Abstract:

Advances in study of mechanisms of foliar nutrition and foliar fertilizer application were reviewed. Plant leaves can absorb nutrients as roots do. There are two basic pathways for nutrients entering into the plant tissue: one is through the stomata and the other is via cuticle hydrophilic pores. Some plant leaves also can absorb nutrients actively through plasmodesmata. So the foliar uptake of nutrients depends upon plant types and the state of plants growth, composition of foliar fertilizer, characters of nutrients and environmental factors such as temperature, illumination and so on. Foliar application to dicotyledon is better than to monocotyledon because of different leaf types and structures of surface wax, and of different varietals plants of homogeneity. It is necessary to spray right fertilizers at right stage of plant growth. Some assistants, such as surfactants are required to enhance nutrients absorption in foliar fertilizers, however, most of the surfactants have a poor solubility among compositions of foliar fertilizers as they are pesticides surfactants. The development of foliar application was promoted by the research on mechanism of foliar nutrition, and now foliar application is becoming an important fertilization method. But soil application can not be replaced by foliar application of fertilizers. Foliar spray can be only as an efficiency assistant method to soil application because the quantity of nutrients supplied is limited. In recent years, foliar fertilizers developed promptly both in quantity and variety, but the quality is poor in China. So the techniques of foliar application need to be improved. Scientists should intensify their research on the mechanism of foliar nutrition and the utilization of assistants in foliar fertilizers. In future, it is necessary to enhance the quality of foliar fertilizers and foliar fertilization, study on optimization of specialized foliar fertilizers and the techniques of foliar application.

Key words: plant nutrition, foliar nutrition, foliar fertilizer, foliar application