Effects of phosphorus application on root characteristics of super-high-yield spring maize

A maize cultivar, Jinshan 27, was used as the test material to study the effects of different phosphorus levels (P2O5 0、100、150 and 200 kg/ha) and application methods (traditional application and application with different depths) on root characteristics of spring maize under superhighyield cultivation. The results show that the root weight, root width in 40 to 60 cm soil layer, root vigor, and the activities of SOD and POD of roots are all increased with the increase of the phosphorus application, while the MDA content of roots is decreased. The phosphate application in different soil layers could promote the increase of the root weight and the number of roots per plant in deep soil layers, delay the decrease of root activity in the later growing stages, enhance the activities of SOD and POD, and reduce the MDA content of roots in different soil layers under the same level of phosphate. Compared with conventional phosphorus application, the phosphate application in different soil layers increases grain yield by 7.1% under the level of phosphorus 100 kg/ha, was improved significantly at the 5% probability levels. But grain yield had no significant difference under the levels of 150 kg/ha and 200 kg/ha.