Carbon and Nitrogen Mineralization in Dark Grey Calcareous Floodplain Soil Is Influenced by Tillage Practices and Residue Retention

Abstract

Very little is known about the changes that occur in soil organic carbon (SOC) and total nitrogen (TN) under an intensive rice-based cropping system following the change to minimal tillage and increased crop residue retention in the Gangetic Plains of South Asia. The field experiment was conducted for 3 years at Rajbari, Bangladesh to examine the impact of tillage practices and crop residue retention on carbon (C) and nitrogen (N) cycling. The experiment comprised four tillage practices—conventional tillage (CT), zero tillage (ZT), strip-tillage (ST), and bed planting (BP) in combination with two residue retention levels—increased residue (R50%) and low residue (R20%—the current practice). The TN, SOC, and mineral N (NH4+-N and NO3−-N) were measured in the soil at different crop growth stages. After 3 years, ZT, ST, and BP sequestered 12, 11, and 6% more SOC, and 18, 13, and 10% more TN, respectively than the conventional crop establishment practice at 0–5 cm soil depth. The accumulation of SOC and TN was also higher compared to the initial SOC and TN in soil. Among the tillage practices, the maximum SOC and TN sequestration were recorded with ST and with R50% that might be attributed to reduced mineralization of C and N in soil particularly with increased residue retention, since decay rates of potentially mineralizable C was lower in the ST with both the residue retention practices. Increased residue retention and minimum tillage practices after nine consecutive crops has altered the C and N cycling by slowing the in-season turnover of C and N, reducing the level of nitrate-N available to plants in the growing season and increasing retained soil levels of SOC and TN.

Legume cover crop type and termination method effects on labile soil carbon and nitrogen and aggregation

“…A similar phenomenon was observed by Zhang et al (2012), where conventional tillage MBC spiked to surpass a no-till treatment before again subsiding. Greater PMC in CT compared with FM adds to evidence suggesting that the disruptive process of tillage would decrease total SOM (Figure 7) (Paustian et al, 2000;Salahin et al, 2021).…”

Estimating the Global Influence of Cover Crops on Ecosystem Service Indicators in Croplands With the LPJ‐GUESS Model

“…It should be noted that assessing the effects of no‐till management on cropland N leaching remains uncertain. Some studies reported that conservation tillage can slightly reduce this hydrological N loss because of the diminished net N mineralization rates (Porwollik et al., 2022; Salahin et al., 2021; Thapa et al., 2018). However, other studies found enhanced nitrate leaching in the reduced‐tillage soils compared with conventional tillage systems, mainly due to the enhanced water drainage caused by greater abundance of macropores (preferential flow channels) and better soil infiltrability (Daryanto et al., 2017).…”

Temporal variation in soil carbon in various paddy soil types in a cold temperate continental monsoon climate

“…Its main components are humic acid carbon (HA–C), fulvic acid carbon (FA–C) and humic carbon (HM–C), which are related to soil fertility and fertilization capacity (Madhavan et al, 2017; Wang et al, 2020; Zhao et al, 2019). The soil mineralized carbon is a measure of the amount of soil organic matter that can be decomposed by microorganisms and represents the carbon volume of the mineralized part of the soil to a certain extent (Lewis et al, 2021; Salahin et al, 2021). Carbohydrates are one of the most important and degradable organic components of soil.…”