AN ANALYSIS OF WILLINGNESS-TO-PAY FOR CROP INSURANCE*

In this paper a method for estimating a producer's willingness-to-pay for crop insurance is presented. The method includes formulae to capture the impact of crop insurance on the producer's expected income and variance of income. These impacts are evaluated in the context of a model of producer welfare which features both price and yield uncertainty, as well as risk aversion on the part of the producer. The method is applied to the Australian wheat industry and estimates of willingness-to-pay are shown to be relatively sensitive to the levels of coverage and yield variability.     

中国渔业保险历史积累风险初探

本文通过简单回顾建国以来中国渔业保险的发展历程,重点对其历史积累风险进行分析,初步将其划分为渔业保险的风险起始期、积聚期和显现期这三大阶段,并对每一阶段的渔业风险特征进行了有益的探讨.通过时间序列分析,以期为中国渔业保险业的风险管理提供一个历史分析的视角.     

TREATMENT OF RISK IN A CROP PROTECTION INFORMATION SYSTEM

The importance of risk in a farm-level management information system designed to help farmers make spraying decisions relating to leaf rust of barley is examined. Using utility functions which were elicited for a small number of cereal growers, and probability distributions of yield losses generated using the information system, it was found that strategy assessment using the criterion of maximisation of expected monetary value or the criterion of maximisation of expected utility could be expected to lead to identical recommendations in most years, for a wide range of risk attitudes.     

MALLEE WHEAT FARMERS' DEMAND FOR CROP AND RAINFALL INSURANCE

Producers' demand for a crop insurance program with indemnities based on their actual yields and a rainfall insurance program with indemnities based on area rainfall is analysed. Actuarial costs of these hypothetical programs are estimated. Tobit procedures are used to analyse factors influencing the amount which farmers would be willing to pay for the alternative insurance programs. Factors related to the absolute size of risk and capacity to bear risk, as well as personal characteristics and risk attitudes of producers, have effects on the demand for insurance as hypothesised. Problems of adverse selection are associated with the area yield-based program, while both crop and rainfall insurance programs may involve some moral hazard. Producer participation in either program would be limited.     

农作物生产风险评估与区划系统的设计与实现

针对农作物生产风险的分析、评估、区划、保险费率厘定和赔付估算的研究及应用需求,提出了基于COM组件技术和MATLAB、ArcGIS Server应用的软件系统设计方法,通过.NET平台开发出农作物风险评估与区划系统,实现了我国不同地区、不同灾种、不同作物生产风险的分析、评估和区划等功能.结果表明,该系统能够很好地完成以上功能并在很大程度上提高专业领域的研究效率.     

ESTIMATION OF EFFECTIVE RISK REDUCION THROUGH IRRIGATION OF A PERENIAL CROP*

This paper outlines an approach to assessing the benefits from in vestment in the irrigation of tea stands in three areas of East Pakistan. Irrigation aflects both the establishment and productive life of the growing crop, and therefore the analysis includes a discounred assessment of the replacement decision, as well as an appraisal of the change in technology. Since the biological and weather eflects that determine annual and long-run productivity of the stand are stochastic variables, the evaluation is made using a simulation model in which these determinants are introduced as known discrete probabilities. Using this model an estimate may be made of rhe net gains to a tea estate of the risk reduction achieved by eliminating harmful crop moisture deficits.     

AN APPROACH TO THE ECONOMETRIC ESTIMATION OF ATTITUDES TO RISK IN AGRICULTURE*

A simple model is developed relating the debt and asset portfolio of the farm to the production decision, which leads to a small non-linear system of equations. The system is estimated with time-series cross-sectional data from Australian broadacre agriculture using non-linear three-stage least squares. This gives a new method of estimating risk aversion coefficients by using actual behaviour of farmers in a realistic economic environment, rather than games played in artificial situations. Australian farmers are found to be risk averse, and the partial coefficient of risk aversion decreases with wealth and increases with income. The results are consistent with the results of studies by Binswanger in India and elsewhere using a completely different method. This consistency suggests that the partial risk aversion coefficient is a relatively robust measure of attitudes to risk.     

AN APPROACH TO THE ECONOMETRIC ESTIMATION OF ATTITUDES TO RISK IN AGRICULTURE: COMMENT

Bardsley and Harris (1987) test empirically the effects of changes In deterministic wealth and random income on the measure partial risk aversion. The paper, which is otherwise well written, failed to impose the relationship between the two effects and estimated them independently. Consequently, inconsistent estimates were derived for the elasticities of the measure of partial risk aversion with respect to wealth and to income. The purpose of this comment is to derive that relationship theoretically and to point out the resulting inconsistencies in the original paper.     

