黄土高原旱区长期施肥条件下土壤钾素形态空间分布特征及有效性研究

Research on characteristics of spatial distribution and availability of soil potassium forms under long-term fertilization in the dryland of the Loess Plateau

在黄土高原南部旱地长期肥料定位试验的基础上研究了土壤钾素空间分布特征及其有效性。结果表明：长期施肥后土壤中特殊吸附性钾（SAK）和非特殊吸附性钾（NSAK）储量增加,但水溶性钾（WSK）和非交换性钾（NEK）则有明显的下降,单施N水溶性钾下降了48.24%,单施P下降32.32%,NP配施和NPK配施分别下降10.61%和17.93%,非交换性钾降幅为8.56%-24.91%。增施钾肥可以缓解因长期施肥作物生长所携出的钾素,增加耕层土壤中的水溶性钾、非特殊吸附性钾及特殊吸附性钾。相关分析结果表明,土壤不同形态钾素对速效钾的重要性依次为WSK〉NSAK〉SAK〉NEK,土壤速效钾与水溶性钾、非特殊吸附性钾呈显著相关,与特殊吸附性钾和非交换性钾无显著相关性。

Research on characteristics of spatial distribution and validity of soil potassium was carried out in the long-term orientation fertilization experiment. The result showed that there was significant increase of specifically adsorbed potassium （SAK） and non-specifically adsorbed potassium （NSAK） reserves, while the water soluble potassium （WSK） and non-exchangeable potassium （NEK） were obviously decreased. The WSK decrease were 48.24% in the single N treatment, 32.32% in the single P treatment, 10.61% in the combination of N and P treatment, and 17.93% in the NPK treatment. The NEK decrease ranged from 8.56% to 24.91% compared to the non-potassium applying treatment. The applying of potassium could supplement the potassium lost during the plant growing, and increase the content of WSK, NSAK and SAK in the top soil. Correlation analysis results showed that soil available K was significantly correlated with the WSK and NSAK, but not significant correlated with the SAK and NEK.