凉山烟区土壤钾素形态变化和供应特征分析

Characterization of Changes in Soil Potassium Patterns and Supply in the Tobacco Region of Liangshan

关注土壤钾素有效性及其供给能力,可以为合理施用钾肥,提高作物产量与品质提供科学依据。分别于凉山会东(湿润季风气候区)和德昌(高原季风气候区)2个生态区,选取主要植烟土壤类型(紫色土和红壤),采集0~20 cm、>20~40 cm和>40~60 cm深度土壤,分析了土壤钾素形态以及容量/强度(Q/I)关系曲线参数变化。结果表明:紫色土速效钾含量变化较大,以德昌地区相对较高,会东地区则相对较低;红壤速效钾含量在会东和德昌2个地区差异不大。相对而言,德昌地区植烟紫色土和红壤0~20 cm土层速效钾/全钾较高,分别为1.99%和1.42%。德昌地区紫色土0~20 cm土层钾素Q/I关系曲线的供钾强度指标(AR_(e)^(0K))、非专性吸附钾(-ΔK_(0))、专性吸附钾(K_(x))、活性钾(K_(L))均为最高,分别为57.23×10^(-3)(mol/L)^(1/2)、1.55 cmol/kg、0.56 cmol/kg和2.11 cmol/kg。会东地区紫色土钾素Q/I关系曲线的钾位缓冲容量(PBC^(K))最大,可达104.65 cmol/[kg·(mol/L)^(1/2)](>40~60 cm土层);钾离子交换自由能(-ΔG)则以会东地区红壤>20~40 cm土层的数值最大,为19.86 kJ/mol。综上所述,在烟草生产过程中,德昌地区紫色土区域需要减少钾肥用量,而会东地区紫色土区域则需要持续加大供给钾肥。

Focusing on soil effective potassium content and potassium supply capacity could provide a scientific basis for rational application of potassium fertilizer to improve crop yield and quality.In the two ecological regions of Huidong(humid monsoon climate area)and Dechang(plateau monsoon climate area)of Liangshan Prefecture,the main soil types(purple soil and red soil)in the tobacco area were selected,and soils were collected from the depths of 0-20 cm,>20-40 cm,and>40-60 cm,and the changes of the soil potassium patterns as well as the parameters of the quantity/intensity(Q/I)relationship curve were analyzed.The results showed that the available potassium content of purple soil varied greatly,which was relatively high in Dechang and relatively low in Huidong.There was little difference in available potassium content of red soil between Huidong and Dechang.Available potassium/total potassium in 0-20 cm layer of purple soil and red soil was higher in Dechang,with the percentage of 1.99%and 1.42%,respectively.The potassium supply intensity index(AR_(e)^(0K)),non-specialized adsorbed potassium(-ΔK_(0)),exclusively adsorbed potassium(K_(x))and active potassium(K_(L))of the Q/I relationship curve were the highest in the 0-20 cm layer of purple soil in Dechang,which was 57.23×10^(-3)(mol/L)^(1/2),1.55 cmol/kg,0.56 cmol/kg and 2.11 cmol/kg,respectively.The potassium site buffer capacity(PBC^(K))of the Q/I relationship curve of the purple soil(>40-60 cm layer)in Huidong was up to 104.65 cmol/[kg·(mol/L)^(1/2)].The maximum potassium ion exchange free energy(-ΔG)of the red soil was in the>20-40 cm layer in Huidong,which was 19.86 kJ/mol.In conclusion,in tobacco cultivation,it needed to reduce the amount of potassium fertilizer in the purple soil of Dechang,while it needed to continuously increase the supply of potassium fertilizer in the purple soil of Huidong.