长期施肥对栗褐土钾素含量的影响

Effect of long-term fertilization on potassium nutrient in chestnut cinnamon soil

在栗褐土上进行的长期定位施肥试验结果表明，18年后不同施肥处理土壤全钾含量无显著差异，而土壤速效钾含量和缓效钾含量则产生了极显著差异。就表层土壤而言，无外源钾补充的3个处理（NP、N、CK），土壤速效钾含量较低，在78～90mg·kg-1之间，已接近中等水平的下限，施低量有机肥的3个处理（M1、M1N、M1NP），土壤速效钾含量为150～185mg·kg-1，施高量有机肥的2个处理（M2NP、M2N），土壤速效钾含量达240mg·kg-1以上。不同处理对土壤缓效钾含量的影响与土壤速效钾含量基本一致，施高量有机肥的处理〉施低量有机肥的处理〉没施有机肥的处理，但处理间土壤缓效钾的变化幅度明显低于土壤速效钾含量的变化幅度。不同处理对20～40cm土壤速效钾和缓效钾含量也产生了一定影响，变化规律与耕层相似，但没有耕层明显。

Soil potassium nutrient is analyzed in the long - term experiment in chestnut cinnamon soil, located at Zhuanyaogou experiment area, northwestern Shanxi province, in the Loess Plateau region. The results show that there is no significant difference in content of total potassium in soil, but there is very significant difference in content of readily available potassium and slowly avail- able potassium in soil, after 18 years different fertilizer treatments, In surface soil layer （0 - 20 cm）, contents of readily available potassium in three treatments （NP, N and CK）, no applications of farmyard manure （no supply of potassium sources）, is between 78 - 90 mg· kg- 1, near the lower limit of medium lever of readily available potassium. The contents in three treatments （ M1, MaN and MINP）, less application of farmyard manure, is between 150- 185 mg· kg-1, around the very high lever, The contents in two treatments （MzNP and M2N）, more application of farmyard manure, is more than 240 mg· kg-1, about one and a half of the very high lever. The effect of treatments on the content of slowly available： potassium is consistent basically with that on the content of readily available potassium in surface soil layer, that is treatments .f more application of farmyard manure 〉 treatments of less application of farmyard manure 〉 treatments of no application of farmyard manure. But the change extent of the content of slowly available potassium is less than that of readily available potassium, In subsurface layer （20 - 40 cm）, there is some effect of treat- ments on the content of readily available potassium and slowly available potassium. The changetrend of the content is the same but not as significant as the surface soil layer.