Vol. 12, Issue 11 (2023)

Author(s):
Nagaraj, Gundappagol RC, Mahadevswamy, Nagaraj M Naik and Sathynarayan Rao

Abstract:
In order to investigate the dynamics of the microbial population and how it relates to sorghum plant growth and yield in an organic farming system, a field experiment was carried out at the Zonal Agricultural Research Station in Kalaburagi in 2017–18. The microbiological and biochemical characteristics of the soil improved in the treatments using organic manures. The results indicate that, when compared to the other treatments, the fully organic manures (100% NP) had a significantly higher population of both beneficial and general microbes, including bacteria (114.25 X 106 cfu/g), fungi (75.50 X 104 cfu/g), actinomycetes (54.50 X 104 cfu/g), azotobacter (17.50 X 104 cfu/g), Azospirillum (30.75 X 104 cfu/g), and phosphorus-soluting microorganism (PSM- 52.25 X 104 cfu/g). Additionally, the highest microbial biomass carbon (361.50 µg CO2-C g-1 soil for 24 hours), as well as the highest enzymatic activity (Dehydrogenase 35.75 μg TPF g-1 soil for 24 hours, Urease 221.63 μg NH4- N g-1 soil for 2 hours, and Phosphatase 92.13 μg PNP g-1 soil for 1 hour). The crop responded well to the different treatment combinations and found higher growth and yield parameters in the treatment applied as per recommended package of practices recorded (Plant height- 212.75 cm, Number of leaves- 10.09/plant, Dry matter accumulation-91.32 g/plant, Grain weight per ear head-31.00 g Stover yield-5.06 t/ha, Grain yield- 1568 kg/ha) but however it was on par with the treatment applied with fully inorganic fertilizers (T₄) and the treatment given with 50 per cent organic manures and 50 per cent inorganic fertilizers (T₃) and treatment applied with fully organic manures of 100% N and P (T₂- in case of yield and yield parameters). Finally to find the comparative profits between the treatments, the economics of the crop was worked out and found that the treatment which was maintained fully organically with 75 per cent N and P (T₁) was superior among all the treatments with highest B:C ratio (2.84).