本期目录
01. Designated market makers and agricultural futures market quality: Evidence from China's Dalian commodity exchange ( 指定做市商与农产品期货市场质量：来自中国大连商品交易所的证据 )
02. Endogenous technologies and productivity in rice production: Roles of social instability in Myanmar since 2021 ( 水稻生产中的内生技术和生产力：2021年以来缅甸社会不稳定的作用 )
03. Herbicide-resistant weed management with robots: A weed ecological–economic model ( 机器人抗除草剂杂草管理：一种杂草生态经济模型 )
04. The implicit market price of soil erosion: An estimation using a hedonic model with spatial spillovers ( 土壤侵蚀的隐性市场价格：基于具有空间溢出效应的特征价格模型的估计 )
05. Aspirations and weather shocks: Evidence from rural Zambia ( 愿望和天气冲击：来自赞比亚农村的证据 )
06. An experimental approach to farmer valuation of African rice genetic resources ( 非洲水稻遗传资源农民价值评估的实验方法 )
07. Growing importance of price: Investigating food values before and during high inflation in Germany ( 价格日益重要：调查德国高通胀之前和期间的食品价值 )
08. Livelihood diversification and household welfare among farm households in the Philippines ( 菲律宾农户的生计多样化和家庭福利 )
内容提要
01. Designated market makers and agricultural futures market quality: Evidence from China's Dalian commodity exchange ( 指定做市商与农产品期货市场质量：来自中国大连商品交易所的证据 )
作者：Miao Li 等
摘要：Many financial markets use designated market makers (DMMs), but the impacts of DMMs on agricultural futures markets – and in particular, how to arrange DMMs among contracts expiring in different months – are largely neglected. In 2017, Chinese exchanges started recruiting DMMs for inactive contracts when they become nearby contracts to address the discontinuous trading activity of nearest-to-maturity contracts, which enables us to study the benefit and cost of recruiting DMMs for inactive contracts using a quasi-experimental framework. Leveraging tick-by-tick data on corn and soybean meal futures, we find that DMMs improve the market quality of inactive contracts without disrupting the market quality of dominant contracts. Heterogeneity analysis in policy settings suggests that more DMMs are conducive to improving market quality for corn and soybean meal futures. We demonstrate that DMM policy is a feasible measure to facilitate continuous activeness in Chinese agricultural futures markets. Our results are important for exchanges and regulators seeking to better design and implement designated market-making programs in agricultural futures markets.[ 机器译文：许多金融市场使用指定做市商，但指定做市商对农产品期货市场的影响--尤其是如何在不同月份到期的合约之间安排做市商--在很大程度上被忽视。2017年，中国交易所开始招募非活跃合约的DMM，当它们成为邻近合约时，以解决最接近到期合约的不连续交易活动，这使我们能够使用准实验框架研究招募非活跃合约的DMM的好处和成本。利用玉米和豆粕期货的逐笔交易数据，我们发现，DMM改善了非活跃合约的市场质量，而不会扰乱主导合约的市场质量。政策环境中的异质性分析表明，更多的DMM有利于提高玉米和豆粕期货的市场质量。我们论证了DMM政策是促进中国农产品期货市场持续活跃的一种可行措施。我们的结果对于交易所和监管机构寻求更好地设计和实施农产品期货市场的指定做市计划具有重要意义。]
02. Endogenous technologies and productivity in rice production: Roles of social instability in Myanmar since 2021 ( 水稻生产中的内生技术和生产力：2021年以来缅甸社会不稳定的作用 )
作者：Hiroyuki Takeshima 等
摘要：Despite technologies' critical roles in agricultural productivity, evidence is scarce on how conflict affects technology adoption and consequent agricultural productivity, often due to a lack of data in fragile states. Our study contributes to filling this knowledge gap by using unique large-scale data on rice producers before and after a military coup in Myanmar in 2021 that led to a significant increase in conflicts in the country. We find that the increase in violent events including those in adjacent townships significantly changed the rice production function in both factor-neutral and non-neutral ways. Specifically, increased violent events have been generally