01868nam a2200217 a 450000100080000000500110000800800410001910000220006024500950008226001800017730000140035749000430037152011160041465000110153065000140154165000140155565000220156965000130159170000220160470000240162610687552012-07-06       2006    bl uuuu     u00u1 u    #d1 aSILVA, P. S. L. e  aEffect of weed control in corn with cowpea intercropping on soil chemical characteristics.  aIn: CONGRESSO NACIONAL DE FEIJÃO-CAUPI, 1.; REUNIÃO NACIONAL DE FEIJÃO-CAUPI, 6., 2006, Teresina. Tecnologias para o agronegócio: anais. Teresina: Embrapa Meio-Nortec2006  c1 CD-ROM.  a(Embrapa Meio-Norte. Documentos, 121).  aWeeds interfere with nutrient absorption by crops. Therefore, there has been interest in knowing the effects of weeds on soil chemical characteristics, aiming at better fertilization management in order to save fertilizers and reduce pollution problems. The objective of this work was to evaluate the effects of weed control on soil pH and soil Ca, Mg, K, Na, P, and SB contents (sum of bases), when the soil is cultivated with corn. The experiment was conducted as random blocks with 5 replicates and split-plots. Four cultivars (BA 8512, BA 9012, EX 4001 and EX 6004) were grown with weed control (two hoeing operations, or intercropped with cowpea, Vigna unguiculata (L.) Walp.) or without weed control. The weed control measures were assigned to subplots, while cultivars were assigned to plots. Ten weed species predominated in the experiment. The weeding operations increased P content, but reduced S content, while the lack of weed control increased pH (in water). These effects were independent from the cultivars evaluated, which were not different with regard to their effects on soil characteristics.  aCapina  aNutriente  aVariedade  aVigna Unguiculata  aZea Mays1 aSILVA, K. M. B. e1 aFREIRE FILHO, F. R.