Effect of preceding crops and nitrogen rates on crop growth indices of winter hybrid maize (Zea mays L.)

A field experiment was conducted at Agronomy research farm of IAAS, Rampur, chitwan, Nepal during summer and winter season 2010 and 2011 to study the effect of crop sequence and nitrogen rates on hybrid maize. There were thirty treatment combination consisting of six crop sequences, maize-maize, fallow-maize, greengram-maize, cowpea-maize, blackgram-maize, clusterbean-maize in main plots and five nitrogen rates 0, 50, 100, 150, 200 kg/ha in subplots with three replication. The research finding revealed that Maximum number of cobs (61,200/ha in 2010 and 61,900/ ha in 2011) was recorded under blackgram –maize sequence which was comparable to number of cobs/ha under greengram-maize while it was minimum under maize-maize sequence during both the years. Number of cobs was maximum 66,200/ha in 2010 and 67,200/ha 2011 with 200kg/ha and it was minimum under no nitrogen application. Percentage of barren plants was minimum (11.7 in 2010 and 11.5 in 2011) under blackgram-maize sequence which was comparable to greengram –maize sequence, while maximum percentage of barren plants was recorded under maize-maize sequence. Minimum percentage of barren plants (5.6 in 2010 and 6.2 in 2011) was recorded with 200kgN/ha and it was maximum under no nitrogen application. Minimum number of days to silking (54 .7 in 2010 and 53.3 in 2011) was recorded under greengram– maize sequence while it was maximum (57.3 in 2010 and 55 .8 in 2011) under maize–maize sequences. Number of days to silking was minimum (53.1 in 2010 and 52 .1 in 2011) with 200 kg N/ha while it was maximum (60 .6 in 2010 and 59 .1 in 2011) under no nitrogen application. At maturity (90 days after sowing), maximum dry matter accumulation per plant (174.7 g in 2010 and 176.0 g in 2011) was recorded under greengram– maize sequences and it was minimum under maize– maize sequences. It was maximum (206.0 g in 2010 and 207.2 g in 2011) with 200kg N/ha minimum with no nitrogen. At maturity (90 DAS) maximum plant height (170.7 cm in 2010 and 173.9 cm in 2011) under greengram– maize sequences while it was minimum under maize– maize. At maturity (90 DAS) maximum plant height (169.2 cm in 2010 and 173.1 cm 2011) was recorded with 200 kg N/ha while it was minimum with no nitrogen application. At silking stages (60 DAS) maximum leaf area index (3.39 in 2010 and 3.45 in 2011) was recorded under greengram – maize sequences and it was minimum under maize – maize. At silking stage (60 DAS) leaf area index was maximum (3.86 in 2010 and 3.72 in 2011) with 200 kg N/ha while it was minimum with no nitrogen application.