A comparison of different algorithms for the delineation of management zones

One approach to the application of site-specific techniques and technologies in precision agriculture is to subdivide a field into a few contiguous homogenous zones, often referred to as management zones (MZs). Delineating MZs can be based on some sort of clustering, however there is no widely accepted method. The application of fuzzy set theory to clustering has enabled researchers to account better for the continuous variation in natural phenomena. Moreover, the methods based on non-parametric density estimation can detect clusters of unequal size and dispersion. The objectives of this paper were to: (1) compare different procedures for creating management zones and (2) determine the relation of the MZs delineated with potential yield. One hundred georeferenced point measurements of soil and crop properties were obtained from a 12 ha field cropped with durum wheat for two seasons. The trial was carried out at the experimental farm of CRA-CER in Foggia (Italy). All variables were interpolated on a 1 × 1 m grid using the geostatistical techniques of kriging and cokriging. The techniques compared to identify MZs were: (1) the ISODATA method, (2) the fuzzy c-means algorithm and (3) a non-parametric density algorithm. The ISODATA method, which was the simplest, subdivided the field into three distinct classes of suitable size for uniform management, whereas the other two methods created two classes. The non-parametric density algorithm characterized the edge properties between adjacent clusters more efficiently than the fuzzy method. The clusters from the non-parametric density algorithm and yield maps for three seasons (2005–2006, 2006–2007 and 2007–2008) were compared and agreement measures were computed. The kappa coefficients for the three seasons were negative or small positive values which indicate only slight agreement. These results illustrate the importance of temporal variation in spatial variation of yield in rainfed conditions, which limits the use of the MZ approach.     

Delineation of management zones with spatial data fusion and belief theory

Precision Agriculture - Precision agriculture, as part of modern agriculture, thrives on an enormously growing amount of information and data for processing and application. The spatial data used...     

不同经管模式下猕猴桃园土壤动物群落结构的变化

【目的】了解不同经营管理模式下猕猴桃园土壤动物群落结构的特征差异,以期为区域农业生产可持续发展提供科学依据.【方法】采用手捡法和干湿漏斗法,于2015年5月,对都江堰市猕猴桃种植基地内3种不同经营管理模式(大棚羊粪地、大棚微生物菌肥地和大棚外露天微生物菌肥地)下的土壤动物群落进行调查.【结果】本次试验共捕获土壤动物868只,隶属于3门7纲10目28个类群;各样地土壤动物平均密度排序为大棚羊粪地(4.47×10~4只/m~2)棚内微生物菌肥地(8.19×10~4只/m~2)棚外微生物菌肥地(4.75×10~3只/m~2);各样地间土壤动物平均密度差异显著(P0.05);各土层的土壤动物个体数和平均密度随土层深度的增加而逐渐减少.【结论】相对于微生物菌肥,施用羊粪土壤动物更加丰富多样,大棚管理下比露天环境更适合土壤动物的生存和聚集.     

三种管理模式仁用杏园主要害虫与天敌动态研究

为制定创新合理的害虫管理方案提高杏园生态稳定性及经济效益,以北京延庆仁用杏主产区的杏园为例,研究了仁用杏园在3种管理模式(自然生草、间作黄芩、清耕)生态条件下的物种多样性指数、害虫亚群落物种数和个体数量和天敌亚群落物种数和个体数量的全年发生动态和特征。结果表明:自然生草园和间作黄芩园物种多样性指数较高;自然生草园害虫数量最高,其次为清耕园,间作黄芩园最低;间作黄芩杏园的天敌比例最高,其次为清耕园和自然生草园。杏园间作黄芩管理模式可以吸引天敌,控制害虫数量,维护杏园生态稳定。     

