坡耕地现状及治理的探索与实践

坡耕地其实是在生产条件相对落后的山区,因人口增长同土地资源减少矛盾当中衍生出来的产物,也是我国一项重要的生产资源。但由于在开发过程中,缺乏合理有效的管理与控制,致使出现掠夺式开垦,不仅破坏了当地的生态平衡,还加剧了水土流失。文章就结合当前坡耕地的现状,对如何有效的解决以及治理坡耕地问题进行简单的介绍与讨论。

Evaluation for Use Efficiency of Agricultural Resources in Grain Production:A Case Study of Changshu,Taihe and Ansai in China

This paper aims to establish an index system for evaluation of agricultural resources use efficiency(ARUE) in grain production and discuss the causes of low efficiency and high consumption of agricultural resources in Changshu of Jiangsu Province,Taihe of Jiangxi Province and Ansai of Shaanxi Province in China by analyzing the data about meteorology,soil,water consumption and grain production. Agro-ecological Zone(AEZ) method was adopted to calculate the potential productivity,and synthetically multivariate equation was used to evaluate the ARUE of study areas. This paper can be concluded as:1) the agricultural resources in grain production can be classified into five categories,i.e.,climatic resources,water resources,land resources,biological resources and assistant resources,and 15 indexes were selected to evaluate their use efficiency in grain production;2) the values of ARUE in grain production are 0.5868,0.6368 and 0.5390 respectively in Changshu,Taihe and Ansai;and 3) Changshu ranks the highest among the three study areas in terms of the use efficiency of climatic resources and biological resources(evaluation values are 0.0277 and 0.1530) ,but Taihe tops the three in terms of the use efficiency of water resources,land resources and assistant resources(evaluation values are 0.0502,0.2945 and 0.1379 respectively) . However,the ARUE remains always low in Ansai for all the resources. The inefficiencies are caused by poor grain revenue in Changshu,deficient agriculture investments in Taihe and unfavorable natural conditions in Ansai.

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.

Challenges of Women Contributing to Food Security in Ghana： Perspectives of Women Farmers in Northern Ghana

Women contribution to all the four pillars of food security （food availability, accessibility, utilization, and sovereignty） has been well established in Ghana and many sub-Saharan African countries. However, the issue of sustainability of their contribution to the food security equation is still a dilemma. This study therefore examined the challenges and vulnerabilities associated with women farmers in accessing and controlling land for sustained agriculture in Northern Ghana. The study was mainly qualitative and utilized various participatory dialogue processes including focus group discussions and key informant interviews of selected women farmer groups, individual farmers, opinion leaders and traditional authorities in eight communities across four districts in three regions of Northern Ghana. The data was analysed thematically. Results of the study showed that women are disadvantaged in all the possible means of acquiring land for agricultural production-- inheritance, marriage, rent, shared cropping, outright purchase, and gift. It was evident that women have appreciable levels of access to land, but have low level of control of such lands for sustained food production. Several factors, such as low income, socio-cultural factors, climate change, mining, urbanization, low level of education, and low levels of awareness of property and inheritance rights, associate women＇s vulnerability to limited land in the study area. The findings of the study imply that any policy geared toward women empowerment in agriculture must not only target their access to land but also consider enhancing their control over agricultural land. The study therefore recommended that in order to increase food production and security in the study regions, there is the need to strengthen women＇s capacity to defend their land tenure rights and enhance their access and control over land within the context of natural resource management.

Vertical Zonation of Horticultural Farming in the Alaknanda Basin of Garhwal Himalaya, India

