Effect of Wheat Straw Addition on Organic Carbon Mineralisation and Bacterial Community in Orchard Soil

Journal of Soil Science and Plant Nutrition (2023) 23:4328–4341 https://doi.org/10.1007/s42729-023-01352-x ORIGINAL PAPER Effect of Wheat Straw Addition on Organic Carbon Mineralisation and Bacterial Community in Orchard Soil Dongmei Lang1,2 · Ruijin Zhou1,2 · Fengge Hao1,2 · Zitan Zhu3 · Peng Zhang1,2 Received: 1 March 2023 / Accepted: 14 June 2023 / Published online: 30 June 2023 © The Author(s) 2023 Abstract Crop straw returning can stimulate organic carbon mineralisation and C sequestration simultaneously, which affects soil fertility. However, the effects of crop straw on organic carbon mineralisation and soil bacterial community in orchards are not fully understood. A 90-day incubation experiment was performed to investigate the effects of wheat straw (0, 1, 4, 6, 8, and 10 t·ha−1) on organic carbon mineralisation and bacterial community in orchard soil. Wheat straw addition enhanced the CO2 efflux rate and cumulative organic carbon mineralisation ( Cmin), especially high level. The trend of C O2 efflux rate was increased sharply, especially during the early incubation stage (the first 13 days), and then decreased in the later phase. Furthermore, soil bacterial community structure displayed distinct changes in response to straw addition. Available nitrogen, potassium, organic carbon, β-glucosidase, and pH were the key factors driving soil bacterial community changes. The bacterial taxa in networks were significantly related to C min. The Proteobacteria, Actinobacteria, and Chloroflexi were positively related to C min; while Planctomycetes, Patescibacteria, and Gemmatimonadetes showed a negative relationship with Cmin by correlation and redundancy analyses. Co-occurrence network analysis showed a discrete bacterial network in 10 t·ha−1 of straw, while cohesive networks in others. Straw addition promoted organic carbon mineralisation by improving the soil biochemical properties, including enzymes activities, and nutrient contents, and regulating bacterial community composition. On the whole, 4 t·ha−1 of straw could be considered an economical level for improving soil organic carbon and bacterial community stability in orchards. Keywords Orchard soil · Organic carbon mineralisation · Soil bacterial community · Co-occurrence network · Wheat straw 1 Introduction Henan province in China is an important agricultural-producing area that has typical saline-alkali soil induced by the Yellow River. Soil with a relatively high pH inhibits plant growth directly, disturbs soil properties, and limits sustainable agricultural development (Setia et al. 2013). * Peng Zhang 1 School of Horticulture and Landscape Architecture, Henan Institute of Science and Technology, Henan 453003 Xinxiang, People’s Republic of China 2 Henan Province Engineering Research Centre of Horticultural Plant Resource Utilisation and Germplasm Enhancement, Xinxiang, Henan, People’s Republic of China 453003 3 Liaoning Institute of Saline-alkali Land Utilisation, Panjin, Liaoning, People’s Republic of China 124000 13 Vol:.(1234567890) Consequently, improvement of alkaline soils to enhance plant qualities and yields are essential for meeting food demand and sustainable ecosystem development goals in China (Zhang et al. 2017). Recently, research has been conducted on ameliorating alkaline soil (Yan et al. 2019). Crop straw is a recyclable organic resource, which when returned to the soil can simultaneously improve soil quality and mitigate air pollution resulting from straw burning (López-Valdez et al. 2010; Liang et al. 2022). Recently, research on the use of organic residues has been widespread implementation in orchards aiming to enhance soil fertility as well as improve fruit quality and yield, particularly in saline-alkaline soil conditions (Cao et al. 2021; Zhang et al. 2021; Shi et al. 2023). Soil organic carbon (SOC) is a major component of soil organic matter (SOM), which is involved in soil biogeochemical cycling (Trivedi et al. 2018). Previous studies have indicated that rice straw increases SOC content (Yan et al. 2019; Zhao et al. 2020) and promotes organic carbon (C) Journal of Soil Science and Plant Nutrition (2023) 23:4328–4341 sequestration in saline-alkali soil (Wu et al. 2021). However, adding crop residue also stimulates organic C mineralisation and induces organic C loss in the form of CO2 (Blagodatskaya and Kuzyakov 2008). Mineralisation is a key process for C balance and nutrient cycling in soils (Zhang et al. 2021). The addition of exogenous organic matter can significantly impact the intensity of C mineralisation, which increases as the level of crop straw addition rises (Li et al. 2022). Furthermore, the increased C O2 emissions resulting from the application of organic matter in saline conditions have adverse effects on the stability of the organic C pool and the efficient utilisation of resources (Zheng et al. 2022). However, the characteristics of organic C mineralisation in orchards under different levels of wheat straw application remain poorly understood. Soil microorganisms and the enzymes derived from them regulate organic matter decomposition (Kallenbach et al. 2016). Organic matter returns not only changes the function and community structure of bacteria in soils but also positively affects bacterial abundance and diversity (Shi et al. 2019). Soil bacteria more actively respond to saline-alkali stress than fungi and more sensitive to soil managements in the short term (Wang et al. 2019). Otherwise, organic C mineralisation is regulated by soil bacterial communities, and some species play an important functional role (Banerjee et al. 2016). Actinobacteria and Proteobacteria of bacteria were mostly involved in organic C mineralisation after straw addition (Xiao et al. 2022). Moreover, soil bacterial networks reveal the ecological interactions among key bacterial taxa and organic C dynamics in response to exogenous organic amendments (Wang et al. 2021). Co-occurrence networks have been used to explore the co-occurrence pattern of the keystone taxa and other co-existing microbes involved in C cycling, providing insights into understanding of organic C mineralisation (Xiao et al. 2022). Understanding these taxa and the correlations among them is essential for revealing the underlying microbial mechanism of organic C mineralisation. Our current understanding of the relationship between the bacterial community, co-occurrence networks, and the process of organic C mineralisation in orchard soils in response to crop straw addition remains limited. Therefore, this study aimed to examine the effects of different levels of wheat straw on organic C mineralisation and the bacterial community in orchard soil. The following hypotheses were tested: (1) organic C mineralisation is linear with increasing levels of wheat straw; (2) soil bacterial community structure and co-occurrence networks are changed by wheat straw addition; and (3) high levels of wheat straw content are (...truncated)