合理施用沼渣对土壤钾素有效性影响

通过室内干湿交替培养研究了沼渣对沈阳地区耕地棕壤和草甸土中速效钾含量及其对外源钾固定的影响,结果发现(1)加入沼渣可以明显促进供试土壤中钾素的释放,棕壤和草甸土对照中速效钾含量分别在高于99.24和83.23mg·kg^-1时,干燥导致速效钾含量降低,含6%沼渣的棕壤和草甸土速效钾含量低于130.53和139.29mg·kg^-1时,干燥就会引起层间钾的释放;(2)加入沼渣可以减少土壤对外源钾的固定量,含2%和6%沼渣的棕壤在干湿交替培养15天后,固钾量分别比对照减少了12.51和54.81mg·kg^-1,相应的草甸土分别比对照减少固钾量达62.57和137.66mg·kg^-1,固钾率分别降低了12.93%和28.46%。

Availability of potassium as affected by biogas residue reasonable application

The availability of potassium and K-fixation as affected by application of biogas residue on farming brown soil & meadow soil has been investigated with wetting-drying incubation experiments. Results indicate that after biogas residue application, (1) potassium releasing from soil can be evidently promoted. Decrease of amount of fast available K can be made with air-drying process when it is higher than 99.24 mg·kg^-1 in brown soil control, and 83.23 mg·kg^-1 in meadow soil control. Interbedded K will be released if only fast available K is lower than 130.53 mg·kg^-1 in brown soil, and 139.29 mg·kg^-1 in meadow soil with 6% biogas residue addition. (2)K-fixation of extra-K can be efficiently reduced. The capacity of K-fixation is respectively decreased 12.51 and 54.81 mg·kg^-1 on brown soil & 62.57 and 137.66 mg·kg^-1 on meadow soil with 2% and 6% biogas residue application after 15 days wetting-drying incubation.