With dwindling water supplies, the timing of rainfall matters

When you give your plants more water, it counts, according to a new study.

The research team created artificial rain to look at the effects on plants over the course of two years. This region has both winter and summer growing seasons that are impacted by the weather.

Desert wildflowers and grasses are usually dead by June. There are two communities of plants in July and August. The wildflowers that make for an extremely popular tourist attraction are included.

We wanted to know if one season is more sensitive to climate change than the other.

In the summer, plants grow more when given more water and more rain. The same was not true in winter.

Adding water in the summer gets us more bang for our buck.

Their paper was published in the University of California journal.

The team observed 24 plots of land in the Palm Desert area. Some of the plots got rain. They were only allowed to get rain in one season. A third group of plots received additional rain.

Adding water in the summer did not increase the diversity of plants that grew. Decreasing rainfall had negative effects on plants across both summer and winter, but may lead to increased growth in the following off-seasons.

When additional water resources are applied to help plants grow, the work's implications extend beyond learning. These plants are important for the whole community of animals. They play a big role in controlling erosion and movement of soils by wind, and they are critical for pollinators such as bees and butterflies.

Studies like this one are critical for understanding the complex effects of climate change on dryland ecosystems, said Darrel Jenerette, UCR landscape ecologist and study co-author.

Desert plants remove carbon dioxide and nitrogen from the atmosphere to use as fuel for growth. Microbes that live in the soil can use the carbon and nitrogen released by plant roots to change the climate in the atmosphere.

Even small changes in the way they take in and emit carbon or nitrogen could have a big impact on the atmosphere.

The team expects to see changes in soil carbon and nitrogen cycling over the next few years, given that plants are already being affected by changes in seasonal rainfall.

Can changes in precipitation patterns alter the feedback between plants and microbes, destabilizing the carbon locked in soils and sending more of it into the atmosphere? Homyak said that they are working on figuring that out.

More information: Marko J. Spasojevic et al, Altered precipitation has asymmetric impacts on annual plant communities in warm and cool growing seasons, Elementa: Science of the Anthropocene (2022). DOI: 10.1525/elementa.2021.00014 Citation: With dwindling water supplies, the timing of rainfall matters (2022, April 18) retrieved 18 April 2022 from https://phys.org/news/2022-04-dwindling-rainfall.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.