Management zones delineation using fuzzy clustering techniques in grapevines

Precision viticulture aims at managing vineyards at a sub-field scale according to the real needs of each part of the field. The current study focused on delineating management zones using fuzzy clustering techniques and developing a simplified approach for the comparison of zone maps. The study was carried out in a 1.0 ha commercial vineyard in Central Greece during 2009 and 2010. Variation of soil properties across the field was initially measured by means of electrical conductivity, soil depth and topography. To estimate grapevine canopy properties, NDVI was measured at different stages during the vine growth cycle. Yield and grape composition (must sugar content and total acidity) mapping was carried out at harvest. Soil properties, yield and grape composition parameters showed high spatial variability. All measured data were transformed on a 48-cell grid (10 × 20 m) and maps of two management zones were produced using the MZA software. Pixel-by-pixel comparison between maps of electrical conductivity, elevation, slope, soil depth and NDVI with yield and grape composition maps, set as reference parameters, allowed for the calculation of the degree of agreement, i.e. the percentage of pixels belonging to the same zone. The degree of agreement was used to select the best-suited parameters for final management zones delineation. For the year 2009 soil depth, early and mid season NDVI were used for yield-based management zones while for quality-based management zones ECa, early and mid season NDVI were utilized. For the year 2010 ECa, elevation and NDVI acquired during flowering and veraison were used for the delineation of yield-based management zones while for quality-based management zones ECa and NDVI acquired during flowering and harvest were utilized. Results presented here could be the basis for simple management zone delineation and subsequent improved vineyard management.     

Geostatistical and fuzzy clustering approach for delineation of site-specific management zones and yield-limiting factors in irrigated hot arid environment of India

Precision Agriculture - Delineation of management zones (MZs) are needed to manage fields in order to maximize economic return, minimize environmental impact, and improve soil and crop management....     

Delineating site-specific management zones for pH-induced iron chlorosis

Iron chlorosis can limit crop yield, especially on calcareous soil. Typical management for iron chlorosis includes the use of iron fertilizers or chlorosis tolerant cultivars. Calcareous and non-calcareous soil can be interspersed within fields. If chlorosis-prone areas within fields can be predicted accurately, site-specific use of iron fertilizers and chlorosis-tolerant cultivars might be more profitable than uniform management. In this study, the use of vegetation indices (VI) derived from aerial imagery, on-the-go measurement of soil pH and apparent soil electrical conductivity (EC_a) were evaluated for their potential to delineate chlorosis management zones. The study was conducted at six sites in 2004 and 2005. There was a significant statistical relationship between grain yield and selected properties at two sites (sites 1 (2005) and 3), moderate relationships at sites 2 and 4, and weak relationships at site 5. For sites 1 (2005) and 3, and generally across all sites, yield was predicted best with the combination of NDVI and deep EC_a. These two properties were used to delineate chlorosis management zones for all sites. Sites 1 and 3 showed a good relationship between delineated zones and the selected properties, and would be good candidates for site-specific chlorosis management. For site 5, differences in the properties between mapped zones were small, and the zones had weak relationships to yield. This site would be a poor candidate for site-specific chlorosis management. Based on this study, the delineation of chlorosis management zones from aerial imagery combined with soil EC_a appears to be a useful tool for the site-specific management of iron chlorosis.     

A comparison between mixed support kriging and block cokriging for modelling and combining spatial data with different support

Precision Agriculture - The paper proposes a geostatistical framework to solve the issues of heterogeneous support for spatial estimation. Apparent soil electrical conductivity (ECa) was measured...     

A wearable module for recording worker position in orchards

This paper describes the design and testing of a wearable position recording system for workers in orchards or in protected cultivation environments, where GPS data are typically unavailable. The major goal of the wearable system is to track worker position in relation to trees. This system consists of a pedometer and a small barcode reader and utilizes barcode tags permanently attached to fixed objects of known location (e.g., individual trees in an orchard). The pedometer computes a worker’s relative displacement with respect to a known starting position, and the barcode provides the absolute (starting) position information at regular intervals to keep the localization error at an acceptable level. Evaluations of the accuracy and reliability of the pedometer revealed a 2-3% accumulated error in the estimation of the worker’s position. The use of the pedometer alone was insufficient and could not establish correctly the association between trees and workers. The prototype system was implemented and tested during manual harvest in two commercial peach orchards. The fruit pickers’ movements were captured accurately and the association between producing tree(s) and fruit picker, as well as the sequence of the trees which the picker visited, were established correctly.     

