S. Fountas

The Analysis of Spatial and Temporal Trends in Yield Map Data over Six Years

Abstract A quantitative analysis of yield data from four fields over 6 years was carried out to identify the spatial and temporal trends. The methodology was modified from previous work to separate the temporal effects into two parts; the inter-year offset and the temporal variance. The inter-year offset quantifies the overall differences in yield between 1 year and the next, whereas the temporal variance indicates the amount of change at a particular point over time. Results from these fields show that the significant spatial variability found within each individual yield map cancelled out over time, leaving a relatively homogenous spatial trend map. The implications of these findings are that each field should be managed according to the current years’ conditions.

Agricultural robots—system analysis and economic feasibility

This paper focuses on the economic feasibility of applying autonomous robotic vehicles compared to conventional systems in three different applications: robotic weeding in high value crops (particularly sugar beet), crop scouting in cereals and grass cutting on golf courses. The comparison was based on a systems analysis and an individual economic feasibility study for each of the three applications. The results showed that in all three scenarios, the robotic applications are more economically feasible than the conventional systems. The high cost of real time kinematics Global Positioning System (RTK-GPS) and the small capacity of the vehicles are the main parameters that increase the cost of the robotic systems.

Farmer Experience with Precision Agriculture in Denmark and the US Eastern Corn Belt

Abstract.Two mail surveys were carried out in Denmark and the Eastern Corn Belt, USA in 2002. Questionnaires were sent to 580 farmers who had used precision agriculture (PA) and 198 responses were received. The surveys focused on the current status of use of PA in both countries, including: PA practices, equipment and software, Internet and e-mail use, information sources for PA, satisfaction level from service providers, data handling, interpretation, storage and ownership, value of data for decision making, changes in management practices, desired information and services, and the next planned step in the practice of PA. The survey results showed more similarities in practicing PA between the two countries than differences. Time requirement and high cost of data handling were cited as the main problems. Survey respondents found soil maps to be more valuable than yield maps in management decisions. About 80% of the respondents would like to store the PA data themselves. The majority of the respondents indicated that they have changed their management practices due to PA, but not substantially. Some 90 of the respondents used the Internet and e-mail for agricultural purposes, but only a small number for PA websites.

Adoption and perspectives of precision farming in Denmark

Precision farming (PF) and site-specific input application based on GPS has been a management tool and option for arable farmers for about 10 years. About 400 Danish farmers have already adopted some PF practices on their farms. This adoption and the technical and economic perspectives of PF have been studied in two mail surveys, personal interviews and focus groups with farmers, advisers and experts. Farmers and stakeholders are in general optimistic about the future perspectives of these high-technology systems despite the difficulties in showing the economic and environmental gains. Lack of compatibility between different technical systems is however mentioned as a barrier for adoption.

A two-stage optimal motion planner for autonomous agricultural vehicles

This paper presents a two-stage motion planning algorithm which can compute low-cost motions for autonomous agricultural vehicles, for a given cost function defined over the entire path (e.g., shortest path, maximum clearance, etc.). In the first stage, the algorithm utilizes randomized motion planning to explore the space of possible motions and computes a feasible sub-optimal trajectory. In the second stage, the optimization of the stage-1 motion is formulated within the optimal control framework and function-space gradient descent is used to minimize the cost of the entire motion. The numerical results suggest that the two-stage motion planner can compute optimal or quasi-optimal motions in free space very quickly. In the presence of obstacles however, the execution time increases significantly. Furthermore, kino-dynamic, or dynamic motion models seem to be necessary in order to produce smooth motion trajectories.

Specification of Behavioural Requirements for an Autonomous Tractor

Over the last decade new information technologies, such as GPS and GIS, have been introducedthat has allowed the scale of management to be reduced from farm level, down to field level andoccasionally to sub field level. With the advent of new information technologies, such asbehaviour-based robotics, this process can be continued into the future by looking at an evensmaller scale such as plant scale technology or Phytotechnology. (From the Greek phyto, whichmeans plant) These new Phytotechnology units will be small autonomous systems that canbehave in a sensible manner for long periods unattended, caring for the individual plant fromseeding through to selective harvesting. With this level of sophisticated equipment, it is likelythat higher value crops such as in horticulture or forestry will be able to justify such aninvestment first. Very little new hardware is needed but the challenge is in defining andimplementing sensible behaviour and developing the systems architecture to support it. Thispaper sets out the criteria for the design of such a system.

A systems analysis of information system requirements for an experimental farm

A systems analysis and design of information requirements for an experimental farm is presented. This study was carried out on the university farm (UF) at the University of Copenhagen in Denmark. The UF has several farm sites, many employees and clients, and collects data on the spatial variability of sites for site-specific management, and is responsible for running field trials. Soft and hard system analyses were performed to better understand the information needs and design an information system for the UF. Soft systems methodology was used to analyse the human activities and to identify user requirements, while a hard systems methodology was used to structure the data handling inside the farm office. The resulting information management system (IMS) includes modules for storage, processing and presentation of spatio-temporal data for research trials and site-specific management. A GIS-based farm IMS including the necessary interfaces was implemented and validated by the UF manager and staff. Limitations and constraints to the full implementation of the IMS in an experimental farm are also discussed.

Proposed System Architecture to Enable Behavioral Control of an Autonomous Tractor

To allow emergent behavior from an autonomous tractor, a new sophisticated system architectureis proposed. It is fundamentally object oriented with only high-level message passing betweenthe objects that allow the overall system to be developed without the complexity becoming toogreat to manage. Each of the agents (Coordinator, Supervisor, Mode Changer, Route PlanGenerator, Detailed Route Plan Generator, Multiple Object Tracking, Object Classifier andHardware Abstraction Layer) could be implemented as separate processors or job-computers ona common bus. This paper describes the overall layout and functions of the elements within thesystem and gives examples of identified instances.

A METHOD TO DEFINE AGRICULTURAL ROBOT BEHAVIOURS

A new method is described that can be used to decompose human controlled agricultural operations into an autonomous tractor. Four main levels of subsumption have been identified: Operation, Task, Optimisation and Primitive Actions where each level is subsumed by the level above. Tasks were classified into two distinctive roles, deterministic tasks that can be planned and optimised before the operation begins and reactive tasks and their associated behaviours that deal with unknown conditions whilst in the field. The tasks and optimisations can be further decomposed into primitive actions, which in turn are converted into the tractor directrix. Examples of this method are given for exploring an unknown area and ploughing a field.

Wireless Sensor Network for Precision Agriculture

Irregular or insufficient rainfall can be a serious limitation to the final yield, causing low yields and even crop failure. Moreover the total amount of water is assessed during the growing stages by the plants¢ characteristics. It is possible, however, to find out how much soil moisture by using sensors This can help farmers in decision making Furthermore the combination of soil moisture sensors with management zones may lead to increase of the final yield. The aim of this research was to calibrate and install the WATERMARK sensors in a commercial vineyard according to the Precision Agriculture practices. The results of the research proved that the WATERMARK sensors can assess the soil moisture with high accuracy (R2 = 0.85).