农牧民生产生活困难诉求的影响因素研究——基于二元Logistic回归模型的实证分析

基于新疆和田地区于田县62个村的280位农牧民的问卷调查数据,构建二元Logistic模型分析于田县农牧民生产生活出现困难诉求的影响因素,探讨进一步解决农牧民生产生活困难的对策与建议。结果显示,婚姻状况、饲料是否充足、参加培训的次数、住房条件等变量对农牧民是否存在生产生活困难诉求的正向影响显著;家庭人数、年收入是否稳定、主要收入来源、牲畜家禽的作用、农产品销售是否顺利、是否有农牧业机械对农牧民是否存在生产生活困难诉求的负向影响显著。为此,提出了解放劳动力、加强农牧民技术培训、拓宽农产品销售渠道、完善农牧区基础设施建设、完善基层医疗卫生服务体系等对策建议。     

Proper Particle Size Range for Resistance to Chemical Oxidation: A Perspective on the Recalcitrance of Beanpod Biochar for Soil Carbon Sequestration

The effect of particle size on the recalcitrance of biochar against oxidation has been regarded as one of the most important factors influencing its stability and transportation in soils. Little is known about the peculiar stability of different particle sizes under chemical oxidation conditions. In this study, several sizes of biochar particles derived from beanpod were produced,and their stabilities were tested by using acid dichromate and hydrogen peroxide. We discovered that the 60-100 mesh size of particles produced at 400 and 500 ℃ showed the least carbon loss under the oxidation of both dichromate and hydrogen peroxide. In addition, this particle size also shows great stability at 600 and 700 ℃, but this stability was not observed below 300 °C for all temperature-dependent biochars. Medium-sized particles composed of exclusively heterogeneous components produced a biochar at temperatures over 400 ℃ with comparatively stronger chemical anti-oxidation characteristics. The chemical recalcitrance of biochar should be reevaluated based on particle size before soil application.     

A technical opportunity index based on the fuzzy footprint of a machine for site-specific management: an application to viticulture

This paper describes a method that allows farmers to (i) decide whether or not the spatial variation of a field allows a reliable variable-rate application, (ii) discover if a particular threshold (field segmentation) based on within-field data is technically feasible according to the application machinery and (iii) make an appropriate application map. Our method aims to improve on a previous technical opportunity index (Oi) with a fuzzy technical opportunity index (FTOi). The FTOi considers (i) a fuzzy footprint model of a variable-rate application controller (VRAC), which describes the area within which the VRAC can operate reliably, (ii) the location inaccuracy of the data and (iii) the ability (accuracy) of the VRAC to perform distinct levels of treatments. The originality of our approach is based on the use of a fuzzy estimation process to decide if a level of treatment is reliable or not for each area over which the VRAC operates. A unique feature of the approach is that it does not require data on a regular grid. Only characteristics of the machinery and the treatment to be applied are necessary; interpolation of the data and geostatistics are not required by the end user. Tests on theoretical fields, obtained from a simulated annealing procedure, showed that the FTOi was able to assess the technical manageability of variation in the field. Tests also showed that our approach could take into account problems related to low resolution data. Finally, the approach has been applied to a real situation in a vineyard block. This has highlighted the practical implementation and the ability to generate useful information for managing the within-field variation (optimal thresholding, and application and error maps).     

教学型大学科技发展定位的思考——以仲恺农业工程学院为例

本文在分析教学型大学的内涵及特征的基础上,讨论了教学型大学科技发展定位的原则和内容,结合仲恺农业工程学院科技发展的现状和存在的主要问题,探讨了仲恺农业工程学院科技发展的定位,并就实现教学型大学的科技定位提出了相应的对策.