Carbon, Nitrogen Dynamics and Soil Organic Carbon Retention Potential after 18 Years by Different Land Uses and Nitrogen Management in RWCS under Typic Ustochrept Soil

Abstract

A long-term field experiment was conducted to design and implement alternative production systems with increased resource use efficiency, productivity and to determine the effect of tillage systems and mineral fertilizers on soil organic carbon patterns. This experiment intended to evaluate the effects of these management strategies on soil structural formation and structural stabilization of a sandy loam soil. The shift from puddled -transplanted rice on the flat land to raised bed systems affects the productivity and resource use efficiency of the rice-wheat system. Therefore, the potential benefits and constraints of tillage crop residue practices need to be quantified on short to long-term basis, optimum layouts and management systems to maximize yield and efficiency. Due to lesser energy input and higher output T3 ZT with 6tha -1 residue retained had 20% and 5% higher energy use efficiency than T7 CT and T6 PRB with 6tha -1 residue retained. Undisturbed soil samples were collected from the 15 to 100 cm soil layer in the field grown with wheat to assess SOC, bulk density, C restoration rate, C sequestered, C sequestration efficiency (%) and crop yield. However, at the end of the 18 years period, SOC was 25% greater with T6 than T7, 16% greater with T4 than T1, and 17% higher with T2 than T7. Average SOC concentration of the control treatment was 0.54%, which increased to 0.65% in the RDF treatment and 0.82% in the RDF+FYM treatment and increased enzyme activities, which potentially influence soil nutrients dynamics under field condition. Compared to F1 control treatment the RDF+FYM treatment sequestered 0.28 Mg C ha -1 yr -1 whereas the NPK treatment sequestered 0.13 Mg C ha -1 yr -1 . As tillage intensity increased there was a redistribution of SOC in the profile, but it occurred only between ZT and PRB since under CT, SOC stock decreased even below the plow layer. Increased SOC stock in the surface 50 kg m -2 under ZT and PRB was compensated by greater SOC stocks in the 50-200 and 200-400 kg m -2 interval under residue retained, but SOC stocks under CT were consistently lower in the surface 400 kg m -2 . Over the last 18 years, CT lost 0.83 ±0.2 kg of C m -2 while ZT gain 1.98 ±0.3 and PRB gain 0.97 ±0.2 kg of C m -2 in the 1200 kg of soil m -2 profile. These findings suggest that carbon sequestration can be improved if treatments T4 or T6 are used in lieu of T7, respectively.

Precision Agriculture Practices Improves Soil Aggregation, Aggregate Associated Organic Carbon Fractions and Nutrient Dynamics in Cereal-based Systems of North-West India: An Overview

“…While SOM's breakdown rate may be faster in the tropics, frequent inputs of organic modifications may promote SOM build-up [37]. Naresh et al [20] revealed that the highest SOC stock of 72.2Mg C ha -1 was found in F6 with T6 followed by that of 64Mg C ha -1 in F4 with T2 followed by that of F3 with T4 (57.9Mg C ha [38] reported that FYM applied 67.9 per cent of C stabilization in a rice-wheat system in the lower Indo-Gangetic plains.…”

“…Stable aggregates provide SOM with physical protection to minimize microbial attack [15]. Many agro-ecosystem studies have recorded the distribution of soil aggregates, soil aggregate stability, and aggregate-associated SOCs under various types of soil management, including no-tillage, fertilization, natural ecosystem conversion into agricultural land, and vice versa [18,19,20]. While the stability of soil aggregates and SOM sequestration are commonly related phenomena [21], their associations with land use transition, including agricultural abandonment, remain uncertain.…”

“…Soil organic carbon (SOC) plays an important role in soil aggregate formation and stabilization [20].There is a close relationship between soil aggregation and SOC accumulation; typically SOC promotes soil aggregation, while aggregates, in effect, store SOC and minimize the rate of its decomposition. The stable soil aggregates serve as the nuclei for SOC stabilization in the long term.…”

Soil Aggregation and Organic Carbon Fractions and Indices in Conventional and Conservation Agriculture under Vertisol soils of Sub-tropical Ecosystems: A Review

“…A minimal input of 2.34 Mg C ha -1 yr -1 is needed to maintain SOC level. Naresh et al, (2018) reported that conservation tillage practices significantly influenced the total soil carbon (TC), Total inorganic carbon (TIC), total soil organic carbon (SOC) and oxidizable organic carbon (OC) content of the surface (0-15 cm) soil. Wide raised beds transplanted rice and zero till wheat with 100% (T 9 ) or with 50% residue management (T 8 ) showed significantly higher TC, SOC content of 11.93 and 10.73 g kg -1 ,respectively in T 9 and 10.98 and 9.38 g kg -1 , respectively in T 8 as compared to the other treatments.…”

“…The G+/Gratio was higher under NPSM treatment compared to other treatments, indicating that NPSM fertilization had changed soil microbial communities. Naresh et al, (2018) revealed that in the turning jointing stage, compared with CT, the ZT and FIRB treatments significantly increased nitrifying bacteria [Gn] by 77% and 229%, respectively. At the booting stage, the Gn rates in ZT and FIRB soils were 2.16 and 3.37 times greater than that in CT soil, respectively.…”