The use of soil cooling for growing temperate crops under tropical climate

Global climate changes have been reported to be affecting the already stressed agricultural ecosystem, especially temperate agriculture which is highly dependent on low soil temperature for optimum growth performance. The current trends of temperate agriculture include enclosed greenhouses or hydroponics techniques, but shown to be inadequate to produce temperate crops under hot and humid weather of tropical climate. This urges the need for a more sustainable farming system which is soil cooling method as described in this study. Soil cooling system cools the soils to temperate soil temperature ranges between 14.6 and 20.1 °C providing a conducive growth condition for temperate produce. The aim of this study is to confirm the usefulness of soil cooling for growing temperate crops under tropical climate. In this study, a model temperate crop, loose leaf lettuce, was grown in an enclosed greenhouse with soil cooling system for its 3-growth cycle. Air and soil temperatures were recorded during the lettuce growth. Lettuces were evaluated in terms of weight, height, number of leaves, leaf area and root length upon each harvest cycle. Under soil cooling, lettuces showed significant difference in average weight ( p < 0.05) and positive development in the roots, shoot and leaves of lettuces for its 3-growth cycle. The findings showed that soil cooling approach was able to prepare soils to temperate soil temperature which serves as a potential alternative for growing temperate crops in the future, throughout the year under unpredictable climate changes.