Absorção de macronutriente por azevém

Abstract

The objective of this study was to evaluate the nutrient uptake and dry matter (DM) yield in ryegrass cultivar BARjumbo up to 150 days after emergence (DAE). The experiment was conducted under green house conditions from the autumn until the spring of 2018. A completely randomized design with five replicates was used, with treatments consisting of 15 different evaluation periods (10; 20; 30; 40; 50; 60; 70; 80; 90, 100, 110, 120, 130, 140 and 150 DAE). The ryegrass plants were cultivated in pots containing 10 kg of soil, with each pot representing an experimental plot. The experiment presented a total of 75 experimental plots. The plant height, tiller number, leaf area index (LAI),DM yield and contents and accumulations of N, P and K in shoot and root DM were evaluated. The plant height increased linearly, while for the tiller number, the highest value was 110 DAE. IAF was strongly increased between 30 and 100 DAE. DM yield was increased during all evaluation periods (between 10 and 150 DAE). The highest rates of DM yield increase occurred between 50 and 60 DAE. The N and P contents in shoot DM decreased according to plant age. For the K content, the values began to decrease only from 100 DAE. There were increases in N, P and K accumulations in shoot up to 120 DAE. From this date, the values decreased up to 150 DAE. Higher rates in increments of nutrient accumulations in shoot coincided with the times of higher rate of DM yield increase. The decreasing order of nutrient accumulation in the shoot was K> N> P, whereas in the root the order of accumulation was N> K> P.