农田杂草还田对土壤磷素形态的影响  

Effects of weed returning on soil phosphorus forms of croplands

作　　者：吴双[1] 袁联国[5] 李利君 金铭[1] 闫泳材 邓泓[1,2,3,4] WU Shuang;YUAN Lianguo;LI Li-jun;JIN Ming;YAN Yong-cai;DENG Hong(School of Ecological and Environmental Science,East China Normal University,Shanghai 200241,China;Shanghai Key Lab for Urban Ecological Processes and Eco-Restoration,East China Normal University,Shanghai 200241,China;Institute of Eco-Chongming,Shanghai 202162,China;Technology Innovation Center for Land Spatial Eco-restoration in Metropolitan area,Ministry of Natural Resource,Shanghai 200062,China;Fengxian Agricultural Technology Extension Center,Shanghai 201400,China)

机构地区：[1]华东师范大学生态与环境科学学院,上海200241 [2]上海市城市化生态过程与生态恢复重点实验室,上海200241 [3]崇明生态研究院,上海202162 [4]自然资源部大都市区国土空间生态修复工程技术创新中心,上海200062 [5]上海市奉贤区农业技术推广中心,上海201400

出　　处：《生态学杂志》2020年第9期2984-2995,共12页Chinese Journal of Ecology

基　　金：上海市科委科研计划项目(18295810400);上海市科技兴农重点攻关项目(沪农科创字(2018)第2-6号)资助。

摘　　要：提高农田土壤磷素的可利用性,减少磷肥施用,对促进农业的可持续发展及缓解全球磷素危机具有重要意义。通过盆栽试验模拟夏季田间植物还田,比较红薯(Ipomoea batatas)、绿豆(Vigna radiata)以及杂草(千金子(Leptochloa chinensis)+水苋菜(Ammannia baccifera)混合)3种夏季经营模式在还田期间土壤磷形态的变化,探索农田杂草还田提高土壤磷素可利用性的潜力。结果表明:绿豆还田主要通过增加碱性磷酸酶和土壤微生物活性促进有机磷矿化;红薯还田在腐解前期增加土壤速效磷,而后期磷素易流失或被固定成有效性较低的磷形态;杂草还田可以显著提升土壤速效磷,使有效性较低的闭蓄态磷(OP)、磷灰石(Ca10-P)及磷酸铁盐(Fe-P)持续性地向有效性较高的磷酸二钙(Ca2-P)、磷酸八钙(Ca8-P)及磷酸铝盐(Al-P)转化,并整体保持在有效性较高的水平。杂草还田使以Ca8-P形式保留在土壤中的磷素显著增加,提升土壤磷素可利用性的同时减小磷素流失的风险;杂草还田也显著增加土壤磷酸酶活性,有助于有机磷的矿化。研究表明,对休耕农田杂草的管理利用是改善低磷素可利用性土壤的一种经济有效的生态手段,可为缓解全球磷素危机提供新的解决思路。It is important to improve soil phosphorus availability in cropland and thus reduce the application of phosphorus fertilizer,in terms of maintaining sustainable development of agriculture and alleviating global phosphorus crisis.We conducted a pot experiment to examine changes of phosphorus forms in soil with the returning of biomass residues from sweet potato(Ipomoea batatas),mung bean(Vigna radiata)and weeds(mixture of Leptochloa chinensis and Ammannia baccifera),to evaluate the role of biomass returning in improving soil phosphorus availability and reveal the underlying mechanism.The results showed that mung bean returning mainly promoted mineralization of organic phosphorus by increasing soil alkaline phosphatase and microbial activity.Sweet potato returning increased soil available phosphorus in the early stage of decomposition,whereas phosphorus in the late stage might be easily lost by leaching or fixed by soil particulates into lower available phosphorus forms.Weed returning had a significantly positive effect on phosphorus availability,by inducing a continuous transformation of soil phosphorus with a lower avail-ability(i.e.O-P,Ca10-P,Fe-P)to other forms with a higher availability(i.e.Ca2-P,Ca8-P,Al-P),and keeping the latter at a relatively higher level.Weed returning significantly increased the concentration of Ca8-P,and thus improved phosphorus availability and reduced the risk of phosphorus leaching.In addition,weed returning improved alkaline phosphatase activity,which is beneficial for mineralization of organic phosphorus.Our results imply that a fallow,which allows the growth of weeds,followed by weed returning may be an economically-sound option for phosphorus management in croplands,providing a new way to alleviate global phosphorus deficiency.

关 键 词：休耕 农田杂草 磷素形态 碱性磷酸酶活性 

分 类 号：S153[农业科学—土壤学]