长期秸秆还田提升稻麦轮作系统土壤供钾容量和强度  

Long-term straw returning increase the capacity and intensity of soil potassium supply in a rice and wheat rotation system

作　　者：杨雅 夏贤格 范先鹏[2] 夏颖[2] 张富林[2] 刘冬碧[2] 吴茂前[2] 张志毅[2] YANG Ya;XIA Xian-ge;FAN Xian-peng;XIA Ying;ZHANG Fu-lin;LIU Dong-bi;WU Mao-qian;ZHANG Zhi-yi(Yangtze University,Jingzhou,Hubei 434000,China;Institute of Plant Protection and Soil Fertilizer,Hubei Academy of Agricultural Sciences/National Station for Qianjiang Agro-Environment/Hubei Engineering Research Center for Agricultural Non-Point Source Pollution Control/Qianjiang Scientific Observing and Experimental Station of Agro-Environment and Arable Land Conservation,Ministry of Agriculture and Rural Affairs/Key Laboratory of Fertilization from Agricultural Wastes,Ministry of Agriculture and Rural Affairs,Wuhan,Hubei 430064,China)

机构地区：[1]长江大学,湖北荆州434000 [2]湖北省农业科学院植保土肥研究所/国家农业环境潜江观测实验站/湖北省农业面源污染防治工程技术研究中心/农业农村部潜江农业环境与耕地保育科学观测实验站/农业农村部废弃物肥料化利用重点实验室,湖北武汉430064

出　　处：《植物营养与肥料学报》2022年第4期589-597,共9页Journal of Plant Nutrition and Fertilizers

基　　金：国家自然科学基金项目(41907071);湖北省农业科学院重大研发成果培育项目(2017CGPY01-03)。

摘　　要：【目的】农作物秸秆中含有丰富的钾素,秸秆还田不仅为植物生长提供钾素,还可以补充农田土壤钾库容。本研究利用动力学模型,评估长期秸秆还田对土壤供钾能力的影响。【方法】基于稻麦轮作制长期秸秆还田定位试验,设置4个处理:秸秆不还田、不施肥(CK);不施肥、每季秸秆还田量为6000 kg/hm^(2)(RS);施化肥、秸秆不还田(NPK);施化肥、秸秆还田量同RS(NPKS)。采集秸秆还田13年土壤和植株样品,分析植株吸钾量和不同形态土壤钾含量,计算土壤钾素表观平衡。采用连续浸提法测定吸附在黏土矿物不同位置的钾含量。测定四苯硼钠和有机酸法模拟条件下钾素的释放过程。【结果】稻麦轮作制长期秸秆还田试验中,RS和NPKS处理每年秸秆输入的钾素约为220 kg/hm^(2),土壤钾表观平衡为盈余,而CK和NPK处理依然为亏缺。秸秆处理的土壤交换性钾和非交换性钾素含量均得到稳步提升,分别提高12.3~18.5和85.6~157.6 mg/kg。秸秆还田增加的非交换性钾素主要分布在粘土矿物层间(i位点),少量分布于表面(p位点),但是并未显著改变p位、e位和i位钾的比例。土壤固定的钾素释放特征分为快速释放和缓慢释放两个阶段,该过程符合一级动力学模型。以四苯硼钠作浸提剂,快速释放阶段土壤钾素的释放速率表现为RS>NPKS>CK>NPK,缓慢释放阶段表现为RS>CK>NPKS>NPK,RS和NPKS处理的释放量快速阶段较NPK处理分别多166.6、81.1 mg/kg,慢速阶段分别多71.4、27.9 mg/kg。以有机酸为浸提剂,快速和缓慢释放阶段的钾素释放量和释放速率都表现为NPKS>RS>NPK>CK,NPKS和RS处理钾素释放量在快速释放阶段较NPK处理分别增加了16.3、14.5 mg/kg,在缓慢释放阶段分别增加了46.2和111.8 mg/kg。【结论】秸秆的外源钾素能够补充土壤钾素,影响土壤钾素表观平衡,长期秸秆还田后土壤钾素由亏缺转为盈余状态。秸秆还田既能提高土壤�【Objectives】Crop straws are rich in potassium and mostly return to the field after harvest.In this paper,we studied the effect of straw K on replenishing soil K supply capacity and storage.【Methods】A long-term straw return experiment in a wheat-rice rotation field was conducted in Qianjiang City,Hubei Province.The experiment was 13 years old when soil samples were collected in 2018.The treatments included no straw return to the field and no fertilizer(CK),straw return to the field at the rate of 6000 kg/hm^(2) per season and no fertilizer(RS),fertilizer without straw return(NPK),fertilizer and straw return at the same rate in RS(NPKS).The plant K and soil K content in different fractions were extracted and analyzed by chemical methods,and the apparent K balance was calculated.The process of soil K release under normal and exhausting conditions was determined by continuous immersion method using sodium tetraphenyl boron and organic acid,respectively.【Results】Under the annual straw K input of 220 kg/hm^(2),the soil K apparent balance in RS and SNPK was abundant,but a deficit was recorded in CK and NPK.RS and NPKS increased non-exchangeable K contents by 85.6-157.6 mg/kg and exchangeable K by 12.3-18.5 mg/kg in soil.The increased non-exchangeable K was mainly distributed in interlays(site i),followed by the surface(site p)of the clay minerals.However,the ratio of K at p,e,and i sites did not change significantly(P>0.05).Extracted by sodium tetraphenyl boron and organic acid,soil K was released rapidly first and then slowly,according to the first-order kinetic model.The release rate of soil K in the rapid stage was in the order RS>NPKS>CK>NPK,and that in the slow stage was RS>CK>NPKS>NPK.The K released in RS and NPKS treatments was 166.6 and 81.1 mg/kg more than NPK treatment in the rapid stage and 71.4 and 27.9 mg/kg higher in the slow stage.Extracted with an organic acid,the release rate of soil K in both rapid and slow stages were in the order NPKS>RS>NPK>CK.Soil K in NPKS and RS was 16.3 and 14.5 mg/k

关 键 词：秸秆还田 交换性钾 非交换性钾 钾吸附位点 钾释放动力学 钾供应强度 钾供应容量 

分 类 号：S158[农业科学—土壤学]