要的耕地类型;旱地次之,占耕地面积的13．7％。     

东营市东营区实施土地开发整理的措施与思考

近年来,东营区针对全区土地资源“一少一多”的实际（即：耕地总量少,总面积29588．15hm2,占土地总面积的25．6％,人均耕地仅有0．12hm2,而且中低产田占耕地总量的55．5％;耕地后备资源多,宜农土地面积8540hm2）,精心组织土地开发整理,有效增加耕地面积,扎实推进社会主义新农村建设,取得了显著成效。2003年,东营区在福建漳州召开的全国土地开发整理会议上作了经验交流;2006年10月,非洲十国考察团到东营区考察学习土地开发整理经验做法;2007年被评为全省土地开发整理工作先进单位,才利民副省长到牛庄镇1133．33hm2（1．7万亩）土地开发整理项目现场进行调研,给予了充分肯定。     

省厅要闻

正青海省耕地占补平衡方式新规明年起施行根据国家对耕地保护的新要求,结合青海省耕地占补平衡实际,8月6日,省国土资源厅下发《关于切实做好耕地占补平衡工作的通知》,将青海省补充耕地落实占补平衡的方式,由2007年以来实行的省级统筹调整为依法由申请用地者自行落实。——明确耕地占补平衡责任主体。从2015年1月1日起,所有建设项目占用的耕地,由市(自治州)、县人民政府通过实施土地整治项目等方式自行落实占补平衡。     

青海省土地开发整理现状及存在的问题

青海宜农后备土地资源大多分布在柴达木盆地,海南台地及河湟流域的荒地和滩地上。耕地后备资源总量为249691.6公顷,占全省土地总面积的0.35％。其中海东地区12808.9公顷,占宜农耕地后备土地资源的5.13％;海西州167860.5公顷,占67.23％;海南州60464.7公顷,占24.22％;海北州8197.53公顷,占3.28％;玉     

全国农业普查公报：全国耕地面积18．266亿亩

国家统计局等三部门日前公布的第二次全国农业普查主要数据第6号公报显示,截至2006年10月31日,全国耕地面积（未包括香港、澳门特别行政区和台湾省的数据）为121775．9千公顷（合18．266亿亩）。从地区分布情况看,西部地区分布的耕地较多,占369％;东部地区、中部地区和东北地区分别占217％、23．8％和17．6％。从耕地类别看,旱地面积比重较大,占55．1％;水田和水浇地面积分别占26．0％和18．9％。从坡度等级情况看,0-15度的耕地比重最大,占8715％;15—25度、25度以上的耕地分别占9．2％和3．3％。这一数据采用国土资源部2006年度的土地变更调查结果,国务院第二次全国农业普查领导小组办公室会同国土资源部、国家统计局进行了耕地面积数据事后质量核实。国家统计局公布的年度统计公报显示,     

耕地占补平衡发展趋势与对策建议

<正>耕地占补平衡制度是保护耕地的一项基本制度,它是指建设项目占用耕地时,须按照"占多少,补多少"的原则补充数量和质量相当的耕地,以确保耕地数量不减少、质量不降低。自1998年《中华人民共和国土地管理法》修订后近二十年来,耕地占补平衡制度在保障发展用地和保护耕地,遏制耕地锐减,实现耕地总量动态平衡和保障国家粮食安全等方面做出了历史性的贡献。     

Assessment of the ecological security in the three gorges reservoir area by using the ecological footprint method

The ecological footprint concept and its calculation models are useful for the measurement of the sustainable level of social and economic development.The ecological security situation of the Three Gorges Reservoir Area(TGRA) was evaluated using this concept in this study.The construction of the Three Gorges Reservoir has led to the change in the ecology and immigration status of TGRA.The ecological footprint method is an important means to study the regional ecological security.Our results suggested that,by excluding the areas for biodiversity conservation(12% of the total land),the ecological footprint per capita was 0.57895 ha,which exceeded the ecological carrying capacity in TGRA.The total ecological deficit was found to be 11,522,193.34 ha,accounting for 95.02% of the ecological carrying capacity.These findings suggested that the ecological security of TGRA was not good.In order to compensate for the ecological deficit,it was essential to introduce natural resources from other regions.     

