WEEDS IN THE DOUBLE CROPPING WITH CORN (Zea mays L.) UNDER NO-TILLAGE

Abstract

It was observed to evaluate the occurrence of the weeds, after 3 years of cultivation with successions of double cropping cultures with the culture of the corn. The double cropping cultures were: corn, soybean, pearl millet, sunflower, sorghum, oat and pigeon pea. The weeds were appraised to the 30 days after the sowing, by means of sampling to the maybe in the portion, using a icture of 0.45 m2 (1.5 m x 0.3 m), placed in a perpendicular way to the plantation lines and being picked up the whole material existent green of weeds in the sample, classifying in for vegetable species, containing the main monocotiledonous, main mocotiledoneous and other weeds. The results demonstrated that there was larger frequency of the species there would Digitaria horizontalis and Commelina benghalensis, the first in the succession corn-corn and second in the succession soybean-corn. The smaller concentration of weeds happened in the succession sunflowercorn. The smallest occurrence of the weeds was observed in the area in that the culture of the sunflower precedes the culture of the corn. Being used the pearl millet in double cropping culture, there is bigger occurrence of species dicotiledoneous in the culture of the corn, especially Euphorbia heterophylla.

KEY-WORDS: Successions of cultures; corn; weeds.