Liang Yuxin (left) planted more than 1 hectare of perennial rice in the southwestern province of Guangxi. Photo: Liang Yuxin (Collected).
More than 40,000 small farmers in China Yunnan University
researchers have chosen to plant perennial varieties developed by PR23. Other
perennials offer good yields, low costs and high soil quality, with repeated
crops without transplanting.
When Liang Yuxin first heard about a new rice variety that
could be harvested for years without replanting, he was eager to try it out.
If his experiment was successful, it would give confidence
to local farmers, said Liang, the representative of a farmers’ cooperative in
China’s southwestern region of Guangxi.
“There are many plots lying fallow in the rural areas of
southern China and the planting cost is high. But if I can plant rice once and
reap harvests for several years, the cost will be greatly reduced,” Liang said.
“Why won’t I try it?”
Liang is one of more than 40,000 small farmers in China who
have chosen to plant this new kind of rice.
Developed by researchers from Yunnan University over two
decades, the perennial rice variety has not only demonstrated yield potential but also lowered costs and enhanced soil quality, according to a study
published recently in the peer-reviewed journal Nature Sustainability.
The researchers crossed an Asian domesticated annual rice
cultivar with a wild perennial African variety to create a new hybrid, which
they called Perennial Rice 23 (PR23).
Its yield has been shown to be slightly higher than that for
annual rice for the first four years, at an average of 6.8 tonnes per hectare
(2.5 acres) per season, compared to 6.7 tonnes of the replanted variety.
While the costs are similar for both kinds of rice in the
first season, the perennial variety does not need seeding, planting and
plowing for several years, which means farmers can save up to US$1,400 per
subsequent season.
Overall, perennial rice can cut labor costs by 60 percent and halve input costs for each regrowth cycle. The net economic benefits can range from 17 percent to as much as 161 percent above annual rice in different planting locations, according to the authors of the study.
PR23 was made commercially available for Chinese farmers in
2018 and was among the 29 varieties recommended to them by the Ministry of
Agriculture and Rural Affairs earlier this year.
Last year, the total planted area of perennial rice in China
was over 15,000 hectares, four times higher than in 2020.
Liang planted another perennial variety, the PR25, across
more than 1 hectare in August and harvested over 8 tonnes three months later.
“We have confidence in perennial rice,” said Liang, who aims
to further expand his area of cultivation.
“Normally it is very hard to earn money by growing rice. But
after planting perennial rice, I am pleased that [we can] make some money if we
manage it well. It will be a great boon to farmers if its cultivation is
promoted.”
Erik Sacks, professor in the crop sciences department at the
University of Illinois Urbana-Champaign and co-author of the study, said less
frequent plowing in the perennial rice system conserved soil and built
organic matter content.
“Soils with high organic matter are more productive than
soils with low organic matter because the organic matter can loosely hold onto
plant nutrients and make them available for crop growth,” he explained.
Growing perennial rice also saved water, as less water was
needed to obtain “ratoon crops” – or second harvests – of rice, compared with
getting a new crop from seeds or transplanted seedlings, Sacks added.
Lead author Zhang Shilai, a professor at Yunnan University’s
School of Agriculture, said the team will continue to work on developing
cold-tolerant, heat-tolerant, and disease-resistant varieties so that they can
be promoted over larger regions.
“We promoted perennial rice across Yunnan and addressed the
key issues that matter most to farmers: yields, costs, taste and stable
production across multiple seasons. Many of these farmers grow rice as a staple
food for their families, so perennial rice must compete against other rice
varieties,” Zhang said.
In April, Yunnan University and genomics organization BGI
Group set up a perennial rice joint venture, focusing on large-scale
localization.
However, the study also noted challenges with pests, diseases
and weeds, which might be easier to control in annual crops.
“But perennial rice is still a very new crop, and we predict
that cropping systems and pest-resistant varieties will be developed,” said Tim
Crews, study co-author and chief scientist at The Land Institute, a
Kansas-based non-profit organization.
The new perennial varieties hold special significance for
China. The world’s most populous country is also its top consumer of rice,
accounting for about 30 percent of total global demand.
Source:
Online/KSU
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