Salahin Nazmus, Alam Md Khairul, Ahmed Sharif, Jahiruddin Mohammad, Gaber Ahmed, Alsanie Walaa F, Hossain Akbar, Bell Richard W
Bangladesh Agricultural Research Institute, Gazipur 1701, Bangladesh.
Bangladesh Agricultural Research Council, Dhaka 1208, Bangladesh.
Plants (Basel). 2021 Aug 11;10(8):1650. doi: 10.3390/plants10081650.
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 (R) and low residue (R-the current practice). The TN, SOC, and mineral N (NH-N and NO-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 R 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.
在南亚恒河平原，从传统耕作转变为少耕并增加作物残茬保留量后，关于集约化水稻种植系统下土壤有机碳（SOC）和全氮（TN）的变化，人们了解甚少。在孟加拉国拉杰巴里进行了为期3年的田间试验，以研究耕作方式和作物残茬保留对碳（C）和氮（N）循环的影响。该试验包括四种耕作方式——传统耕作（CT）、免耕（ZT）、条耕（ST）和垄作（BP），并结合两种残茬保留水平——增加残茬量（R）和低残茬量（R-当前做法）。在不同作物生长阶段测量土壤中的TN、SOC和矿质氮（NH-N和NO-N）。3年后，在0-5厘米土壤深度处，ZT、ST和BP分别比传统作物种植方式多固存12%、11%和6%的SOC，以及18%、13%和10%的TN。与土壤初始SOC和TN相比，SOC和TN的积累也更高。在耕作方式中，ST和R处理下记录到最大的SOC和TN固存，这可能归因于土壤中C和N矿化减少，特别是随着残茬保留量增加所导致，因为在两种残茬保留处理的ST中，潜在可矿化C的分解速率较低。连续九季作物后增加残茬保留量和采用少耕方式，通过减缓C和N的季内周转、降低生长季植物可利用的硝态氮水平以及增加土壤中SOC和TN的保留量，改变了C和N循环。
