关于我国林下经济作物认证问题的研究——以黑龙江省伊春林菌代表产品黑木耳为例

进行林下经济作物认证,是保障食品安全的需要,有利于更好地开拓市场、促进农民增收,这也从根本上符合当前提倡的森林可持续发展战略,符合建立和谐林业生产体系的发展目标。对黑龙江省林区林下经济作物认证工作开展了调研,介绍了黑龙江省林下经济作物认证的研究进程、认证产品的选择及原因,同时对开展林下经济作物认证工作方面存在的问题进行了剖析,并且提出了相应的建议。     

1980～2010年西藏农作物播种面积 与人口数量变化的相关分析

以1980 ～2010年西藏农业统计数据为基础,分析了西藏农作物总播种面积、粮食、油料、蔬菜、果树播种面积变化情况及与西藏人口数量的相关关系.结果表明,1993年为西藏农作物播种面积变化的分界点,1993年以前,变化幅度较小,而1993年后有很大的变化幅度,种植结构也从“重粮食作物、轻经济作物”向“提高经济作物比重”转变.在1980 ～2010年间,西藏农作物总播种面积显著增加;粮食作物播种面积在1980～1994和2001～ 2010年间呈降低趋势,1995～2000年间显著增加.油料作物、蔬菜作物和果园面积呈不断增加趋势.西藏人口保持高于全国的人口自然增长率增长,人口总数呈极显著线性增加(R=0.9974),与总农作物、油料作物、蔬菜作物播种面积呈极显著正相关关系,而与粮食作物播种面积呈极显著负相关关系.人均总农作物和粮食作物播种面积低于全国水平,且呈现不断下降趋势.人口的快速增加和粮食作物播种面积的不断下降,将会对西藏粮食安全产生威胁.     

Profitability and opportunity of conservation agriculture in acid savannah grasslands of Laos

In north-eastern Laos, the savannah grasslands of the Plain of Jars cover vast areas of potentially cultivable land. However, soil acidity, low inherent fertility, and the absence of alternatives to tillage represent significant constraints to the development of sustainable smallholder agriculture. Our objective was to evaluate the potential for conservation agriculture (CA) to enhance soil productivity and farming system profitability. A three-year rotation of rice/maize/soybean was tested under three fertilization levels and four agricultural systems: one conventional tillage-based (CT) system and three CA systems based on no-tillage with cover crops. After four cropping seasons, our results show that, compared with CT, CA systems led to similar-to-higher grain production, similar-to-higher profits, higher opportunity of livestock system intensification, and higher labour productivity regardless of fertilization levels. While CA represents a relevant alternative to current practices, our results suggest that its contribution to the emergence of a sustainable smallholder agriculture is conditioned by broader institutional transformations, including the enrolment of local manufacturers and traders for deploying no-till implements and seed market channels for cover crops, long-term public support to maintain active research and technical mentoring to farmers, and possibly the integration of ecosystem services in agricultural policy.     

A discussion of the market and policy failures associated with the adoption of herbicide-tolerant crops

Weed control in the U.S. Midwest has become increasingly herbicide-centric due to the adoption of herbicide-tolerant (HT) crops in the 1990s. That integrated weed management (IWM) practices, including ecological and mechanical controls, are scarcely used is concerning. IWM would be a more sustainable form of farming for two reasons. First, it would reduce the negative health and environmental externalities associated with herbicide use. Second, it would reduce the selection pressure on weed populations and the development of weed resistance to some herbicides, thereby reducing the uncertainty of the long-term effectiveness of herbicidal weed control. In this context, we develop an economic framework to clarify the interplay among the different market failures that either contribute to the herbicidal ‘lock-in’ or make it problematic. We then analyse the evidence for and perceptions of these market failures based on twenty-four semi-structured interviews with farmers and experts conducted in 2017, as well as on discussions in the academic literature. To this end, we put into perspective the possible self-reinforcing effects in the adoption path of HT crops, such as increasing farm size, changes in farm equipment, increasing incentives for simplified crop rotations, and the loss of practical knowledge of IWM practices.     

