Microbial and enzymatic activity as influenced by existing cropping pattern in the soils of Ganges floodplain

Effect of multi cropping (Potato-Jute-Sweetgourd-T.Aman, Sweet gourd-Brinjal-Jute, Cauliflower-Radish-Lentil-Basil, Jute-Lentil-Mustard-Wheat and Sweetgourd-Turnip, designated as P-J-S-T, S-B-J, C-R-L-B, J-L-M-W and S-T, respectively) and mono cropping systems (orchard of Lychee, Teak, Turmeric and Banana) on microbial and enzymatic activity of Ganges floodplain soil was investigated. Organic carbon, microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), soil respiration, total nitrogen and urease activity (UA) of the soils were examined. Upon examination it was observed that soils under mono cropping pattern (Lychee, Teak, and Banana) showed significantly (p <= 0.05) higher MBC, MBN and UA than those under multi cropping pattern. Highest values of MBC and UA found in teak plant were 95.44 milligram/kilogram (mgkg(-1)) and 6.51 mu g N released g(-1)day(-1) respectively while for multi cropping pattern the respective values were 37.52 mgkg(-1) and 2.23 mu g N released g(-1)day(-1) found in S-T and J-L-M-W cropping pattern. The highest MBN (12.70 mgkg(-1)) was obtained in soil where lychee was practiced. Multi cropping soil showed significantly (p <= 0.05) higher respiration rate than mono cropping soil and the highest rate was found 508.75 mg CO2 g(-1)day(-1) in J-M-L-W cropping pattern. Turmeric showed the lowest respiration rate (120.75 mg CO(2 )g(-1) day(-1)) among the cropping pattern studied. Both MBC and UA showed positively significant relation with soil organic carbon, and total N at 0.01 % level. High microbial and enzymatic activity of mono cropping soil represent combined effect of vegetation and low tillage practices in soil.