ICAR Research Complex for North Eastern Hill Region, Tripura Centre, Tripura, 799 210, India; Division of Agronomy, ICAR-Indian Agricultural Research Institute, New Delhi, 110 012, India.
ICAR Research Complex for North Eastern Hill Region, Umiam, Meghalaya, 793 103, India.
J Environ Manage. 2021 Apr 1;283:111978. doi: 10.1016/j.jenvman.2021.111978. Epub 2021 Jan 19.
Globally, various estimates are available on the above-ground (plant parts) carbon (C) sequestering potential of agroforestry systems (AFSs). However, information on soil organic carbon (SOC) sequestration potential is limited for AFSs. Furthermore, the impacts of AFSs established for the restoration of C in degraded soils (prone to soil erosion, C and nutrients loss, etc.) of Himalayas are rarely investigated. Thus, a study was conducted on an agroforestry block established in 1989 at the Indian Council of Agricultural Research (ICAR), Research Complex for North Eastern Hill (NEH) Region, Lembucherra, Tripura, India. The AFSs comprised of four multipurpose tree species viz., teak (Tectona grandis Linn), sissoo (Dalbergia sissoo Roxb. Ex DC.), eucalyptus (Eucalyptus globulus L.), and neem (Azadirachta indica A. Juss) in combination with pineapple (Ananas comosus L. merr.). Planted in three times replicated randomized block design. After 28 years of establishment, the impacts of these AFSs were assessed on SOC stocks and its fraction pools. Results revealed that sissoo + pineapple system stored the highest SOC stocks in 0-15 cm (22.1 ± 1.4 Mg/ha) and 30-60 cm (18.0 ± 4.3 Mg/ha) depths, whereas the SOC stocks in 15-30 cm (12.2 ± 1.2 Mg/ha) and 0-30 cm (34.0 ± 1.6 Mg/ha) were the highest under teak + pineapple. When considering the entire 0-100 cm soil profile, the SOC stocks ranged between 65.3 and 71.6 Mg/ha across the diverse AFSs which was significantly higher than that under cultivated land (52.8 ± 2.6 Mg/ha). The sissoo + pineapple system had the highest SOC stock in 0-100 cm (71.6 ± 5.8 Mg/ha). The share of passive carbon (PC, less labile + non-labile) pools to SOC stocks under AFSs followed the order of sissoo + pineapple > teak + pineapple > neem + pineapple > eucalyptus + pineapple. The PC or recalcitrant pools of SOC stocks at 0-100 cm were 54.2-60.6% under various AFSs. Results revealed that the establishment of AFSs with pineapple on degraded lands increased a significant amount of C and had a considerable effect on soil quality in comparison to C present in soils under cropland. Thus, a large scale adoption of AFSs may restore C lost through the cultivation of the crop in degraded lands and provide a feasible option for livelihood through concurrent cultivation of multipurpose tree species and agri-horticulture crops.
全球范围内，人们对农林复合系统（AFS）地上部分（植物部分）的碳（C）固存潜力有各种估计。然而，关于 AFS 土壤有机碳（SOC）固存潜力的信息有限。此外，对于为恢复退化土壤（易受土壤侵蚀、C 和养分流失等影响）中的 C 而建立的 AFS 的影响，喜马拉雅山地区很少进行研究。因此，在印度农业研究理事会（ICAR）位于印度特里普拉邦伦布楚拉的东北山地研究综合体（NEH）进行了一项研究。该 AFS 由四种多用途树种组成，即柚木（Tectona grandis Linn）、西达树（Dalbergia sissoo Roxb. Ex DC.）、桉树（Eucalyptus globulus L.）和印度楝（Azadirachta indica A. Juss），与菠萝（Ananas comosus L. merr.）相结合。采用三次重复随机区组设计种植。建立 28 年后，评估了这些 AFS 对 SOC 储量及其分馏池的影响。结果表明，西达树+菠萝系统在 0-15 厘米（22.1±1.4 Mg/ha）和 30-60 厘米（18.0±4.3 Mg/ha）深度储存的 SOC 储量最高，而 15-30 厘米（12.2±1.2 Mg/ha）和 0-30 厘米（34.0±1.6 Mg/ha）的 SOC 储量最高在柚木+菠萝下。当考虑整个 0-100 厘米的土壤剖面时，不同 AFS 下的 SOC 储量在 65.3 至 71.6 Mg/ha 之间，明显高于耕地（52.8±2.6 Mg/ha）。西达树+菠萝系统在 0-100 厘米处具有最高的 SOC 储量（71.6±5.8 Mg/ha）。AFS 下 SOC 储量的被动碳（PC，较少的不稳定+非不稳定）池份额遵循西达树+菠萝>柚木+菠萝>印度楝+菠萝>桉树+菠萝的顺序。0-100 厘米处 SOC 储量的 PC 或难降解池在各种 AFS 下为 54.2-60.6%。结果表明，在退化土地上建立 AFS 并种植菠萝可以显著增加 C 的数量，并对土壤质量产生相当大的影响，与耕地中存在的 C 相比。因此，大规模采用 AFS 可以恢复在退化土地上种植作物所损失的 C，并通过同时种植多用途树种和农业园艺作物为生计提供可行的选择。
