面向资源认知变化的耕地评价研究进展与展望

科学的耕地评价是耕地合理开发、利用、保护的前提,耕地资源认知的深化引领耕地评价研究发展。为明晰耕地评价研究的发展历程、热点动态和未来前景,系统梳理1949—2023年引领耕地资源认知变化的理念、事件和政策,探讨耕地资源认知发展的阶段性特征,借助文献调查、文献计量分析、理论分析等方法,对不同阶段耕地评价研究的主要内容、政策支撑、技术方法与代表成果等进行总结,并提出面向新时期社会发展需求的耕地评价研究展望与关键问题。研究表明：1）耕地资源认知按时间顺序可划分为资源本体、资源平衡体和资源综合体3个阶段,认知对象由耕地数量单一维度向耕地数量与质量、数量-质量-生态、实体耕地与虚拟耕地等多维度转变,研究范围也由宜耕地、耕地等实体资源向近远程耦合框架下的全球虚拟耕地拓展;2）各阶段耕地评价的研究重点围绕耕地数量、耕地质量和耕地综合利用展开。在资源本体阶段,侧重土地开发适宜性评价,关注本底要素宜耕性;在资源平衡体阶段,注重耕地质量提升,对耕地资源的可持续利用潜力进行评价。在资源综合体阶段,评价对象向全球粮食贸易中的虚拟耕地拓展,评价内容关注耕地多功能及功能间权衡与协同关系。因此,未来耕地评价的研究内容需适应新时代发展的现实需求,耕地本体评价需兼顾实体和价值量,耕地质量评价需匹配人类福祉需求,耕地综合评价需考虑多元对象和指标。在评价理论与方法层面应加强学科交叉融合,充分利用新调查监测手段,丰富精细化耕地资源数据,为进一步拓展资源认知、丰富评价范式、优化耕地保护制度等提供支撑。     

碳交易视域下养殖户畜禽粪污资源化利用受偿意愿与影响因素——基于河北省7市694户养猪户调研数据

为进一步探究养殖户粪污资源化利用受偿意愿、受偿水平及其影响因素,基于碳交易视角,利用2023年3—4月对河北省7市694户养猪户的调研数据,运用条件价值评估法、二元Logit模型和Tobit模型对此进行系统分析。结果表明：1）88.76%的养猪户愿意接受补偿,其受偿水平在25.03~31.50元/t;2）养猪户年龄、养殖场地面积以及粪污资源化利用生态效益等因素会显著影响养猪户受偿意愿;风险偏好、场地面积、养殖规模、养殖信息获取渠道、粪污资源化利用经济效益显著影响其受偿水平;3）规模异质性视角下,粪污资源化利用生态效益显著正向影响不同规模养猪户受偿意愿。自动化设施配置数量和粪污资源化利用社会效益显著影响不同规模养猪户受偿水平,但其影响方向存在显著差异。为使养殖户更好参与资源化利用,应加强对畜禽粪污资源化利用正面效果的宣传,将宏观政策规范与地方实际相结合、因地制宜,有序推进碳交易补偿机制的建立。     

长江中下游地区温室内温湿度预测模型的研究

该文利用传热学理论,以温室热平衡模型为基础,分析了温室内温度和湿度的动态模型,并以此建立了室内温湿度预测模型.最后,作者通过SR5.2型连栋塑料温室的实验研究,求出该模型参数,为实现智能温室前馈控制奠定基础.     

融入区域特色食品资源的“食品工艺学”课程教学改革研究

HUANG Huifu(College of Biological Resources and Food Enginggring,Qujing Normal University,Qujing,Yunnan 655011,China)     

梅县苦笋竹资源产业化开发探讨

文章概述了梅县的苦笋竹资源情况,同时介绍了苦竹笋的栽培管理技术、开发利用现状,并在此基础上提出相应的开发利用措施。     

我国观光果园的现状及发展建议

分析了我国观光果园的发展现状及存在的问题,并提出了相关建议。     

Adoption of improved fallow technology for soil fertility management in Zambia: Empirical studies and emerging issues

