Evaluating the Efficiency of Wicking Bed Irrigation Systems for Small-Scale Urban Agriculture

iPOTs: Internet of Things-based pot system controlling optional treatment of soil water condition for plant phenotyping under drought stress

A cultivation facility that can assist users in controlling the soil water condition is needed for accurately phenotyping plants under drought stress in an artificial environment. Here we report the Internet of Things-based pot system controlling optional treatment of soil water condition (iPOTs), an automatic irrigation system that mimics the drought condition in a growth chamber. The Wi-Fi-enabled iPOTs system allows water supply from the bottom of the pot, based on the soil water level set by the user, and automatically controls the soil water level at a desired depth. The iPOTs also allows users to monitor environmental parameters, such as soil temperature, air temperature, humidity, and light intensity, in each pot. To verify whether the iPOTs mimics the drought condition, we conducted a drought stress test on rice (Oryza sativa L.) varieties and near-isogenic lines, with diverse root system architecture, using the iPOTs system installed in a growth chamber. Similar to the results of a previous drought stress field trial, the growth of shallow-rooted rice accessions was severely affected by drought stress compared with that of deep-rooted accessions. The microclimate data obtained using the iPOTs system increased the accuracy of plant growth evaluation. Transcriptome analysis revealed that pot positions in the growth chamber had little impact on plant growth. Together, these results suggest that the iPOTs system is a reliable platform for phenotyping plants under drought stress.

Productivity, resource efficiency and financial savings: An investigation of the current capabilities and potential of South Australian home food gardens

As the dominant form of urban agriculture (UA) in Australia, existing home food gardens potentially represent a significant resource in the context of future urban food security and sustainability. However, a severe lack of in-field data has hindered our understanding of the form and function of home food gardens which in turn may hinder innovation and improvement. We investigated the productivity, resource efficiency and potential financial savings of home food gardens in South Australia. A group of 34 citizen science participants measured and recorded inputs and outputs from their gardens. Inputs included time spent on various gardening activities, financial costs, and water use. Outputs included crop yields, from which retail value and nutritional content were then derived. The paper outlines a field-demonstrated, comprehensive methodology for continued and consistent data collection for all forms of UA. We found smaller gardens to be more intensive than larger gardens, requiring higher inputs, but also returning higher outputs per unit area. Both productivity and resource efficiency varied among the gardens, and labour requirements were significantly lower than previously estimated. Water use efficiency of the gardens were calculated and found to have comparable water use efficiency to commercial horticulture. Of the gardens involved, we calculated that 65% should break even in five or less years and save money. After applying a minimum wage almost one in five gardens were financially viable. The results represent the most comprehensive measurements on home food gardens to date, and allow practical, evidence-based recommendations for diversification, time saving and smart irrigation practices to improve garden productivity and enhance the viability of UA.

A Semi-Systematic Review of Capillary Irrigation: The Benefits, Limitations, and Opportunities

Capillary irrigation systems have been investigated for some years as a means to deliver water to plants in container gardening. This review paper identifies that traditional capillary irrigation systems such as capillary wicks, capillary mats, and ebb and flow systems have been shown to produce higher crop yields and use less water than conventional irrigation methods. In addition, capillary irrigation offers an added advantage by reducing the volume of potentially harmful leachate into surrounding soil environments. However, these systems are basically limited to small pot sizes and are widely used for growing ornamental and nursery plants in glasshouse conditions. Further, the cost and complexity of Negative Pressure Difference Irrigation may have limited its practical use. Conversely, wicking beds (WBs) are low-tech and water-efficient systems which can be used for growing plants with different rooting depths. Irrespective of the wide acceptance of WBs among the growing community, this review recognises that there is no published research providing design recommendations for WBs and their expected performance relative to other irrigation systems. Therefore, some potential advantages of WBs are noted in the context of capillary irrigation research; however, a substantial knowledge gap exists relating to the optimised design and use of WBs.