兼业化程度对玉米种植农户农地经营权转出行为的影响研究

本文以吉林省玉米种植农户为研究样本开展实地调研,通过二元Logistic回归模型分析探究兼业化程度对玉米种植农户农地经营权转出行为影响的作用机理,为加快农地经营权流转进程相关政策决策提供依据。回归结果显示,兼业化在一定程度上影响了农户的农地经营权转出行为。首先,非农户与二兼农户更愿意参与农地经营权转出,即农户收入中非农收入比例越高,农户越愿意转出农地;其次,农户兼业劳动力人口比越高,农户越愿意转出农地经营权。同时,研究发现户主最高学历、户主健康状况、家庭年收入、农机具总价值、流转价格认知都对农户参与农地经营权转出行为有一定的影响。为促进玉米种植农户农地经营权快速流转,应提高农业兼业化程度。     

东北玉米种植户农业生产性服务采纳行为差异研究——基于兼业异质性视角

利用辽宁省和吉林省黄金玉米带地区的564份农户调研数据,采用Probit模型分析兼业农户不同类型农业生产性服务采纳行为差异,从兼业异质性视角探讨不同类型兼业农户农业生产性服务采纳行为的差异及原因.研究结果表明,兼业农户对劳动密集型服务采纳的概率大于对技术密集型采纳的概率,且兼业化程度低的农户采纳生产性服务的概率大于兼业...     

不同产业组织模式对玉米生产技术效率的影响研究——基于黑龙江省904个农户数据的实证分析

利用2019年黑龙江省农村经济社会情况入户调查的904份农户数据,选择数据包络分析法和倾向得分匹配法,测算玉米生产与加工融合下不同产业组织模式对玉米生产技术效率的影响。结果表明,黑龙江省玉米生产加工整体的生产技术效率均值为0.874,表明生产技术效率较高;玉米生产加工融合形成的产业组织模式都可以提高农户的生产技术效率,但不同产业组织模式提升效果具有差异性,纵向一体化模式对玉米生产技术效率影响程度最高,净效应为0.021 9,生产合同模式又高于订单合同模式。户主特征、家庭经营特征、土地特征和环境特征等因素也对玉米生产技术效率的提升具有一定的影响。     

农户选择玉米新品种行为及影响因素分析

自2000年《中华人民共和国种子法》正式颁布后,农户可更加自主的选择新品种。吉林省作为我国著名商品粮生产大省,在全国粮食主产省份中占重要位置,其农户对新品种的选择行为具有典型性和代表性。基于吉林省粮食主产区129个农户的调查数据,运用Logistic模型对吉林省农户选择玉米新品种行为及影响因素进行实证分析。研究结果表明,吉林省农户选择玉米新品种行为受多种因素的影响,玉米种植规模、受教育年限、增产效果、对种子熟悉程度、新品种宣传推广力度、农户种植经验、农户风险偏好对农户选择玉米新品种行为有正向影响,玉米种植收入占总收入比重、种子价格对农户选择玉米新品种行为有负向影响。在此基础上,从资金投入、价格、品种、新品种宣传推广力度4个方面提出调动吉林省农户选择玉米新品种积极性的相应对策。     

农户玉米收获环节损失影响因素分析

利用全国25个省2186份玉米种植户的实地调查数据评估玉米收获环节的损失率,并利用OLS模型和Tobit模型分别分析影响农户收获损失的影响因素,其中影响农户收获环节玉米损失的原因有户主年龄、户主文化程度、玉米商品化率、收获方式、收获时作业精细度和收获时人手充裕度。从提高农户文化程度、改进玉米收获机械的工艺水平和提高收获人员的作业态度提出政策。     

玉米条带耕作密植高产技术应用效果评价——基于示范户与非示范户的连续跟踪数据

利用辽宁省铁岭市蔡牛镇玉米生产农户2018 ～ 2019年连续跟踪实地调研数据,对春玉米条带耕作密植高产技术的应用经济效果进行分析,并基于随机前沿生产函数模型对农户玉米生产的技术效率进行评价.研究表明,种粮大户、合作社等有较大生产规模、农业收入占家庭总收入比重大、户主受教育程度较高的农户更倾向于应用技术,普通农户应用技...     

我国玉米生产要素配置效率研究——基于黑龙江、河南和四川3个玉米主产省的调查

基于黑龙江、河南、四川3个玉米主产省份742个地块的调查数据,运用两阶段数据包络分析法对3省玉米生产要素配置效率进行测算,分析其相关影响因素。结果表明,3个玉米主产省平均要素配置效率为0.69,存在较大的效率损失。户主务农年限、政治身份、地块规模以及村年人均纯收入对玉米生产要素配置效率具有显著正向作用,户主年龄显著抑制了玉米生产要素配置效率的提升。黑龙江省玉米生产的要素配置水平显著高于河南、四川省。针对研究结论,提出相关对策建议。     

农业产业化地区玉米生产技术效率研究

运用两阶段双重自助抽样DEA方法研究农业产业化地区玉米生产技术效率,研究结果表明,72.6%的农户玉米生产技术效率值处于无效区间,在影响农户玉米生产技术效率的因素中,农户投资规模对玉米生产技术效率具有负效应,表明农户玉米生产投资已进入无效率区间,进一步提高投资规模,已不能提升农户玉米生产技术效率。此外,政府给予玉米种植补贴对玉米生产技术效率的提高并不显著。     

农户玉米生产技术效率及影响因素研究——基于黑龙江省农村固定观察点数据

当前我国粮食安全面临诸多挑战,持续提升农户玉米生产技术效率有利于释放生产潜力、提升玉米产量。以黑龙江省玉米种植农户为研究对象,采用随机前沿模型测度农户玉米生产技术效率,使用技术效率损失模型确定技术效率影响因素。结果表明,样本农户玉米生产平均技术效率0.878 7,在6.67 hm2以内经营规模与技术效率呈倒"U"型关系,是否转入农地经营对技术效率有负向影响;农户劳动力规模、全年总收入等6个因素对技术效率有正向影响,化肥和除草剂投入量对技术效率近乎无影响。提出引导农户适度规模经营,推进化肥除草剂减量化施用和强化对农业的支持等政策建议。     

农户采用水稻新技术的影响因素研究——以江苏兴化、高邮两市的调查为案例

改革开放以后,由于我国农村实行家庭联产承包责任制,对调动农民生产积极性及推动我国农业进步起到了很重要的作用。但是,在新形势下,这种小规模的生产方式在一定程度上阻碍了农户采用农业新技术的积极性,阻碍了农业生产的进一步发展。笔者通过对江苏省兴化市钓鱼镇、高邮市周巷镇195户农户水稻新技术采用行为的实证研究,得出以下结论：影响农户技术采用的内部环境因素有户主文化程度、人口和劳动力数量及土地面积等,其中户主文化程度和土地面积对农户决策的影响较大;影响农户决策的外部环境因素主要有新技术成本与效益、政策、市场、意见领袖作用和推广服务体系等。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).