Slow and controlled release nanofertilizers as an efficient tool for sustainable agriculture: Recent understanding and concerns

The growing population is driving up the demand for food, but the inadequate efficiency of traditional fertilizers is constraining crop production. Nanotechnology-based fertilizers represent a novel strategy for boosting agricultural output and show great potential as viable options in the fertilizer industry, as they can significantly enhance nutrient retention and promote optimal growth. Very recently, slow and controlled release nanofertilizers have evolved through the development of nanocomposites or coating techniques with the aid of various chemical entities. These types of slow release nanofertilizers are more effective than normal nanofertilizers as these fertilizers deliver nutrients in a controlled manner and can be regulated by various environmental and physical stimuli (pH, temperature, humidity, etc.). Their nutrient use efficiency (NUE) is also far better than the normal nanoparticles (individual nanoparticles like iron, zinc, copper nanoparticles etc.), as these nanocomposites demonstrate zero or very little nutrient leaching. Utilizing controlled release fertilizers mitigates nutrient loss from volatilization and leaching and offers a meticulously tailored nutrient release system harmonizing with the objective of sustainable agriculture. Therefore, this review article provides insights into slow and controlled release nanofertilizers, including preparation approaches, nutrient-release techniques, analytical detection methods, current status, role in crop improvement, commercial viability, and future perspectives.