Response of Arbuscular Mycorrhizal Fungi on Wheat (Triticum aestivum L.) Grown Conventionally and on Beds in a Sandy Loam Soil

The present study was undertaken to assess the benefit and compare the functioning of AM fungi on wheat grown conventionally and on beds. Ten treatment combinations were used, treatments 1 and 2: no fertilizers with and without arbuscular mycorrhizal (AM) fungi (In vitro produced Glomus intraradices); 3:100% of recommended NPK: (120 kg ha-1 N; 60 kg ha-1 P; 50 kg ha-1 K), and 4 and 5: 75% of recommended NPK dose with and without AM inoculation in a 5 × 2 split-plot design on wheat using conventional/flat system and elevated/raised bed system. The maximum grain yield (3. 84 t ha-1) was obtained in AM fungi inoculated plots of raised bed system applied with 75% NPK and was found higher (although non- significant) than the conventional (3. 73 t ha-1) system. The AM inoculation at 75% fertilizer application can save 8. 47, 5. 38 kg P and 16. 95, 10. 75 kg N ha-1, respectively, in bed and conventional system. While comparing the yield response with 100% fertilizer application alone, AM inoculation was found to save 20. 30, 15. 79 kg P and 40. 60, 31. 59 kg N ha-1, respectively, in beds and conventional system. Mycorrhizal inoculation at 75% NPK application particularly in raised bed system seems to be more efficient in saving fertilizer inputs and utilizing P for producing higher yield and growth unlike non-mycorrhizal plants of 100% P. Besides the yield, mycorrhizal plants grown on beds had higher AM root colonization, soil dehydrogenases activity, and P-uptake. The present study indicates that the inoculation of AM fungi to wheat under raised beds is better response (although non-significantly higher) to conventional system and could be adopted for achieving higher yield of wheat at reduced fertilizer inputs after field validation. © 2011 Association of Microbiologists of India.