Crop growth indices of wheat-Japanese mint intercropping as influenced by land configurations and nutrition levels

Abstract

A field experiment was conducted during winter to summer seasons of 2006-07 and 2007-08 at Gurdaspur (Punjab) on silty clay loam soil to study the crop growth rate (CGR) and relative growth rate (RGR) of wheat-Japanese mint (J. mint) intercropping system under different planting methods and nitrogen levels. The experiment was laid out in randomized block design having two planting methods viz. two rows of wheat (November sown) with 20 cm row spacing and two rows of J. mint (intercropping in February) on outer sides of wheat rows under flat and bed (37.5 cm top + 30 cm furrow) methods covering a total width of 67.5 cm and five levels of nitrogen i.e. 0+0 (control), 90+75, 120+75, 150+75 and 180+75 kg N ha-1 to wheat and J. mint, respectively. In wheat, the bed method gave significantly higher CGR over flat and it was higher by 8.9, 12.4 and 24.4 per cent during 2006-07 and 11.9, 16.6 and 40.4 per cent during 2007-08 at 60-90 DAS, 90-120 DAS and 120 DAS-harvest stage, respectively. In J. mint, during both the years from 60-90 DAS, the flat recorded significantly higher CGR than the bed. However, at 120 DAS-harvest stage during 2007-08, the bed produced significantly higher CGR than the flat, possibly due to variable rainfall pattern between the years. Between 120 DAS-harvest stage, the CGR of wheat decreased from 0 to 90 kg ha-1 and then increased upto 150 kg N ha-1 during 2006-07 and it enhanced upto 180 kg ha-1 during 2007-08. The impact of higher rate of N application to wheat remained effective for wheat only and it was not shifted on the CGR of J. mint. During both the years at all the stages, the RGR of wheat did not differ significantly due to both the planting methods except at 120 DAS-harvest stage during 2007- 08. In J. mint, at almost all the crop growth intervals, both the planting methods differed significantly in RGR. The RGR of wheat at N120 over control showed an increment of 71 and 39 per cent at 60-90 DAS and 9 and 35 per cent at 90-120 DAS during 2006-07 and 2007-08, respectively but, reversely, at 120 DAS-harvest stage, the respective increase in control over N120 was 109 and 276 per cent. Interactive impact of planting method and nitrogen levels on CGR of wheat was significant between 120 DAS-harvest stage during 2007-08.