Fengqiu Agro-ecological Experimental Station, State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
Department of Chemistry and Biochemistry, Old Dominion University, Norfolk, VA 23529, United States.
Sci Total Environ. 2019 Nov 20;692:89-97. doi: 10.1016/j.scitotenv.2019.07.221. Epub 2019 Jul 16.
Reducing the applications of mineral phosphorus (P) fertilizers and supplementing them by organic fertilizers is becoming a necessary practice in the North China Plain due to overuse of mineral P fertilizers and improper disposal of organic wastes. Knowledge is needed about how the long-term substitution of mineral fertilizers by organic fertilizers affects soil P forms in order to understand soil P transformation and crop P uptake. In this study, we used solution P nuclear magnetic resonance (NMR) spectroscopy to characterize P forms in fluvo-aquic soil after 26 years of different fertilization management strategies, organic compost (OM), half compost in combination with half mineral fertilizer NPK (1/2 OM), mineral fertilizer NPK (NPK), mineral fertilizer NK (NK), and an unfertilized control (CK). Results showed that the P extraction efficiency using NaOH-EDTA varied from 13.0 to 27.7% for the soils of the treatments. P NMR spectra indicated that the majority of P was in the form of orthophosphate for all the treatments, which constituted 64.3-83.5% of the total extracted P. The application of P fertilizers significantly increased the concentrations of orthophosphate, monoesters and diesters regardless of the P fertilization method, although the proportions of monoesters and diesters were higher in CK. The proportions and concentrations of orthophosphate significantly decreased when all mineral fertilizers were replaced by compost. There was no significant difference in the proportions and concentrations of total organic P, corrected monoesters and diesters in NaOH-EDTA extracts of soils among NPK, 1/2OM and OM treatments. Decreasing mineral P fertilizers and partly replacing them by organic fertilizer in fluvo-aquic soil might increase soil test (Olsen) P and crop P uptake through the degradation of applied organic P forms.
减少矿物磷 (P) 肥料的应用，并通过有机肥进行补充，这在中国北方平原已经成为一种必要的做法，因为矿物 P 肥料的过度使用和有机废物的不当处理。为了了解土壤 P 的转化和作物 P 的吸收，需要了解长期用有机肥替代矿物肥如何影响土壤 P 形态。在这项研究中，我们使用溶液 P 核磁共振 (NMR) 光谱法来描述经过 26 年不同施肥管理策略（有机堆肥 (OM)、半堆肥与半矿物肥 NPK（1/2 OM）、矿物肥 NPK（NPK）、矿物肥 NK（NK）和未施肥对照（CK））处理后潮土中的 P 形态。结果表明，NaOH-EDTA 提取的 P 效率在处理土壤中为 13.0-27.7%。P NMR 光谱表明，所有处理中 P 主要以正磷酸盐的形式存在，占总提取 P 的 64.3-83.5%。无论施肥方式如何，施用 P 肥料都会显著增加正磷酸盐、单酯和二酯的浓度，尽管 CK 中的单酯和二酯比例更高。当所有矿物肥料都被堆肥替代时，正磷酸盐的比例和浓度显著降低。在 NPK、1/2 OM 和 OM 处理中，NaOH-EDTA 提取的土壤中总有机 P、校正单酯和二酯的比例和浓度没有显著差异。减少潮土中的矿物 P 肥料，并部分用有机肥替代，可能会通过应用有机 P 形态的降解增加土壤测试（Olsen）P 和作物 P 的吸收。
