Molecular Soil Biology 2025, Vol.16, No.6, 314-324 http://bioscipublisher.com/index.php/msb 316 such as wheat–corn or wheat–rice, fertilizer use can be planned across seasons. Nitrogen, phosphorus, and potassium do not need to be fully applied in one season. Part of the fertilizer can be moved to periods with lower crop demand. The corn season is one such period (Zhang et al., 2025). In addition, fertilizer placement matters. Compared with surface broadcasting, furrow application, trench placement, and deep application usually give better results. 3.2 Organic nutrient sources In rice-wheat and corn-wheat rotations, farmyard manure, green manure or wheat straw can be used to replace 25% to 50% of the recommended NPK dosage (Bhardwaj et al., 2023). Farmyard manure has the most obvious effect on increasing soil organic carbon (SOC) and microbial carbon and nitrogen. The effect of returning wheat straw to the field is slightly weaker. Green manure can also significantly improve the overall soil quality (Dhaliwal et al., 2021). In the corn-wheat system, when 50% NPK is used in combination with poultry manure, oil cakes, or wheat and corn stalks, both soil organic carbon and microbial biomass carbon are significantly increased. Compared with the application of NPK alone, the average wheat yield increased by approximately 23%. Long-term continuous application of farmyard manure can increase the SOC content from 0.44% to 0.66%, and the contents of mineralized nitrogen and available phosphorus and potassium also increase accordingly (Dhaliwal et al., 2021). 3.3 Biofertilizers and microbial inputs When Azotobacter or Azospirillum is used with chemical fertilizers, the effect is usually steady. The results do not change much between seasons. In most cases, chemical fertilizer can be kept at 75%~100% of the recommended rate. Under this level, nitrogen fertilizer can be cut by about 15%~25%. Yield does not go down. In some trials, it even goes up (Saini et al., 2025). In corn–wheat rotation systems and in orchards, phosphorus fertilizer is often not used alone. It is applied together with phosphorus-solubilizing bacteria. Trichoderma and similar microbes are also added. This helps phosphorus work better in the soil. Because of this, less phosphorus fertilizer is needed. Crops take up more phosphorus. Seed yield also shows an increase (Imran, 2024). In wheat production, the same pattern is often seen. Azotobacter and PSB are combined with about 75% of the recommended NPK rate. This already gives good results. When farmyard manure or vermicompost is added, the effect becomes stronger. Many field experiments report this result. When chemical fertilizer is kept at 75%~100% of the recommended level and is used together with organic fertilizer and bio-fertilizers such as Azotobacter, PSB, and AMF, wheat yield is usually the highest. Nutrient uptake by the crop is also better under these conditions (Varinderpal-Singh et al., 2020). 4 Integrated Nutrient Management Strategies in Wheat Cropping Systems 4.1 Combined application of organic-inorganic-bionutrient sources In trials conducted in multiple locations in India, wheat treatments using 75% of the recommended fertilizer dose (RDF) combined with 5 t/ha of vermicompost and inoculated with nitrogen-fixing and phosphorus-solubilizing bacteria (Azospirillum/Azotobacter + PSB) showed higher grain yield and net income than those using 100% RDF alone, and were comparable to or slightly better than the treatment using 75% RDF + 10 t/ha of farmyard manure (FYM) + biofertilizer. The 85% RDF + 15% organic nitrogen source (vermicompost) treatment (N3) significantly improved wheat growth, yield, and economic returns (Saini et al., 2025). The cumulative available nitrogen during the season was approximately 962 μg cm-2 for the green manure (GM) treatment, higher than the 878 μg cm⁻ ² for the 100% full fertilizer treatment. The total seasonal nitrogen supply (872 and 865 μg cm-2) for the legume residue (LE) and FYM treatments was also close to or slightly lower than that of the full fertilizer treatment (Bhardwaj et al., 2021). Under irrigated wheat conditions, the combined application of the recommended amount of NPK with Azotobacter and arbuscular mycorrhizal fungi reduced ammonia volatilization loss to 10.2~10.6 kg N ha-1 and denitrification loss to only 2.4~2.5 kg N ha-1, significantly lower than the NPK monotherapy treatment, while increasing grain yield to 6.4 t ha⁻ ¹ (Darjee et al., 2022). Meta-analysis covering 338 experimental data pairs from 1989–2016 showed that, compared to the "no organic fertilizer only," "organic fertilizer only," and no fertilization treatments, INM increased wheat yield by 2.5%, 29.2%, and 90.9% in loam soils, and by 0.6%, 24.9%, and 93.7% in clay soils, respectively, with a net gain of 127% compared to no fertilization (Sharma et al., 2019) (Figure 1).
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