浅谈精准农业与农业可持续发展

世纪之交,精准农业成为农业高新技术应用研究的“热门”课题。本文认为实施精准农业是促进农业可持续发展的有效途径,必将对我国农业生产产生重大影响。根据我国是1个农业大国,农业是国民经济基础产业的国情,剖析精准农业发展的理论基础和技术体系,探讨我国推进精准农业的难点及应采取的措施具有重要的意义。     

Farm and Operator Characteristics Affecting the Awareness and Adoption of Precision Agriculture Technologies in the US

Precision agriculture (PA) technologies have been commercially available since the early 1990s. However, not only has the pace of adoption in the US been relatively modest but a surprisingly large number of producers are not familiar with these technologies. Using farm level survey data, this study quantifies the role that awareness plays in the decision to adopt PA technology and allows us to explore the potential for public or private information programs to affect the diffusion of PA. PA adoption and awareness are modeled as jointly determined dichotomous variables and their determinants are estimated using a two-stage (i.e. instrumental variable) logistic specification. The first-stage logit model indicated that operator education and computer literacy, full-time farming, and farm size positively affected the probability of PA awareness while the effect of age was negative. Grain and oilseed farms (i.e. corn, soybean, and small grains) and specialty crop farms (i.e. fruits, vegetables, and nuts) as well as farms located in the Heartland and Northern Great Plains regions were most likely to be aware of PA technologies. The second-stage PA adoption logit model, which included an instrumental variable to account for the endogeneity of awareness, revealed that farm size, full-time farming, and computer literacy positively influenced the likelihood of PA adoption. Grain and oilseed farms were the most likely types of farms to adopt PA as were farms in the Heartland region. Awareness, as defined in this study, was not found to be limiting the adoption of PA, suggesting that farmers for whom the technology is profitable are already aware of the technology and that a sector-wide public or private initiative to disseminate PA information would not likely have a major impact on PA diffusion.     

Educational Resources for Precision Agriculture

As site-specific management evolved into precision agriculture and began to be adopted by producers in the late 1980s and early 1990s, information about precision agriculture emerged in a variety of forms. Much of the information was initially available only in industry guides and popular press articles, such as Successful Farming and Farm Journal. Today, a variety of educational resources for both producers and advisors on precision agriculture has emerged, including books, proceedings of conferences, Extension bulletins, newsletters, industry guides, and multimedia modules. Recently, the Internet has had a significant influence on the production and dissemination of information on precision agriculture. The Internet has been a particularly valuable mode of information exchange due to the rapid evolution of technology and practices associated with precision agriculture, and because many of the early adopters of precision agriculture technologies were also early adopters of electronic communication technologies.     

噪声对瞬时测频接收机性能的影响

瞬时测频接收机性能最基本的要求就是测频精度，而空问内的各种非接收信号的电磁辐射源和由于各种反射体引起与接收信号路程差的反射信号等噪声信号，对瞬时测频接收机的测频精度和频率的分辨力的性能有着不可忽视的影响，并且这种影响具有不确定性。本文着重分析了噪声对瞬时测频接收机测频误差、系统的灵敏度及接收机的虚警概率和探测概率所造成的影响。     

除草剂变量施药技术的研究现状与进展

除草剂的田间大面积均匀喷洒不仅造成了浪费,而且加剧了环境污染,作为精确农业关键技术的除草剂的变量施药能够精确地对准杂草喷洒除草剂,从而有效地减少除草剂用量,降低了农业生产成本、减轻了环境污染压力。文章介绍了基于颜色、形状、纹理、光谱、位置特征的计算机视觉杂草识别技术;给出了变量施药技术的概念和介绍了变量施药技术的国内和国外的研究概况,并探讨了该技术的实施难点和未来研究发展方向。     

散乱数据光顺拟合的SOR方法

针对CAGD中散乱数据光顺拟合的一般模型的求解问题，采用罚函数方法处理几何约束。根据最优性条件，将反映曲面光顺性的泛函极小化问题，离散化为曲面参数域网格点上的九点差分格式。得到了关于拟合曲面在网格点上函数值的线性方程组，并证明了该线性方程组的系数矩阵对称正定的性质．保证了采用超松弛法求解线性方程组的收敛性。为了验证所提出方法的有效性，对空间散乱分布的14个数据点，当模型参数取不同值时。分别进行了拟合。试验结果表明，用超松弛法能够简单快速实现散乱数据点的光顺拟合。     

XG—15功率油耗检测仪的研制

为了同步测量１５ＫＷ以下的农用手扶拖拉机和小型柴油机的功率油耗，ＸＧ１５功率油耗自动检测仪选用Ｓ形拉压力传感器测量加在柴油机飞轮上的正压力所产生的摩擦力，光电式转速传感染测量柴油机的转速，微压力传感器测量柴油机的耗油量，采用单片微机对测量的信号进行运算处理。结果表明，测量的数据可靠，误差小，为小型柴油机的适时检修提供了科学的依据。     

On-line Sensor Pendulum-Meter for Determination of Plant Mass

A vehicle-based mechanical sensor (pendulum-meter) was developed to measure the plant mass of crops. For testing under defined conditions, a dynamometer with pendulum-meter, sensory and electronic equipment was developed. The ability and accuracy of the sensor for measuring plant mass in different crops (winter wheat, winter rye, grass, rice) and different growth stages are discussed in this paper. Parameter trials were done for optimising pendulum parameters. The correlations between plant mass and pendulum angle measurements were good (r ² < 0.89) for all pendulum parameters, with no significant differences between suitable parameters. The speed of the pendulum-meter causes a linear increase of the measured pendulum angle. The pendulum-meter is of simple construction.     

精准农业与变量施肥技术

本文以精准农业为背景,介绍了变量施肥的概念和关键技术。结合黑龙江垦区发展变量施肥技术作了一些探索,探讨了当前精确变量施肥技术的发展和不足。     

Comparison of Statistical Models for Regional Crop Trial Analysis

Based on the review and comparison of main statistical analysis models for estimating varietyenvironment cell means in regional crop trials, a new statistical model, LR-PCA composite model was proposed, and the predictive precision of these models were compared by cross validation of an example data. Results showed that the order of model precision was LR-PCA model ＞ AMMI model ＞ PCA model ＞ Treatment Means (TM) model ＞ Linear Regression (LR) model ＞ Additive Main Effects ANOVA model. The precision gain factor of LR-PCA model was 1.55, increasing by 8.4% compared with AMMI.