Effect of cropland occupation and supplement on light-temperature potential productivity in China from 2000 to 2008

There are more people but less land in China,so food safety has always been a most important issue government concerned.With continuous population increase,economic development and environment protection,cropland occupation and supplement are unavoidable.It not only leads to the variation of cropland area,but also makes the light-temperature potential productivity per unit area different due to regional climate differentiation,therefore impacts the total potential productivity and food output eventually.So,it is necessary to analyze the climate differentiation between occupation and supplement cropland areas and to study its impact on total potential productivity,which is significant to reasonably develop natural resources and instruct agricultural arrangement.This study firstly discussed the variation and distribution of occupation and supplement croplands in China from 2000 to 2008,then analyzed the climate differentiation between occupation and supplement cropland areas and its effect on light-temperature potential productivity.The results demonstrate:1) From 2000 to 2008,the cropland variation presented occupation in the south and supplement in the north,but overall decreased.Supplement cropland was mainly from ecological reclamation(77.78%) and was mainly distributed in Northeast China and Northwest China with poor climatic and natural conditions.Occupation cropland was mainly used for construction(52.88%) and ecological restoration(44.78%) purposes,and was mainly distributed in the Huang-Huai-Hai Plain,and the middle and lower reaches of the Changjiang(Yangtze) River with better climatic and natural conditions.2) The climate conditions were quite different in supplement and occupation cropland areas.The annual precipitation,annual accumulated temperature and average annual temperature were lower in the supplement cropland area,and its average po-tential productivity per unit was only 62% of occupation cropland area,which was the main reason for the decrease of total potential productivity.3) Cropland occupation and supplement led to the variation of total potential productivity and its spatial distribution.The productivity decreased in the south and increased in the north,but had a net loss of 4.38315×107 t in the whole country.The increase of cropland area was at the cost of reclaiming natural forest and grassland resources,and destroying natural ecological environment,while the decrease of cropland area was mainly due to a lot of cropland occupied by urban-rural construction,which threatened the sustainable use of cropland resources.     

淡水鲳池塘一年二季养成试验

利用南方年平均温度高、生长期长的有利的自然条件,池塘中主养淡水鲳,一年养成二季商品鱼。第一季淡水鲳鱼种4月初放养,每公顷放养7500尾,平均规格12.17g;第二季鱼种在7月底前放养,每公顷放养4185尾,平均规格16.67g。每季淡水鲳上市规格均达500g以上,每公顷净产9511.8Kg。     

ANALYSIS AND MODELING ON CULTIVATED LAND CONVERSION —— Case Study of Hebei Province

1INTRODUCTION With the acceleration of the urbanization and industrial- ization of China, it is inevitable that cultivated land con- vertsto built-up land for industrial, commercial and resi- dential uses. During 1986- 2002 around 168.4×103ha cultivated land had converted to non-agriculture use an- nually (QU et al., 2005). Though the urbanization rate had increased from 17% in the late 1970s to 41% in 2004, China has a long way to go compared with the de- veloped countries whose urbani…     

Identification of agricultural systems in the mountains of Northeast Thailand

Agricultural systems in Thailand’s northeastern mountains are described in terms of their type of crops, marketing channels, and labor requirements. Five distinctive systems are identified: The Field crop system, Fruit tree system, Industrial tree plantation system, Specialty crop system and Agro-tourism system. The different systems are compared with each other in order to identify their respective strengths and weaknesses as development models. The Field crop system covers the largest area of agricultural land and is found in all mountainous villages but it generates very low net profits per hectare. The Specialty crop system and Agro-tourism system generate very high net profits per hectare but cover only a small land area and have a restricted spatial distribution. Expansion of these high value systems may be limited because they are capital and labor intensive and require highly skilled farmers to manage them successfully. If these constraints can be overcome, they may offer a useful model for mountain agricultural development.     

Response of the distributary channel of the Huanghe River estuary to water and sediment discharge regulation in 2007

The water and sediment discharge regulation (WSDR) project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe (Yellow) River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m³/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m³/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the river status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the river mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m³/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of “To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment”.     

