Many people in the world rely on rice as a primary source of nutrition.
I don't, but I'm an exception. Rice is the most consumed staple food in the world, especially in Asia. Rice is classified as an annual plant, completing its life cycle within one growing season, then dies. But in some tropical areas, rice can continue to grow year after year when taken care of properly. Just like 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.
Rice ratooning allows farmers to harvest more rice from the same fields.
But it requires a longer growing season, compared to traditional single-harvest rice farming. In many areas where rice is grown, a long growing season is possible, due to the tropical climate. But in Japan, cooler weather means rice ratooning has been rare.
Hiroshi Nakano, a researcher at the National Agriculture and Food Research Organization, and a research team, set out to learn more about the potential of ratooning to help Japanese rice farmers. Average temperatures in Japan have been higher in recent years, so rice farmers should 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 ... we want to propose new farming strategies to increase yield as farmers in southwestern Japan adjust to climate change."
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."