石灰性土壤中硫形态组分及其影响因素

Composition of sulphur fractions and impact factors in calcareous soils

对陕西 ,湖南等 7省 (市 ) 2 2个农田耕层土壤硫形态组分的分析表明 ,供试土壤总硫平均为4 0 5 .5± 111.8mg/kg ,总有机硫占总硫 85 .4 %± 10 .0 %。供试土壤中酯键硫 (C -O -S)、碳键硫(C -S)、惰性硫平均含量分别为 130 .3± 6 4 .6、6 5 .5± 2 9.4、15 2 .5± 96 .7mg/kg ,分别占总硫的31.4 %± 12 .9%、18.0 %± 10 .7%、36 .0 %± 17.8% ;分别占总有机硫的 36 .6 %± 14.4 %、2 1.8± 13.8%、4 1.5 %± 19.1%。石灰性土壤C -O -S、C -S形态硫与土壤有机碳之间分别呈极显著 (r =0 .7334 )和显著 (r =0 .4 4 2 6 )正相关。石灰性母质发育土壤C -O -S含量显著大于黄土母质发育的土壤。供试土壤无机硫组分中主要是难溶硫 ,其平均含量达 2 8.4mg/kg ,占总无机硫 5 0 .7%。土壤中难溶硫与总无机硫 (r =0 .6 0 4 0 )和CaCO3 (r =0 .6 80 0 )之间呈极显著正相关 ,而与总有机硫 (r =- 0 .5 2 86 )、C -O -S (r =- 0 .4 4 17 )和有机碳 (r =- 0 4 786 )之间呈显著负相关。黄土母质发育土壤难溶硫含量 ,占总硫和占总无机硫的比例显著或极显著高于石灰性母质发育的土壤。为了全面评价石灰性土壤硫素供应潜力 ,有必要开展石灰性土壤难溶硫形成及转化规律和生物有效性的研究。

Sulphur fractions in twenty two top layer soils collected from Shaanxi, Hunan Provinces, etc. were determined. Results indicated that content of total S in soils was average 405.5±111.8 mg/kg, among of which 85.4%±10.0% was organic S. The contents of C O S, C S and inert S in soils were 130.3±64.6mg/kg, 65.5±29.4mg/kg, 152.5±96.7mg/kg respectively, percentage of C O S, C S and inert S in total S were 31.4%±12.9%, 18.0%±10.7% and 36.0%±17.8%, and percentage of C O S, C S and inert S in total organic S were 36.6±14.4%, 21.8±13.8% and 41.5±19.1%, respectively. The significant position correlation between contents of C O S (r=0.7334 ** ), C S (r=0.4426 * ) and organic C in soil were found. The contents of C O S in soils derived from calcareous parent material was significantly higher than that in soils from loess parent material. The slow soluble S was major inorganic S fractions in tested calcareous soils, average contents of which was 28.4mg/kg, and the percentage of which in total inorganic was 50.7%. The extremely significant position relationship between the contents of slow soluble S and total inorganic S (r=0.6040 ** ), and CaCO 3 (r=0.6800 ** ) in soils were found. However, the significant negative correlation between the contents of slow soluble S and total organic S, ( r= 0.5286 * ), C O S(r= 0.4417 * ) and organic C (r= 0.4786 * ) in soils were obtained. The content of slow soluble S, its distribution coefficient in total S and total inorganic S in soils derived from loess parent material were extremely significantly higher than that in soils from calcareous parent material. It is necessary to study the trend of transformation and produce for the slow soluble S in calcareous soils in order to evaluate fully supply capacity of sulphur in calcareous soils.