农户技术采纳行为偏好及影响因素研究--以水稻种植户为例

农户是农业技术的使用者,是农业新技术推广的重要力量。引导农户理性进行技术决策,积极采纳新技术,对推进新技术在现代农业发展中的主导作用具有十分重要的意义。通过对湖南省湘北、湘东2个水稻主产区县的138个水稻种植农户的技术采纳行为的实地调查,了解农户在水稻种植中主要采纳的技术类型,对农户的技术选择偏好进行了排序,并采用计量分析方法分析了主导农户技术采纳行为的主要外因和内因,最后提出了相应的建议。     

Uptake and use efficiency of N, P, K, Ca and Al by Al-sensitive and Al-tolerant cultivars of wheat under a wide range of soil Al concentrations

The impacts of acidic soils and Al toxicity on wheat nutrient economy have been scarcely researched under field conditions even though these soils are widely spread in wheat production areas around the world. The main objective of this study was to quantitatively evaluate the element (N, P, K, Ca and Al) economy of an Al-sensitive and an Al-tolerant wheat cultivar growing under different soil Al concentrations at field conditions. To reach this objective, two field experiments were conducted in an Andisol in Valdivia (39°47′18″S, 73°14′05″W), Chile. Treatments were a factorial arrangement of: (i) two spring wheat cultivars (Al-sensitive, Domo.INIA and Al-tolerant, Dalcahue.INIA) and (ii) five exchangeable Al levels (0-2.7 cmol₍₊₎ kg⁻¹) with three replicates. At harvest, plant biomass was sampled and divided into 5 organ categories: ears, grains, blade leaves, stems plus sheath leaves and roots. The element content (N, P, K, Ca and Al) in each organ was measured to quantify element uptake and concentration, nutrient uptake efficiency (UPE) and nutrient utilization efficiency (UTE). Element uptake (N, P, K, Ca, and Al) was negatively affected by the increased soil Al concentration in above-ground and root biomass in both cultivars (R² = 0.61-0.98, p < 0.01), although clear differences were found between cultivars. On the contrary, the impact of soil exchangeable Al on the plant element concentration was minor, showing weak associations with soil Al levels. However, the Al concentration in above-ground tissues of the Al-sensitive cultivar was an exception because it increased exponentially with the Al soil concentration (R² = 0.96-0.99, p < 0.001). Nutrient uptake efficiencies, UPEs (N, P, K and Ca), were negatively affected by soil Al concentrations and were well described by linear equations in both cultivars (R² = 0.58-0.98, p < 0.05), with notable differences between them. Both nutrient uptake (capture) and UPE were the traits that best explained above-ground biomass production (R² = 0.82-0.99, p < 0.001, n = 20). Nutrient utilization efficiency, UTEs (N, P, K and Ca) responded more conservatively to the soil Al concentration, except for the Al sensitive cultivar under very high soil Al levels.     

Adjustive Mechanism Design Based on Planar Constraint Uncertainty

For normal planar closed chain mechanism, it is based on ideal planar constraint condition. The authors took crank leader mechanism as an example, and analyzed influences resulted from uncertain factors, such as manufacturing error. The result shows it belongs to statically indetermination mechanism. After analyzing its over-constraint and eliminating it, in this way, it become statically determination mechanism and can be assembled without obstacle. However, in the process of practical running, the mechanism can give birth to new kinematic constraint, frictional constraint and dynamic constraint etc., so over constraint emerges again. Therefore, it is necessary to analyse its adaptability in total running process. The conclusion shows that design of adaptability mechanism normally eliminate geometry over constraint at first, then it is analyzed that whether there is new over constraints from all kind of external constraints in the process of running.     

A Review of “World Food: Production and Use”

The credibility, reliability, and adequacy of information sources are cardinal to adoption of technologies that increase agricultural productivity. Date palm production in Nigeria is low and, considering its high demand, makes the country a net importer of date to meet local demands.

