摘要
研究长期施钾下烤烟/油菜轮作土壤钾素供应能力变化特征及其机制,为农田合理施用钾肥和农业土壤发生发育的研究提供科学依据。烤烟/油菜轮作下选取连续20 a烤烟季施钾量0、187.5和375 kg·hm^-2处理,测算其土壤钾素表观平衡(Kab)以及土壤钾素容量和强度关系曲线(Q/I曲线)的土壤钾素平衡活度比(ARe)、土壤活性钾(KL)、非专性活性钾(-ΔK0)、专性活性钾(KX)、土壤钾位缓冲容量(PBC)、K^+与Ca^2++Mg^2+交换自由能(-ΔG)等参数,以及速效钾(Kav)、缓效钾(Knex)、K^+饱和度(KS)、黏土矿物组分等土壤性质,分析Q/I曲线参数变化及其与土壤理化性质变化之间的关系。结果表明,经过20 a定位试验后,ARe在0.38×10^-3~8.91×10^-3(mol·L^-1)0.5之间,-ΔK0在0.02~0.55 cmol·kg^-1之间,KL在1.61~2.16 cmol·kg^-1之间,KX在1.06~2.14 cmol·kg^-1之间,PBC在6.20~7.76 cmol·kg^-1(mol·L^-1)-0.5之间,-ΔG在11.70~19.72 kJ·mol^-1之间。持续施钾土壤的ARe、-ΔK0较不施钾土壤显著增大,KL、KX、PBC、-ΔG较不施钾土壤显著减小。ARe、-ΔK0与Kav、Knex、KS、Kab呈极显著正相关,KL、Kx、PBC、-ΔG与Kav、Knex、KS、Kab呈极显著负相关。土壤钾素Q/I曲线参数彼此之间显著相关。上述指标可被整合成一个主成分指标,不施钾肥土壤的主成分指标值显著大于施钾肥土壤。施钾肥土壤的活性钾主要保持在黏土矿物晶体的契形边缘点位,植物有效性较高,不施钾肥土壤的活性钾主要保持在黏土矿物晶体的层间点位,植物有效性降低。不施钾肥土壤的蛭石含量高于施钾土壤,而伊利石含量小于施钾土壤。综上,土壤钾素Q/I参数ARe、-ΔK0、KL、Kx、PBC和-ΔG可作为土壤供钾能力指标,土壤钾素表观平衡驱动了土壤钾素Q/I曲线形状与参数分异、土壤供钾能力分异及土壤黏土矿物变化,施钾肥量越大、土壤钾素盈余越大,土壤供钾能力越强。长期钾素亏缺下,矿物钾转化为专
【Objective】This study was to explore effect of long-term potassium application on soil potassium supply capacity,so as to provide certain scientific basis for rationally potassium application and continuing research on development of agricultural soil.【Method】From a long term potassium fertilization experiment on a tobacco-rape rotation system,which was designed to have 0,187.5 or 375 kg·hm^-2 K2O applied to flue-cured tobacco and 36 kg·hm^-2 to rape,soil samples were collected for analysis of apparent balance and Quantity-Intensity(Q/I)of soil potassium,and relevant parameters,i.e.,K equilibrium activity ratio(ARe),soil labile K(KL),non-specific labile K(-ΔK0)and specific labile K(KX),potential buffering capacity(PBC),K and Ca+Mg exchange free energy(-ΔG),and soil properties,like readily available K(Kav),slowly available K(Knex),K saturation degree(KS),clay minerals components and so on,and moreover,relationships between Q/I parameters and soil properties in the flue-cured tobacco-rape cropping system.【Result】Results show that after 20 years of the stationary experiment,ARe varied in the range of 0.38×10^-3~8.91×10^-3(mol·L^-1)0.5,-ΔK0 of 0.02~0.55 cmol·kg^-1,KL of 1.61~2.16 cmol·kg^-1,KX of 1.06-2.14 cmol·kg^-1,PBC of 6.20~7.76 cmol·kg^-1(mol·L^-1)-0.5,and-ΔG of 11.70~19.72 kJ·mol^-1.Obviously K application enhanced both ARe and-ΔK0,but reduced KL,KX,PBC and-ΔG.Kav,Knex,KS and Kab were extre-significantly and positively correlated with ARe and-ΔK0,but negatively with KL,Kx,PBC and-ΔG.Significant relationships were observed between the parameters of the Q/I curve of soil K,and these parameters could be integrated into a principal component index,which was significantly lower in K application treatments than in no K application treatments.Soil potassium was retained mainly interlaminarly in clay mineral crystals and lower in bio-availability in the soils with no K applied,but on joint position interface of the clay mineral crystals and higher in bio-availability in the soils applied
作者
代快
李江舟
张立猛
计思贵
龙怀玉
徐照丽
段玉琪
杨宇虹
卢秀萍
焦永鸽
卜令铎
DAI Kuai;LI Jiangzhou;ZHANG Limeng;JI Sigui;LONG Huaiyu;XU Zhaoli;DUAN Yuqi;YANG Yuhong;LU Xiuping;JIAO Yongge;BU Lingduo(Yunnan Tobacco Company Yuxi Branch/Biological Control of Tobacco Diseases and Insect Pests Engineering Research Center Of China,Yuxi,Yunnan 653100,China;Institute of Agriculture Resources and Regional Planning,Chinese Academy of Agricultural Sciences,Beijing 100081,China;Yunnan Academy of Totacco Agricultural sciences,Kunming 650031,China)
出处
《土壤学报》
CAS
CSCD
北大核心
2019年第6期1401-1413,共13页
Acta Pedologica Sinica
基金
中国科协青年人才托举工程项目(2016QNRC001)
中国烟草总公司云南省公司科技计划重点项目(2018530000241018)资助~~
关键词
烤烟/油菜轮作
长期施钾定位实验
山原红壤
钾素Q/I关系
供钾能力
Flue-cured tobacco/rape rotation
Long-term stationary experiment of potassium application
Mountain red soil
Potassium Q/I relationship
Potassium supply capacity
