Enhanced phosphorus mobility in a calcareous soil with organic amendments additions: Insights from a long term study with equal phosphorus input. (15th March 2022)

• Record Type: Journal Article
• Authors: Zhang, Shuai; Wang, Liying; Chen, Shuo; Fan, Bingqian; Huang, Shaowen; Chen, Qing
• Is Part Of: Journal of environmental management. Volume 306(2022)
• Publication Date: 2022-03-15
• Subjects: P transformation -- P transport -- Sorption/desorption -- Iron oxide -- Spectroscopy -- Long-term fertilization; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.114451
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: The agricultural practice of replacing chemical fertilizers with organic amendments (manure and/or straw) may have consequences for phosphorus (P) loss to the environment. Such a knowledge gap was examined using a ten-year field trial in calcareous soil containing four treatments with the equal annual P input but varied organic amendment combinations as follows: mineral fertilizer only as control (MF), mineral fertilizer coupled with manure (MM), mineral fertilizer coupled with manure and straw (MMS) and mineral fertilizer coupled with straw (MS). The soil P distribution, P fractions and speciation, Fe(III) reduction and P sorption kinetics were investigated using the chemical extraction, K edge X-ray absorption near-edge structure and Langmuir equations. The electronic shuttle capacity of soils and speciation of soil dissolved organic matter (DOM) were also evaluated using electrochemical methods, three-dimensional excitation-emission matrix fluorescence spectroscopy and Fourier transform infrared spectra methods. Results showed that soil Olsen-P and total P increased at depths of 20–40 cm in MM, MMS and MS treatments, suggesting that manure and/or straw addition significantly mobilized P in the soil profile. Manure and/or straw addition also decreased soil maximum P sorption capacity ( S max ) and increased the desorption rate at depths of 0–20 cm in soil across treatments. At a depth of 0–20 cm in soil of the MS treatment, the enhanced Fe(Ⅲ) reduction coupled with a decrease of Fe-bound P supports that Fe reduction dominates the mobilization of P. The transformation of Ca bound-P to Al/Fe bound-P in a depth of 0–20 cm in soil of the MM treatment may be due to the high proportion of humic-like substances in the DOM at a depth of 0–20 cm in soil of the MM treatment, which may have caused a slight/microsite acidification. These results can help to develop optimized fertilization practices to effectively mitigate P loss from calcareous soils with manure and/or straw addition. Highlights: Organic amendments coupled with mineral fertilizers were applied for 10 years. Organic amendments addition enhances P mobilization in soil profile. Organic amendments addition decreased soil P adsorption capacity. Fe (Ⅲ) reduction mainly contributed to the P mobilization after straw addition. Organic acid accumulation may contribute to the P mobilization after manure addition.