Biochar and potassium humate shift the migration, transformation and redistribution of urea-N in salt-affected soil under drip fertigation: soil column and incubation experiments

文献类型： 外文期刊

第一作者： Yao, Rongjiang

作者： Yao, Rongjiang;Li, Hongqiang;Zhu, Wei;Yang, Jingsong;Wang, Xiangping;Xie, Wenping;Li, Hongqiang;Zhu, Wei;Yin, Chunyan;Jing, Yupeng;Chen, Qiang

作者机构：

期刊名称：IRRIGATION SCIENCE （ 影响因子：2.94； 五年影响因子：3.214 ）

ISSN： 0342-7188

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收录情况： SCI

摘要： Improper fertilization or excessive nitrogen input may cause serious environmental problems and affect soil health. This is particularly the case in saline agroecosystems, as soil salinization alters nitrogen cycling and contributes to substantial nitrogen losses. However, the impact of amendment materials on the combined processes of nitrogen transformation and migration in salt-affected soil has not yet been explicitly clarified. Here, soil column and incubation experiments on biochar (BC)- and potassium humate (PH)-amended salt-affected soil were conducted. The transport and redistribution characteristics of soil water, salt and mineral nitrogen under drip fertigation (urea as fertilizer) were investigated, and the responses of urea hydrolysis and nitrification to BC and PH addition under soil salinity gradients were elucidated. The results showed that BC application increased the migration and redistribution ranges of soil water, salt and mineral nitrogen by improving soil macropores and infiltration and diffusion rates. PH addition maintained higher contents of soil water, salt and mineral nitrogen in the wetting pattern by enhancing the soil water-holding capacity. Both BC and PH addition shifted not only the transport and redistribution but also the morphological conversion of urea-N. BC and PH addition delayed the rise and decline of ammonium nitrogen (NH4+-N) content and postponed the rise of nitrate-nitrogen (NO3--N) content in the wetting pattern. The results of the incubation experiment corroborated those of the column experiment. Both BC and PH aggravated the inhibitory effect of soil salinity on urea hydrolysis and nitrification by prolonging the duration by 2-7 days and postponing the time when the maximum NH4+-N and NO3--N concentrations were reached. PH showed a stronger inhibitory effect on nitrification than BC. The redistribution of urea-N in soil under drip fertigation was primarily dominated by water migration and diffusion, as physically mediated by BC and PH addition, and by the morphological conversion biochemically affected by the interactions of soil salt and BC and PH addition. It was concluded that morphological conversion played an important role in soil nitrogen transport and redistribution, and it is essential to consider the interactive impact of amendment materials and soil salinity level on nitrogen transformation for efficient and sustainable management of fertilizer nitrogen in salt-affected soil.

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