基于面源污染约束的油菜生产效率时空变化及成因分析

[目的]分析面源污染约束条件下我国油菜生产效率的动态变化、省际差异及其影响因素,提出提升途径。[方法]采用基于非期望产出的非径向、非角度的数据包络分析模型测算面源污染约束下的油菜生产效率,根据投入冗余、期望产出不足或非期望产出冗余等,分析效率损失成因。[结果]我国油菜生产效率总体上呈现"N型"年际变化特征,其中黄淮区、江浙、重庆、青海和甘肃的油菜生产效率均值高于0.9,云贵和内蒙古的油菜生产效率则低于0.8。全国和长江流域省际差异表现为先扩大后缩小趋势,西北区省际差异最大,黄淮区省际差异最小。总氮和总磷排放量过高是长江流域乃至全国油菜生产效率损失的主要原因。近3年总氮可缩减比例均值大于30%的地区从大到小依次为湖南、内蒙古、贵州、云南和江西,总磷可缩减比例均值大于30%的地区依次为云南、贵州、四川和内蒙古。此外,湖北用工投入冗余、内蒙古化肥投入冗余和单产不足也是其油菜生产效率损失的重要原因。[结论]长江流域需重点削减氮磷径流损失,黄淮区应重点控制氮磷淋溶损失,西北区应重点治理氮磷侵蚀流失。     

基于"3S"的内外业一体化地籍变更模式研究

为促进现代测量技术和信息化成果在地籍管理工作中的应用,保证地籍数据的现势性,在传统地籍变更模式的基础上提出了基于"3S"的内外业一体化地籍变更模式.利用"3S"技术、无线电通讯技术、网络技术使得外业变更地籍调查与内业数据处理一体化,做到实地调查实地变更,遇到问题现场解决,与传统工作模式相比大大提高了地籍变更工作效率.     

Agricultural Policy Reform and Off‐farm Labour Decisions

Off‐farm labour decisions of a sample of Kansas farmers are evaluated. The central question of our analysis pertains to whether 1996 US farm policy reforms may have altered the decisions to work off the farm. The effects of policy decoupling on off‐farm labour are complex: different aspects of policy changes can have opposing effects on off‐farm work decisions. Essentially, this makes this issue an empirical question. Results show that the introduction of fixed, decoupled payments in 1996 might have reduced the likelihood of off‐farm labour participation. However, the new policy environment may have increased farm households’ revealed aversion to risk, motivating a higher participation in non‐farm labour markets. The effects of 1996 policy reforms on farm income variability could have been attenuated by changes in US crop insurance programmes and by an increase in emergency assistance payments towards the end of the 1990s. The reduction in price supports may have increased the motivation for working off the farm. The net effect of the overall reforms on off‐farm work participation is not likely to have been large.     

Trade-off relationship between modern agriculture and biodiversity: Heavy consolidation work has a long-term negative impact on plant species diversity

Human-driven land-use changes often cause a decline in biodiversity. Although traditional agricultural practices maintained biodiversity at high levels, recent land-use changes may have negative consequences on species composition. In this study, we examined the hypothesis that land consolidation, which is a major recent land-use change in agricultural areas, decreases plant species diversity over the long term (the so-called negative legacy). To test this hypothesis, we examined the relationships between consolidated areas and the occurrence of threatened plant species across Japan and at the prefecture scale. Twenty-three threatened plant species were selected, all of which were formerly common. Our results show that areas containing records of threatened plant species rarely experienced consolidation at whole-country and prefectural scales. Breakdown analysis showed that unconsolidated agricultural areas contained significantly more threatened species than consolidated agricultural areas. These results suggest that threatened plant species require unconsolidated agricultural areas (i.e., these species could not grow in consolidated areas). Thus, we propose that consolidation history could be used as an indicator of the potential for biodiversity recovery. We also suggest that consolidated agricultural areas should be used for food production rather than for the restoration of biodiversity, for reasons of cost efficiency.     