A PORTFOLIO MODEL FOR EVALUATING RISK IN ECONOMIC DEVELOPMENT PROJECTS,WITH AN APPLICATION TO AGRICULTURE IN NIGER

After a literature review, a planning and project evaluation model is developed that includes both risk and profit considerations but avoids some weaknesses of other mean-variance models. Agricultural extension and project evaluation results of an application of this model are compared to those of the common profit-maximisation model. The two sets of results differ on the worth of intercropping, the relative merits of raising small ruminants and cattle, the likelihood of success of a major livestock development programme (which would benefit only wealthier farmers), the benefits of introducing labour-saving technologies, and the value of teaching/demonstration components in the projects being evaluated.     

我国大豆种植时空分布与风险费率研究

[目的]在我国大豆种植锐减、进口攀升和自然灾害加重的背景下,摸清我国大豆种植时空分布特征、风险费率对制定大豆种植和保险政策,保障大豆粮食安全有重要意义。[方法]文章依据1978—2016年全国省级大豆播种面积、产量、单产及进口等数据,基于风险损失和产量分布模型,运用数理统计、直线滑动平均模拟法和单产分布模型模拟推导法,分析全国大豆种植的时空分布变化,评估相应的生产风险并厘定各地大豆农业保险费率。[结果] 1978—2016年我国大部分省份都有大豆种植,1998年后,仅青海未种植大豆,东北和黄淮海地区一直是我国大豆主产区。2005年全国大豆达到最大播种面积959万hm~2,随后锐减,2015年仅为2005年的67.8%;产量变化趋势和面积变化趋势一致;平均单产为1 153 kg/hm~2,呈现出上升趋势。大豆进口逐年增加,2016年大豆进口总量8 391万t,创历史新高。全国大豆发生灾害风险的平均频率为27.24%,西藏、宁夏、陕西发生灾害风险的频率较高,各地呈现出轻灾(18.24%)中灾(5.74%)重灾(1.95%)巨灾(1.30%)的特征。全国大豆种植的平均费率为4.40%,陕西、河南、安徽、辽宁、吉林和内蒙古大豆种植大省的费率较高,而黑龙江大豆种植的费率则较低,为3.72%。[结论]我国大豆种植结构需要调整,在大豆种植大省,如陕西、河南、安徽等,降低种植面积;在保持黑龙江大豆种植优势的同时,发展河北、山东等低风险地区的大豆种植;在开展大豆农业保险时,实行地区差异化费率。     

SUPPLY RESPONSES IN CROP AND LIVESTOCK PRODUCTION

This paper is concerned with regression models of time series data, where the data relate to market level aggregates not to individual farms or groups of farms. It presents ideas and preliminary explorations rather than final results. Some aspects of Nerlove's agricultural supply response model are examined, and some conceptual and practical problems discussed. Two general models are then proposed, one for annual crops and one for livestock products. In the time available little empirical work could be undertaken, so that the usefulness, or otherwise, of the thoughts and models presented rests on rather little evidence.     

中国作物秸秆资源量估算与利用状况研究进展

该文用文献研究法、综合分析法研究中国主要农作物草谷比取值、中国作物秸秆资源量估算、中 国作物秸秆主要利用方式、秸秆利用存在的问题以及秸秆综合利用的对策。研究结论认为:（1）广义的秸 秆资源包括田间秸秆和农产品加工副产品。田间秸秆量的估算采用作物经济产量与收获指数或草谷比来计 算转换,农产品加工副产品量的估算多采用比重法。（2）目前对主要作物草谷比的取值以及秸秆资源量估 算结果尚存在较大差异。研究表明不同作物草谷比取值差异较大,同类作物受自然条件、品种差异、科技 水平等因素的影响也存在差异。因生长环境、播种面积、估算精度等因素不同,中国秸秆资源量估算结果 有年际差异和年内差异。（3）作物秸秆的利用方式主要有:秸秆还田、秸秆作饲料、秸秆作能源、秸秆作 工业原料和秸秆栽培食用菌,但目前作物秸秆利用效果尚难令人满意。秸秆资源利用仍存在利用率低、转 化率低、经济效益低和环境污染严重等问题。该文对中国作物秸秆资源量估算与利用状况进行综合研究, 提出今后的研究方向,应进一步规范秸秆资源量的估算范畴,准确测量和确定各地作物草谷比,探索秸秆 资源利用与主体产业的结合方式,拓展相关产业。     

