几种耕作土壤钾素状况的综合评价

Comprehensive Evaluation on soil Potassium in Some Cultivated Solils

供试土壤的钾选择性系数(Gapon系数)和容量/强度特性因粘土矿物组成不同而差异明显,利用Gapon系数(K_G)和Q/I参数(PBC^k、△K^o和AR_o^k)综合评价供试土壤钾素有效状况的结果表明:以蛭石和伊利石占优势的1、2、6和7号土壤,具有较高的K_G和PBC^k,其有效钾库(△K^o)虽高,但多数钾被牢固束缚在对钾有极大选择性的层间位上而难于解吸,钾有效性(AR_c^k)较低;而以高岭石为主的3、8、9和10号土壤,其K_G和PBC^k值均较低,有效钾库虽然不高,但多数钾被吸持在选择性弱的平面位而易于解吸,钾的有效性却较高;以伊利石为主、高岭石为次的4和5号土壤,其钾素的有效状况介于上述两者之间。

The available status of soil potassium in some cultivated soils were comprehensively appraised by using Gapon coefficient (KG) and Q/I parameters (PBCl, AK°and ARkG) . The results showed that KG, PBCK, ΔK°and ARKG of the soils were significantly different with the composition of clay minerals. Soil samples 1, 2, 6 and 7 with predominant vermiculite and illite had high KG, PBCK and ΔK° but low ARke, which indicated that most of potassium in these soils were firmly retained on interlattice sites and difficult to be desorbed , so these soils showed strong potassium fixation and low potassium availability. Conversely, soil samples 3, 8, 9 and 10 with Kaolinite as dominant clay mineral had low KG, PBCK and ΔK°but high ARKe, which indicated that most of potassium in these soils were bound on planar sites with low selectivity to potassium and more easy to be desorbed, so these soils showed weak potassium fixation and high potassium availability , and the others (soil samples 4 and 5) with most abundant illite and sub-dominant Kaolinite showed intermediate potassium availability.