associated with downward factor-neutral shift in production function, and more importantly, increased output elasticity to agricultural capital (equipment) owned (in other words, reduced output resilience against capital ownership shocks). Our evidence also suggests that this has been led partly through reduced access to agricultural extension services, which would otherwise help farmers maintain productivity even with limited capital ownership by substituting it with human capital and skills. Our results consistently hold for both panel and cross-sectional production functions across various specifications and particularly in Lower Myanmar. Results also indicate that lower mechanization service fees partly mitigate these effects.[ 机器译文：尽管技术在农业生产力中起着关键作用，但关于冲突如何影响技术采用和随后的农业生产力的证据很少，这往往是由于脆弱国家缺乏数据。我们的研究通过使用关于2021年缅甸军事政变前后大米生产者的独特大规模数据来填补这一知识空白，这场政变导致该国冲突显著增加。我们发现，包括邻近乡镇在内的暴力事件的增加，无论是以要素中性还是非中性的方式显着改变了水稻生产函数。具体地说，暴力事件的增加通常与生产功能向下的要素中性转移有关，更重要的是，农业资本(设备)拥有的产出弹性增加(换句话说，对资本所有权冲击的产出弹性降低)。我们的证据还表明，这在一定程度上是由于获得农业推广服务的机会减少，否则将帮助农民保持生产率，即使资本所有权有限，也可以用人力资本和技能取代。我们的结果一致适用于各种规格的面板和横截面生产功能，特别是在缅甸下部。结果还表明，较低的机械化服务费在一定程度上缓解了这些影响。]
03. Herbicide-resistant weed management with robots: A weed ecological–economic model ( 机器人抗除草剂杂草管理：一种杂草生态经济模型 )
作者：Chengzheng Yu 等
摘要：The heavy reliance on herbicides for weed control has led to an increase in resistant weeds in the United States. Robotic weed control is emerging as an alternative technology for removing weeds mechanically using artificial intelligence. We develop an integrated weed ecological and economic dynamic (I-WEED) model to examine the biophysical and economic drivers of adopting robotic weed management and simulate the optimal timing and intensity of robotic adoption within and across growing seasons. We specify a cohort-based weed growth model that relates yield damages to effective weed density and treats the susceptibility of weeds to herbicides as a renewable resource that can be regenerated by using mechanical weeding robots, due to a fitness cost that makes resistant weeds less prolific. Compared to myopic weed management which ignores resistance development, forward-looking management leads to earlier adoption of robots and treating robots as complements instead of substitutes to herbicides. This weed management results in adopting fewer robots, deploying robots on a smaller portion of the land, higher profitability, and lower yield loss in the long run, relative to myopic management. Counterintuitively, myopic management leads to a lower resistance level through its higher robot adoption intensity. We also find that a lower level of initial weed seed resistance and/or a higher fitness cost result in a higher level of resistance because they create incentives for farmers to delay the adoption of robotic weed control. Our analysis shows the importance of jointly considering the interactions between weed ecology and economics in analyzing the incentives and effects of robotic weed management on weed resistance.[ 机器译文：严重依赖除草剂来控制杂草，导致了美国抗药性杂草的增加。机器人除草正在成为一种使用人工智能机械除草的替代技术。我们开发了一个综合的杂草生态和经济动态(I-WIDD)模型来研究采用机器人杂草管理的生物物理和经济驱动因素，并模拟在生长季节内和整个生长季节采用机器人的最佳时机和强度。我们指定了一个基于队列的杂草生长模型，该模型将产量损害与有效杂草密度联系起来，并将杂草对除草剂的敏感性视为一种可再生资源，可以使用机械除草机器人再生，因为适应成本会使抗性杂草不那么多产。与忽视抗药性发展的短视杂草管理相比，前瞻性管理导致更早采用机器人，并将机器人视为除草剂的补充而不是替代品。与目光短浅的管理相比，这种杂草管理导致采用更少的机器人，在更小的土地上部署机器人，更高的盈利能力，以及更低的产量损失。与直觉相反的是，近视管理通过其更高的机器人采用强度导致了较低的阻力水平。我们还发现，较低的初始杂草种子抗性和/或较高的适应成本会导致较高的抗性水平，因为它们会激励农民推迟采用机器人控制杂草。我们的分析表明，在分析机械化杂草管理对杂草抗性的激励和效果时，联合考虑杂草生态学和经济学之间的相互作用是重要的。]
