What are the rolls of each science subject in agriculture?

Agricultural chemistry,Soil chemistry,Soil physics, Pesticide chemistry, Agricultural entamology and plant pathology,Nematology, Agricultural engineering, Irrigation and drainage engineering, Agricultural meteorology etc are related subjects. Quantum physics is pure science and more specific in investigations. But Agricultural scientists use such tools only if it is highly required mostly as part of collaborative research between different institutions. Nanotechnology is slowly emerging in Agriculture especially in pesticide research.

Agriculture is an applied science.There is role of every science in agriculture including social sciences.

That's a very broad question. All of those play a significant role in anything. Chemistry is the building blocks of life and will be applied from pesticides to additives used in farm machinery. Biology is an expansion on chemistry and explains how things grow and live, this is useful for understanding plants, animals and anything alive. Physics plays a part in figuring out how it all works together and also comes into effect anytime you are dealing with weight. Quantum physics is a more specialized field that deals with the behavior of energy and matter. Hope I came close to what you are asking..