基础设施在中国农业全要素生产率中的作用

This paper uses the Malmquist index to examine the sources of Total Factor Productivity (TFP) in Chinese agriculture. The overall goal of this study is to create a framework for assessing the trend of China’s agricultural infrastructure and to measure its impact on Total Factor Productivity. The main methodological contribution is to provide more contributive measure of crop-specific technologies. Based on the province-level panel data set during 1988–2002, the primary finding is that infrastructure has positively and statistically significant association with the estimated coefficient on Total Factor Productivity for rice, wheat, maize, and bean. An erratum to this article is available at .     

Economic impacts of smallholder farmers’ adoption of drought-tolerant maize varieties

Drought and high temperatures are major threats to sustainable food production and consequently the livelihoods of the majority of Africans who depend on fragile agricultural systems. As a response to these threats, climate-smart agricultural technologies, such as drought-tolerant maize (DTM) varieties, have been developed and promoted on the continent. It is well-known that the adoption of improved technologies generally impacts positively on the wellbeing of adopters. Nevertheless, the magnitude of the impact of any technology or intervention is always an empirical question. Therefore, this study sought to determine the factors that influence the adoption of DTM and subsequently estimate how yield, commercialization intensity, and farm income are affected by adoption. To establish causation, we relied on observations from 200 farm households in the Northern Region of Ghana and estimated an instrumental variable regression. Consistent with findings reported in the literature, we found that DTM adoption is primarily driven by access to seed, extension service, labor availability, and location of farm households. In addition, we found that DTM adoption positively impacts on yield and commercialization intensity. The magnitude of impact is not trivial. For example, the yield of farm households increased by more than 150% (936 kg/ha) following DTM adoption. These results imply that policy-makers and development practitioners must support research and promotion of climate-smart agriculture to improve adoption and welfare indicators, such as yield and commercialization.     

Incomplete Credit Markets and Commodity Marketing Behaviour

We use a simple theoretical model of seasonal market participation in the presence of liquidity constraints and transaction costs to explain the ‘sell low, buy high’ puzzle in which some households do not take advantage of inter‐temporal price arbitrage through storage and sell output postharvest at prices lower than observed prices for purchases in the subsequent lean season. We test our model with data from western Kenya using maximum likelihood estimation of a multivariate sample selection model of market participation. Access to off‐farm income and credit indeed seem to influence crop sales and purchase behaviours in a manner consistent with the hypothesised patterns.     

Estimating the Enduring Effects of Fertiliser Subsidies on Commercial Fertiliser Demand and Maize Production: Panel Data Evidence from Malawi

Most studies of input subsidy programmes confine their analyses to measuring programme effects over a one‐year period. This article estimates the potential longer‐run or enduring effects of fertiliser subsidy programmes on smallholder farm households' demand for commercial fertiliser and maize production over time. We use four waves of panel data on 462 farm households in Malawi for whom fertiliser use can be tracked for eight consecutive seasons between 2003/2004 and 2010/2011. Panel estimation methods are used to control for potential endogeneity of subsidised fertiliser acquisition. Results indicate that farmers acquiring subsidised fertiliser in three consecutive prior years are found to purchase slightly more commercial fertiliser in the next year. This suggests a small amount of crowding in of commercial fertiliser from the receipt of subsidised fertiliser in prior years. In addition, acquiring subsidised fertiliser in a given year has a modest positive impact on increasing maize output in that same year. However, acquiring subsidised fertiliser in multiple prior years generates no statistically significant effect on maize output in the current year. These findings indicate that potential enduring effects of the Malawi fertiliser subsidy programme on maize production are limited. Additional interventions that increase soil fertility can make using inorganic fertiliser more profitable and sustainable for smallholders in sub‐Saharan Africa and thereby increase the cost‐effectiveness of input subsidy programmes.     

河北省夏玉米需水量变化特征及未来可能趋势

基于1963—2015年近50年间河北省夏玉米主产区8个气象站点气象资料,采用联合国粮食与农业组织(FAO)推荐的Penman-Monteith模型和作物系数法计算夏玉米需水量,再结合《IPCC排放情景特别报告》中的两种排放情景RCP2.6(低排放情景)和RCP8.5(持续排放情景)预估的未来气候情景,探讨气候变化下未来河北省夏玉米需水量的时空演变规律。结果表明:1963—2015年河北省夏玉米需水量呈现下降趋势,在空间上大致以黄骅为高值中心,由东北向西南逐渐递减,并在邢台形成低值中心的分布特征;从未来气候变化情景来看,相对于基准时段(2015年),RCP2.6和RCP8.5情景下,在2020年、2030年、2050年、2070年未来4个典型年份夏玉米的需水量均表现出增加的特征。