Nitrogen content and uptake studies in wheat-mentha intercropping system under different crop establishment methods

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 nitrogen content and its uptake in wheat-mentha intercropping system under different crop establishment methods. The experiment was laid out in randomized block design with three replications having 10 treatments comprising two (T1), three (T2) and four (T3) rows of wheat with 20 cm row spacing and two rows of mentha on outer side of wheat rows covering a total width of 67.5, 135 and 135 cm in flat situation, respectively. Similar pattern was also followed in T6, T7 and T8 where two, three and four rows of wheat were grown with 20 cm row spacing and two rows of mentha on outer side of wheat rows on the bed top covering a total width of 67.5 (37.5 cm top+30 cm furrow), 135 (105 cm top+30 cm furrow) and 135 (105 cm top+30 cm furrow) cm, respectively. Sole wheat and mentha crops were sown under T4 and T5 in flat and T9 and T10 in bed situation, respectively. Wheat was sown in November and mentha suckers were intercropped in February under different treatments. Planting methods did not have any significant impact on N content of wheat and mentha whether sole or in intercropping system which indicated that component crops were not competitive. In intercropping system, wheat and mentha in 2 : 2 rows ratio on 67.5 cm bed (T6) recorded maximum nitrogen uptake of 203.3 and 216.5 kg/ha during 2006-07 and 2007-08, respectively, which was significantly higher over all the intercropping systems except T1 during first year. In the same planting method, intercropping of mentha with three or four rows of wheat did not differ significantly but these row arrangements were significantly lower than mentha intercropping with two rows of wheat.