关于农民增收问题的几点思考

缩小城乡差距，增加农民收入，需要在减轻农民负担的同时，努力扩大我国具有竞争优势的农产品出口，增加农业基础建设的投入，实施科教兴农战略，积极发展农村非农产业，加快农村富余劳动力的转移，拓展农民增收渠道。     

甘肃安西农业生态经济系统构成因素与效益的灰色关联分析

以安西县４５户农户为研究对象，对其农业生态经济系统的构成因素与效益进行了灰色关联分析研究。结果表明，系统中养殖业占有较大优势，但效益较差，认为在该系统中，发展经济作物，提高草食家畜的生产效益，才能提高农业生产的总效益。     

庆阳站持久高效草地农业优化模式

根据多年的技术资料和生产实际，采用线性规划法作为系统优化的基本方法，拟定了庆阳黄土高原试验站草地农业结构的优化模式。     

建立和发展农村社会化服务体系的探讨

运用系统学原理剖析了农村经济系统中农村社会化服务子系统的结构、功能、需求与供给,在揭示并分析我国农村在建立社会化服务体系实践中存在的矛盾与困惑的基础上,提出构成以乡镇经济联合社为依托,以农科教结合为核心内容的农村社会化服务体系的新观念与对策.     

广东外向型农业发展问题探讨

外向型农业是农业现代化的重要组成部分。改革开放以来,广东的外向型农业有了较大的发展,但就总体而言,其发展速度还远低于外向型经济的发展速度。因此,我们要使外向型农业登上一个新的台阶,必须制订合理的外向型农业发展战略和基本措施。     

用生态农业的观点试论林区草地的开发与利用

通过对地球所面临的资源、环境和人口“三大危机”的概述,表明了生态农业在林草业开发中的重要性。并从生态学和宏观发展战略角度论述了林草业开发利用的价值、途径、前景及对策。     

Landscape characteristics of disturbed shrubsteppe habitats in southwestern Idaho (U.S.A.)

We compared 5 zones in shrubsteppe habitats of southwestern Idaho to determine the effect of differing disturbance combinations on landscapes that once shared historically similar disturbance regimes. The primary consequence of agriculture, wildfires, and extensive fires ignited by the military during training activities was loss of native shrubs from the landscape. Agriculture created large square blocks on the landscape, and the landscape contained fewer small patches and more large shrub patches than non-agricultural areas. In contrast, fires left a more fragmented landscape. Repeated fires did not change the distribution of patch sizes, but decreased the total area of remaining shrublands and increased the distance between remaining shrub patches that provide seed sources. Military training with tracked vehicles was associated with a landscape characterized by small, closely spaced, shrub patches.Our results support the general model hypothesized for conversion of shrublands to annual grasslands by disturbance. Larger shrub patches in our region, historically resistant to fire spread and large-scale fires because of a perennial bunchgrass understory, were more fragmented than small patches. Presence of cheatgrass (Bromus tectorum), an exotic annual, was positively related to landscape patchiness and negatively related to number of shrub cells. Thus, cheatgrass dominance can contribute to further fragmentation and loss of the shrub patch by facilitating spread of subsequent fires, carried by continuous fuels, through the patch. The synergistic processes of fragmentation of shrub patches by disturbance, invasion and subsequent dominance by exotic annuals, and fire are converting shrubsteppe in southwestern Idaho to a new state dominated by exotic annual grasslands and high fire frequencies.     

Does kriging predict weed distributions accurately enough for site‐specific weed control?

Numerous studies have demonstrated the patchy distribution of weeds within fields. The majority of these studies have used discrete sampling, recording weed densities at the intersections of regular grids. In this study, Avena spp. seedlings were recorded on square grids at four sites. The data were then divided into test and real data sets using the whole, two-thirds and one-half of the data to evaluate the consistency of global variogram models and accuracy of ordinary kriging estimates. Kriging provided poor weed density estimates at both very low and high densities, i.e. data were smoothed when compared with true values. Grid sampling took considerable time and, therefore, money to complete, whereas continuous sampling with multispectral imagery (performed at one site) was much quicker and at a finer resolution. It is suggested that sampling systems that collect continuous rather than discrete data are currently more appropriate for site-specific weed management.     

中国的生态农业建设

介绍了生态农业的产生背景，论述了中国生态农业的发展历程及其特点，指出我国的生态农业既不同于西方的生态农业，也不完全是传统农业的回归，它是在中国具有的历史条件和生态经济条件下形成的一种多层次、多结构、多功能的集约经营管理的综合农业生产体系。简介了近20年来在我国生态农业实践中形成的几种成功的生态农业模式，同时对目前生态农业建设中应注意的问题进行了探讨。     

Spatial distribution of weeds in arable crops: are current sampling and analytical methods appropriate?

This paper reviews the literature concerning the spatial distribution of weeds; highlighting the limitations of our current sampling and analytical methodologies, and suggesting how these inadequacies can be addressed. Most research studies have used discrete sampling, i.e. weeds are counted within a quadrat, on a grid basis. Few have mapped weeds at a whole-field scale, either with a resolution appropriate to spraying operations or key ecological processes. Statistical analyses used to describe the data can be divided into two main types, spatially implicit (also at the scale of the sampling unit) or spatially explicit, in which the location of individuals is included in the analyses. Spatially implicit methods can be strongly affected by quadrat size and mean density and are of doubtful benefit. More attention is required to address sampling resolution issues for spatially explicit methods. Our understanding of the formation and dynamics of spatial pattern, as well as predicting the consequences of site-specific management, can be improved with models. Unfortunately, most models consider only newly expanding patches and appear incapable of predicting spatial distributions when an area has been fully invaded. More detailed biological information is required if models are to become more realistic and informative. We also need to ensure that we understand the spatial processes in the context of the whole field environment, to optimize the success of site-specific weed management in the longer term.