ABSTRACT The present experiment was carried out at Balindi Research Complex Farm, Bidhan Chandra Krishi Viswavidyalaya during 2018-2019 and 2019-2020. The field was divided into three tillage systems viz. Conventional tillage (CT), Zero tillage (ZT) and Reduced tillage (RT). Each tillage plot was further subdivided into five different nutrient residue combinations. The cropping system Mustard – Black gram – Rice was selected for the present study. It was found that highest bio diversity value of soil mesofauna (1.63) and (1.68) was obtained from the treatment Zero tillage with 50% paddy straw residue + 75% N.P.K. during both the experimental period 2019 and 2020. In Mustard, diversity value of soil mesofauna (1.69) and (1.71) was highest in Reduced tillage with 50% paddy straw residue + 75% N.P.K. during 2018-2019 and 2019-2020. From Black gram, maximum mesofauna diversity value (1.74) was recorded from Reduced tillage with 50% paddy straw residue + 100% N.P.K and Zero tillage with 100% paddy straw residue + 75% N.P.K during 2019 and 2020.

Keywords: Biodiversity, conservation-agriculture, mesofauna, tillage