The impact of agricultural activities on water quality: a case for collaborative catchment-scale management using integrated wireless sensor networks

The challenge of improving water quality is a growing global concern, typified by the European Commission Water Framework Directive and the United States Clean Water Act. The main drivers of poor water quality are economics, poor water management, agricultural practices and urban development. This paper reviews the extensive role of non-point sources, in particular the outdated agricultural practices, with respect to nutrient and contaminant contributions. Water quality monitoring (WQM) is currently undertaken through a number of data acquisition methods from grab sampling to satellite based remote sensing of water bodies. Based on the surveyed sampling methods and their numerous limitations, it is proposed that wireless sensor networks (WSNs), despite their own limitations, are still very attractive and effective for real-time spatio-temporal data collection for WQM applications. WSNs have been employed for WQM of surface and ground water and catchments, and have been fundamental in advancing the knowledge of contaminants trends through their high resolution observations. However, these applications have yet to explore the implementation and impact of this technology for management and control decisions, to minimize and prevent individual stakeholder’s contributions, in an autonomous and dynamic manner. Here, the potential of WSN-controlled agricultural activities and different environmental compartments for integrated water quality management is presented and limitations of WSN in agriculture and WQM are identified. Finally, a case for collaborative networks at catchment scale is proposed for enabling cooperation among individually networked activities/stakeholders (farming activities, water bodies) for integrated water quality monitoring, control and management

A new wireless underground network system for continuous monitoring of soil water contents

A new stand-alone wireless embedded network system has been developed recently for continuous monitoring of soil water contents at multiple depths. This paper presents information on the technical aspects of the system, including the applied sensor technology, the wireless communication protocols, the gateway station for data collection, and data transfer to an end user Web page for disseminating results to targeted audiences. Results from the first test of the network system are presented and discussed, including lessons learned so far and actions to be undertaken in the near future to improve and enhance the operability of this innovative measurement approac

ANTENNA FOR WIRELESS UNDERGROUND COMMUNICATION

Systems and methods are disclosed for an underground antenna structure for radiating through a dissipative medium, the antenna structure. The antenna structure includes a dielectric substrate, a feeding structure disposed on the substrate, and one or more electrical conductors. The one or more electrical conductors are disposed on the substrate, oriented, and buried within the dissipative medium. The electrical conductors are also adapted to radiate signals at a frequency in half-space adjacent to the dissipative medium. The adaptation includes a beamwidth state for one or more of the electrical conductors based at least in part on the relative permittivity of the dissipative medium

Dynamic connectivity in wireless underground sensor networks

In wireless underground sensor networks (WUSNs), due to the dynamic underground channel characteristics and the heterogeneous network architecture, the connectivity analysis is much more complicated than in the terrestrial wireless sensor networks and ad hoc networks, which was not addressed before, to our knowledge. In this paper, a mathematical model is developed to analyze the dynamic connectivity in WUSNs, which captures the effects of environmental parameters such as the soil composition and the random soil moisture, and system parameters such as the operating frequency, the sensor burial depth, the sink antenna height, the density of the sensor and sink devices, the tolerable latency of the networks, and the number and the mobility of the above-ground sinks. The lower and upper bounds of the connectivity probability are derived to analytically provide principles and guidelines for the design and deployment of WUSNs in various environmental conditions.US National Science Foundation (NSF) Grant No. CCF-0728889http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=7742ai201

Root Zone Sensors for Irrigation Management in Intensive Agriculture

Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency is decisive to sustain the food demand from a fast-growing world population. This objective may be accomplished by cultivating more water-efficient crop species and/or through the application of efficient irrigation systems, which includes the implementation of a suitable method for precise scheduling. At the farm level, irrigation is generally scheduled based on the grower’s experience or on the determination of soil water balance (weather-based method). An alternative approach entails the measurement of soil water status. Expensive and sophisticated root zone sensors (RZS), such as neutron probes, are available for the use of soil and plant scientists, while cheap and practical devices are needed for irrigation management in commercial crops. The paper illustrates the main features of RZS’ (for both soil moisture and salinity) marketed for the irrigation industry and discusses how such sensors may be integrated in a wireless network for computer-controlled irrigation and used for innovative irrigation strategies, such as deficit or dual-water irrigation. The paper also consider the main results of recent or current research works conducted by the authors in Tuscany (Italy) on the irrigation management of container-grown ornamental plants, which is an important agricultural sector in Italy