Revista Brasileira de Milho e Sorgo (Dec 2004)
POPULATION DENSITIES AND NITROGEN FERTILIZATION IN OFF SEASON CORN
Abstract
The off season corn named “Safrinha”, in the State of Parana-Brazil occupied an area of 990.904 hectares in the 2000 cropping year. This is an important fact for the overall corn supply in the country. However, research efforts have not produced enough agricultural practices information for this activity. The objective of the present work was to study the effect of population densities and nitrogen fertilization on agronomic characteristics and grain yield in off season corn cultivation. The trials were set up on no-tillage system after soybean cultivation in 1998, 1999 and 2001 in Londrina, Primeiro de Maio, Palotina and Mal. Candido Rondon in Parana. The experimental design used was randomized blocks with three replications. Treatments were arranged in factorial schemes of 2x3x4 represented by: two cultivars (AG 5011 and C 909); three populations densities of approximately 33, 44 and 55 thousand plants per hectare in 90cm rows and four levels of nitrogen (0, 45, 90 and 135 kg ha¯¹) as urea. The third part of nitrogen levels was applied at planting along with 60 kg ha¯¹ of P205 and 45 kg ha¯¹ of K20. The results showed significant differences for the population densities at different studied sites. The yield responses achieved with different nitrogen levels were low and varied in different sites and planting years. Results also showed that the greatest grain yields were achieved upon increasing both population densities and nitrogen levels.
