Abstract
Effects of plant establishment technique and nitrogen management on the performance of maize were evaluated by conducting nine experiments during three consecutive rabi seasons, 2002-03, 2003-04 and 2004-05 at the Regional Agricultural Research Station of Jamalpur, Bangladesh. Seedling raising method, variety, planting date, age of seedling, rate and split application of fertilizer nitrogen were included as treatments in the study. The results revealed that crops of mud cake, poly bag and tray nurseries gave significantly the highest grain yields (9.30-10.77 t ha') compared to dry bed, compost, and dapog nurseries, and direct planting of seed (Dp) (8.78-9.51 t ha'), which were statistically identical. Maximum benefit cost ratio (BCR) of 1.94 was obtained from dry bed underneath polythene sheet, compost and dapog nurseries which was followed by Dp (1.84), mud cake (1.84), poly bag (1.55) and tray (1.46) nurseries. Effects of planting date and age of seedling (raised in dry bed nursery underneath polythene sheet) showed that Dp, and 14- and 21-day old seedlings produced the highest and statistically identical grain yields in the earlier two plantings of 20 (10.61, 10.48 and 10.38 t ha', respectively) and 30 (10.50, 10.33 and 10.26 t ha', respectively) November irrespective of varieties. Whilst 14-day old seedlings produced higher grain yield than Dp and 21-day old seedlings at the later plantings of 20 and 30 December (9.14 and 8.24 t ha', respectively). Significantly the highest grain yields were obtained from both the varieties of Pacific-11 and BARI hybrid maize-3 with Dp, and 14- and 21-day old seedlings. Grain yield reduced gradually beyond 21-day old seedlings and 42-day old seedlings produced the lowest in all the varieties. Effects of rate and split application of N showed that 250, 300 and 350 kg N ha' applied 1/2 N as basal + 1/2 N at 25 days after planting (DAP) or 2/3rd N as basal + 1/3rd N at 25 DAP gave the highest and statistically identical grain yields (10.60-11.13 t ha') in which 21-day old seedlings were used. The relationship between rates of N and grain yields of maize was quadratic and the optimum estimated N rate was 322.22 kg ha'. Both the N rates of 250 and 325 kg ha with Dp, and 14- and 21-day old seedlings of dry bed underneath polythene sheet and compost nurseries gave the highest and statistically identical grain yields. Fourteen-day old seedlings of dapog nursery also produced similar grain yields to Dp and 21-day old seedlings of dry bed underneath polythene sheet and compost nurseries with the same N rates of 250 and 325 kg ha'. But 21-day old seedlings of dapog nursery produced lower grain yields than the crops of earlier nurseries with the same N rates. Considering 28-day old seedlings, it was found that grain yield increased significantly with 325 kg N ha than 175 and 250 kg N ha'. Field duration was reduced by 7-9 days for 14-day old seedlings and 12-14 days for 21-day old seedlings compared to Dp.