Rice cultivation and production are not environmentally friendly, despite its importance in worldwide diets. Pesticides and chemical fertilizers are used extensively in rice farming to increase yields and reduce insect and weed problems. Researchers have now discovered a solution to reduce pesticide use in rice fields by employing aquatic animals to help control weeds and boost crop yields.
Planting huge monocultures, or acres of the same crop, is a common practice in conventional farming. This exposes each crop to pests and weeds, which might wipe out the majority of a field. As a result, farmers use pesticides to keep weeds, pests, and illnesses out of their crops while also increasing yields.
But some farmers are testing ways to grow their crops while using natural methods to keep away pests and weeds.
“One example includes farmers experimenting with growing aquatic animals in rice paddies,” said Liang Guo, study author and postdoctoral fellow at the College of Life Sciences at Zhejiang University in Hangzhou, China. “Learning more about how these animals contribute to rice paddy ecosystems could help with producing rice in a more sustainable way.”
The research, published in eLife, analyzes three experiments and four years of study. In each experiment, the study authors considered rice grown alone or alongside carp, mitten crabs, or softshell turtles. According to the study, growing rice alongside these aquatic animals helped prevent weed growth.
The animals also improved decomposition of organic matter and ultimately provided better yields compared to the rice that was grown alone. The researchers found yields that were 8.7% to 12.1% higher than the control crop grown without the aquatic animals.
Lufeng Zhao, author of the study and a Ph.D. student at the College of Life Sciences at Zhejiang University, added that the nitrogen levels in the soil remained stable with the aquatic animals present, so less chemical fertilizers were needed for the rice. The animals were given feed, but they scavenged for up to half of their diet. In turn, the rice plants absorbed 13% to 35% of nitrogen from leftover feed that the animals didn’t eat.
“These results enhance our understanding of the roles of animals in agricultural ecosystems, and support the view that growing crops alongside animals has a number of benefits,” said Xin Chen, co-senior author of the study and an ecology professor at Zhejiang University. “In terms of rice production, adding aquatic animals to paddies may increase farmers’ profits as they can sell both the animals and the rice, spend less on fertilizer and pesticides, and charge more for sustainably grown products.”
This article by Paige Bennett was first published by EcoWatch on 24 February 2022. Lead Image: A local carp living with rice plants in the co-culture experiment. Lufeng Zhao (CC BY 4.0).
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