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1.
利用"智慧芽"数据库对我国1997-2018年间的转基因小麦专利文件进行统计分析,从申请趋势、IPC分类、核心专利分析等层面得出转基因小麦技术发展趋势,从专利角度分析目前我国研究机构所面临的问题并提出专利布局的思路。  相似文献   
2.
With continually increasing demand for food accompanied by the constraints of climate change and the availability and quality of soil and water, the world’s farmers are challenged to produce more food per hectare with less water, and with fewer agrochemical inputs if possible. The ideas and methods of the system of rice intensification which is improving irrigated rice production are now being extended/adapted to many other crops: wheat, maize, finger millet, sugarcane, tef, mustard, legumes, vegetables, and even spices. Promoting better root growth and enhancing the soil’s fertility with organic materials are being found effective means for raising the yields of many crop plants with less water, less fertilizer, reduced seeds, fewer agrochemicals, and greater climate resilience. In this article, we review what is becoming known about various farmer-centred innovations for agroecological crop management that can contribute to agricultural sustainability. These changes represent the emerging system of crop intensification, which is being increasingly applied in Asian, African, and Latin American countries. More research will be needed to verify the efficacy and impact of these innovations and to clarify their conditions and limits. But as no negative effects for human or environmental health have been identified, making these agronomic options more widely known should prompt more investigation and, to the extent justified by results, utilization of these methodologies.  相似文献   
3.
面筋含量是影响小麦和小麦粉品质的重要因素,面筋吸水率是小麦储存品质的重要指标。本文对小麦面筋含量测定中的关键步骤和重点环节进行了分析,探讨不同因素对试验结果造成的影响及应注意的事项,以期为各基层试验人员提供借鉴,为未来标准的修订提供参考。  相似文献   
4.
The objective of the paper is to determine if the futures prices of hard red spring wheat (HRSW) have stabilizing or destabilizing impact on spot HRSW price in North America. Several important results emerge from thorough empirical analysis. First, both Granger causality tests and directed acyclic graph algorithms (DAGs) point to two-way causality between futures and spot HRSW prices and thus endogeneity in both prices formation. To the contrary, both procedures suggest that ending stocks are exogenous to spot and futures HRSW prices. Both vector error correction model and impulse response functions point to a large and long-lasting impact of a shock to futures price on spot price level. Finally, variance decomposition analysis indicates that futures prices are responsible for the bulk of spot price volatility in both short and long run. Our result is consistent with those of theoretical models suggesting that when production (supply side) is the dominant disturbance, spot price is destabilized in both the short and the long run by futures prices. An important implication of this research is the need for alternative market mechanisms or alternative farm policy measures that would mitigate price risk and ensure sustainable farming of American HRSW farmers.  相似文献   
5.
[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。  相似文献   
6.
Using wheat market support data from 55 countries for 1961–2011 from the World Bank Agricultural Distortion database, we develop a fixed effect model that shows a more complicated, nonlinear relationship between income and wheat support and its components than previously realised. We find that income generally has a greater effect on border market price support than on domestic price support. Moreover, the difference between these types of support is greater for net importers than for net exporters and has increased with the URAA or WTO accession. Holding other variables constant, the wheat support level of China, driven mainly by border market price support, is projected to rise with future income growth. Meanwhile, Japan is projected to maintain its high level of support, while the US and EU are projected to maintain their lower levels of support. These results are relevant in the context of multilateral trade negotiations, arguing against a narrow focus on past or current policy profiles and for long‐run analyses that might mistakenly rest on the inconsistent assumptions of constant agricultural policies against the backdrop of rising incomes.  相似文献   
7.
Sex selection has been linked to son preference and discrimination against girls in many Asian countries. In this study, we shed light on the shaping role of rice–wheat cropping system to the subsequent gender inequality in China. Using an individual-level dataset compiled from a national scale survey and an archaeology publication, we show regional differences in gender inequality across China: parents show strong gender discrimination against girls in wheat regions. And 15.2 percentage points more parents from wheat regions engage in successful sex selection than those from non-wheat regions. The mechanism analysis reveals that women empowerment matters.  相似文献   
8.
[目的]小麦是我国重要的口粮之一,提高小麦的技术效率对于保障粮食安全具有重要的战略意义。在测算小麦技术效率的基础上,找出影响小麦技术效率的关键因素,为保障国家口粮安全提供参考。[方法]基于调研数据,运用超越对数生产函数以及一步随机前沿分析方法,构建计量模型分析土地细碎化和土地质量对小麦技术效率的影响。[结果]全部样本的技术效率差距较大,规模经营农户的技术效率高于小农户,农户技术效率最高的种植面积为67~333hm2,代表小麦种植的适宜规模。从技术效率的影响因素来看,土地细碎化程度和土地质量都对小麦生产的技术效率产生显著影响。[结论]为了提高小麦的技术效率,应该发展多种形式适度规模经营,鼓励创新土地流转形式,提高农业机械化水平; 深入开展土地质量调查,因地制宜地选择土地修复路径; 实行精准补贴,切实保护农民的利益。  相似文献   
9.
Interdependence between first and second moments of producer and consumer wheat prices in Slovenia is assessed, in light of the recent major historical events that the country has undergone, as well as the recent rumours of cartel agreements between millers causing a decline in farm-gate prices, while leaving consumer prices untouched. A threshold vector error correction and multivariate generalized autoregressive conditional heteroscedasticity model with exogenous variables is applied. Results indicate that price-level adjustments mainly favour retailers by increasing their marketing margins. Important second-moment interactions are also identified. Increases in international wheat stocks reduce producer prices, while higher interest rates increase their instability.  相似文献   
10.
基于光能利用率模型的河南省冬小麦单产估算研究   总被引:2,自引:0,他引:2  
[目的]快速、准确估算空间尺度上作物产量,对于评价农田生态系统对气候变化的响应、制定科学合理的粮食政策、对外粮食贸易等具有重要意义。河南省冬小麦产量占全国1/4,准确估算河南省冬小麦产量对维护国家粮食安全具有重要作用。单产估算作为农作物估产中的关键技术,也是作物估产的难点之一。[方法]文章首先利用VPM(Vegetation Photosynthesis Model)估算冬小麦NPP(Net Primary Product),结合收获指数、冬小麦收获部分的含水量、含碳量、NPP分配到地上或地下部分比例等一系列符合该研究区的经验指数,进行河南省冬小麦单产估算研究,并分析了引起模拟误差的原因。[结果]模拟单产较实测单产低估4.4%(实测单产为6 810kg/hm~2,模拟单产为6 519kg/hm~2),但两者之间存在显著相关关系,两者相关系数的平方R2=0.70(n=50,p0.01)。通过与MODIS-GPP产品获得的冬小麦单产数据比较,基于VPM模型的模拟结果优于MODIS-GPP产品。[结论]基于VPM可快速、准确估算河南省空间尺度冬小麦单产,该方法具有较好的适用性。  相似文献   
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