04. The implicit market price of soil erosion: An estimation using a hedonic model with spatial spillovers ( 土壤侵蚀的隐性市场价格：基于具有空间溢出效应的特征价格模型的估计 )
作者：Marcelo Caffera 等
摘要：We estimate the implicit market price of soil erosion using quarterly data of 2824 agricultural farms traded in Uruguay between 2000 and 2014. A unique feature of our estimation is that we allow for possible spatial spillovers. We find evidence of a negative and statistically significant association between erosion and land values. On average, an additional loss of 1% of the original topsoil due to erosion is associated with a direct (own) decrease of .24% in the per-hectare price of agricultural land (P-value: .012, 95% CI: −.0042, −.0005). In 2023 dollars, this is equivalent to a decrease of USD 8.7 in the average price per hectare, or USD 1130 in the price of the average farm. In terms of tons of soil, the average value is
05. Aspirations and weather shocks: Evidence from rural Zambia ( 愿望和天气冲击：来自赞比亚农村的证据 )
作者：Martin C. Parlasca 等
摘要：Aspirations defined as future-oriented desires or ambitions, can determine agricultural investments and rural development. Aspirations are shaped by people's social, cultural, and physical environment and can be affected by external factors such as natural disasters. This article addresses the question of how weather shocks can influence individual and community aspirations. Using primary panel data from two survey rounds before and during a major drought in Zambia, we show that such extreme weather events can be associated with adverse impacts on individual aspirations. Further exploratory analyses suggest that aspirations towards assets that are particularly vulnerable to droughts are affected most. We do not find any significant effects of drought on community aspirations.[ 机器译文：抱负被定义为面向未来的愿望或野心，可以决定农业投资和农村发展。抱负是由人们的社会、文化和物质环境塑造的，并可能受到自然灾害等外部因素的影响。本文探讨了天气冲击如何影响个人和社区愿望的问题。使用赞比亚大干旱之前和期间两轮调查的初级小组数据，我们表明此类极端天气事件可能与对个人愿望的不利影响有关。进一步的探索性分析表明，对特别容易受干旱影响的资产的期望受到的影响最大。我们没有发现干旱对社区愿望有任何重大影响。]
06. An experimental approach to farmer valuation of African rice genetic resources ( 非洲水稻遗传资源农民价值评估的实验方法 )
作者：Nicholas Tyack 等
摘要：Genebanks serve as both providers of valuable traits for breeding programs and repositories of diverse crop genetic material representing society's agricultural heritage. In this study, we use a Becker-DeGroot-Marschak mechanism to elicit the willingness-to-pay of rice farmers in Côte d'Ivoire for small amounts of African rice (Oryza glaberrima) landraces held by the genebank of the Rice Biodiversity Center for Africa, and for seed of newly developed ARICA rice varieties bred using genebank materials. Using a field experiment, we additionally investigate how randomized exposure to and experimentation with small amounts of African rice landrace seed or seed of advanced rice varieties developed by AfricaRice affect how smallholder rice farmers value these novel genetic resources. Surprisingly, we find that farmers generally value having access to African rice landraces at approximately the same level as for advanced rice varieties (and far above market rates for improved seed), and that those farmers who grew landrace seed in the offseason were willing to pay more than those who did not. Our results demonstrate the additional value provided by the conservation of African rice landrace varieties (apart from their use in breeding) and highlight the importance of experimentation in the adoption process.[ 机器译文：基因库既是育种计划中有价值的特征的提供者，也是代表社会农业遗产的各种作物遗传物质的储存库。在这项研究中，我们使用Becker-DeGot-Marschak机制来诱导科特迪瓦稻农对非洲水稻生物多样性中心遗传库持有的少量非洲水稻(Oryza Glberrima)地方品种的支付意愿，以及利用遗传库材料培育的新开发的Arica水稻品种的种子。通过田间实验，我们还研究了随机接触少量非洲水稻地方品种种子或非洲水稻开发的先进水稻品种的种子如何影响小农对这些新遗传资源的评价。令人惊讶的是，我们发现，农民普遍看重获得非洲地方水稻品种的机会，与获得先进水稻品种的价值大致相同(而且远远高于改良种子的市场价格)，那些在淡季种植地方品种种子的农民愿意支付比不在淡季种植地方品种种子的农民更高的价格。我们的结果证明了保护非洲水稻地方品种所提供的额外价值(除了在育种中的使用之外)，并强调了在采用过程中进行实验的重要性。]
