title: Organic C dynamics and its conservation under wheat (Triticum aesetivum) - mint (Mentha arvensis)-Sesbania rostrata cropping in sub-tropical condition of northern Indo-Gangetic plains.
abstract: Soil organic carbon (SOC) is accumulated or depleted as a result of cropping and management strategies. It plays a significant role in maintaining soil quality, plant productivity and mitigating greenhouse gas emission. We studied the long-term (20 years) influence of a wheat-mint-Sesbania cropping system on the SOC stock. Estimates of stabilization of SOC in different pools and a tentative C budget were also developed. Twenty years of cultivation caused a decrease in SOC only in control soils, which received no manure and fertilizer. However, it increased with balanced use of NPK inputs. Soil C stock decreased significantly with increased in soil depth 0-15 cm to 15-30 and 30-45 cm. About 6% (-2 to+14) of the C added in crop residues and green manure were stabilized in the soil. On an average 12%, 14%, 59%, 15% of the water stable aggregates were in the >2 mm, 2.0-0.25 mm, 0.25-0.05 mm, and <0-0.5 size fractions, respectively. Significant improvements in structural stability and nitrogen availability were detected in all the treatments compared to the control. The amount of organic C oxidizable by a modified Walkley and Black method, which involves using only half of the amount of sulphuric acid, is a more sensitive indicator of the improvement in soil quality parameters under investigation, namely SOC, and increases in mineralizable N and water stable aggregation than the standard method.
authors: CSIR - Central Institute of Medicinal and Aromatic Plants, Picnic Spot Road, Lucknow 221615, Uttar Pradesh, India. Electronic address: ddpatra@rediffmail.com.
authors: D D
authors: DD
authors: Patra
authors: CSIR - Central Institute of Medicinal and Aromatic Plants, Picnic Spot Road, Lucknow 221615, Uttar Pradesh, India.
authors: Sukhmal
authors: S
authors: Chand
authors: CSIR - Central Institute of Medicinal and Aromatic Plants, Picnic Spot Road, Lucknow 221615, Uttar Pradesh, India.
authors: M
authors: M
authors: Anwar
mesh_terms: D002244:Carbon / Q000737:chemistry*; D018556:Crops, Agricultural / Q000254:growth & development*; D005308:Fertilizers / Q000032:analysis; D008372:Manure / Q000032:analysis; D027541:Mentha / Q000254:growth & development*; D009584:Nitrogen / Q000737:chemistry; D049931:Sesbania / Q000254:growth & development*; D012987:Soil / Q000737:chemistry*; D014908:Triticum / Q000254:growth & development*
chemical_list: D005308:Fertilizers; D008372:Manure; D012987:Soil; D002244:Carbon; D009584:Nitrogen
keywords: Carbon sequestration; Long term experiment; Oxidizable C; Water stable aggregation; Wheat-mint-green manuring