可食性小麦蛋白膜的研究

本文介绍了小麦蛋白及其成膜特性,总结了国内外可食性蛋白膜的研究现状,提出了可食性小麦蛋白膜的研究方案,并对膜的安全性及其应用作了展望。     

农村劳动力转移对小麦生产环境效率的影响路径研究基于并行中介效应模型的实证

[目的]近年来中国粮食生产带来的环境问题已经不容忽视,而计算环境效率可以直接反映粮食生产对生态环境的影响,认清粮食生产的环境代价,并促进中国粮食生产向更可持续的方向发展。[方法]文章以中国三大主粮之一小麦为例,基于1990—2018年15个小麦主产省区面板数据,采用SBMDEA方法测算了中国主产省小麦生产的环境效率,并进一步建立并行中介效应模型考察了劳动力转移对小麦生产环境效率的影响机制。[结果]中国小麦生产环境效率的平均值为0.649,可以看出目前中国小麦生产环境效率水平仍然较低,并且自2000年开始均呈现出递减的趋势,这说明小麦生产背后的生态成本也越来越高。[结论]农村劳动力转移虽然能够促进小麦规模化生产改善环境效率,但是总体影响仍为负向,而财政支农水平、有效灌溉率、机械化水平和小麦最低收购政策对生产环境效率具有显著的正向影响。     

高分1号冬小麦解译面积核算方法研究

[目的]以高分1号(GF-1)融合2m卫星遥感影像为基础数据源,结合土地利用现状数据、高分多源遥感影像和地面样方等数据,对冬小麦分类提取中存在的面积误差问题进行研究和分析。[方法]文章以河南省永城市为研究区,在冬小麦提取结果聚类处理基础上,基于线性地物缓冲区数据,采用GIS空间运算实现线性地物面积扣除,接着分析了样方数据和土地利用现状数据再扣除零星地物面积比例上的差异,并采用样方零星地物平均扣除系数对全市各乡镇耕地与非耕地中冬小麦提取面积进行了相关统计和误差分析。[结果]永城市冬小麦最终解译面积11. 29万hm~2,其中线性地物和零星地物扣除面积分别为6 613. 08hm~2和3 875. 22hm~2,占研究区冬小麦解译面积的5. 86%和3. 32%,与统计上报数据相比,其处理前后误差由14. 12%降低至4. 41%,有效地提高冬小麦提取面积精度。[结论]误差来源分析与修正对冬小麦解译面积核算精度具有重要影响,该研究为县级区域尺度下冬小麦面积提取核算提供了思路和借鉴。     

基于HJ-1卫星的冬小麦叶片SPAD遥感监测研究

SPAD能够反映植株叶绿素含量,而植株叶绿素的含量及动态变化,对评价作物生产能力、预测产量和品质均有重要意义。该研究以湖北省潜江市后湖管理区冬小麦为研究对象,通过田间观测不同生育期冬小麦叶片SPAD变化情况,结合我国自主研发的HJ-1卫星对研究区域进行同步监测,选取并计算RVI、DVI、NDVI、GRVI四种植被指数,通过对4种植被指数与冬小麦叶片SPAD进行相关性分析,并构建植被指数与冬小麦叶片SPAD回归反演模型,结果显示相关性均较高。通过对比四种植被指数模型反演精度,NDVI-SPAD对数模型预测精度较高,精度检验表明平均相对误差为-2.34,均方根误差(RMSE)为5.65,能够较好的反演研究区域内的冬小麦SPAD。利用HJ-1卫星结合NDVI-SPAD对数模型能够有效对研究区域冬小麦叶片SPAD进行遥感监测。     

用循环经济理念发展小麦产业——以安徽省淮北市为例

农业循环经济是一种新兴的经济发展模式,发展循环农业是实施实现农业可持续发展战略的重要途径。该文以安徽省淮北市为例,从农业循环经济理念的角度分析小麦产业存在的问题,并提出投入减量化,产出最优化,主副产品再利用、再循环,构筑小麦产业经济利益共同体以及优惠政策支持等小麦产业发展对策。     

基于Nerlove模型的中国小麦供给反应研究

依据1981—2006年中国小麦播种面积、价格和生产成本的时间序列数据,应用Nerlove模型,测算了我国小麦播种面积对价格和成本的反应程度。研究结果表明:我国小麦播种面积对价格的反应程度短期较小,但长期较大,这说明小麦供给对价格的反应存在滞后性;与价格弹性相比,小麦的成本弹性要小得多。因此,制定小麦政策时,应在稳定小麦生产资料价格的同时,加大对小麦价格支持政策的连续性,以促使麦农形成对小麦价格增长的稳定预期。     

小麦赤霉病及控制技术研究进展

赤霉病作为小麦常见病症的一种,近年来发生的越来越频繁。本文简述小麦赤霉病发生的性状、影响因素、处理手段,为赤霉病小麦的处理方法提供一些参考。     

Valuing GM technologies using real options: the case of drought tolerant wheat in Australia

ABSTRACT

In this article we seek to estimate the value of a partially-developed crop technology from the perspective of the firm developing the technology. Firms need this value estimation to decide whether their technology will earn a sufficient return in the market to justify investing in it. However, determining the (ex-ante) value of the technology before it is commercialised is challenging as the technology is not yet in the market and hence the demand function has not yet been defined. An alternative valuation method is required. We use risk premiums, Monte Carlo simulation and real options analysis and we demonstrate this combination of valuation tools on wheat that is currently being developed in Australia to be drought tolerant. The results indicate that this drought tolerant wheat variety is likely to be adopted by farmers in most regions and has a pre-commercialisation value that justifies continued investment in its development. We also identified South Australia as a region in which the new variety would not be sufficiently valuable to farmers to see them adopt it and we consider possible explanations for this outcome.     

Price relationships between qualitatively differentiated agricultural products: organic and conventional wheat in Germany

Organic agriculture, which produces commodities that can be qualitatively differentiated from conventional food products, has grown into an important market in many countries. The dynamics of commodity prices in both sectors are partly interdependent, but are also shaped by independent determinants and have rarely been studied. We analyze organic food markets and their interdependencies with conventional markets in the context of wheat markets in Germany, which have been subject to a number of fundamental changes during the last two decades. Based on institutional market characteristics, we suggest a flexible Markov‐switching asymmetric time series model. We find a pronounced temporal sequence of market phases that differ in their asymmetric dynamics and the extent to which the organic price is influenced by the conventional price. Organic wheat prices tend to be increasingly connected to prices of conventional wheat.     

Crop genetic diversity, farm productivity and the management of environmental risk in rainfed agriculture

This paper presents an assessment of the linkages between cropgenetic diversity, farm productivity and risk management. Aflexible moment-based approach is used to analyse the impactof crop genetic diversity on the mean, variance and skewnessof yield. Using farm-level data from Sicily (Italy), econometricevidence shows how crop genetic diversity can increase farmproductivity and reduce risk exposure. The empirical resultsindicate that crop genetic diversity can reduce variance, butonly if pesticide use is low. Furthermore, high diversity levelscan reduce downside risk exposure (e.g. the risk of crop failure).This provides useful insights on the linkages between resilienceand crop genetic diversity.