Biological response of hybrid maize to plantation methods and nutrient management

Ridge plantation increased the ear number plant-1, grain number ear-1 grain weight ear-1 and 1000-grain weight significantly over double-row strip plantation which was superior to single-row plantation. The different methods of plantation affected the plant height and leaf area per plant to a significant level. The crop sown on ridges produced plants of significantly greater height than that sown either in double-row strips or in single-rows, which were also significantly different from each other. As regards nutrient levels, although all the nutrient levels improved the yield components and grain yield ha-1 significantly over the control, among the nutrient levels, application of 250-150-100-15 kg NPKS ha-1 proved to be the best in all respects indicating, thereby, a significant role of S in conjunction with NPK in improving the productivity potential of maize plants. All the nutrient levels increased the dry matter, LAI, CGR and NAR signific antly over the control. However, from amongst the nutrient levels, application of 250-150-100-15 kg NPKS ha-1 was found to be superior to all other nutrient revels in respect of the above mentioned physiological traits. Overall effect of Mg in combination with NPK on maize grain yield was less pronounced than S in both years. The interactive effects of plantation methods and nutrient levels on nutrient efficiency were significant in both years. The nutrient efficiency was found to be the highest (12.50 kg kg-1) in the crop sown on ridges and fertilized @ 250-150-0 NPK ha-1 (M3F2) which was statistically on a par with that sown on ridges and fertilized a 250-150-100-15 kg NPKS ha-1 (M3F4) showing nutrient efficiency of 11.69 kg kg-1 of nutrients during 1997. However, in 1998 although the crop planted on ridges and fertilized @ 250- 150-100-15-15 kg NPKS Mg gave the highest nutrient efficiency (11.44 kg kg-1), it was on a par with M3F4, M3F5, M3F3 and M2F4 showing nutrient eff i ciency of 11.25, 10.78 and 10.68 and 10.74 kg kg-1, respectively. The crop sown on 70 cm spaced ridges and fertilized @ 250-150-100-15 kg NPKS ha-1 (M3F4) gave the highest net income of Rs.36633.0 ha-1 in 1997 and Rs.36156.0 ha-1 in 1998 and was followed by the crop sown on ridges and fertilized @ 250-150-100-15-15 kg NPKS Mg ha-1 (M3F6) giving on an average net income of Rs.34870.0 ha-1 in 1997 and Rs.34580.0 ha-1 in 1998.