candidates

People have been cultivating rice for more than 9,000 years. Cultivated rice is an annual crop which is often extended to two crops a year by a process called ratooning, which is cutting back annual rice to obtain a second, weaker harvest.

An extensive project involving multiple institutions in China, the U.S., and Australia has been developing perennial rice. The researchers developed it through hybridization, crossing a type of Asian domesticated annual rice with a wild perennial rice from Africa. Using modern genetic tools to identify candidate plants, the team identified a promising hybrid in 2007, planted large-scale field experiments in 2016, and released the first commercial perennial rice variety, called PR23, in 2018.

The researchers spent five years studying the performance of the perennial rice alongside annual rice on farms in China’s Yunnan Province. For the most part, the yield of the perennial rice was equivalent to that of annual rice over a period of four years.

Because farmers don’t have to plant rice each season, growing perennial rice requires almost 60% less labor and saves nearly half the costs of seed, fertilizer, and other inputs.

Perennial rice is already changing the lives of more than 55,000 smallholder farmers in southern China and Uganda. The economic benefits vary by location, but overall profit increases ranged from 17% to 161% over annual rice.

There are already three perennial rice varieties available to farmers, but researchers aren’t done refining the crop. They plan to use their methodology to enhance traits such as aroma, disease resistance, and drought tolerance to newer versions.

**********

Web Links

Farmers in China, Uganda move to high-yielding, cost-saving perennial rice

Photo, posted February 25, 2002, courtesy of Matthieu Lelievre via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The United States installed 3.6 gigawatts of photovoltaic solar capacity in the first quarter of this year to reach a total installed capacity of 81.4 GW. That is enough to power about 16 million American homes. More than 2/3 of that capacity has been installed during the past five years.

There has been a boom in solar installations in recent years and, until the Covid-19 pandemic stuck, 2020 was expected to be the biggest year yet. Now the unprecedented health, social, and economic conditions in our country creates great uncertainty in such forecasts.

Nevertheless, the opportunities for growth in solar power continue to be substantial. A new report from the energy research firm Wood Mackenzie looked at the prospects for using the roof space of commercial buildings for solar power.

Currently, just 3.5% of commercial buildings in the U.S. have solar panels on their roofs. Another 1% of those buildings are attached to solar projects located off-site. The report looked at how many buildings are potential targets for solar projects.

After accounting for buildings that are too small or that use too little electricity to make solar power a worthwhile investment, the report estimated that 70% of commercial buildings in the U.S. – amounting to some 600,000 sites – are candidates for solar installations. Doing this would provide 145 GW of new solar capacity, which is nearly twice as much as currently exists in this country.

Commercial solar installations have their own unique logistical and financial challenges. While utility solar can scale to lower costs and residential solar has financing opportunities, commercial solar has neither. But ultimately, it represents an important opportunity for our future energy system.

**********

Web Links

U.S. Commercial Rooftops Hold 145 Gigawatts of Untapped Solar Potential

Photo, posted June 25, 2014, courtesy of Rob Baxter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.