Incorporating risk in a positive mathematical programming framework: a dual approach

In this study we develop a new methodological proposal to incorporate risk into a farm‐level positive mathematical programming (PMP) model. We estimate simultaneously the farm nonlinear cost function and a farmer‐specific coefficient of absolute risk aversion as well as the resource shadow prices. The model is applied to a sample of representative arable crop farms from the Emilia‐Romagna region in Italy. The estimation results confirm the calibration ability of the model and reveal the values of the individual risk aversion coefficients. We use the model to simulate different scenarios of crop price volatility, in order to explore the potential risk management role of an agri‐environmental scheme.     

Optimal surveillance against foot‐and‐mouth disease: the case of bulk milk testing in Australia

Previous foot‐and‐mouth disease (FMD) outbreaks and simulation‐based analyses suggest substantial payoffs from detecting an incursion early. However, no economic measures for early detection have been analysed in an optimising framework. We investigate the use of bulk milk testing (BMT) for active surveillance against an FMD incursion in Australia. We find that BMT can be justified, but only when the FMD entry probability is sufficiently high or the cost of BMT is low. However, BMT is well suited for post‐outbreak surveillance, to shorten the length of time and size of an epidemic and to facilitate an earlier return to market.     

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.     

A Meta‐Analysis on the Elasticity of Demand for Pesticides

There is an increasing policy interest in pesticide taxation schemes as a measure to reduce harmful effects of pesticide use. The effectiveness of such tax depends, however, on the price elasticity of demand for pesticides. Moreover, information on these demand elasticities and their determinants is of crucial relevance for policy‐making and normative modeling approaches. In this article, we present a meta‐analysis based on studies that have estimated pesticide demand elasticities in Europe and North America. Our meta‐analysis reveals that the own‐price elasticities of demand for pesticides are, with a median of ?0.28, significantly smaller than zero, but also significantly larger than ?1, i.e. to be inelastic. We find that the demand for pesticides for special crops is less elastic than that for arable and grassland. In addition, the demand for herbicides is more elastic than for other pesticides. Studies that consider only short‐term horizons and little flexibility for farmers to adjust to price changes generate significantly less elastic pesticide demands. The results also indicate that more recent studies identify lower pesticide price elasticities of demand. Furthermore, we find that peer‐reviewed studies tend to find more inelastic results compared to grey literature.     

The Impact of an EU–US Transatlantic Trade and Investment Partnership Agreement on Biofuel and Feedstock Markets

We assess the impact of a potential TTIP bilateral free trade agreement on the EU and US bio‐economies (feedstock, biofuels, by‐products, and related competing crops) and major trade partners in these markets. The analysis develops a multi‐market model that incorporates bilateral trade flows (US to EU, EU to US, and similarly with third countries) and is calibrated to the OECD‐FAO baseline for 2013–2022 to account for recent policy decisions. The major policy reforms from a TTIP involve tariff and TRQ liberalisation and their direct contractionary impact on US sugar supply, EU biofuel production, and indirect negative effect on US high fructose corn syrup (HFCS) production. EU sugar and isoglucose production expand along with US ethanol and biodiesel and oilseed crushing. EU sugar would flow to the US, US biofuels and vegetable oil to the EU. We further quantify non‐tariff measures (NTM) affecting these trade flows between the EU and the US. EU oilseed production contracts, and EU crushing expands with improving crushing margins following reduced NTM frictions. Our analysis reveals limited net welfare gains with most net benefits reaped by Brazil and not the two trading partners of the TTIP.     

Designing and evaluating sustainable development pathways for semi‐subsistence crop–livestock systems: lessons from Kenya

Achieving the Sustainable Development Goals (SDGs) in African agriculture requires a better understanding why high levels of poverty and resource degradation persist in African agriculture despite decades of policy interventions and development projects. In this article, we hypothesize that policies need to account for the key features of the semi‐subsistence crop–livestock systems (CLS) in the region to become effective. The semi‐subsistence CLS are characterized by a high degree of biophysical and economic heterogeneity and a complex, diversified production system involving a combination of subsistence and cash crops with livestock. We investigated the potential for interventions proposed by the Government of Kenya to meet the SDGs by 2030. The analysis uses an integrated modeling approach designed to deal with the key features of these systems. A strategy that stimulates rural development, increases farm size to a sustainable level, and reduces distortions and inefficiencies in input and output markets could lead to a sustainable development pathway and achieve the SDGs for rural households dependent on CLS.