Effect of Plant Density and Nitrogen Rate on PAR Absorption and Maize Yield

A field experiment was conducted at the University of Zabol, The experimental farm in Southeast of Iran during 2007-08 to investigate the impacts of nitrogen (N) rate and plant density of maize (Zea mays L.) c.v. K.S.C 704. Split plot experimental treatments comprising three plant densities under title subplot included (P1 = 60,000 plants ha-1, P2 = 80,000 plants ha-1 and P3 = 100000 plants ha-1) and Four nitrogen rates (N1 = 200 kg ha-1, N2 = 250 kg ha-1, N3 = 300 kg ha-1 and N4 = 350 kg ha-1) were kept in main plots. Maize produced significantly as well as grain yield at high than at low density. Grain yield and Photosynthesis Active Radiation (PAR) absorption increase with increasing N rate and the highest amount of grain yield were obtained at N4 treatments. Grain yield and PAR absorption increase with increasing plant density and the highest amount of grain yield were obtained at P3 treatment. It is concluded that growing maize at high density with application of 350 kg h-1 N rate that could result in maximum Grain yield of maize and hence increase productivity of maize crop.