Effect of Graphene and its Oxidized Derivatives on Plant Germination and Macronutrients Adsorption

The developing world has witnessed a rapid growth in crop production since the green revolution in the 1960s. Even though the population has almost doubled since then, food production has tripled; most of this growth can be attributed to crop research, fertilizers, infrastructure, and market development. Although the green revolution came with benefits, it has been widely criticized for its negative impact on the environment. The excessive and inappropriate use of fertilizers has led to human and livestock diseases, polluted waterways, loss of soil fertility, and soil acidity. Even though the green revolution was started to ensure food security, it has unintended consequences on human health and the surrounding environment. This dissertation focuses on the surface characteristics of graphene nanomaterials (GNMs) and their application in agriculture. Among the nutrients needed for crops, some can be easily obtained from the environment (e.g., carbon, hydrogen, oxygen, etc.), while others, like nitrogen (N), phosphorus (P), and potassium (K), often requires supplementation by fertilizers. However, conventional fertilizers have caused problems associated with soil pH changes, stunted plant growth, and disrupted beneficial microbial processes. Implementing nano-fertilizers, which can act as controlled-release fertilizers, is important. GNMs have shown some promising characteristics for the controlled release of drugs and other chemicals. Therefore, in the first part of this study, the loading capacity of the three macronutrients (N, P, and K) over GNMs of different surface chemistry was characterized. In the second part of this thesis, the effect of graphene oxide (GO) addition on wheat germination was evaluated. Rapid germination is essential for crop establishment to ensure low-cost and high-quality products and keep in check the sustainable use of resources in commercial agriculture. The results of this thesis indicated that the application of GO significantly enhanced the seed germination potential of the wheat crops. It not only increases the root weight but also improves its volume. Future work should focus on the impact of surface chemistry of GNMs on germination, which, when combined with the materials’ ability to bind nutrients, could help better guide the use of GNMs in agriculture.