Gliricidia sepium Carbon Inputs and Soil Carbon Pools in a Costa Rican Alley Cropping System

Alternative land management practices, including agroforestry, help to maintain levels of soil organic matter (SOM) and can facilitate soil carbon (C) sequestration for mitigating atmospheric CO₂ emissions. This study quantified C inputs and determined the changes of the soil C pool in a 19-year-old Gliricidia sepium alley cropping system, studied at two fertiliser levels (tree prunings only [? N], and tree prunings plus chicken manure [+ N]), and was compared to a sole crop system. Carbon input from tree prunings ranged from 455 to 457 g C m^{? 2} y^{? 1}, whereas C inputs from crop residues were similar between alley- and sole crops ranging from 121 to 159 g C m^{? 2}y^{? 1}. The soil organic C (SOC) pool in the alley crop was 16–23% higher than the sole crop. In the 19th year of alley farming, SOC was significantly higher (p < 0.05) in the alley crop (3.2%) compared to the sole crop (2.4%), and was also greater compared to that at the time of establishment of the agroforestry system (2.8%). Gross SOC turnover to a 20-cm depth ranged from 12 to 14 years in the + N and ?N alley crops compared to 49 and 50 years in the + N and ?N treatments for the sole crops. Residue stabilisation efficiency in the alley crops was 39% and 55% in + N and ?N treatments respectively.     

我国城镇消费者有机农产品消费行为分析

目前,国际市场对有机农产品需求不断提高,营养、安全与价格在我国消费者购买评价有机农产品时居于重要地位。基于对北京、武汉消费者的调查,本文统计评价了我国消费者对有机农产品的认知水平,并对有机农产品消费行为及其影响决策因素进行了分析,发现我国消费者对有机农产品的整体认知水平偏低,这是导致我国有机农产品购买水平不高的重要因素。     

化肥价格变化对粮食价格的影响研究--基于省际动态面板数据模型的系统GMM检验

基于我国粮食价格与化肥价格变动趋势的分析,运用2006年~2017年省际动态面板数据模型和系统GMM方法,实证检验了化肥价格变动对粮食价格的影响。结果表明:化肥价格变动对粮食价格存在显著的正向影响,在考虑化肥价格影响下,农业生产服务、种子等农资价格对粮食价格也存在显著的正向影响,机械化农具和农药价格对粮食价格不显著,"价补分离"政策对粮食价格存在显著负向影响。因此,在化肥减量行动背景下,适度调控化肥价格,避免化肥价格上升挤占粮农利润,大力发展农业生产性服务业和种子业,继续实行"价补分离"政策,提高补贴精准性,减少农民投入成本。     

The Impact of Sustainability Aspects in the Meat Sector: A Cluster Analysis Based on Consumer Attitudes and Store Format Choice

Several consumer studies have shown considerable market potential for sustainable meat products, however, their markets shares are still marginal. In Germany, the sustainable aspects “organic,” “local origin,” and “animal welfare” are of special interest. To obtain a precise overview of potential target groups for these meat categories and their choice of store format, 620 German consumers were surveyed on their attitudes toward sustainable meat production and their shopping behavior. First, target groups based on consumers’ attitudes were identified by cluster analysis, taking into account possible overlaps. Consumers were also clustered by their store format choice and their preferred type of meat packaging. A cross tabulation of the results then provided insights into which store format and type of meat packaging is preferred by the target groups for sustainable meat products. Due to overlaps found in the target groups, the existence of important subgroups was shown. Amongst the target groups, only a slight preference for unpackaged meat products was found. Basically, the offer of sustainable meat products appears of interest for all store formats, with particular emphasis on supermarkets. The results of this study can support producers and retailers developing new and tailored marketing strategies for sustainable meat products.     

Reduction in nitrogen fertilizer use results in increased rice yields and improved environmental protection

Overuse of nitrogen fertilizer represents a considerable environmental problem globally, but especially in China. Recently, a recent approach on an experimental scale based on the diffusion of the so-called Three-Control Technology (TCT) successfully alleviated the overuse of nitrogen fertilizer in southern China villages in the Guangdong Province, serving as a reference point for other rice-producing countries tackling similar challenges. Here, we assessed the correlation between rice yields and reduction in the use of nitrogen fertilizer following the introduction of TCT. Our study was based on the collection of primary data from 248 households randomly selected from four rice-growing areas of Guangdong Province, China. Our results show that TCT significantly improved the efficiency in the use of nitrogen. Crucially, participating farmers, including both full adopters and partial adopters, were found to fundamentally change their application practices of nitrogen fertilizer, resulting in major improvements in the local soil and water systems.     