遥感技术在“两区”作物种植结构监测中的应用研究——以黑龙江省富锦市为例

目的 粮食生产功能区和重要农产品生产保护区（以下简称“两区”）划定是确保国家粮食安全和保障重要农产品有效供给的重要举措。文章调查“两区”内作物实际种植情况,探索遥感技术在“两区”作物种植结构监测和“两区”数据更新中的应用方法。方法 以黑龙江省富锦市为研究区,以Landsat8多光谱影像为数据源,采用遥感监测技术,对研究区范围内2020年水稻、玉米和大豆3种作物种植情况进行监测,识别3种作物并提取地块边界,形成作物空间分布矢量图,与“两区”划定成果图叠加对比,分析“两区”划定情况与实际种植情况的一致性。结果 （1）富锦市水稻生产功能区内水稻实际种植面积占比88.2%,玉米生产功能区内玉米实际种植面积比例为17.8%,大豆实际种植面积占大豆生产功能区的68.8%。（2）富锦市实际种植情况与“两区”划定成果要求种植面积存在明显差异,差异大小因作物不同而不同,主要受当地自然条件、国家政策和农民种植意愿的影响。结论 鉴于遥感技术可以在“两区”作物种植监测中发挥特殊作用,建议农业农村部门采用遥感技术对“两区”范围内作物种品种和种植面积等情况进行动态监测,及时掌握实际种植情况并更新“两区”数据库,实现精细化管理,进而为决策部门优化农业种植结构,保障国家粮食安全。     

农作物空间格局变化研究进展评述

农作物空间格局及其时空动态变化研究具有重要的理论和实际意义,已经成为地理学和生态学的前沿和热点研究问题。该文从农作物空间格局变化的特征、机理机制和模拟模型等3个方面系统总结了国内外最新研究进展,讨论了研究中存在的关键问题,并对未来发展趋势和重点进行了展望。研究认为,农作物空间格局变化特征研究主要包括基于统计数据的方法、基于遥感信息的方法和基于空间模型的方法。农作物空间格局变化机理研究主要围绕不同自然 -社会经济驱动因子对农作物格局演变的作用机制开展,剖析农作物空间格局演变的内外部原因。农作物空间格局变化模拟模型从早期非空间模型发展到空间模型,而且越来较多模型对微观农户的作物选择或决策行为及其对农作物空间格局变化的影响给予了很多关注。在未来相当长的一段时间内,基于多尺度和多信息源数据融合的农作物空间格局变化特征提取、综合自然-社会经济多因素、宏观和微观多层次、静态和动态多机制的农作物空间格局变化机理分析、以及多学科和多方法综合的农作物空间格局变化模拟模型构建将是农作物空间格局变化研究的重点发展方向。     

我国农作物秸秆利用生态补偿制度探索与实践

目的 农作物秸秆综合利用通过生态系统内物质循环实现养分高效利用。系统总结国内外秸秆利用补偿政策,可为创设适合我国秸秆综合利用的生态补偿政策提供借鉴与参考,调动各方开展秸秆利用的积极性,促进生态的可持续发展。方法 文章通过分析国内外秸秆利用补偿政策,系统梳理秸秆利用生态补偿方面的研究与探索实践,对我国秸秆利用生态补偿制度的创设提出针对性建议。结果 我国秸秆综合利用政策正在逐步完善,初步形成了一定的政策框架体系。但与发达国家相比,我国主要通过行政手段推进农作物秸秆综合利用,参与主体和方式较为单一,需结合法律、政策和经济手段,构建一种市场化的生态补偿机制。结论 建议我国在未来的秸秆还田生态补偿工作中,要建立利益驱动和政策导向机制,加强政策法规建设、扩大补偿内容、完善配套支持政策、开展多形式宣传引导,推动秸秆利用高质量发展。     

基于遥感技术的耕地复种指数研究进展

复种是我国重要的农作制度之一,对于提高我国耕地综合生产能力和确保国家粮食安全具有重要作用。该文在介绍复种指数基本概念和研究方法的基础上,对基于遥感技术的耕地复种指数研究进展进行了评述,尤其对时序植被指数平滑方法和复种指数的判别方法等两个关键技术进行了详细阐述。该文提出了遥感技术和地面观测的结合将是未来耕地复种指数遥感监测的发展趋势之一。如何进行遥感数据平滑最优化处理,以及获取高时空分辨率遥感数据及规范准确的地面观测数据将是需要重点解决的关键问题。     

ON-FARM FACTORS INFLUENCING INVESTMENT IN CROP SOWING MACHINERY*

Farmers in grain industries make important decisions about investment in crop sowing machinery. This paper shows how some on-farm factors affect profit-maximising levels of investment in crop sowing machinery. The paper examines the effect on optimal investment of discontinuities in sowing opportunities, varietal portfolios and soil portfolios.     

农作物面积空间抽样调查研究进展

农作物面积信息对于准确估计农作物产量、制定农业政策和确保国家粮食安全具有重要意义。该文主要总结了国内外农作物面积空间抽样调查方法,主要回顾了美国、欧盟和中国的农作物面积空间抽样调查的发展历程。该文还预测了农作物面积空间抽样调查的发展趋势,希望能对农作物面积调查的研究和应用提供指导。