LEAF-Linking Landscape, Environment, Agriculture and Food Research Center, Associated Laboratory TERRA, Instituto Superior de Agronomia, Universidade de Lisboa, Lisboa, Portugal.
Área de Producción Vegetal, Escuela de Ingenierías Agrarias-IACYS, Universidad de Extremadura, Badajoz, Spain.
Sci Total Environ. 2022 Aug 20;835:155488. doi: 10.1016/j.scitotenv.2022.155488. Epub 2022 Apr 26.
Sprinkler irrigation has been successfully introduced in rice production as an alternative to the traditional flooding system, allowing water savings and the reduction of As accumulation in the grain. However, the same conditions can increase Cd mobility and grain accumulation, an effect that needs to be countered. A 3-year field experiment was set-up in a Mediterranean region (Extremadura, Spain), to evaluate how the application of compost from olive mill waste (single application, 80 t ha), influences the accumulation of As and Cd in the grain under different irrigation regimes. Accumulation of As in the grain was always lower in the sprinkler irrigation when compared with the flooding irrigation, reaching a 5-fold difference in the third year. Compost application did not evidence a clear effect on the As accumulation in the rice grain, but highly significant negative correlations (p < 0.001) were obtained between As content in the grain (total, inorganic, and organic) and the humification parameters in the soil, evidencing the importance of using a mature and stable organic amendment to avoid As accumulation in the grain. Cadmium accumulation in the rice grain decreased in each treatment where compost was applied, relatively to the non-treated counterpart (e.g., from 0.080 to <0.010 mg kg, in direct seeding with sprinkler irrigation, in the third year). There were no significant differences in the total inorganic As between treatments with or without compost application, but it was possible to observe an increase in the predominance of the organic As over the more toxic inorganic As, when compost was applied, allowing a decrease in the risk associated to As accumulation. Therefore, the aerobic cultivation of rice, with the simultaneous application of an adequate source of organic matter, can be considered a good solution to cope with the risk of accumulation of As and Cd in the rice grain.
喷灌已成功引入水稻生产，作为传统淹灌系统的替代方式，可实现节水和降低稻谷中砷积累的目标。然而，相同的条件也可能增加镉的迁移和稻谷积累，这需要加以应对。在一个地中海地区（西班牙埃斯特雷马杜拉）进行了一项为期 3 年的田间试验，以评估橄榄压榨废物堆肥（单次施用 80 t/ha）的应用如何在不同灌溉制度下影响砷和镉在稻谷中的积累。与淹灌相比，喷灌时稻谷中的砷积累总是较低，在第 3 年达到 5 倍的差异。堆肥的应用并未对稻谷中砷的积累产生明显影响，但在土壤腐殖化参数与稻谷中砷（总砷、无机砷和有机砷）之间获得了高度显著的负相关（p < 0.001），这表明使用成熟稳定的有机改良剂对于避免稻谷中砷积累非常重要。在施用堆肥的每个处理中，镉在稻谷中的积累均低于未处理的对照（例如，在喷灌直播的情况下，在第 3 年从 0.080 降至 <0.010 mg/kg）。在有或没有施用堆肥的处理之间，总无机砷没有显著差异，但可以观察到当施用堆肥时，有机砷对毒性更大的无机砷的优势增加，从而降低与砷积累相关的风险。因此，水稻好气栽培，同时施用适量的有机物质，可以被视为应对稻谷中砷和镉积累风险的一种良好解决方案。
