Affiliation:
1. Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS-CSIC), Avenida Reina Mercedes 10, 41012 Sevilla, Spain
2. Med_Soil Research Group, Facultad de Química, Universidad de Sevilla, C/Profesor García González, 1, 41012 Seville, Spain
Abstract
Compost amendments, apart from improving fertility and the general characteristics of agricultural soils, have known implications for global C cycling and sequestration in soils. Their effects are usually assessed via the quantification of soil organic carbon (SOC) pools, usually labile (fast) and recalcitrant (slow) pools, with varying intrinsic decomposition rates and distinct resident times. However, the real C-sequestration potential of organic additions to soil is still under discussion. In this study, a field trial and a lab incubation experiment were designed to study the C-sequestration mechanism in an agricultural Mediterranean soil. Soil with a history of C3 photosystem crop was amended with two maize composts from maize harvesting surpluses (C4 photosystem) with different maturity stages (AC: aged compost; NC: new, less mature compost). The evolution of SOM was monitored for 6 months using complementary analytical techniques, including analysis of stable C isotopes (IRMS), thermogravimetry (TG) and C-stock and priming effect (PE) modelling. Based on the natural C-isotope labelling, the proportion of new C was calculated. More than 50% of the C added to the soil with the compost was incorporated into the SOM in only 6 months. However, the application of maize compost did not always enhance soil C-sequestration capacity. The addition of compost caused a general PE, enhancing SOM decay and reducing the fast (labile) SOM mean residence time (MRT) (11.2 days). This was more pronounced with the addition of a higher dose of AC, causing a PE up to a 718%. On the other hand, a higher MRT (54.4 days) occurred in soils with NC applied, likely due to its deleterious effects, limiting heterotrophic activity. Despite that, the average MRT of the slow (recalcitrant) SOM pool was lower than usually reported. The application of higher doses of both composts generally showed greater MRT values compared to control (1.7 years vs. 3.8 and 2.9 years for NC and AC, respectively), leading to an increase in this more stable C pool and effective soil C sequestration. The results described in this work may help readers to better understand SOM dynamics and may be of use in designing appropriate management strategies for improving OM quantity and quality and to optimize C storage in Mediterranean soils.
Funder
EU Horizon 2020 research and innovation programme
Ministerio de Ciencia Innovación y Universidades
Subject
Agronomy and Crop Science
Cited by
1 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献