A Long-Term Impacts of Planted Fodder Grasses on Soil Quality and Organic Carbon Fraction Pools Das Anup*, Yadav Gulab Singh, Kandpal Basant, Roy Saptamita, Nath Mandira, Singh Vinay, Das Ripan Chandra ICAR Research Complex for NEH Region, Tripura Centre, West Tripura, Tripura, India *Corresponding author email id: anup_icar@yahoo.com
Online published on 17 February, 2020. Abstract Different fractions of soil organic carbon (SOC) act as a major source and sink for atmospheric carbon (C). Thus, understanding SOC dynamics and its allocation into various resistance organic C pools especially in grassland ecosystem may have a greater role in environmental stability. A perennial grass block with three fodder species namely hybrid Napier (Pennisetum glaucum × P. purpureum), Congo signal (Brachieria rosenesis) and combo Napier (P. purpureum) were established at ICAR Research Complex for NEH Region, Tripura centre in 2003 to study the impact of grasses on SOC dynamics and its distribution into different organic C pools in comparison to a natural mixed-grass soil [grasses, those were grown naturally without any management and might be an admixture of non-legume and legume species suitable for this region for example bermuda grass (Cynodon dactylon), buffalo grass (Bouteloua dactyloides), crab grass (Digitaria sanguinalis), green fingers (Lotrochota birotulata), para grass (Brachiaria mutica), rhodes grass (Chloris gayana), crown grass (Paspalum scrobiculatum), Mimosa (Mimosa diplotricha), Euphorbia hirta, Cassia tora, Vicia hirsuta, V. sativa, Melilotus indica etc.]. Water holding capacity (WHC) and field capacity (FC) of different soils under three fodder species of hybrid Napier, Congo signal and combo Napier ranged between 40.65–59% and 28.62–46.84%, respectively. The soils under natural mixed grasses had the highest WHC. Bulk density was the lowest in soils under hybrid Napier. Available nitrogen and potassium were the highest in soils under hybrid Napier, however, available phosphorus was the highest in soils under Congo signal. Total pool of Walkley and Black carbon (WBC) and total carbon (TC) in top 1 m soil profile ranged from 59.7 to 86.3 Mg/ha and 74.8 to 112.6 Mg/ha, respectively, across the treatments. However, TC pools in soils under mixed grasses were 50.4, 22.1 and 28.6% higher than those in soil under hybrid Napier (74.8 Mg/ha), Congo signal (92.2 Mg/ha) and combo Napier (87.5 Mg/ha), respectively. The most important aspect of the study is that about 62.9–65.5% WBC pool and 64.4–66.8% TC pools lied below 30 cm depth across the grasses. Although soils under combo Napier had higher AC pools by 26.4, 28.2 and 57.1% over those of soils under hybrid Napier (49.4 Mg/ha), Congo signal (48.7 Mg/ha) and mixed natural grasses (62.4 Mg/ha), respectively. The PC pools were higher in soils under mixed natural grasses by 99.5, 16.4 and 6.2% over the soils under three fodder species, that is, hybrid Napier (25.4 Mg/ha), Congo signal (43.4 Mg/ha) and combo Napier (47.3 Mg/ha), respectively. Thus, study suggests that the restoration of low carbon degraded land through establishment of mixed grasses is a feasible option in northeastern Indian Himalayan region as grasses have high potential for allocation of SOC into passive carbon (PC) pool (recalcitrant pool). However, among the perennial grasses, combo Napier maintained more of PC pool in soil, thus, it has potential to increase the stable SOC pools in degraded lands and mitigate the changing climate. Top Keywords Soil organic carbon dynamics, SOC pools, Passive carbon, Water holding capacity, Non-labile carbon. Top |