Horticultural practice in the Himalayas has great importance not only for economic development but also for environmental restoration. In the entire Himalayan mountain system, from Jammu and Kashmir Himalaya to Assam Himalaya, the practice of horticulture is centuries old, which includes varieties of fruits along with availability of high quality and quantity. In terms of the Alaknanda Basin, which is centrally located in the Himalayan system, the practice of horticulture does not get commercial level; only it is cultivated domestically. The climatic conditions ranging from sub-tropical (low-lying river valleys) to alpine and frigid (highly elevated regions) are suited for varieties of fruit cultivation, yet the benefit of this could not be utilized by the residents who are working in the agricultural fields. Besides, less proportion of land is devoted for fruit cultivation along with domestic production of fruits. The varieties of fruit cultivated in the basin range from mango-guava-papaya, stone-net, citrus to apple at the different elevations. Along with the cultivated fruits, varieties of wild fruits are also found in the jungle. There are four climatic zones suitable for the production of various fruits as below:? Sub-tropical zone including the lower part of the Alaknanda, Pindar, Nandakini, and Mandakini rivers is suitable for mango, guava, and papaya; ? Sub-temperate zone in the middle basin of the Alaknanda, Pindar, Nandakini and Mandakini rivers is a good place for citrus fruits, particularly orange and lemon; ? Temperate zone occupying the Dauli, Vishnu Ganga, Upper Pinder, Nandakini and Mandakini rivers is highly productive for apple, nut and stone fruits; ? Alpine meadows in the highly elevated region are known as Bugyal famous for herb culture. Each of these zones has distinct physical features, environmental conditions and socio-economic identity for fruit cultivation. The present paper aims to discuss about the vertical zonation of the horticultural farming and its nature, in terms of development, in the Alaknada Basin.

Carbon Footprint Determination When Using Residual Agricultural Biomass for Energy Production

At present, the focus is on distributed energy generation with low or negative carbon emissions as well as high conversion yields. In Romania, the renewable energy resource that can be used and produced when and wherever necessary is residual agricultural biomass with a potential of 31 million tons, which can produce over 40% of the national energy demand. Residual agricultural biomass is produced with an average energy efficiency of 6 kWh·bm/kWh input. The CHAB （combined heat and biochar production） concept produces high yield thermal energy as well as BC （biochar） with an average carbon footprint of 140 kg/ton biomass. If the energy produced is used to produce agricultural output, the negative carbon footprint increases by reducing the consumption of fossil fuels. It increases energy independence, the safety of agricultural production, the number of jobs, and regional economic development.

Analysis of Irrigation Systems Employing Comparative Performance Indicators： A Benchmark Study for National Irrigation and Communal Irrigation Systems in Cagayan River Basin

Comparative performance analysis of four irrigation schemes within Cagayan River Basin was assessed using comparative performance indicators between the years 2008 and 2012. The objectives were to establish benchmarks for both productivity and performance of irrigation schemes along the valley and to inquire whether small schemes function better than large schemes. The performance evaluation study of the systems composed of three general performance indicators, based on three domains-（1） system operation performance; （2） agricultural productivity and economics; （3） financial performance. Each indicator was assessed based on the prescribed descriptors used by the International Water Management Institute （IWMI） and Food and Agriculture Organization （FAO）. Analysis showed an overall system performance efficiency of 59%, 55%, 47% and 36% for Magat River Integrated Irrigation System （MARI1S）, Lucban, Garab and Divisoria Communal Irrigation Systems （CIS）, respectively. In terms of annual productivity performance, Lucban CIS dominates the three other systems with 0.35 kg/m3, which was classified as moderately performing system, while the rest were classified with low productivity index. Financial sustainability of the systems were extremely poor with cost recovery ratio of 0, 0.33, 0.41 and 0.49 for Divisoria, Garab, Lucban and MARIIS, respectively, which were exceptionally below the standard value of at least one. Also, analysis of the indicators revealed that on average, large schemes performed similarly to small-scale schemes, but small schemes were more variable, particularly in input-use efficiency. The benchmarking study will provide strategic information to policy makers of agricultural and irrigation agencies on the existing weaknesses of irrigation systems in the country and determine in a more quantifiable terms levels of potential improvement and intervention targets.

Animal Production Systems in Algeria： Transformation and Tendencies in the Setif Area

Algeria registers only 0.25 ha of agricultural surface per capita. This indicates very low agricultural capacities. Otherwise agricultural activities are concentrated in a narrow fringe of the Northern part of the country where the dominant climate is semi-arid with very irregular rainfalls. A majority of farms produces its main part of income from cereal crops--livestock association system. However, the diversity of the climate and the physical environment, on one hand, and the agricultural policies on the other hand, induce major transformations in this system. Transformations are also the result of a significant demographic growth in rural area. In this context, significant issues appear in term of resource＇s uses and systems＇ sustainability. To shed light in the actual situation, this study, based on a survey of 90 owners, shows that： the intensification can constitute a threat on the pastoral resources; the weakness of the farms encourages the generalization of practices characterised by a weak feed autonomy and a bad management of stock fodders; the animal interspecific integration and partial intensification are positive if they follow models which ensure autonomy, performance and optimal pastoral resource management.

