Dipartimento di Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, Viale delle Scienze, 90128 Palermo, Italy; Dipartimento di Agraria, Università Mediterranea di Reggio Calabria, Feo di Vito, 89124 Reggio Calabria, Italy.
Departamento de Protección Ambiental, Consejo Superior de Investigaciones Científicas (CSIC), Estación Experimental del Zaidín (EEZ), Calle Profesor Albareda 1, 18008 Granada, Spain.
Sci Total Environ. 2018 Oct 15;639:350-359. doi: 10.1016/j.scitotenv.2018.05.157. Epub 2018 May 20.
The introduction of legumes into crop sequences and the reduction of tillage intensity are both proposed as agronomic practices to mitigate the soil degradation and negative impact of agriculture on the environment. However, the joint effects of these practices on nitrous oxide (NO) and ammonia (NH) emissions from soil remain unclear, particularly concerning semiarid Mediterranean areas. In the frame of a long-term field experiment (23 years), a 2-year study was performed on the faba bean (Vicia faba L.) to evaluate the effects of the long-term use of no tillage (NT) compared to conventional tillage (CT) on yield and NO and NH emissions from a Vertisol in a semiarid Mediterranean environment. Changes induced by the tillage system in soil bulk density, water filled pore space (WFPS), organic carbon (TOC) and total nitrogen (TN), denitrifying enzyme activity (DEA), and bacterial gene (16S, amoA, and nosZ) abundance were measured as parameters potentially affecting N gas emissions. No tillage, compared with CT, significantly increased the faba bean grain yield by 23%. The tillage system had no significant effect on soil NH emissions. Total NO emissions, averaged over two cropping seasons, were higher in NT than those in CT plots (2.58 vs 1.71 kg NO-N ha, respectively; P < 0.01). In addition, DEA was higher in NT compared to that in CT (74.6 vs 18.6 μg NO-N kg h; P < 0.01). The higher NO emissions in NT plots were ascribed to the increase of soil bulk density and WFPS, bacteria (16S abundance was 96% higher in NT than that in CT) and N cycle genes (amoA and nosZ abundances were respectively 154% and 84% higher in NT than that in CT). The total NO emissions in faba bean were similar to those measured in other N-fertilized crops. In conclusion, a full evaluation of NT technique, besides the benefits on soil characteristics (e.g. TOC increase) and crop yield, must take into account some criticisms related to the increase of NO emissions compared to CT.
将豆科植物引入作物轮作和减少耕作强度都被提议作为减轻土壤退化和农业对环境负面影响的农业措施。然而，这些措施对土壤中一氧化二氮（NO）和氨（NH）排放的联合影响仍不清楚，特别是在半干旱地中海地区。在一项长期田间试验（23 年）的框架内，对蚕豆（Vicia faba L.）进行了为期 2 年的研究，以评估免耕（NT）与传统耕作（CT）相比对半干旱地中海环境中Vertisol 土壤产量和 NO 和 NH 排放的长期影响。通过耕作系统测量土壤容重、水填充孔隙空间（WFPS）、有机碳（TOC）和总氮（TN）、反硝化酶活性（DEA）以及细菌基因（16S、amoA 和 nosZ）丰度的变化，作为可能影响 N 气体排放的参数。与 CT 相比，免耕显著增加了 23%的蚕豆籽粒产量。耕作系统对土壤 NH 排放没有显著影响。两个种植季节的平均总 NO 排放量在 NT 中高于 CT （分别为 2.58 和 1.71kgNO-Nha；P<0.01）。此外，NT 中的 DEA 高于 CT（74.6 比 18.6μgNO-Nkgh；P<0.01）。NT 中较高的 NO 排放归因于土壤容重和 WFPS 的增加、细菌（16S 丰度比 CT 高 96%）和 N 循环基因（amoA 和 nosZ 丰度分别比 CT 高 154%和 84%）。蚕豆中的总 NO 排放量与其他施氮作物的测量值相似。总之，除了对土壤特性（例如 TOC 增加）和作物产量的有益影响外，还必须考虑到与 CT 相比增加 NO 排放的一些批评。
