Prediction of Rice Yield Loss by Aneilema keisak and Aeschynomene indica Competition in Flooded Direct-Seeded Rice

Abstract

This study was conducted to make the rice yield prediction model system as affected by densities of Aneilema keisak and Aeschynomene indica and to determine their economic threshold levels in flooded direct-seeded rice. When the density of A. keisak was 8 plants per m 2 , the yield of rice reduced to 8% and as the density increased up to 96 plants per m 2 , the reduced rate of rice yield reached to 45% and in A. indica, the reduced rate of rice yield were 20 and 77%, respectively. The rice yield loss models of A. keisak and A. indica were predicted as Y=553.2 kg (1+0.00913X), R 2 =0.912 ** and Y=567.9 kg/(1+0.04434X), R 2 = 0.961 ** , respectively. Economic threshold levels calculated using cousens' equation were 3.0 plants per m 2 in A. keisak and 0.6 plants per m 2 in A. indica.

Seed dynamics of Aeschynomene denticulata and Aeschynomene indica

“…Jointvetch (Aeschynomene spp., Fabaceae) is the main broadleaf weed for rice production in Brazil, the United States, and Asia (Cho et al, 2012;Fruet, Merotto Jr., & Ulguim, 2019;Norsworthy, Bond, & Scott, 2013). The presence of 25-31 plants per square meter can cause crop yield losses of 57.2% by interfering with harvesting operations and reducing grain and seed quality (Andres & Theisen, 2009).…”