Lime and phosphogypsum impacts on soil organic matter pools in a tropical Oxisol under long-term no-till conditions

Abstract

Improving soil organic matter (SOM) quality in tropical acid soils is important for increasing the sustainability of agricultural ecosystems. This research evaluated the effect of the surface application of lime and phosphogypsum on the quality and amount of SOM in a long-term crop rotation under no-till conditions. The research was performed in a kaolinitic, thermic Typic Haplorthox for 12 years with annual crops under no-till. The treatments included no soil amendments, and amendment with phosphogypsum, lime, and lime + phosphogypsum. After three applications of soil amendments (2002, 2004, and 2010), surface liming increased the SOM input through addition of aboveground and root biomass, varying amount according to crop species, growing season, and soil depth. Although phosphogypsum had no effect on plant biomass production, the application of phosphogypsum with lime increased nitrogen (N) by up to 50% in the uppermost soil depths. The application of lime alone significantly increased the total organic carbon (TOC) at all depths, although the greatest effects were observed at 0.10-0.20 and 0.20-0.40 m, with an increase of 44% and 41%, respectively. Moreover, lime + phosphogypsum also exhibited the highest potential for C mineralization, which was attributed to an increased proportion of TOC as particulate organic carbon (POC). The proportion of TOC as humin and fulvic acid increased with the application of lime + phosphogypsum at 0-0.05 m, with an increase from 55% to 92% and from 1.4% to 1.6%, respectively. Overall, the combination of lime and phosphogypsum increased both the labile and stable C pools.

Response of Fungal Diversity, Community Composition, and Functions to Nutrients Management in Red Soil

“…Similarly, oyster shell powder has a significant effect on improving the soil pH [ 18 ]. These improvements in soil profile result in providing a better soil environment for the functioning of soil microbiota through the addition of lime [ 13 , 19 ], gypsum [ 12 , 20 ], mushroom residue [ 21 ], and oyster shell powder [ 18 , 22 ]. Magnesium (Mg) fertilizers have also been used to increase the soil pH, and earlier studies have also shown that their addition into the soil has a significant effect on soil physicochemical properties and microbial communities [ 23 , 24 ].…”

The effect of dolomite amendment on soil organic carbon mineralization is determined by the dolomite size

“…The decomposition rate constant (k) was regulated by environmental factors and soil conditions (Campbell et al 1994). Previous studies indicated that liming could increase the turnover rate of soil organic matter due to increase in soil pH thus facilitating microbial activity (Carmeis Filho et al 2017;Lochon et al 2018). Soil pH is considered as a key factor governing the microbial turnover of organic carbon (Bertrand et al 2007;Xiao et al 2018).…”

“…Changes in pH, substrate, and nutrient availabilities for microbes in the soil after liming can affect SOC mineralization. In general, liming has positive effects on SOC mineralization since it can ameliorate soil acidity and has the potential to increase microbial activity (Adams and Adams 1983;Carmeis Filho et al 2017). Increase in soil pH may increase dissolved organic carbon (DOC), which can be rapidly mineralized (Ahmad et al 2013;Marcelo et al 2012), and induces a microbial respiratory flush in the first few days following lime application (Fuentes et al 2006).…”

Controls on variation of soil organic carbon concentration in the shrublands of the north‐eastern Tibetan Plateau

“…Ca 2+ is an environmentally ubiquitous cation that could potentially play an important role in the stabilization of SOC (Rowley et al, 2018). Ca is a plant macronutrient and there is evidence that Ca also has localized positive effects on net primary productivity and SOC inputs through aboveground and belowground biomass (Carmeis Filho, Penn, Crusciol, & Calonego, 2017). Therefore, leaching of Ca resulting from increasing precipitation may lead to a decrease of SOC concentration in the Tibetan Plateau shrublands.…”