Author：Song J., Y. Hui, C. Yu, Q. Zhang, Y. Zhou, Y. Li, X. Liu, L. Zhu, D. Hui, and S. Wan.
Journal：Plant and Soil
Differences in cropping systems and their impacts on plant growth and carbon (C) uptake as well as soil C release pose a major challenge in projecting agroecosystem C balance.
A four-year (2012–2015) field experiment was conducted to examine crop C uptake and soil respiration in two conventional (wheat-cotton and wheat-maize) and two legume-based (wheat-soybean and alfalfa-maize) double-season cropping systems in North China Plain.
During the 4 experimental years, crop C uptake was greater in the two conventional systems than the two legume-based systems. However, soil respiration was higher in the two systems with C4 (i.e. maize) than C3 crops (i.e. cotton and soybean) planted in summer. As consequences, cropland C balance was positive in the two conventional cropping systems, with greater value in the wheat-maize comparing to wheat-cotton system. However, the two legume-based cropping systems showed negative cropland C balance.
Our findings indicate that, although more CO2-C is emitted in maize-related cropping systems, the conventional agricultural activities may sequestrate more C in comparison with the legume-based farming in North China Plain due to higher C uptake, and highlight the importance of management strategy in improving agroecosystem C storage.