Zhu Yongli, Yuan Gen, Zhao Zihui, Tang Yifan, Li Pingping, Han Jiangang
College of Biology and the Environment, Nanjing Forestry University, Nanjing, People's Republic of China.
Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, People's Republic of China.
Environ Technol. 2023 Apr;44(10):1415-1425. doi: 10.1080/09593330.2021.2003440. Epub 2021 Nov 23.
Pig farm biogas slurry is being increasingly used as a potent organic fertilizer for sustainable agriculture under circular economy. However, the effect of biogas slurry on soil pH is currently controversial, and the underlying mechanisms especially in saline-alkali soils are not well understood. A saline-alkali soil (pH = 9.2, EC = 2.0 ms/cm) was selected for soil column (0-50 cm) experiments with (BS) and without (CK) addition of pig farm biogas slurry to investigate the soil pH change and its driving factors. Our results show that the soil pH under CK ranged between 9.1 and 9.5 across different soil depths. Compared to CK, the BS-treated soil had lower pH at 0-20 cm depth and higher pH at 20-30 cm depth (). The soil concentrations were negatively correlated with pH values under BS (), indicating that the oxidation of ammonium mainly contributed to the decrease of soil pH. Interestingly, the anions, such as Cl, and , were accumulated in the topsoil (0-20 cm) under BS, resulting in the changed correlations of these anions with Na when compared to the control. FT-IR and C-NMR spectra uncovered that carboxyl, amide C, and total alkyl C groups may be responsible for reducing pH of the saline-alkali soil tested. The soil surface morphology confirmed a much tighter granular aggregate microstructure when mixing the biogas slurry with the soil. Overall, we concluded that from the perspective of soil pH, the utilization of biogas slurry for improving saline-alkali soil is feasible and sustainable.
在循环经济模式下，猪场沼液作为一种有效的有机肥料，在可持续农业中得到了越来越广泛的应用。然而，沼液对土壤pH值的影响目前仍存在争议，尤其是在盐碱土中的潜在机制尚不明确。本研究选取了一种盐碱土（pH = 9.2，EC = 2.0 ms/cm）进行土柱（0 - 50 cm）试验，设置添加猪场沼液（BS）和不添加沼液（CK）两个处理，以探究土壤pH值变化及其驱动因素。结果表明，CK处理下不同土壤深度的土壤pH值在9.1至9.5之间。与CK相比，BS处理的土壤在0 - 20 cm深度处pH值较低，在20 - 30 cm深度处pH值较高（）。在BS处理下，土壤铵根离子浓度与pH值呈负相关（），表明铵根离子的氧化是导致土壤pH值下降的主要原因。有趣的是，在BS处理下，Cl、硫酸根离子和碳酸根离子等阴离子在表层土壤（0 - 20 cm）中积累，与对照相比，这些阴离子与Na的相关性发生了变化。傅里叶变换红外光谱（FT - IR）和碳核磁共振光谱（C - NMR）分析发现，羧基、酰胺C和总烷基C基团可能是导致所测盐碱土pH值降低的原因。土壤表面形态证实，将沼液与土壤混合时，颗粒团聚体微观结构更加紧密。总体而言，从土壤pH值的角度来看，利用沼液改良盐碱土是可行且可持续的。
