Influência do resíduo de plantas de adubação verde no desenvolvimento de digitaria insularis

Abstract

The bitter grass (Digitaria insularis) is an important invasive plant known for having difficult control and causing interference in the cultivation of several commercial species. The present work aimed to evaluate the influence of the aerial part residue of winter green manure plants: black oats (Avena strigosa), turnip (Raphanus sativus) and ryegrass (Lolium multiflorum) in different densities in the development of D. insularis. The experiment was conducted in the greenhouse of the Federal University of Fronteira Sul, located in the municipality of Laranjeiras do Sul-PR. The experimental design used was completely randomized with 10 treatments consisting of 3, 6 and 9 t ha-1 of black oat straw; turnip and ryegrass, in addition to the control (without cover) with four repetitions. The variables analyzed were chlorophyll a and b, leaf area, length of shoot and root and dry matter of shoot and root system of D. insularis. The evaluated treatments showed no significant effect on the development of D. insularis for the variables chlorophyll a and b, leaf area and dry matter of the aerial part and the root system. The shoot development of D. insularis was lower in the control, oats 6 t ha-1, turnip 6 t ha-1 and ryegrass 3 and 6 t ha-1, whereas the root system was lower in the control, oats 9 t ha -1, turnip 3, 6 and 9 t ha-1 and ryegrass 3 t ha-1. Although the length of the aerial part and the root system of D. insularis were influenced by the treatments, variable amount of straw of the species evaluated did not show a proportional effect on the development of D. insularis. The absence of a direct relationship between the amount of phytomass of the aerial part of the green manure species in the variables of aerial part length and the root system of D. insularis was not expected and demonstrates that there are still little understood processes in the interaction between the fertilization plants. green and weeds. Thus, for the management of spontaneous plants, the species of green manure and the amount of straw used is a factor to be evaluated, since even in similar quantities, treatments with different species resulted in different responses in the development of D. insularis.