Field Crop 2024, Vol.7, No.2, 79-92 http://cropscipublisher.com/index.php/fc 85 Reduced Environmental Impact: By minimizing nitrogen surplus and losses, IAP reduces the environmental footprint of maize cultivation. This is achieved through better nitrogen balance and lower greenhouse gas emissions, making IAP a sustainable approach to improving NUE (Liu et al., 2018; Wang et al., 2020). In conclusion, the implementation of integrated agronomic practices significantly enhances nitrogen use efficiency in maize cultivation through improved root development, optimized fertilizer application, enhanced soil fertility, balanced hormone levels, and reduced environmental impact. These practices not only increase maize yield but also contribute to sustainable agricultural systems. 6 Integrated Nutrient Management (INM) 6.1 Description of INM Integrated Nutrient Management (INM) is a holistic approach aimed at maintaining or adjusting soil fertility and optimizing plant nutrient supply to achieve sustainable crop productivity. This strategy involves the balanced use of both chemical fertilizers and organic sources such as farmyard manure (FYM), compost, green manures, and biofertilizers. The primary goal of INM is to enhance nutrient availability, improve soil health, and reduce environmental impacts associated with excessive use of chemical fertilizers (Wang et al., 2020; Sarwar et al., 2023). 6.2 Impact on maize yield and NUE The implementation of INM has shown significant positive impacts on maize yield and nutrient use efficiency (NUE). Studies have demonstrated that combining chemical fertilizers with organic amendments can lead to substantial improvements in crop growth, yield, and nutrient uptake. For instance, the application of 75% of the recommended dose of NPK fertilizers supplemented with biochar resulted in increased dry matter production, grain weight, and grain yield in maize, as well as improved nutrient uptake and economic sustainability. Similarly, integrated agronomic practices, including optimal planting density and split fertilizer application, have been found to increase maize grain yield and NUE, particularly in fields with high soil fertility (Zhou et al., 2019; Ghosh et al., 2020). Long-term studies have also highlighted the benefits of INM in maintaining soil fertility and achieving sustainable high yields. For example, an 11-year field study in Northeast China showed that INM with a combination of inorganic and organic fertilizers significantly increased maize yield and NUE while reducing nitrogen losses and greenhouse gas emissions. Another long-term experiment in the Indo-Gangetic plains of India revealed that INM practices led to higher sustainable yield indices and better nutrient balance compared to the sole use of chemical fertilizers (Saha et al., 2018). 6.3 Successful INM strategies Several successful INM strategies have been identified in various studies. One effective approach involves the partial substitution of chemical fertilizers with organic amendments. For example, substituting 50% of the recommended nitrogen dose with farmyard manure or other organic sources has been shown to enhance maize growth and yield parameters. Additionally, the use of biochar as a supplement to chemical fertilizers has proven to be beneficial in improving crop productivity and nutrient uptake (Sarwar et al., 2023). Another successful strategy is the integration of weed management practices with nutrient management. Combining chemical weed control with mechanical methods, such as hoeing, has been found to reduce weed density and enhance maize grain yield. Furthermore, the adoption of integrated soil-crop system management (ISSM) strategies, which include the use of both inorganic and organic fertilizers, has been shown to achieve sustainable high yields and improved NUE in maize cropping systems (Wang et al., 2020). In conclusion, INM is a promising approach to enhance maize yield and nutrient use efficiency while maintaining soil health and sustainability. The integration of chemical and organic nutrient sources, along with appropriate agronomic practices, can lead to significant improvements in crop productivity and environmental sustainability.
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