Influencia de tres fechas de siembra sobre el crecimiento y la relación fuente- demanda del cultivo del maíz (Zea mays L.)

in order to evaluate the influence of three planting dates on growth and the demand supply ratio in the cultivation of maize (zea mays), this work was developed at the national institute of agricultural sciences, were studied 3 planting dates november 2008, june 2009 and july 2009, using a density of 50000 plants.ha-1. destructive samplings were conducted every 15 days the plants emerged until harvest determined total dry mass of shoot and leaf area index (lai), adjusting the data to an exponential function of second-degree polynomial, "x" was days after emergence and y the variable in question, from the regression equations were calculated net assimilation rate (nar) and leaf area ratio (lar), also were calculated the ratio between the power supply and demand power, finding that greater efficiency in the use of radiation leads to higher peaks in the net assimilation rate (nar) and in potential between the supply and demand organs and therefore greater accumulation of biomass at a time close to physiological maturity, standing in this case study, dated june 2009 which showed a higher efficiency compared to rates reaching evaluated in this the greatest returns.