Understanding nitrogen (N) release patterns and kinetics is a key challenge for improving N use efficiency in any agroecosystem. An incubation experiment was done to study the N release pattern and kinetics of contrasting soils amended with compost (CO), poultry manure (PM), rice husk biochar (RHB), poultry manure biochar (PMB) and cowdung (CD) combined with chemical fertilizer (integrated plant nutrient system, IPNS approach) under two moisture regimes, viz. field capacity (FC) and continuous standing water (CSW) at 25 °C for 120 days. Our results revealed that NH₄⁺-N was the dominant under CSW conditions, whereas NO₃⁻-N was dominant under FC conditions. Net mineral N data fitted well to the first order kinetic model. Both N release potential (N₀) and rate constant (k) were greater in acidic soil than those of charland soil. The maximum N release varied between 24.90–76.29% of input depending on soil type and moisture status. N mineralization was strongly correlated with urea N application. PM and PMB mineralized in all soil and moisture conditions whereas N immobilization was observed in the case of RHB. N mineralization was strongly correlated with urea N application. Gaseous N losses were different for the organic amendments exhibiting more gaseous N losses in PM, CD and CO based IPNS whereas the lowest gaseous N loss was observed in PMB based IPNS. Biochar based IPNS increased soil pH in all conditions. Thus, the present study suggests that N release depends on soil type, soil moisture and type of organic amendment. However, CO, PM and CD based IPNS can be recommended for both acidic and charland soils in terms of N release as short duration crops will suffer from N deficiency if biochar based IPNS is used in the field.

Having up-to-date knowledge on the mineralization of organic materials and release of nutrients is of paramount significance to ensure crops’ nutrient demands, increase nutrient use efficiency and ensure the right fertilizer application at the right time. This study seeks to evaluate the mineralization patterns of various manures viz. cowdung (CD), cowdung slurry (CDSL), trichocompost (TC), vermicompost (VC), poultry manure (PM), poultry manure slurry (PMSL), and mungbean residues (MR). The objective being to establish their efficiency in releasing nutrients under aerobic (field capacity) and anaerobic (waterlogging) conditions. The incubation experiment was designed using a Completely Randomized Design (CRD) that took into account three variables: Manures, soil moisture, and incubation period. The mineralization of carbon (C) and nitrogen (N) ranged from 11.2 to 100.1% higher under aerobic conditions rather than anaerobic ones. The first-order kinetic model was used to mineralize both elements. C mineralization was 45.8 to 498.1% higher in an amount from MR under both moisture conditions. For N release, MR and PM exerted maximum amounts in anaerobic and aerobic scenarios, respectively. However, the rate of C and N mineralization was faster in TC compared to other manures in both moisture conditions. Although TC was 1.4 to 37.7% more efficient in terms of rapidity of mineralization, MR and PM performed better concerning the quantity of nutrient release and soil fertility improvement. PM had 22–24% higher N mineralization potential than PMSL while CDSL had 46–56% higher N mineralization potential than CD. C and N mineralization in soil was greater under aerobic conditions compared to what occurred in the anaerobic context. Depending on mineralization potential, the proper type and amount of manure should be added to soil to increase crops’ nutrient use efficiency, which in turn should lead to better crop production.

Integrated Plant Nutrient System (IPNS) is practiced worldwide to maintain soil quality. Two field experiments were conducted in 2019 and 2020 in acidic and charland soils to assess the impact of different manures, viz., poultry manure (PM), vermicompost (VC), compost (OF), rice husk biochar (RHB), poultry manure biochar (PMB)-based IPNS, and dolomite over control on productivity and nitrogen use efficiency (NUE) of the Mustard-Boro-Transplanted Aman and Maize-Jute-Transplanted Aman cropping patterns, and on soil properties. The experiments were laid out in a randomized complete block design with four replications. The results showed that IPNS treatments significantly improved soil aggregate properties and total nitrogen in acidic soil, and bulk density in charland soil. In both years, IPNS treatments increased system productivity from 55.4 to 82.8% in acidic soil and from 43.3 to 115.4% in charland soil over that of control. IPNS and dolomite treatments increased nitrogen uptake from 35.5 to 105.7% over that of control and NUE in both soils in 2019 and 2020. PMB- and OF-based INPS treatments exhibited superior performances in both soils, and the impact was more prominent in 2020. Therefore, PMB- and OF-based IPNS can be recommended for maximizing system productivity and NUE with concurrent improvement of physicochemical properties of acidic and charland soils.

The impacts of integrated soil fertility management (ISFM) in conservation agriculture need short-term evaluation before continuation of its long-term practice. A split-split plot experiment with tillage (minimum tillage, MT vs. conventional tillage, CT) as the main plot, residue (20% residue, R vs. no residue as a control, NR) as the sub-plot, and compost (Trichocompost, LC; bio-slurry, BS; and recommended fertilization, RD) as the sub-sub plot treatment was conducted for two consecutive years. Composite soils were collected after harvesting the sixth crop of an annual mustard-rice-rice rotation to analyze for nutrient distribution and soil structural stability. The LC increased rice equivalent yield by 2% over RD and 4% over BS, and nitrogen (N) uptake by 11% over RD and 10% over BS. Likewise, LC had higher soil organic carbon (SOC), N, and available sulphur (S) than BS and RD. Conversion of CT to MT reduced rice equivalent yield by 11%, N uptake by 26%, and N-use efficiency by 28%. Conversely, soil structural stability and elemental quality was greater in MT than in CT, indicating the potential of MT to sequester C, N, P, and S in soil aggregates. Residue management increased rice yield in the second year by 4% and corresponding N uptake by 8%. While MT reduced the yield, our results suggest that ISFM with Trichocompost and residue retention under MT improves soil fertility and physical stability to sustain crop productivity.

Soil acidity is a major problem when it comes to improving crop productivity and nutrient uptake. This experiment was therefore conducted at a farmer’s field—Nalitabari Upazila under AEZ 22 (northern and eastern Piedmont plains) to evaluate the effects of lime and organic manure (OM) amendment on crop productivity and nutrient uptake of the wheat–mungbean–T. Aman cropping pattern in acidic soils of northern and eastern Piedmont plains. The experiment was laid out in a randomized complete block design with three replications. There were nine treatments applied, varying doses of lime (dololime at the rate of 1 and 2 t ha⁻¹), OM (cow dung at the rate of 5 t ha⁻¹, poultry manure at the rate of 3 t ha⁻¹) and a lime–OM combination to the first crop; T. Aman and its residual effects were evaluated in the succeeding second crop, wheat, and the third crop, mungbean. Results demonstrate that application of lime and organic manure to soil had significant effects on the first crop. However, the effects of lime and organic manure were more pronounced in the second and third crops. The increase in grain yield over control ranged from 0.24 to 13.44% in BINA dhan7. However, it varied from 10.14 to 54.38% in BARI Gom30 and 40 to 161.67% in BARI Mung6. The straw yields of the crops also followed a similar trend. The N, P, K, and S uptake by grain and straw of T. Aman, wheat, and mungbean were influenced significantly by the combined application of lime and organic manure. Sole or combined application of lime and manure amendment significantly improved nutrient availability and soil quality. Therefore, application of lime in combination with manure can be practiced for uplifting the crop productivity and improving soil quality in acidic Piedmont soils of northern and eastern Piedmont plains.