In order to provide scientific basis for the regional management of soil nutrients

the optimization of crop fertilization and the guidance of agricultural production in Shaanxi Province

the temporal and spatial variation of soil available potassium(AK) in Shaanxi Province and its influencing factors were analyzed. A total of 705 soil samples were collected from farmland in Shaanxi Province 2016-2017 to determine the content of available potassium. Common Kriging interpolation method was used for spatial interpolation analysis

and the influencing factors were discussed. On this basis

suggestions for scientific fertilization were put forward. The results were as follows

the AK content in farmland soil of Shaanxi province ranged from 55 mg/kg to 301 mg/kg

and the AK content in three natural geomorphic areas followed the order of Guanzhong plain (GZ)>Northern Shaanxi plateau (SB)>Southern Shaanxi mountainous area(SN)

and the AK content in each administrative region followed the order of Xianyang>Weinan>Xi'an>Baoji>Yan'an>Tongchuan>Ankang>Hanzhong>Yulin>Shangluo. In terms of time

compared with 1980s

the average AK content in all cities of Shaanxi Province increased in different degrees in 2017. Among the three natural geomorphic areas

GZ had the largest increase of 82%. The average AK content in Shaanxi Province was 181 mg/kg

which was at a very high level

and the AK content in GZ was mainly at the first and second levels

while the AK contents in SB and SN were mainly at the second level. Spatially

the AK content in Shaanxi Province increased first and then decreased from north to south

while the AK content in SB increased from north to south

and it was enriched in southwest Yan'an. The AK contents in the junction of Xianyang and Xi'an

the northeast of Weinan in GZ were significantly higher than those in other areas. In SN

the AK content was higher in the north than that in the south

while the AK content in the central part of Shangluo city was lower. The spatial and temporal variation of AK in farmland soil in three natural geomorphic regions of Shaanxi Province were significantly different (P<0.05)

which was related to soil pH values

soil types

topography

climate and human factors. It was suggested that all regions of Shaanxi Province should implement potassium fertilizer zoning management to maintain the profit and loss balance of soil potassium.