Effect of Consumption Values on Women’s Choice Behavior Toward Organic Foods: The Case of Organic Yogurt in Iran

The purpose of this study is to examine the effects of consumption values (i.e., functional value, social value, emotional value, conditional value, epistemic value, environmental value, and health value) on women’s choice behavior toward organic yogurt. Structural equation modeling is used to assess data collected by a questionnaire survey. The results indicate that functional value–quality, functional value–taste, and functional value–price; conditional value; epistemic value; and health value have positive effects on choosing organic yogurt by women, and social value, emotional value, and environmental value have no effects on the subject. Among variables, epistemic value and health value have the highest impact on consumer choice behavior toward organic yogurt. So this study concludes that the main influence factors on choice behavior regarding organic yogurt are epistemic value and health value. In fact, consumers have high knowledge about organic yogurt benefits related to their health.     

废旧有机纤维制备活性炭纤维的性能研究

以CO2和H2O作为活化剂，利用废旧有机纤维来制备活性炭纤维，对制备的活性炭纤维的性能进行研究。通过收率和吸附量的测试选出一种较好的原料；利用XRD、IR和SEM，描述了较好原料制备的活性炭纤维晶体结构、基团组成和表面形貌，并以某厂家生产的活性炭纤维为标样，进行了比较。利用废弃物可成功制备活性炭纤维，节省了原料成本。     

土壤有机碳储量估算方法及土地利用调控措施研究进展

研究目的:综述土壤有机碳储量估算及调控措施的进展,展望中国有关研究的发展趋势。研究方法:文献资料法、对比法。研究结果:全球与中国陆地生态系统碳储量估算方法主要有土壤类型法、模型法、GIS估算法、生命带类型法等,但受资料来源、区域土壤的空间异质性等的限制,估算方法的适用性和结果差异较大;土壤固碳的土地利用调控措施主要有农艺措施、生物措施、化学措施、政策措施等。研究结论:正确评价土壤碳储量与合理的土地利用,对减缓可能的温室效应、减少全球碳循环通量具有重要意义。     

农户生物菌肥购买意愿及行为的影响因素研究*——基于山东省设施菜农的调研数据

[目的]生物菌肥对于土壤改良、环境改善、食品安全具有重要意义,但目前生物菌肥在整个肥料产业中所占份额较小,迫切需要探讨如何从农户角度提高生物菌肥的施用比例。[方法]基于设施蔬菜农户的数据,构建Bivariate Probit模型,对农户生物菌肥的购买意愿和行为的影响因素进行比较研究。[结果]农户的生物菌肥购买意愿和行为总体上呈现一致性,愿意购买的农户中有97. 77%的农户具有实际的购买行为;但两者的影响因素有所差异,从差异因素来看,质量安全检测对购买意愿具有显著的正向影响,但对购买行为的影响并不显著;农户文化程度、种植年限、对无公害、绿色、有机蔬菜的了解程度,经销商推荐,施肥指导对购买行为具有显著的正向影响。从共同因素来看,生态环境认知变量对购买意愿和购买行为影响不显著。[结论]要推广生物菌肥,需要进一步加强质量安全检测体系对农业行为的约束性,提升经销商的规范经营意识,采用集中招标等灵活的价格政策,提升农户的生态技能,并在保护生态环境方面出台更完善的农业绿色发展政策。     

四川省重点生态功能区有机农业生产效率研究——基于三阶段DEA模型的实证分析

[目的]有机农业为我国农业绿色发展起到良好的带动作用,但我国有机农业发展中,西部贫困地区较为滞后。针对西部贫困地区有机农业生产效率进行定量分析,揭示影响有机农业生产效率的主要因素,旨在提高该地区有机农业生产效率,丰富区域视角下的有机农业生产研究。[方法]采用三阶段DEA模型对2014年四川省重点生态功能区有机农业生产效率进行量化分析,识别环境变量对有机农业生产效率的影响。[结果]环境因素和随机误差对四川省重点生态功能区有机农业生产效率产生了显著的影响。环境因素中,农民人均纯收入的增加有利于促使农机、耕地等资源的有效利用,但同时也导致化肥投入冗余增加;城镇化率的提高会降低耕地、劳动力、化肥、农药等使用效率,从而对有机农业生产效率产生不利影响;财政支出占GDP比重的增加有利于提高农机使用效率,但同时也导致化肥和农药投入冗余增加;粮食播种面积占耕地面积比重对有机农业生产效率产生了不利影响。剔除环境因素和随机误差的影响后,四川省重点生态功能区各县平均技术效率和规模效率有所下降,纯技术效率则略有提升。基于纯技术效率和规模效率,四川省重点生态功能区各县有机农业生产效率可分为"双高型""高低型""低高型"和"双低型"等4种类型。[结论]三阶段DEA模型有效剔除了环境因素和随机误差对有机农业生产效率的影响,估计的效率值更真实地反映了四川省重点生态功能区有机农业生产效率水平。针对四川省重点生态功能区各县有机农业生产效率的不同特征,应结合地方实际,通过扩大要素投入规模或改进要素配置效率和使用效率,提高有机农业生产效率。