Plant facilitation shifts along with soil moisture and phosphorus gradients via rhizosphere interaction in the maize-grass pea intercropping system

• Published in: Ecological indicators Vol. 139; p. 108901
• Main Authors: Zhu, Shuang-Guo, Cheng, Zheng-Guo, Batool, Asfa, Wang, Yi-Bo, Wang, Jing, Zhou, Rui, Khan, Aziz, Zhu, Sai-Yong, Yang, Yu-Miao, Wang, Wei, Zhu, Hao, Wang, Bao-Zhong, Tao, Hong-Yan, Xiong, You-Cai
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2022; Elsevier
• Subjects: Biodiversity; Competition; Environmental gradients; Phosphatase; Productivity; Competition; Productivity; Biodiversity; Phosphatase; Environmental gradients
• ISSN: 1470-160X; 1872-7034
• DOI: 10.1016/j.ecolind.2022.108901

Note: P (phosphorus), W (water), + (positive or increase), – (negative or decrease). [Display omitted] •Plant facilitation was found in the intercropping system of maize and grass pea.•Facilitation shifted from +/+, +/0 to +/- from low to high water and P gradients.•In low P, rhizosphere soil acidification of grass pea fostered P mineralization.•Soil microbial biomass P was improved for higher productivity in +/+ facilitation.•Soil water and phosphorus availability altered interspecific facilitation model. Plant-plant facilitation is widely studied to increase productivity and resource utilization in cereal-legume intercropping system. However, physiological and ecological mechanisms driving interspecific interaction shift along the environmental gradients is largely unknown. To clarify this issue, we first tested plant-plant facilitation along with four phosphorus (P) gradients in maize-grass pea intercropping system. Results illustrated a progressive transition of seed yield-based facilitation from mutually facilitated (+/+) to maize facilitated but grass pea as facilitator (+/-) along with low to high P gradients. Secondly, above trend was evidently enhanced when combining with drought stress gradients, in which severe drought amplified facilitative effects, whereas the magnitude of facilitation was relatively weak under well-watered condition. Interestingly, biomass-based facilitation transition did not synchronize with seed-based one, in which occurred in a broader threshold range of water and P gradients. Specifically, total yield, biomass, N and P uptake increased by 0.5%, 4.1%, 1.8% and 2.9% under the sufficient P and water availability, whereas these indicators increased by 25.3%, 18.5%, 20.5% and 21.4% in P and water deficient soils. And the total net effect was positive under all the environmental conditions. Rhizosphere interaction plays a crucial role in facilitation judgment, and the driving mechanism was associated with soil acidification and microbial community promotion under P-deficient condition. Under low soil moisture and available P, soil acidification and lower rhizosphere soil pH of intercropped maize were observed. Rhizosphere phosphatase secretion were significantly activated in P-deficient soils and accelerated the mineralization of soil organophosphorus, and the microbial biomass P was improved for stronger facilitation. Taken together, our findings confirmed the P and water driven facilitation shift along with stress gradients and highlighted the roles of rhizosphere interaction in affecting species diversity advantage. In conclusion, our work provided a relatively full picture for plant facilitation evaluation and more accurate management regarding intercropping productivity.