This study assessed the sources of information on date palm in Dutse Local Government Area of Jigawa State. A multi-stage sampling technique was used to select 115 date palm farmers. The results show that friends and relatives, extension agents, and radio are the preferred sources of information. The frequency and adequacy of use follow a similar pattern of preference.     

Role of farmers' attitudes in adoption of irrigation in Saskatchewan

Adoption of a new technology, such as irrigation, is a complex phenomenon. Several factors of economic and social nature contribute to the farm-level decisions affecting adoption. In this study, the role played by attitudes of potential adopters towards irrigation and its subsequent adoption on their farm unit was estimated. Two models were estimated, one incorporating only adopters' socio-economic characteristics, and the other, only their attitudes towards irrigation. Results suggest that adopters' attitude, particularly with respect to economic and environmental effects of irrigation, were significant determinants of their decision to proceed with adoption of irrigation, and have a role to play in adoption of irrigation over and above that explained by socio-economic characteristics. In particular, these results suggest that negative perceptions with respect to economics of irrigation and those related to its detrimental impacts on environmental quality, particularly through soil salinity, may be significant deterrents for adoption of irrigation. The study suggests that planning of large scale water development projects, particularly those involving irrigation, must be cognizant of attitudes of potential adopters. Furthermore, during the planning stages, more attention should be paid to the development of proper educational programs, as well as extension packages, to ensure that potential adopters formulate correct attitudes towards the new technology.     

“玉米生产管理智能决策系统”推广应用制约因素分析

[研究目的]通过对"玉米生产管理智能决策系统"推广应用制约因素分析,为农业信息技术的大规模推广应用提供理论和实践依据;[方法]在实证法基础上,利用SPSS软件、借助Logit模型对制约因素进行定性、定量分析;[结果]影响农户采用"玉米生产管理智能决策系统"的制约因素包括技术自身优势是否明显、农户的性别、年龄、受教育程度及农户是否接受过相关技术培训等方面;[结论]模型分析表明影响农户采用"玉米生产管理智能决策系统"的决定因素是技术自身优势能否充分发挥出来及农户是否接受过相关技术培训.     

北京郊区农技推广情况分析及展望

农业推广是农业科技进步过程中一个不可缺失的重要环节.为了实现北京郊区农业可持续发展,拓展都市型农业功能,科技推广工作将成为重中之重.通过调研大兴、密云、顺义3个区县的农技推广工作,较为全面地描述了北京郊区农技推广的现状,揭示了存在的问题,并对未来发展前景进行了展望.     

内蒙古阴山北麓缓坡丘陵坡耕地的农业自然生产潜力及其限制因子分析

内蒙古阴山北麓后山地区处在中国北方农牧交错区。这一地区自然条件恶劣,水土流失、风蚀沙化严重,生态环境极其脆弱,急需治理。本区地形以缓坡丘陵为主,坡耕地占很大比重,因此加强坡耕地的治理显得十分必要。根据研究区的自然条件及生产特征,建立了光、温、水和土壤条件对丘陵坡耕地的农业自然生产潜力的分析模型和综合模型,表明制约阴山北麓缓坡丘陵坡耕地农业自然生产潜力的主要限制因子是风蚀引起的土壤肥力的变化,其次是地势造成的土壤水分的不同,再次是光、热、水配制结构不平衡。通过农业自然生产潜力的分析,得出丘陵顶部的农业自然生产潜力最低,其次是北坡,最高是南坡,因此,要加大对坡顶和北坡的综合治理力度。     

基于DE算法的再入飞行器横向机动能力研究

根据马克思主义的观点,社会制度沿着正义方向的演进是一个历史的发展过程。基于人类的历史实践活动,正义是以人的自由与平等为目标,不断发展的,正义之发展要求人们对社会制度作出与之相应的变革。人是差异性与同一性的现实统一体,基于此,正义可以分为差异性正义与同一性正义。这两种正义总是共存于人类社会的发展过程中,它们共同作用,推动着社会制度的发展。差异性正义与同一性正义的生成及其运动,是不断推动社会和谐发展的内在动力。