安徽省热量资源空间分布模型及插值方法研究

【目的】对安徽省热量资源进行栅格化处理,解决无测站地区的热量资源估算问题,为区域农业气候资源评估提供依据。【方法】利用安徽省1971~2000年气象站地面资料,在地理信息系统技术(GIS)支持下,采用多元回归结合空间插值方法,建立安徽省热量资源要素空间分布模型,并比较反距离权重法(IDW)、克里格和样条函数3种空间插值方法的精度。【结果】基于GIS平台,建立了安徽省250 m×250 m分辨率的温度和积温栅格化数字地图。对空间插值方法的交叉验证结果表明,3种空间插值方法的平均绝对误差、平均误差平方的平方根排序均为IDW<克里格法<样条函数法,IDW法效果最优。【结论】应用GIS空间内插技术,构建高分辨率的栅格化热量资源要素集,可有效提高农业气候资源分析和利用的精细化程度。     

临安山核桃主产区土壤pH值和有效养分的时空变化

于2007-2008年在山核桃Carya Cathayensis主产区临安市岛石镇开展了山核桃林地周年土壤pH值和土壤有效养分状况的动态监测和调查研究。结果表明：随着山核桃的生长和施肥,易于变化的土壤肥力指标表现出明显的季节性动态波动。其中：从早春3月到山核桃果实成熟期（9月）土壤pH值下降明显;不同山核桃林地之间土壤pH值和土壤有效氮磷钾养分水平差异巨大。它们的变幅为：土壤pH 4.6～8.2,土壤有效氮、有效磷、有效钾分别为50.8～236.2 mg.kg-1,0.5～40.6 mg.kg-1,24.8～391.0 mg.kg-1。由于农户之间施肥管理水平不一,导致土壤pH值和养分状况很大的差异,部分山核桃林地土壤酸化严重,土壤养分不平衡现象普遍。建议根据土壤养分的实际情况,平衡施肥,保障山核桃产业稳步发展。     

Methodology for selective coffee harvesting in management zones of yield and maturation

Precision Agriculture - The non-uniformity of coffee fruit maturation is an intrinsic plant condition that is not favorable for the beverage quality. This could be overcome by using the precision...     

中美教育模式比较

20 0 1年 3月 2日《环球时报》报道 ,华裔教师在美国挺受欢迎 ,甚至有一位黄皮肤黑头发的中国人在讲《美国历史》。在美国 ,有 2 0 0 0多名华裔文科教授在大学执教 ,在中美相互了解和沟通中扮演着独特的角色 ,并且发挥了取长补短的重要作用。这使我们顿悟了许多。但是 ,不是所有中式教学方式都受欢迎 ,也有一些受到质疑。因此 ,华裔教授便改变策略 ,特别注意语言 ,认真改进教学方式和内容 ,还有意创造轻松的课堂气氛 ,甚至常常模仿有关节目来一两段笑话 ,以赢得学生和校方的好评。看来 ,光中式也是不行的。1　问题我们曾经特别崇尚美国的自…     

广东果园生物多样性利用与生态农业模式概述

分析了广东省果园利用的现状,指出全省果园利用中存在单一化种植尧病虫害多尧农药使用多尧循环产 业链短尧土地利用效率低尧外来入侵生物多尧土壤退化尧水土流失严重等问题。在此基础上,分别从结构尧效益以及地 域分布等方面阐述了当前广东省果园利用的典型生态模式,如野猪-沼-果冶模式尧野林-果-草-鱼冶模式尧野果-草-禽 （牧）冶模式尧果园养蜂模式尧果园套种蔬菜尧食用菌模式以及果园间作花生尧牧草模式等。     

涡阳县果园草害及其综合防除技术

介绍了涡阳县果园杂草的主要种类、危害和综合防除技术策略。     

Role of soil bed-banks in orchards with the fallow soil management system

The paper considers the properties of applying the fallow soil management system in apple orchards with a rectangular tree spacing resulting in the formation of bed-banks. The reasons for the low productivity of apple-trees in plots with an anthropogenic microrelief are substantiated. The ways for avoiding its negative effect in an orchard by changing the soil management method are suggested: grassing according to the sod-muck system and the fallow soil management system are recommended for interrows and tree rows, respectively.     

