Wang Jian, Lin Chunye, Han Ziming, Fu Chunbao, Huang Di, Cheng Hongguang
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing Normal University, No.19th XinJieKouWai St, HaiDian District, Beijing 100875, PR China.
State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Beijing Normal University, No.19th XinJieKouWai St, HaiDian District, Beijing 100875, PR China.
Sci Total Environ. 2022 Jun 10;824:153863. doi: 10.1016/j.scitotenv.2022.153863. Epub 2022 Feb 14.
Planting rice is an effective way to reclaim salt-affected soils, but overapplying nitrogen fertilizer has resulted in a large loss in the amounts of soil dissolved nitrogen (SDN) from paddy fields. While the dynamic of SDN and its response to changes in soil physicochemical properties by planting rice are well-studied in non-salt-affected soils, little is known about the relationship between the SDN and soil physicochemical properties in reclaimed salt-affected soils. To fill this knowledge gap, soil samples were collected from bare salt-affected soils and three paddy fields with different reclaimed years (4, 9, 20) in six soil layers. Compared with bare salt-affected soils, soil salinity and sodicity exhibited trends of firstly increasing and then decreasing, whereas organic matter and total nitrogen tended to increase with the extension of the reclamation year. Soil dissolved organic carbon and total dissolved phosphorous showed decreasing trends. The sand content showed an increasing tendency, whereas the silt and clay contents tended to decrease. Ammonium nitrogen concentrations in reclaimed paddy fields were higher than those of bare salt-affected soils, and nitrate nitrogen concentrations in reclaimed paddy fields were smaller than those of bare salt-affected soils. However, the changing trends of dissolved organic nitrogen concentrations were not consistent among paddy fields with different reclamation years. Meanwhile, statistical analysis results revealed significant correlations between SDN and soil physicochemical properties. Moreover, dominant drivers influencing SDN were grouped using principal component analysis, identifying the following factors including soil sodicity, active nutrients, soil texture and water retention. Redundancy analysis also revealed that the soil physicochemical properties explained 69.65% of the variation in SDN and the influenced relationship between soil physicochemical properties and SDN nutrients. This study enhances our understanding of the mechanisms influencing SDN during planting rice and has implications for the management of the nutrient application of reclaimed salt-affected soils.
种植水稻是改良盐渍土的有效方法，但过量施用氮肥导致稻田土壤溶解态氮（SDN）大量流失。虽然在非盐渍土中，对SDN动态及其对种植水稻引起的土壤理化性质变化的响应已有充分研究，但对于改良盐渍土中SDN与土壤理化性质之间的关系却知之甚少。为填补这一知识空白，从裸盐渍土和三个不同开垦年限（4年、9年、20年）的稻田中，在六个土层采集了土壤样本。与裸盐渍土相比，土壤盐分和碱度呈现先增加后降低的趋势，而有机质和全氮则随着开垦年限的延长而增加。土壤溶解有机碳和总溶解磷呈下降趋势。砂含量呈增加趋势，而粉砂和黏粒含量则呈下降趋势。开垦稻田中的铵态氮浓度高于裸盐渍土，而开垦稻田中的硝态氮浓度低于裸盐渍土。然而，不同开垦年限稻田中溶解有机氮浓度的变化趋势并不一致。同时，统计分析结果表明SDN与土壤理化性质之间存在显著相关性。此外，利用主成分分析对影响SDN的主要驱动因素进行了分组，确定了以下因素，包括土壤碱度、活性养分、土壤质地和持水性。冗余分析还表明，土壤理化性质解释了SDN变异的69.65%以及土壤理化性质与SDN养分之间的影响关系。本研究增进了我们对种植水稻过程中影响SDN机制的理解，并对改良盐渍土养分管理具有启示意义。
