Effect of plant population on corn evapotranspiration in an oxisol of the "cerrados"

Abstract

In a field study, conducted during the dry season of 1977, it was evaluated the effect of four plant populations: 20.000 (D₁), 40.000 (D₂), 60.000 (D₃) and 80.000 (D₄) plants/ha on the evapotranspiration (ET) of corn (Zea mays L., cv. C-111 X). The results indicate that up to 70 days after planting all the treatments, except D₁, showed same ET. After 80-90 days ET values were the following: 7.61, 6.84, 5.57 and 5.32 mm/day for treatments D₁, D₂, D₃ and D₄, respectively. ET was found to be associated to leaf area index (LAI), being ET- 12,64 + 0,04 LAI. Seasonal ET (140 days) was found to be: 369.28, 399.88, 443.79, and 513.09 mm for treatments D₁, D₂, D₃ and D₄, respectively, which correspond to 180, 104,77 and 64 liters of water evapotranspired by each plant in the same treatments. In summary, higher populations result in higher losses due to ET, which did not reflect on yields.