Agricultural biogeochemistry is a branch subject of biogeochemistry as well as a new overlapping knowledge in the filed of life sciences, agriculture sciences, food sciences〖KG*2〗and medicine sciences. This new research field, based on the theory of biogeochemistry, focused chiefly on chemical elements and ecological relation among agricultural organism, geochemical and biogeochemical process in the mass agricultural background, agricultural planning, nutrimental evaluation and promotion of the crop produces. The role of element cycles through the food chains (rock, weathering rock, soil, crop, animal and human) and the increase of trace element contents of crop produces for human health requirement have became the recent research aspects of agricultural biogeochemistry.
One of the most important applications of agricultural biogeochemistry technique is the method of biotransformation of element nutrition. On the basis of agricultural biogeochemistry theory, the trace elements of the crops can be improved through biological process by using selected agricultural variety as the carrier to transform the inorganic elements to organic matters with biological activities. The purpose is to increase the trace element content in the agricultural products and to strengthen the human health requirement. It is obvious that the agrobiogeochemistry is both the practical application and development of theory of biogeochemistry.
The agricultural products (such as soybean) of rich biological organic trace element nutriments cultivated through biogeochemical techniques are much better than the medicine products of inorganic nutrient element. The development of the relative techniques is significant for the exploitation of new medicines drug and new food of rich nutrient element that is crucial for the health of human beings in the 21 century.
As we know, the development of green agriculture and organic agriculture is proposed because of the serious pollution of environment and farm produces which threaten the people's health. The work of biogeochemical nutrition aims at the issue human sub-health resulted from regional shortage of nutrient trace elements.
The purpose of developing agriculture is not only to improve the quality of produces and ensure the food supply, but also to solving the problem of nutrient crises in the world. The most important reasons are: (1) many diseases are caused by the food chains of regional inappropriate proportion or shortage of trace elements for normal demand of human health in the biogeochemistry background; (2) more and more people have "sub-health" because of inadequate content of trace element taken from the food. Therefore, a new subject of interdisciplinary sciences (agriculture, food, medicine, geochemistry, biology, etc.) is developed.
In the Chinese history of social and agricultural development, four stages may be divided: the primeval cultivating by destroying forest; feudal traditional agriculture; petroleum agriculture of last century; green agriculture and rich nutrient element agriculture of this century. It seems that the
agricultural biogeochemistry combines agronomy technology, social economy and human health evolution and becomes a sustained research topic that is related closely to the catchword “nutrient crises”, “agricultural revolution” and “food revolution”. The research of this new scientific field is significant for promoting agriculture technology, national economy and human health.