LAUSR

ABSTRACT: Experiments were run in a greenhouse where samples of Eragrostis pilosa and Eragrostis plana, species that infest rice crops, were subjected to three soil moisture conditions (50% of soil water retention capacity (WRC), 100% of WRC, 10 cm water depth), simulating three different environments (upland, lowland and irrigated rice farm, respectively), with the aim of studying how these conditions affect the morphology and vegetative cycle of these plants, by means of development and growth assessments. Results show that each species responds differently when subjected to varying amounts of water in the soil. Soaking the soil with 10 cm of water was the treatment that most negatively influenced the development of E. plana plants, reducing the formation of panicles per plant, as well as the aerial part dry mass. The responses of E. pilosa plants to the waterlogged environment manifested as reductions in tillering parameters, number of panicles per plant, root and aerial part dry mass, changes in flag leaf formation, and vegetative cycle increases, which allows inferring that these plants are more sensitive to hypotoxic environments. Thus, the water depth treatment is possibly what caused negative effects on the development of the study plants, which indicates that water management in irrigated rice farming is of uttermost importance for management of invasive plants.