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

Abstract

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

6.51μg N released g-1day-1 respectively while for multi cropping pattern the respective

values were 37.52 mgkg-1 and 2.23 μg N released g-1day-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-1day-1 in J-M-LW

cropping pattern. Turmeric showed the lowest respiration rate (120.75 mg CO2 g-1day-

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.