Analysis of earthing-up effects on number and diameter of nodal roots in spring maize

Ridge-till with earthing-up is a widely used practice in maize production, while earthing up is also a key practice in crop production.To understand the effects of earthing-up height on the number and diameter of nodal roots in maize, a field experiment, by using PVC tube, was conducted with following treatments:2 maize varieties, Zhengdan 958(ZD) and Xianyu 335(XY); 3 erathing-up heights, H1(8 cm) and H2(15 cm) and CK(no earthing-up).The results showed that the earthing-up height significantly influenced the total number of nodal roots per plant.Compared with CK, the number of nodal roots of plant with earthing-up treatments increased significantly, and the number of nodal roots in Zhengdan 958 and Xianyu 335 with H2 treatment was increased by 13.8% and 7.4% respectively, which was mainly due to the increased number on the ninth phytomer though the effects varied between maize varieties.Compared with CK, earthing up treatments significantly decreased the diameter of nodal roots on the eighth and(or) ninth phytomers and differences between maize varieties also existed.