In the subsistence-agricultural region of eastern Zambia, less than 10% of the households have adequate supply of maize (Zea mays L.), the staple food, throughout the year. A major constraint to increasing crop production in the region is poor fertility status of the soil. In order to address this problem, improved fallow has been introduced as a technology for improving soil fertility within a short span of two to three years. Farmers have been testing the technology and a number of empirical studies have been undertaken over the years to identify the factors influencing farmers' decision to adopt the technology. This paper presents a synthesis of the results of adoption studies and highlights generic issues on the adoption of improved fallows in Zambia. The synthesis indicates that farmers' decision on technology adoption does not have a simple directed relationship of some technological characteristics only, but constitutes a matrix of factors including household characteristics, community level factors, socioeconomic constraints and incentives that farmers face, access to information, local institutional arrangements and macro policies on agriculture. The adoption of improved fallows is not strictly speaking a binary choice problem but a continuous process in which farmers occupy a position along a continuum in the adoption path. Further, adoption of improved fallows may not take place in a policy vacuum but needs to be facilitated by appropriate and conducive policy and institutional incentives. Several questions and issues that require further study emerge from the synthesis. These include determination of the relative importance of the factors in the adoption matrix, identification of the conditions under which farmers use a combination of inputs and their profitability under changing price scenarios, exact definition to delineate between `non-adopters', `testers' and `adopters' of agroforestry technologies, and understanding the impact of cash crop farming in farmers' adoption decisions of improved fallows (where off farm opportunities exist). Further, there is a need to determine the inter-relationship between household poverty, labor availability and the adoption of improved fallows and, to evaluate a combination of policy interventions at both national and local level to promote the adoption of agroforestry-based soil fertility management. This revised version was published online in June 2006 with corrections to the Cover Date.     

Long-term patterns of microhabitat use by fish in a southern Appalachian stream from 1983 to 1992: effects of hydrologic period, season and fish length

Abstract— We quantified microhabitat use by members of a southern Appalachian stream fish assemblage over a ten-year period that included both floods and droughts. Our study site (37 m in length) encompassed riffle, run and pool habitats. Previous research indicated that species belonged to either benthic or water-column microhabitat guilds. Most species exhibited non-random microhabitat use in all seasons, and benthic and water column species generally were over-represented in the deeper portions of the site. In addition, water column species generally were over-represented in microhabitats with lower average velocities. The majority of seasonal shifts in microhabitat use were passive (i. e. correlated with changes in microhabitat availability), whereas, most shifts associated with hydrological periods appeared to be active responses to changing environmental conditions. Most species exhibited length-related shifts in microhabitat use, which were strongly affected by hydrologic period for four of ten species. Microhabitat use patterns of assemblage members appeared to be a consequence of species-specific responses to changing environmental conditions. The highly flexible patterns of microhabitat use exhibited by these species necessitate that decisions regarding their management be based on data covering a range of environmental conditions.     

Marine temperatures experienced by postsmolts and the survival of Atlantic salmon, Salmo salar L., in the North Sea area

The survival of two Atlantic salmon stocks that inhabit rivers confluent with the North Sea was examined in respect to historical distributions of sea surface water temperatures. The rivers Figgjo and North Esk are relatively small salmon rivers in southern Norway and eastern Scotland, respectively. Wild salmon smolts have been tagged in these rivers since 1965. Tag returns were used to evaluate the survival of salmon in the North Sea. Survival rates of one-sea-winter (1SW) and 2SW fish were correlated within stocks, as well as between stocks. Survival rates were compared with the areal extent of thermal habitat in the north-eastern Atlantic Ocean. A positive correlation was found between the area of 8–10°C water in May and the survival of salmon. A reciprocal negative correlation was also found between survival and 5–7°C water in the same month. An analysis of sea surface temperature distributions for periods of good vs. poor salmon survival showed that when cool surface waters dominate the Norwegian coast and North Sea during May, salmon survival has been poor. Conversely, when the 8°C isotherm has extended northward along the Norwegian coast during May, survival has been good. The effect of water temperature distributions on the growth of postsmolts and other survival factors are discussed.     

鲁甸县核桃种质资源表型多样性调查初报

通过调查鲁甸核桃604株成年结果树的物候特征、植物学特性、坚果的经济性状及丰产性得出:鲁甸县核桃种质资源萌芽期为2月上旬至4月上旬,集中期为2月下旬到3月中旬,雌雄花开放期集中在3月中下旬至4月上旬,果实成熟期集中在9月至10月;植物学上,在叶形、枝条颜色、雌花柱头、子房颜色、雄花序长度、青果性状等方面存在多样性;鲁甸核桃每果枝坐果数为1~7,还有串串核桃的存在,丰产性好;在树形方面,表现为自然圆头形、自然开心形、自然分层形、自然圆锥形的多样性,核桃坚果的三径均值、出仁率、仁重、单果重、壳厚的变异系数分别为9.48%、13.46%、24.05%、25.46%、25.74%,多样性较丰富。