荒漠草原土壤有机磷组分及其矿化对放牧强度的响应  

Response of Soil Organic Phosphorus and Mineralization to Grazing Intensity in Desert Steppe

作　　者：张育涵 王赟博 韩国栋 ZHANG Yuhan;WANG Yunbo;HAN Guodong(Key Laboratory of Grassland Resource,Ministry of Education.College of Grassland,Resources and Environment,Hohhot 010011,China;Key Laboratory of Forage Cultivation,Processing and High Efficient Utilization of Ministry of Agriculture,Hohhot 010011,China;Inner Mongolia Key Laboratory of Grassland Management and Utilization,Inner Mongolia Agricultural University,Hohhot 010011,China)

机构地区：[1]内蒙古农业大学草原与资源环境学院草地资源教育部重点实验室,内蒙古呼和浩特010011 [2]农业部饲草栽培、加工与高效利用重点实验室,内蒙古呼和浩特010011 [3]内蒙古自治区草地管理与利用重点实验室,内蒙古呼和浩特010011

出　　处：《中国草地学报》2023年第7期60-70,共11页Chinese Journal of Grassland

基　　金：国家自然科学基金项目(31770500);呼和浩特市科技计划项目重大科技专项(2019-社-重-1)。

摘　　要：荒漠草原生态系统可利用磷资源匮乏,放牧是最普遍的利用形式,但放牧强度对其土壤有机磷矿化速率的影响尚未明确。本文采用Bowman-Cole磷分级体系分析比较了不同放牧强度对短花针茅荒漠草原土壤有机磷组分及矿化速率的影响,及其与土壤理化性质的关系。主要研究结果如下:(1)不同放牧强度下土壤总磷(TP)含量保持相对稳定,但不同有机磷组分变化明显。与不放牧相比,放牧处理下活性有机磷(LOP)含量增加29.2%~40.0%,中活性有机磷(MLOP)含量减少18.6%~37.0%,稳性有机磷(NOP)含量基本稳定。放牧促进土壤有机磷组分由NOP到MLOP再到LOP的转化,进而加速有机磷的矿化。(2)除稳性有机磷(NOP)外,放牧强度对土壤有机磷矿化的影响存在季节差异。在生长季初,放牧促进活性有机磷(LOP)的矿化而抑制中活性有机磷(MLOP)的矿化;生长季末,轻度放牧处理促进中活性有机磷(MLOP)的矿化。(3)土壤理化性质是影响土壤有机磷各组分间转化以及矿化速率的主要因素,其中土壤全碳含量及碳氮比与土壤总磷含量均呈显著正相关关系。因此,在荒漠草原生态系统中,可通过提高碳底物浓度缓解放牧导致的磷资源短缺,从而维持草地生态功能的可持续利用。Limited phosphorus resources are available in desert grassland ecosystems,and the effect of grazing intensity on the rates of soil organic phosphorus mineralization remains poorly understood.This study employed the Bowman-Cole phosphorus grading system to investigate the variations in organophosphorus components and mineralization rates in the soil of Stipa breviflora desert steppe under different grazing intensities,as well as their associations with soil physicochemical properties.The results showed that despite relatively stable soil total phosphorus(TP)content under different grazing intensities,there were significant variations in different organic phosphorus components.Compared to the non-grazing control,the labile organic phosphorus(LOP)content exhibited an increase of 29.2% to 40.0%,while the moderately labile organic phosphorus(MLOP)content decreased by 18.6%~37.0%.Interestingly,the nonlabile organic phosphorus(NOP)content showed no significant change.These findings suggest that grazing activities promoted the transformation of soil organophosphates from NOP to MLOP and then to LOP,thereby accelerating the mineralization of organophosphates.(2)There were seasonal differences in the effect of grazing intensity on organic phosphorus mineralization,except for NOP.Grazing was found to enhance the mineralization of soil LOP during the early growing season,while it inhibited the mineralization of soil MLOP.However,by the end of the growing season,light grazing promoted the mineralization of MLOP.Notably,grazing had no significant effect on NOP and its mineralization.(3)Soil physicochemical properties played a significant role in affecting the conversion and mineralization rate of soil organic phosphorus components.Particularly,soil total carbon content and carbon to nitrogen ratio exhibited a positive correlation with soil total phosphorus content.In conclusion,grazing-induced phosphorus shortage could be alleviated by increasing carbon substrate concentration in natural grassland ecosystem,so as to support th

关 键 词：荒漠草原 放牧强度 有机磷组分 矿化速率 土壤碳氮比 

分 类 号：S154.1[农业科学—土壤学]