Beijing Key Laboratory of Farmland Soil Pollution Prevention-control and Remediation, College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian, Beijing, 100193, PR China.
Institute of Agricultural Resources and Environment, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang, 050051, PR China.
J Environ Manage. 2022 Mar 15;306:114451. doi: 10.1016/j.jenvman.2022.114451. Epub 2022 Jan 7.
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) 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.
用有机肥料（粪肥和/或秸秆）代替化肥的农业做法可能会对磷（P）向环境的流失产生影响。通过在含有四种处理的钙质土壤中进行为期十年的田间试验来检查这种知识差距，这些处理的年磷投入相同，但有机肥料组合不同，如下所示：仅使用矿物肥料作为对照（MF）、矿物肥料与粪肥结合（MM）、矿物肥料与粪肥和秸秆结合（MMS）以及矿物肥料与秸秆结合（MS）。使用化学提取、K 边 X 射线吸收近边缘结构和 Langmuir 方程研究了土壤中 P 的分布、P 形态和形态、Fe(III)还原和 P 吸附动力学。还使用电化学方法、三维激发-发射矩阵荧光光谱法和傅里叶变换红外光谱法评估了土壤的电子穿梭能力和土壤溶解有机物质（DOM）的形态。结果表明，在 MM、MMS 和 MS 处理中，20-40 厘米深处的土壤奥尔森磷和总磷增加，表明粪肥和/或秸秆的添加显著增加了土壤剖面中的磷。粪肥和/或秸秆的添加还降低了土壤最大磷吸附容量（S），并增加了所有处理中 0-20 厘米深处的解吸率。在 MS 处理的 0-20 厘米深的土壤中，增强的 Fe(III)还原伴随着 Fe 结合磷的减少，这表明 Fe 还原主导了磷的释放。在 MM 处理的 0-20 厘米深的土壤中，Ca 结合磷向 Al/Fe 结合磷的转化可能是由于 MM 处理的 0-20 厘米深的土壤中 DOM 中腐殖质样物质的比例较高，这可能导致轻微/微位点酸化。这些结果有助于制定优化施肥措施，以有效减轻添加粪肥和/或秸秆的钙质土壤中磷的流失。