Data fusion techniques for delineation of site-specific management zones in a field in UK

Fusion of different data layers, such as data from soil analysis and proximal soil sensing, is essential to improve assessment of spatial variation in soil and yield. On-line visible and near infrared (Vis–NIR) spectroscopy have been proved to provide high resolution information about spatial variability of key soil properties. Multivariate geostatistics tools were successfully implemented for the delineation of management zones (MZs) for precision application of crop inputs. This research was conducted in a 18 ha field to delineate MZs, using a multi-source data set, which consisted of eight laboratory measured soil variables (pH, available phosphorus (P), cation exchange capacity, total nitrogen (TN), total carbon (TC), exchangeable potassium (K), sand, silt) and four on-line collected Vis–NIR spectra-based predicted soil variables (pH, P, K and moisture content). The latter set of data was predicted using the partial least squares regression (PLSR) technique. The quality of the calibration models was evaluated by cross-validation. Multi-collocated cokriging was applied to the soil and spectral data set to produce thematic spatial maps, whereas multi-collocated factor cokriging was applied to delineate MZ. The Vis–NIR predicted K was chosen as the exhaustive variable, because it was the most correlated with the soil variables. A yield map of barley was interpolated by means of the inverse distance weighting method and was then classified into 3 iso-frequency classes (low, medium and high). To assess the productivity potential of the different zones of the field, spatial association between MZs and yield classes was calculated. Results showed that the prediction performance of PLSR calibration models for pH, P, MC and K were of excellent to moderate quality. The geostatistical model revealed good performance. The estimates of the first regionalised factor produced three MZs of equal size in the studied field. The loading coefficients for TC, pH and TN of the first factor were highest and positive. This means that the first factor can be assumed as a synthetic indicator of soil fertility. The overall spatial association between the yield classes and MZs was about 40 %, which reveals that more than 50 % of the yield variation can be attributed to more dynamic factors than soil parameters, such as agro-meteorological conditions, plant diseases and nutrition stresses. Nevertheless, multivariate geostatistics proved to be an effective approach for site-specific management of agricultural fields.     

长绒棉氮肥运筹动态知识模型及系统仿真

通过对长绒棉氮肥运筹管理的最新资料的研究及实验论证,在分析氮肥对长绒棉产量、株高和叶面积影响的基础上,综合考虑气候条件、土壤理化性质、产量目标和品种特性等影响因子,根据养分平衡原理,建立长绒棉氮肥运筹的动态知识模型,并利用VC++开发平台和SQL Server数据库软件设计实现了长绒棉种植管理支持决策系统.     

Application of a web-based remote agro-ecological monitoring system for observing spatial distribution and dynamics of Bactrocera dorsalis in fruit orchards

Improving fruit farm profitability through integrated pest management (IPM) programs is always an important issue to modern agriculture systems. In order to enhance IPM programs against Bactrocera dorsalis, an automatic infield monitoring system is required to efficiently capture long-term and up-to-the-minute environmental fluctuations in a fruit farm. In this study, a remote agro-ecological monitoring system built upon wireless sensor networks has been developed to provide precision agriculture (PA) services with large-scale, long-distance, long-term, scalable, and real-time infield data collection capabilities. Historical data with spatial information is available through a web-based decision support program built upon a database. Pest population forecast results are also provided so that farmers and government officials would be able to accurately respond to infield variations. Compared with the previous version of the system, various useful functions have been added into the system, and its accuracy has been improved when measuring different parameters in the field. The system could provide a valuable framework for farmers and pest control officials to analyze the relations between population dynamics of the fruit fly and meteorological events. Based on the analysis, a better insect pest risk assessment and accurate decision-making strategy can be made as an aid to PA against B. dorsalis.