Climate change could increase rice yields

Date:
September 2, 2020
Source:
American Society of Agronomy
Summary:
Research reveals how rice ratooning practices can help Japanese
farmers increase rice yields.



FULL STORY ==========================================================================
Rice is the most consumed staple food in the world. It is especially
common in Asia, where hunger concerns are prevalent.


==========================================================================
Rice is classified as an annual plant, which means it completes its life
cycle within one growing season then dies. However, in some tropical
areas, rice can continue to grow year after year when taken care of
properly.

Just as grass grows back in a lawn after it is mowed, rice can be cut
after it is harvested, and the plant will regrow. The farming practice
of cutting the rice above ground and allowing it to regrow is called
ratooning.

Although Rice ratooning allows farmers to harvest more rice from the
same fields, it requires a longer growing season compared to traditional single- harvest rice farming.

In many areas of the world where rice is grown, a long growing season
isn't a problem due to the tropical climates. But in Japan, cooler
weather means rice ratooning has been a rare farming practice.

Hiroshi Nakano and a research team set out to learn more about the
potential of ratooning to help Japanese rice farmers. Nakano is a
researcher at the National Agriculture and Food Research Organization.



========================================================================== Average temperatures in Japan have been higher in recent years. As
climate change continues to affect the region, rice farmers may have
a longer window for growing rice. "Rice seedlings will be able to be transplanted earlier in the spring, and farmers can harvest rice later
into the year," explains Nakano.

"The goal of our research is to determine the effects of harvest time
and cutting height of the first harvest on the yield of the first
and second rice crops," says Nakano. "Ultimately, we want to propose
new farming strategies to increase yield as farmers in southwestern
Japan adjust to climate change." During the study on rice ratooning, researchers compared two harvest times and two cutting heights of the
first crop. After the first harvest, they collected the seeds from the
cut off portions of the rice plants. Researchers measured the yield by
counting and weighing the seeds. The second harvest of rice was done by
hand and the yield was determined in the same way.

The total grain yield and the yields from the first and second crops
were different depending on the harvest times and cutting heights. This
wasn't too surprising, since the team already knew harvest time and
height affected yield.

Rice plants harvested at the normal time for the first crop yielded more
seed than the rice plants harvested earlier. "That's because the plants
had more time to fill their spikelets with seed," explains Nakano.

"At both harvest times, rice harvested at the high cutting height had a
higher yield than the low cutting height," says Nakano. That's because
the plants cut at a higher height had access to more energy and nutrients stored in their leaves and stems.

"Our results suggest that combining the normal harvest time with the
high cutting height is important for increasing yield in rice ratooning
in southwestern Japan and similar climate regions," says Nakano. "This technology will likely increase rice grain yield in new environments
that arise through global climate change."

========================================================================== Story Source: Materials provided by American_Society_of_Agronomy. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Hiroshi Nakano, Ryo Tanaka, Hiroshi Wada, Midori Okami, Koji
Nakagomi,
Makoto Hakata. Breaking rice yield barrier with the ratooning
method under changing climatic conditions: A paradigm shift in
rice‐cropping systems in southwestern Japan. Agronomy Journal,
2020; DOI: 10.1002/agj2.20309 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/09/200902082347.htm

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