Crop diversification and their impact on soil C pools and C indices in Eastern plateau region of India is yet to be clearly understood. To explore this, a nineteen years field experiment was carried out to identify suitable diversified cropping system of this region with assessing the SOC pool, C and humification indices. Selected cropping systems were, uncultivated grassland (D-0), rice-fallow (D-1), rice-fallow/rice-okra/rice-maize (D-2), rice-fallow/rice-capsicum/rice-mungbean (D-3) and rice-fallow/rice-capsicum/rice-babycorn/rice-groundnut systems (D-4). Total organic carbon (TOC), various fractions of reactive and recalcitrant C pools, humification indices, dehydrogenase activity and carbon management index (CMI) were determined for 0−15, 15−30 and 30−45 cm soil layers. After 19 years of cultivation, SOC content (g kg⁻¹) of the soil was improved by 22.9 % in D-1 system in 0−15 cm soil depth. Depth dynamics revealed decrement of SOC fractions and stocks with increasing soil depth, although minimum decrement has noticed in D-3 and D-4 systems. D-1 system had the highest very labile C (VLC), labile C (LC) stock, whileless labile C (LLC) and humus C (Hum-C) was found to be highest in D-0. In deeper soil layers (30−45 cm), D-4 system had the highest reactive C pool (RP) stock. Percent deviation of RP-C stock under D-4 system had also the lowest across the 45 cm soil profile. D-2, D-3 and D-4 systems had ∼34, 52 and 40 % higher C lability index (CLI) than D-0 in 0−15, 15−30 and 30−45 cm soil depths, respectively. Besides, D-1 system had similar and ∼ 63 % higher CMI value at 0−15 and 15−30 cm, while, ∼76 % higher CMI value was observed in D-4 system at 30−45 cm in respect to the reference. At lower depth, rate of humification and dehydrogenase activity were enriched in D-4 system. Thus D-4 can be considered as efficient agro-ecosystem to maintain temporal soil fertility and soil health. At regional scale, more diversified rice-based cropping system with legumesappears to be more promising cropping practice that sustains SOC with higher rate of humification and microbial activity.

印度东部高原地区的作物多样化及其对土壤碳库和碳指数的影响尚不清楚。为了探索这一点，进行了十九年的田间试验，通过评估SOC库，碳和增湿指数，确定了该地区合适的多样化种植系统。选定的耕作制度为：未耕种的草地（D-0），水稻休耕（D-1），水稻休耕/大麦秋葵/水稻-玉米（D-2），水稻休耕/大米辣椒/大米绿豆（D-3）和小米/小辣椒/大米-婴儿玉米/大米-花生系统（D-4）。确定了0-15、15-30和30-45厘米土壤层的总有机碳（TOC），反应性和顽固性碳库的各个部分，增湿指数，脱氢酶活性和碳管理指数（CMI）。培养19年后，SOC含量（g kg^-1D-1系统在0-15 cm的土壤深度下）的土壤养分提高了22.9％。深度动态显示，随着土壤深度的增加，SOC分数和储量会减少，尽管在D-3和D-4系统中注意到了最小的减少。D-1系统的极不稳定C（VLC），不稳定C（LC）库存最高，而D-0系统中不稳定C（LLC）和腐殖质C（Hum-C）最高。在更深的土壤层（30-45厘米）中，D-4系统具有最高的活性碳库（RP）库。在D-4系统下，RP-C原料的百分比偏差在45 cm的土壤剖面上也最低。D-2，D-3和D-4系统在0-15、15-30和30-45 cm的土壤深度中比C-0分别高出约34％，52％和40％。此外，D-1系统在0-15和15-30 cm处的CMI值相近且高出约63％，而 在D-4系统中，相对于参考，在30-45 cm处观察到的CMI值高出约76％。在较低的深度，D-4系统中的腐殖化速率和脱氢酶活性得到了丰富。因此，D-4可以被视为维持暂时土壤肥力和土壤健康的有效农业生态系统。在区域范围内，豆科植物更多样化的水稻种植系统似乎是更有前途的耕作方式，能够以更高的增湿率和微生物活性维持SOC。