Regional Land Use Patterns and Water Consumption in the Jordan Valley Using Geographic Information Systems

Trends in land use and water consumption are crucial components in understanding the changing nature of agricultural production and water use in- the Northern Jordan Valley. The objective of this study is to examine current agricultural land uses in the Jordan Valley and their water consumption patterns as well as to examine the changes in land use and water consumption that occurred between the years 2002 and 2010. Farm level cropping patterns and total annual water use were analysed in order to examine inter-basin land use and water consumption characteristics as well as to estimate the amount of water consumed by each respective crop in total and per unit of land devoted to its production. It was found that citrus production dominated both land and water usage in every basin of the Northern Jordan Valley and that between 2002 and 2010 there were shifts toward increasing citrus production in almost every basin surveyed. It was found that agricultural irrigation water usage decreased overall between 2002 and 2010 by approximately 15 percent and irrigated land usage in the Jordan Valley increased by 5 percent. The role of citrus farming is becoming more important in the Jordan Valley as Jordan＇s agricultural economy shifts away from subsistence farming for staple food crops like wheat and vegetables toward more financially lucrative crops grown for an increasingly international market. This trend is at least partly due to the increasing cost of agricultural irrigation water from Jordan＇s national canal system.

Doha Round： The Environment and Agricultural and Biofuels Markets

The agricultural liberalization market process remains stalled Doha Round. The terms in protection levels reductions are negotiated, but the emergence of the global crisis constrains public resources to sustain them. In addition, the use of some grains as inputs in the production of biofuels, has contributed to the price increase in foods, although this production is an alternative to fossil fuels use and can help to reduce further environmental degradation. In this paper we analyze the main variables to be taken into account when negotiating the liberalization of agricultural trade, but also ofbiofuels in the context of Doha Round.

Urban Food Supply under Constrained Land Resources in Beijing:Potential and Optimization

The recent global food security crisis is garnering increasing attention and calls for innovative solutions to mitigate its negative impacts on people, especially the most economically vulnerable. In urban regions, this issue is aggravated by the fact that, on one hand, rapid urbanization and greater levels and diversity of food consumption associated with the growing affluence of urban inhabitants has led to rising urban food demand, while on the other hand, the rapid loss of farmland due to urban expansion or irrational sprawl and increasing extreme weather events for agricultural producers due to the impact of global climate change is sharply reducing the urban food production and local supply capacity. Therefore how to realize the urban food supply potential and optimize the utilization of the urban farmlands to enhance the local food supply rate and improve urban food security more generally is becoming a key issue. In this paper, we use the case of Beijing to examine the opportunities to enhance the supply of local, affordably priced food under existing land resource constraints, by restructuring farmland utilization. In this paper, we firstly calculate the changes in the food footprint needed by Beijing and its food self-sufficiency rate over the thirty year period from 1981 to 2011. We show that although Beijing’s food footprint has grown from 11 800 to 29 400 km2 over this 30-year period, its food self- sufficiency rate has dropped from 59.3%, 35.8%, 37.3% and 13.1% to about 39.0%, 27.0%, 6.7% and 2.2% for vegetable, fruit, grain and edible oil, respectively. Following this analysis, we calculate Beijing’ s potential food production under different agricultural production allocation scenarios. We conclude that with a proper shift of farmland use, full utilization of temporary idle land, and the development of rooftop farming, Beijing could increase its vegetable self-sufficiency rate to 60% without significantly reducing the production of other types of local food. Given the sensitivity of fresh vegetables to long- distance transport, and the potential to reduce transport-related carbon emissions, this is a worthwhile adjustment that will benefit the city both by meeting the growing need of its residents for fresh food, and by improving the overall regional eco-environment.