Reliance on inorganic fertilizers with less or no use of organic fertilizers has impaired the productivity of soils worldwide. Therefore, the present study was conducted to quantify the effects of integrated nutrient management on rice yield, nutrient use efficiency, soil fertility, and carbon (C) sequestration in cultivated land. The experiment was designed with seven treatments comprising of a zero input control, recommended inorganic fertilizers (RD), poultry manure (PM) (5 t ha⁻¹) + 50% RD, PM (2.5 t ha⁻¹) + 75% RD, vermicompost (VC) (5 t ha⁻¹) + 50% RD, VC (2.5 t ha⁻¹) + 75% RD, and farmers’ practice (FP) with three replications that were laid out in a randomized complete block design. The highest grain yield (6.16–6.27 t ha⁻¹) was attained when VC and PM were applied at the rate of 2.5 t ha⁻¹ along with 75% RD. Uptake of nutrients and their subsequent use efficiencies appeared higher and satisfactory from the combined application of organic and inorganic fertilizers. The addition of organic fertilizer significantly influenced the organic carbon, total carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, soil pH, phosphorus, potassium, sulfur, calcium, and magnesium contents in post-harvest soil, which indicated enhancement of soil fertility. The maximum value of the organic carbon stock (18.70 t ha⁻¹), total carbon stock (20.81 t ha⁻¹), and organic carbon sequestration (1.75 t ha⁻¹) was observed in poultry manure at the rate of 5 t ha⁻¹ with 50% RD. The soil bulk density decreased slightly more than that of the control, which indicated the improvement of the physical properties of soil using organic manures. Therefore, regular nourishment of soil with organic and inorganic fertilizers might help rejuvenate the soils and ensure agricultural sustainability.

Information on carbon dioxide (CO₂) emission from different organic sources and their temperature sensitivity to decomposition is scarce in Bangladesh. Therefore, this study quantified the rates of CO₂ emission and carbon (C) degradation constants from different organic material mixed soils at variable temperatures in two laboratory experiments.

Rice–fallow–rice, the dominant cropping system in Bangladesh, has received little attention regarding soil organic carbon (SOC) changes through organic amendments. Understanding the contributions of organic amendments in C sequestration is important for carbon budgeting. This study determined the effect of organic amendments on CO₂ emission to the atmosphere and C sequestration in soil. A series of field experiments in five consecutive rice seasons were conducted during 2010–2012 at the research farm of Bangabandhu Sheikh Mujibur Rahman Agricultural University, Bangladesh, using five treatments – control, cow dung (CD), poultry manure (PM), rice straw (RS) and soil test-based fertilizer (STB). The carbon application rate from CD, PM and RS was 2 t C ha⁻¹ season⁻¹. Carbon dioxide production from rice fields was measured through NaOH absorption followed by HCl titration. The difference in the amount of cumulative CO₂ evolution and SOC accretion between the control and organic treatments gave apparent C balance and C sequestration. CD, PM and RS contributed to the positive soil nutrient balance. Application of CD, PM and RS resulted in 36, 28 and 37% loss of applied C through emission, respectively. The application of organic C through RS, CD and PM accounted for 10, 30 and 49% sequestration, respectively. There were 34, 23 and 53% unaccounted amounts of applied C from CD, PM and RS, respectively, which may be attributed to anaerobic decomposition where CO₂ was not produced, or escaping of the produced CO₂ through aerenchyma channels to the leaf surface. Poultry manure was found to be efficient in increasing carbon and other nutrients in soils, and contributed to a higher grain yield of rice compared to RS and CD. Due to STB fertilization, microbial activities might be enhanced and favored better growth of root biomass, which contributed to slight sequestration of SOC in the rice–rice cropping system.

A large amount of nitrogen (N) fertilizer is required for paddy cultivation, but nitrogen use efficiency (NUE) in paddy farming is low (20–40%). Much of the unutilized N potentially degrades the quality of soil, water, and air and disintegrates the functions of different ecosystems. It is a great challenge to increase NUE and sustain rice production to meet the food demand of the growing population. This review attempted to find out promising N management practices that might increase NUE while reducing the trade-off between rice production and environmental pollution. We collected and collated information on N management practices and associated barriers. A set of existing soil, crop, and fertilizer management strategies can be suggested for increasing NUE, which, however, might not be capable to halve N waste by 2030 as stated in the “Colombo Declaration” by the United Nations Environment Program. Therefore, more efficient N management tools are yet to be developed through research and extension. Awareness-raising campaign among farmers is a must against their misunderstanding that higher N fertilizer provides higher yields. The findings might help policymakers to formulate suitable policies regarding eco-friendly N management strategies for wetland paddy cultivation and ensure better utilization of costly N fertilizer.