Growth and root interaction during symbiotic period when intercropping cassava with maize

【Objective】The purpose of this research was to explore the effects on the agronomic traits, root distribution, soil physicochemical characteristics and root nutrients contents during their symbiotic period within different intercropping models, to provide theoretical basis to improve high-yield and high-efficient cultivation techniques of cassava in-tercropping maize.【Method】Using South China No. 9 edible cassava variety and Fresh Edible Glutinous Maize No. 808 of extra-early mature variety as materials, a total of 4 treatments were set up with equidistant row sole cassava(CK1), wide-narrow row sole cassava(CK2), equidistant row cassava intercropping 1 row of maize(T1), wide-narrow row cassava intercropping 2 rows of maize(T2). Then comparative analysis of the agronomic traits, three-dimensional root distribution, soil physical and chemical properties, root nutrients contents in the different soil layers between cassava and maize during the symbiosis period was conducted.【Result】The growth potential of cassava and maize in wide-narrow row was better than equal row spacing. T2 increased maize yield by 21.1% compared with T1. The root systems were distributed horizontally and symmetrically from dense to sparse where from the center towards the surround around the individual plant of maize or cassava. The root system of single maize was distributed with dense top and bottom sparse, narrow top and wide bottom, and their 68.7%-77.3% root weight(RW), 46.2%-49.4% root length(RL), and 52.7% -59.3% root surface area(RSA) were gathered in the soil belt, where was 10 cm deep and 10 cm wide on the two sides along maize planting line. The root system of single cassava was distributed with top dense and sparse bottom, wide top and narrow bottom, and their 50.8% -61.4% RL and 47.7% -57.2% RSA of fine roots were gathered in the soil belt, where was 10 cm deep and 20 cm wide on the two sides along the base terminal line of cassava stem, meanwhile, 35.7% -42.0% RL and 39.3% -48.8% RSA of rough roots and 35.9%-46.3% RW of total root weight were gathered in the soil block within the range of 10 cm deep, 20 cm wide on the two sides along the base terminal line of cassava stem, 30 cm wide on the two sides along the central line of cassava stem. Alkali-hydrolyzable nitrogen(N), available phosphorus(P) and potassium(K) of soil and PK content in the crop roots were basically showed the order of surface layer(0-10 cm) > middle layer(10-20 cm) > deep layer(20-30 cm), while their nitrogen(N) content was opposite. Available NPK of soil and NPK content of the crop roots were basically showed the order of intercropping > single cropping, and the most nutrient indexes of T2 were the highest.【Conclusion】There is weave growth among the root systems between cassava and maize, and their dense growth belts or blocks do not overlap each other, therefore the roots interaction between cassava and maize is weak competition, particularly, T2 is the weakest competition in the two intercropping models, meanwhile, T2 is beneficial to increase root nutrients, soil nutrient content and maize yield, so the T2 intercropping model is recommend in production.