Nitrogen doses and water balance components at phenological stages of corn

Abstract

Determining the intensity of the water balance components in the control volume of a soil, and consequently defining the most likely periods of occurrence of a water deficit in a crop, is an exercise that requires knowledge about soil, climate and plant factors. This research aimed to evaluate soil water balance components at phenological stages of corn (Zea mays L.) under no-till system, when fertilized with 60, 120, and 180 kg ha -1 of nitrogen. Runoff was not taken into account. Measurements were made for precipitation (P), internal drainage (D) (or capillary rise) at a 0.8 m depth, and water storage variation (Δh) in the soil layer from 0.0-0.80 m; actual evapotranspiration (ET) was considered the unknown quantity of the equation. Corn grain yield was evaluated as well. In general, the soil water balance components were modified by N doses, because the soil had been relatively smaller Δh in treatments involving N application than in the treatment without N, resulting in smaller D values in those treatments, which resulted in greater absorption by the plants and greater ET. As expected, the plant developmental stage II had a higher ET value. Key words: internal drainage, hydraulic conductivity, actual evapotranspiration, tensiometer, no-till system DOSES DE NITROGÊNIO E COMPONENTES DO BALANÇO HÍDRICO EM FASES FENOLÓGICAS DO MILHORESUMO: Determinar a intensidade dos componentes do balanço de água no solo num certo volume de controle de solo e, por conseguinte, a definição dos períodos mais prováveis de déficit hídrico para a cultura, está relacionada ao conhecimento de fatores do solo, do clima e da planta. Avaliaram-se componentes da equação do balanço de água no solo para fases fenológicas do milho (Zea mays L.), sob sistema de plantio direto, adubado com 60, 120 e 180 kg ha

Periodicity of crop coefficient and soil water depletion fraction in a climatological water balance

“…The ETa CWB had its highest values in the same periods when the largest precipitation occurred (Figures 4 and 5). This relation is similar to obtained by Silva et al (2009) with corn in Piracicaba, Southestern Brazil.…”

Disponibilidade de nitrogênio, sobrevivência e contribuição dos perfilhos ao rendimento de grãos do milho

“…Houve acréscimo de 130 kg no rendimento total de grãos de milho para cada 10 kg de N aplicados em cobertura, sendo a produtividade máxima maior que 11,7 t ha -1 . Resposta similar foi observada por Silva et al (2009) (Escosteguy et al, 1997;Freire et al, 2001;Amado et al, 2002;Silva et al, 2005).…”

Basic principles of graphing data

“…Remember that the human eye can work efficiently with very composite images, detecting large amount of information in small spaces (Tufte, 2001). However, always be careful to make the graph readable and understandable: avoid clutter (see, e.g., Reynolds et al, 2009;Silva, 2009c). …”