Vol. 12, Special Issue 10 (2023)

Author(s):
Aradhana Barooah, Aradhana Phukan and Rekhashree Kalita

Abstract:
A study was conducted to assess the fertility status of soils under different cropping sequences in seven different villages of Dibrugarh district, Assam, India. Seven villages viz., Jhanjimukh, Bhogamur, Melengial, 1 No. Kachari Pathar, Gozpuria, Chetia Gaon and Luramukh Bokolial, having three cropping sequences were selected. A total of 350 numbers of surface soil samples (0-15 cm depth), comprising of 50 composite soil samples from each site were collected using auger, after harvesting of Rabi crops during 2019-20. The collected soil samples were processed and analyzed for different soil parameter like soil pH, electrical conductivity, organic carbon, available nitrogen, available phosphorus and available potassium using standard analytical methods. Nutrient index value was calculated for each parameter for soil fertility rating as low, medium and high. Results revealed that pH of all the samples of study area was in the acidic range and majority of the samples (41%) lie in the strongly acidic range (5.1 to 5.5). Electrical conductivity of all the samples were found normal (< 1.0 ds m^-1). The organic carbon content of the study area varies from low to medium. Majority of the soil samples of all the villages except Jhanjimukh contain low status of organic carbon. Available nitrogen content was low to medium, 49% of the samples found in the low range (< 272 kg ha^-1) and 44% samples were in the medium (272-544 kg ha^-1) range. Available phosphorus and potassium content of the soils varied from low to high. More than 60% samples of the study area had medium available phosphorus (66% samples) and available potassium (62%). Based on nutrient indices, highest organic carbon and available nitrogen was observed in soil under vegetable based cropping sequence. On the other hand, higher available phosphorus was found in soils under potato based cropping sequence and higher available potassium was under paddy-rapeseed cropping sequence. Available nitrogen and electrical conductivity showed a positive correlation with cropping intensity might be due to application of inorganic fertilizer and plant biomass incorporation. On the other hand, pH, electrical conductivity, available phosphorus and available potassium exhibited a decreasing trend with cropping intensity.