BANCO DE SEMENTES DE PLANTAS DANINHAS EM SUCESSÃO DE CULTURAS NOS SISTEMAS IRRIGADO E SEQUEIRO

Abstract

The tomato and sweet corn are one of the main vegetable crop cultivated in Brazil destined to industry processing, and of great importance in the world scene. Weed interference is a factor of great importance for tomato and sweet corn crops, which can cause losses in quality and productivity. Due to the cultivation of tomato and sweet corn, the objective of this study was to determine the seed bank of weeds in crop succession and systems (irrigated and dryland): area I (sweet corn under irrigated system and corn under dryland), area II (crop of tomato under irrigated system and corn under dryland system), area III (cultivation of tomato under irrigated system and soybean under the dryland system) and area IV (crop of tomato under irrigated system and corn under the dryland system). The experiment was carried out in a greenhouse in the experimental area of the Instituto Federal Goiano (IF Goiano), Campus Morrinhos - GO. The experimental design was a randomized complete blocks, in a factorial scheme 4x2, with four replicates, considering four sampling depths and two management system. In each area, 15 simple samples were collected in the sampling depths (0.0-2.5 cm, 2.5-5,0 cm, 5.0-10 cm, 10.0 -20.0 cm), obtaining four compound samples, which were allocated in plastic trays and taken to greenhouse. The trays were evaluated every 15 days for a period of 120 days, determining the number of emergent seedlings in each trays. There were calculated the phytosociological parameters, diversity indexes, number of non-dormant seeds, and the importance value of the main species. The main species identified in the areas are Cenchrus echinatus L., Euphorbia hirta L., Digitaria insularis (L.) Fedde, Digitaria sanguinalis (L.) Scop., Eleusine indica (L.) Gaertn., Nicandra physaloides (L.) Pers. e Solanum americanum P. Mill. The highest seed bank of weeds was found in area I under dryland system (14,183 non-dormant seeds m-2).