07. Growing importance of price: Investigating food values before and during high inflation in Germany ( 价格日益重要：调查德国高通胀之前和期间的食品价值 )
作者：Corinna Hempel 等
摘要：Considering the consumption-induced intensification of global challenges and the continuously changing consumer needs, it is important to understand the drivers of consumer food choices under external pressures. We applied best–worst scaling to elicit the relative importance of 11 food values and conducted latent class cluster analyses based on individual scores, allowing us to gain insights into distinctive consumer segments. Data were collected through online surveys of 1000 consumers in Bavaria, southern Germany, in November 2020 and November 2022. As expected, the relative importance of food valuepricehas strongly increased during this period. Similarly, the price-sensitive segment has become larger in 2022 than in 2020, while the societal impact-centered segment has become much smaller in 2022. These findings call for target-specific measures to counteract this trend of increasing price focus that challenges sustainable dietary transitions.[ 机器译文：考虑到消费引发的全球挑战加剧和消费者需求的不断变化，了解外部压力下消费者食品选择的驱动因素非常重要。我们应用最佳-最差比例来得出11种食品价值的相对重要性，并根据个人评分进行潜在类别集群分析，使我们能够深入了解不同的消费者群体。数据是通过2020年11月和2022年11月对德国南部巴伐利亚州1000名消费者进行的在线调查收集的。正如预期的那样，食品价值和价格的相对重要性在此期间大幅增加。同样，2022年对价格敏感的部分比2020年要大，而以社会影响为中心的部分在2022年要小得多。这些发现呼吁采取针对特定目标的措施，以抵消这种对可持续饮食转型构成挑战的日益关注的趋势。]
08. Livelihood diversification and household welfare among farm households in the Philippines ( 菲律宾农户的生计多样化和家庭福利 )
作者：Valerien Olivier Pede 等
摘要：Diversification of income sources is one of the most common strategies households employ to minimize household income variability and to ensure a minimum level of income that guarantee their food security. This study examines the impact of livelihood diversification on farm profits among smallholder rice farmers in the Central Luzon Region (CLR) of the Philippines using long-term farm-level panel data spanning from 1966 to 2016. We employed a random-effects ordered probit model to investigate the drivers of livelihood diversification and then used the mixed Markov chain model to analyze the transition of households from less to more diversified livelihoods and its impact on farm profits over time. Our findings reveal substantial diversification among households over time. In particular, the elevation of the farm location is a key driver of rice farm households’ probability to diversify. The estimates show that an increase in the latitude of the farm location increases the probability of rice farmers in the CLR to diversify. We find that 64% of the rice farm households constitute farmers for whom diversification can be a strategy for survival. For medium- to high-profit farm categories, diversification tends to protect farmers against farm profit losses arising from adverse climatic and weather variability.[ 机器译文：收入来源多样化是家庭为尽量减少家庭收入差异和确保保证其粮食安全的最低收入水平而采用的最常见战略之一。这项研究使用1966至2016年的长期农场面板数据，考察了菲律宾吕宋岛中部地区(CLR)小农户生计多样化对农场利润的影响。我们使用随机效应有序概率模型来研究生计多样化的驱动因素，然后使用混合马尔可夫链模型来分析家庭从较少生计向较多元化生计的转变及其随着时间的推移对农场利润的影响。我们的发现显示，随着时间的推移，家庭之间的差异很大。特别是，农场位置的提升是稻田家庭实现多样化的一个关键驱动因素。估计表明，农场位置的纬度增加增加了CLR的稻农进行多样化种植的可能性。我们发现，%的稻农家庭构成了农民，对他们来说，多元化是一种生存战略。对于中高利润农场类别，多样化往往会保护农民免受不利气候和天气变化造成的农场利润损失。]
