What is a rainout shelter?
A rainout shelter refers to a structure that is designed to ensure that a certain area of land does not receive any precipitations through rain so that experimentally controlled drought stress can be induced in the protected area. This is done to understand the drought tolerance in plants. These shelters incorporate sensitive rain sensor that actives electric motors to move the shelters across the area using a chain drive to cover the crops incase of rain. A system of drip irrigation can be installed to water the plants and the water levels can be controlled with the automated system. Pesticides and additional nutrients can be distributed using the drip irrigation system as well.
Benefits of rainout shelters:
• Helps in studying the drought tolerance of plants
• Understanding how rainfall influences crops
• Relation between plant productivity and natural irrigation through rain
The rainout shelters provide a precise separation of the roots and the tree canopy from natural rainfall while maintain a natural flow of air, temperature and humidity. Below the soil level, the barriers to prevent the movement of moisture can extend for 1 meter and this prevents lateral movements. Naturally occurring rainfall can be measured and then replicated in a controlled format to understand the effects of drought on the plants and trees.
The rainout shelters are equipped with external environmental sensors that are directly linked to data loggers to measure wind speed, relative humidity, air temperature, soil temperature, soil moisture and light at different levels and throughout the location. Creating a sustainable link where the rain water that is run off from the shelter walls can be collected and stored in a tank which can be reused in the shelter as needed for irrigation of other purposes.
A set of rain sensors alert the automatically retractable roofs and curtains of the shelter that close as soon as rain is detected and ensure that little to no rain enters the structure.
There are 2 main designs of a rainout shelter:
- Moveable shelter: the moveable shelter can be an automatic or manually operated structure where the shelter is closed during rains. The automatic system has a set of sensors that detect rain and signal the electric drive system to close the structure. In a manual system, the structure is closed by wither manually driving the roof or pushing it using human labor over the plot. The manual version can be incorporated in a small scale and is not feasible for multiple structures in the same location or for a larger study.
- Static shelter: this refers to a structure of a greenhouse that can be rain-proofed as and when required. The main advantage of this is that during non-rainy seasons the greenhouse is well ventilated and the plants are in touch with the natural environment and climate. There are drip irrigation systems installed to ensure that the plants have enough moisture when the greenhouse is closed and converted in to a rain out shelter.