Effects Of Fertilization On The Improvement Of Root-soil System Vertical Distributions Of Maize And Cotton In The Loess Subsoil

In order to investigate the effects of fertilization on the improvement of root-soil system vertical distributions of maize (Zea mays) and cotton (Gossypium hirsutum) in immature loess subsoil, cotton and maize were planted in root canals, which height of the former is100cm and of the latter is200cm.(1) For cotton, four kinds of fertilizers and three soil layers of fertilizing were respectively applied as:N, P, NPK, and organic fertilizer (ORG), with0-20cm,40-60cm and80-100cm.(2) For maize, organic matter with five soil layers of fertilizing were respectively applied as:0-20cm,60-80cm,100-120cm,140-160cm and180-200cm. The control treatment (CK) was without fertilization. Cotton and maize productivities, root weights, root nutrients (N, P, K), rhizospheric soil enzymes (urease, alkaline phosphatase, sucrase), and rhizospheric soil nutrition (available nitrogen, available phosphoms and organic matter) were investigated.The results showed that (1) Fertilization promoted significantly root development, increased root weights and rhizospheric soil enzymes activities and soil nutrition compared with CK and blank soil, in the Furthermore, improved productivities of cotton and maize in the immature loess subsoil.(2) Fertilization with deeper soil layer, especially, the fertilizations of P or organic fertilization, took advantages of inducing root elongate, increasing root weight percentage, and improving rhizospheric soil enzymes activities with soil nutrition in deeper soil layer.(3) In the shoot-root-soil systems of different treatments of cotton in the immature loess subsoil, there were significant or extremely significant positive correlations among their productivities, root weights, root nutrition, rhizospheric soil enzymes activities with soil nutrition. Three factors (including12items) that influencing shoot-root-soil system were obtained by the FACTOR procedure of SAS9.1.3. and then, organic fertilizer and the fertilizing soil layer of40-60cm were optimized by the CLUSTER procedure of SAS9.1.3.(4) In the root-soil systems of different treatments of maize in the immature loess subsoil, there were also significant positive correlations among their10items of root-soil system. Organic fertilizer in the soil layer of60-160cm was optimized by the FACTOR and CLUSTER procedure of SAS9.1.3.