2000-2010年新疆陆地生态系统变化格局与分析

本文以Landsat TM/ETM+数据和HJ-1卫星CCD数据,系统分析了2000-2010年新疆地区陆地生态系统变化。10年间,新疆地区建设用地、农田和湿地生态系统迅速扩张,分别增加了30.5%、26.7%和10.2%;草地与灌丛生态系统则大量减少,分别减少了2.4%和5.1%;冰川积雪减少也较为明显,减少了1.6%;荒漠和森林生态系统变化较小。生态系统变化热点区域主要分布在传统绿洲区,尤其是天山南北麓的绿洲区。水利设施改善与灌溉节水技术进步,以及国家西部开发战略导致灌草地被大量开垦为农田,人口增长则是建设用地增加的主因;全球气候变暖使冰川积雪减少明显,20世纪60年代至今面积减少了16.7%~32.5%,导致山区湿地生态系统增加;国家生态环境保护工程则有效地遏制了林地与荒漠生态系统的恶化趋势。山地水源涵养区除了要严格控制森林砍伐外,还要严格禁止灌草的开垦,控制绿洲农田的增加和重视生态过渡带的保护,并加强全球气候变化对新疆水资源影响的研究,以制定相关对策。     

Land Cover Changes and Drivers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China from 2000 to 2015

The Middle Route of the South-to-North Water Diversion Project(MR-SNWDP)in China,with construction beginning in 2003,diverts water from Danjiangkou Reservoir to North China for residential,agriculture and industrial use.The water source area of the MR-SNWDP is the region that is most sensitive to and most affected by the construction of this water diversion project.In this study,we used Landsat Thematic Mapper(TM)and HJ-1 A/B images from 2000 to 2015 by an object-based approach with a hierarchical classification method for mapping land cover in the water source area.The changes in land cover were illuminated by transfer matrixes,single dynamic degree,slope zones and fractional vegetation cover(FVC).The results indicated that the area of cropland decreased by 31%and was replaced mainly by shrub over the past 15 years,whereas forest and settlements showed continuous increases of 29.2% and 77.7%,respectively.The changes in cropland were obvious in all slope zones and decreased most remarkably(–43.8%)in the slope zone above 25°.Compared to the FVC of forest and shrub,significant improvement was exhibited in the FVC of grassland,with a growth rate of 16.6%.We concluded that local policies,including economic development,water conservation and immigration resulting from the construction of the MR-SNWDP,were the main drivers of land cover changes;notably,they stimulated the substantial and rapid expansion of settlements,doubled the wetlands and drove the transformation from cropland to settlements in immigration areas.     

HYDROCHEMICAL STATE OF INTERMEDIATE CULTURE POND FOR CHINESE PRAWN JUVENILES

This study deals with the hydrochemical state and management measures for the intermediate culturepond for Chinese prawn (Penaeus orientalis) juveniles. The test result showed that the intermediate cultureof Chinese prawn juvenile can be advanced to around March 20 in the Shanghai area if they are culturedin ponds in simple greenhouses of plastic knitting cloth.The density of juveniles introduced was about35 million per hectare, survival was up to 55%.     

Cropland physical disturbance intensity: plot-scale measurement and its application for soil erosion reduction in mountainous areas

Various kinds of human disturbances on cropland are the main reasons for soil erosion and land degradation. Farming practices in mountainous areas vary greatly among cropland plots because of the heterogeneity of biophysical conditions and differences in farmers’ management behavior. The main purpose of this paper is to develop a composite index of cropland physical disturbance intensity (CLDI) to reflect the plot-scale discrepancy of potential soil erosion in mountainous areas. The study was based on both plot survey and household interview data, collected from six typical catchments in mountainous areas of southwestern China. Four kinds of physical disturbance practices and two kinds of conservation practices during one crop rotation period were synthesized to develop the CLDI index. The rough set theory was referenced to avoid subjectivity during weight allocation. The results show that conventional tillage, deep fertilization, and manual weeding are the main causes of cropland soil erosion, whereas manure application in combination with seasonal fallow reduces soil erosion. Different crop types as well as cropland location factors determine the spatial pattern of CLDI. Crop rotation modes with major crops of tobacco and maize resulted in a maximal CLDI, and cropland plots with a distance radius of 150 meters away from households received the most intensive physical disturbance. These results are critical to help better protect rural environments in mountainous areas. Based on the results, methods to reduce cropland soil erosion are suggested.