Isotope Tracer Technique·Ecology and Environment·Physiology
CHEN Yibo, YANG Qin, WANG Jingjing, MIAO Zhengyan, ZHAO Wenlong, JIA Xucun, DONG Pengfei, WANG Qun
In order to explore the changes of root morphological distribution, nutrient accumulation and yield under different root configuration maize varieties intercropping, monoculture and intercropping treatments were conducted both in the field and pot-cultivation to study the variation characteristics of intercropping of maize (Zea mays L.) on root traits, spatial distribution, nutrient accumulation and grain yield, two maize varieties JS501 (small root angle type) and LY16 (large root angle type) with different root system architecture were used as experimental materials. The results showed that the total root length, total root surface area, total root volume and root diameter of maize population under intercropping treatments increased by 10.19%, 19.55% and 15.95% on average compared with monoculture treatments, respectively. But there was no significant change in root diameter between intercropping and monoculture treatment. In 0~20 cm soil layer, the total root length, total surface area and total volume of maize in intercropping were 15.27%, 21.82% and 9.44% higher than those in monoculture, and 12.95%, 9.18% and 20.31% higher than monoculture at 20~40 cm, respectively. Intercropping enlarged the horizontal distribution of JS501 root and extends outward by 5 cm, deepened root vertical distribution by 10 cm in intercropping treatments and increased root length density by 26.03% on average in 40~60 cm soil layer. Intercropping also significantly improved root activities by 27.83% compared with monoculture. The accumulation of nitrogen, phosphorus and potassium in intercropping population increased by 18.27%, 14.79% and 15.75% on average compared with monoculture, respectively. Land equivalent ratio was more than 1 under intercropping and dry matter weight and grain yield were increased significantly by 11.03% and 15.36% on average compared with monoculture, respectively. Path analysis showed that total root surface areas significantly affected the accumulation of N and K, which indirectly affected dry matter accumulation and 100-grain weight, and significantly increased grain yield under intercropping conditions. However, the correlation coefficient between factors in monoculture was lower than that in intercropping. In summary, intercropping changed the spatial distribution of maize roots with different root architecture and increased the proportion of roots in deep soil. It reshaped root architecture in 40~60 cm soil layer, improved root activities and make use of the root spatial complementary. These characteristics promoted the nutrient accumulation and increased grain yield. This study provided a theoretical and practical strategy for high efficiency of nutrient resources and sustainable agriculture.