Singh, A.P.Basta Ram2022-12-042022-12-042022-09https://krishikosh.egranth.ac.in/handle/1/5810190362Field experiments were conducted during the year 2020-21 and 2021-22 in E2 block of Norman E. Borlogue Crop Research Center of GovindBallabh Pant University of Agriculture and Technology, Pantnagar, Uttarakhand on the long term effect of different crop rotations on soil health and different carbon pools in a Mollisol. The objective was to study the effect of different approaches to crop rotations on soil health and to investigate the impact of different crop rotations on soil health. The experiment was laid out in randomized block designs with three replications and eleven treatments i.e. T1 (Rice - Wheat - fallow), T2 (Rice - Veg. pea - summer rice), T3 (Maize - Wheat - Cowpea), T4 (Rice - Wheat - Sesbania), T5 (Maize - Toria - Urd), T6 (Rice - Yellow Sarson - Grain Cowpea), T7 (Multi Cut Sorghum - Barseem + Oat - Maize + Cowpea), T8 (H. Napier + Fodder cowpea - Barseem - Fodder cowpea), T9 (Basmati rice - Potato - Maize Cob), T10 (Maize - Broccoli -Okra) and T11 (fallow). Green manure (Sesbania) was used in crop rotation, cut and incorporated intothe soil each year during the kharifseason only and its residual effect on the crop was seen. The inclusion of legume crops was done between the different crop rotations. After the harvest of crops, the data for grain and fodder yield was recorded for respective plots. The soil samples (0-20cm) were collected in June 2021 and June 2022 for the fourth and fifth-year crop rotation study respectively. The experiment results revealed that better soil health and carbon pools of soil were observed with the sesbania and legume-based crop rotations during the fourth (2020) and fifth (2021)year crop rotations as compared to the cereals crop rotations and fallow land. Per cent achievement of physical chemical and biological properties were also recorded relatively higher under green manure and legume-based crop rotations during the fourth (2020) and fifth (2021) year crop rotations as compared to the fallow land. The incorporation of sesbania and legume crops in crop rotation did not have any remarkable influence on soil texture, particle density, pH and EC. Soil physical(Bulk density, water holding capacity and porosity) chemical properties (OC, NPK, Ca2+ Mg2+ Sulfur and zinc) and biological properties (Microbial counts, microbial biomass carbon and enzymatic activity), carbon status (Total organic carbon,organic carbon storage, KMnO4oxidizable carbon and organic matter), carbon pools (active and passive) and soil health indices (Structure stability index, soil health index, biochemical index and carbon management index) improved under the sesbania and legume-based crop rotations as compared to the uncultivated land in fourth(2020) and fifth(2021) year crop rotations.A correlation and scoring technique was adopted to identify the relationship between different soil properties and soil health determination respectively. The high category soil health index was identified with legume and sesbania-based crop rotations under fourth(2020) and fifth(2021) year crop rotations. Thus, the present study provides a strong basis for the recommendation of sesbania and legume-based crop rotation which helps conserve soil health, soil fertilityand environmental quality.EnglishThesis