Zhu Xingjuan, Ros Gerard H, Xu Minggang, Xu Donghao, Cai Zejiang, Sun Nan, Duan Yinghua, de Vries Wim
State Key Laboratory of Efficient Utilization of Arid and Semi-arid Arable Land in Northern China, Key Laboratory of Arable Land Quality Monitoring and Evaluation, Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Wageningen University and Research, Environmental Research, Environmental Systems Analysis Group, PO Box 47, 6700AA Wageningen, the Netherlands.
Wageningen University and Research, Environmental Research, Environmental Systems Analysis Group, PO Box 47, 6700AA Wageningen, the Netherlands.
Sci Total Environ. 2024 Jul 15;934:172986. doi: 10.1016/j.scitotenv.2024.172986. Epub 2024 May 9.
Excessive application of mineral fertilizers has accelerated soil acidification in China, affecting crop production when the pH drops below a critical value. However, the contributions of natural soil acidification, induced by leaching of bicarbonate, and anthropogenic causes of soil acidification, induced by nitrogen (N) transformations and removal of base cations over acid anions, are not well quantified. In this study, we quantified soil acidification rates, in equivalents (eq) of acidity, by assessing the inputs and outputs of all major cations and anions, including calcium, magnesium, potassium, sodium, ammonium, nitrate, bicarbonate, sulphate, phosphate and chloride, for 13 long-term experimental sites in southern China. The acidification rates strongly varied among fertilizer treatments and with the addition of animal manure. Bicarbonate leaching was the dominant acid production process in calcareous soils (23 keq ha yr) and in non-calcareous paddy soils (9.6 keq ha yr), accounting for 80 % and 68 % of the total acid production rate, respectively. The calcareous soils were strongly buffered, and acidification led no or a limited decline in pH. In contrast, N transformations were the most important driver for soil acidification at one site with upland crops on a non-calcareous soil, accounting for 72 % of total acid production rate of 8.4 keq ha yr. In this soil, the soil pH considerably decreased being accompanied by a substantial decline in exchangeable base cation. Reducing the N surplus decreased the acidification rate with 10 to 54 eq per kg N surplus with the lowest value occurring in paddy soils and the highest in the upland soil. The use of manure, containing base cations, partly mitigated the acidifying impact of N fertilizer inputs and crop removal, but enhanced phosphorus (P) accumulation. Combining mineral fertilizer, manure and lime in integrative management strategies can mitigate soil acidification and minimize N and P losses.
在中国，过量施用矿物肥料加速了土壤酸化，当土壤pH值降至临界值以下时会影响作物产量。然而，由碳酸氢盐淋溶引起的自然土壤酸化以及由氮（N）转化和碱性阳离子相对于酸性阴离子的去除所导致的人为土壤酸化贡献尚未得到很好的量化。在本研究中，我们通过评估中国南方13个长期试验点所有主要阳离子和阴离子（包括钙、镁、钾、钠、铵、硝酸盐、碳酸氢盐、硫酸盐、磷酸盐和氯离子）的输入和输出，以酸度当量（eq）量化了土壤酸化速率。酸化速率在不同肥料处理之间以及添加动物粪便后差异很大。在石灰性土壤（23 keq ha-1 yr-1）和非石灰性水稻土（9.6 keq ha-1 yr-1）中，碳酸氢盐淋溶是主要的产酸过程，分别占总产酸率的80%和68%。石灰性土壤具有很强的缓冲能力，酸化导致pH值没有下降或下降有限。相比之下，在一个种植旱地作物的非石灰性土壤试验点，氮转化是土壤酸化的最重要驱动因素，占8.4 keq ha-1 yr-1总产酸率的72%。在这种土壤中，土壤pH值显著下降，同时可交换碱性阳离子大幅减少。减少氮盈余使酸化速率降低了每千克氮盈余10至54 eq，最低值出现在水稻土中，最高值出现在旱地土壤中。使用含有碱性阳离子的粪肥部分减轻了氮肥输入和作物移除的酸化影响，但增加了磷（P）的积累。在综合管理策略中结合使用矿物肥料、粪肥和石灰可以减轻土壤酸化并使氮和磷的损失最小化。