Cropland use,yields, and droughts: spatial data modeling for Burkina Faso and Niger

For countries with recurrent droughts, the design of drought impact mitigation measures could benefit from analyses of determinants of yields and prices of local crops at regional and district level. This study applies dynamic spatial panel data regression models to yields and prices of four major food crops across regions of Burkina Faso and Niger, over sample periods between 1984 and 2006. Results lend support to mainly simultaneous spatial spillovers, particularly for millet and cowpea prices and sorghum yields in Niger, and maize yields in Burkina Faso. After accounting for these effects, most crop yields are found to be weakly price‐responsive, as envisaged by a supply‐side geographical diffusion hypothesis. Seasonal rainfall elasticity estimates suggest that dominant food crops have slight advantage margins in terms of relative resilience to rainfall shortages. However, this result is to be weighed against low millet yields in Niger, and marked drops in sorghum yields during officially declared droughts in Burkina Faso.     

2000～2010年我国洪涝灾害损失综合评估及其成因分析

利用我国的洪涝灾害损失数据,分析了我国2000～2010年洪涝灾害受灾人口、农业受灾面积和直接受灾经济损失之间的关系,洪涝灾害损失的空间分布特征以及受灾损失与年平均降水量之间的关系。根据近10年来我国洪涝灾害的新特点,提出了我国洪水管理及防灾减灾的若干措施。     

Men wielding the plough: Changing patterns of production and reproduction among the Balanta of Guinea‐Bissau

This paper is centred on the fast‐track changes occurring among the Balanta of Guinea‐Bissau—at present, the only ethnic group in West Africa still able to produce a mangrove swamp rice surplus with a manual plough—in their traditionally intensive farming system and their social organization, and on the consequences that these changes have had for gender relations, especially with regard to married women's spatial mobility, sexual and economic independence, and access to land, labour, and capital. In doing so, the paper contributes to old debates about the relationship between means of production and gendered power dynamics in contexts where African societies based on domestic modes of production progressively embrace the market economy. The Balanta case offers a new layer of complexity to this debate due to their long‐term resistance to westernization and market integration, their particular conjugal relations, and the paradoxical way in which women have been losing their traditional rights.     

Conservation practice complementarity and timing of on-farm adoption

The adoption of conservation practices is a dynamic process. Factors that vary over time can affect farmers’ decision to adopt and adoption timing. We used a duration model to evaluate the farmer's adoption time for continuous no-till (CNT), cover crops (CCs), and the variable-rate application of inputs (VRA). We found that producers who had previously adopted soil conservation practices were more likely to adopt additional complementary practices. Farmers using crop rotation adopted CNT and CCs approximately 48% and 62% faster than farmers without a crop rotation, respectively. The CC adoption time was also reduced by 70% for farmers who had adopted CNT. Complementarities between conservation practices may enhance the benefits from adoption and allow farmers to adopt bundles of conservation practices more quickly over time. This can be taken advantage of in conservation programs by promoting or requiring practices first that enhance adoption of other practices. We also found important heterogeneity in the adoption speed associated with farm management characteristics, producers’ attitudes, weather patterns, and crop prices.     

Adopting bioenergy crops: Does farmers’ attitude toward loss matter?

We apply prospect theory to examining farmers’ economic incentives to divert a share of their land to bioenergy crops (miscanthus and switchgrass in this study). Numerical simulation is conducted for 1,919 rain‐fed U.S. counties to identify the impact of loss aversion on bioenergy crop adoption, and how this impact is influenced by biomass price, discount rate, credit constraint status, and policy instruments. Results show that ignoring farmer's loss aversion causes overestimation of miscanthus production but underestimation of switchgrass production, particularly when farmers are credit constrained and have a high discount rate. We find that establishment cost subsidy induces more miscanthus production whereas subsidized energy crop insurance induces more switchgrass production. The efficacy of these two policy instruments, measured by biomass production increased by per dollar of government outlay, depends on the magnitude of farmers’ loss aversion and discount rate.